The main concerns associated with roof coverings are the large surface area for potentially catching embers or the roof slope (i.e., steeper roofers) for radiant exposure and direct flaming from crown fires leading to ignition. If the structure has a combustible roof covering, is not maintained in good condition, or is littered with vegetative debris, then it is far more vulnerable to ignition from wildfire. The complexity of the roof shape can also play a key role in the risk of ignition. ¹ Valleys, roof-to-wall intersections at split levels or dormers, joints, and other architectural embellishments on the roof can also support the collection of embers (“ember accumulation ”) or vegetative debris that can lead to ignition.

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1 FEMA, "Technical Fact Sheet No. 5: Roofs," in Home Builder's Guide to Construction in Wildfire Zones (Washington, D.C.: Government Printing Office, 2008).

• Roof Covering: The exterior roof cover or skin of the roof assembly comprised of a range of materials² (e.g., shingles, tiles, slate, metal panels, fiberglass asphalt shingles, bitumen membrane).
• Roof Assembly: An assembly of interacting roof components, including the roof deck, underlayment (comprised of a range of components such as vapor retarder, insulation, insulation cover boards, wood battens), and the roof covering.³
• Asphalt Fiberglass Composition Shingles: Shingles composed of a fiberglass mat with asphalt and mineral overlay.
• Polyvinyl Chloride (PVC) Roofing: Thermoplastic roofing membrane typically used for buildings or structures with flat or low profiles and consisting commonly of 60 mil sheets with reinforced membranes. Seams are either hot-air heat welded, or chemical welded, and the membrane is either fully adhered, ballasted, or mechanically fastened.
• Thermoplastic Polyolefin (TPO) Roofing: Thermoplastic roofing membrane also used for buildings or structures with flat or low profiles. Sheets range from 40-100 mil, with reinforced or non-reinforced membranes, and installed fully adhered, mechanically fastened, or loose-laid with ballast. Seams are heat welded with hot air.
• Modified Bitumen (MB) Roofing: An asphalt-based membrane designed for buildings with low-slope or "flat" roof structures. MB roofing systems typically have five layers of protection (i.e., insulation, piles, MB membranes, adhesive or waterproofing material, surfacing).
• Fire Retardant Treated Wood (FRTW): According to the IBC 2018 Chapter 2 and Section 2303.2, wood products that, when impregnated with chemicals by a pressure process or other means during manufacture, shall have, when tested in accordance with ASTM E108 or UL 790, a listed flame spread index of 25 or less and show no evidence of significant progressive combustion when the test is continued for an additional 20-minute period. Additionally, the flame front shall not progress more than 10.5’ (3200 mm) beyond the centerline of the burners at any time during the test. FRTW must typically also be tested per weather protocols such as ASTM D2898.⁴

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2 FEMA, "Technical Fact Sheet No. 5: Roofs," in Home Builder's Guide to Construction in Wildfire Zones (Washington, D.C.: Government Printing Office, 2008).

3 FEMA.

4 International Code Council, Inc., International Building Code (Country Club Hills, IL: International Code Council, Inc., 2018).

The fire resistance of roof assemblies to exterior fire exposures is defined by ASTM E108 or UL 790 Standard Test Methods for Fire Tests of Roof Coverings. The test method includes measurements of the surface spread of flame, the ability of the roof assembly to resist fire penetration from the exterior of the building to the underside of the roof deck, and the potential for the roof covering to develop flying brands of burning material.⁵


Note: Some roof coverings rely on an underlying material, or special installation techniques, to improve their fire rating.⁹ These types of roofs are considered fire-rated roof assemblies. An example of a fire-rated roof assembly are fire-retardant treated wood shakes, aluminum and recycled plastic and rubber roof coverings. Examples of underlayment materials include a mineral surfaced cap sheet (formerly referred to as a Type 72 cap sheet) adequate to provide Class A membrane construction, and a fiberglass gypsum panel¹⁰ with a thickness adequate for passing the ASTM E108/UL 790 Test.

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5 ASTM International, “ASTM E108-20a Standard Test Methods for Fire Tests of Roof Covers,” ASTM International, April 17, 2020, https://www.doi.org/10.1520/E0108-20A.

6 ASTM International.

7 ASTM International.

8 ASTM International.

9 University of California, Agriculture and Natural Resources, "Roof," Fire in California, accessed May 2022, https://ucanr.edu/sites/fire/Prepare/Building/Roof/.

10 University of California, Agriculture and Natural Resources.

• ASTM E 108 Standard Test Methods for Fire Tests of Roof Coverings: https://www.astm.org/e0108-20a.html
• UL 790 Standard Test Methods for Fire Tests of Roof Coverings: https://standardscatalog.ul.com/ProductDetail.aspx?productId=UL790
• ASTM C 1177 Standard Specification for Glass Mat Gypsum Substrate for Use as Sheathing: https://www.astm.org/c1177_c1177m-17.html

• International Wildland Urban Interface (IWUI) Code: Section 504.2 Roof Assembly
• California Building Code (CBC): Chapter 7A, Section 705A.2 Roof Coverings
• NFPA 1140 Standard for Wildland Fire Protection: Section 25.3 Roof Design and Materials

Codes and standards will vary depending on location and adoption in individual jurisdictions.

• Check local, county, and state amendments for any additional requirements.
• Check local general plan, multi-hazard mitigation plan or zoning documents for any additional requirements.
• IRC (if applicable – check for wildfire amendments).

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11 FEMA, "Technical Fact Sheet No. 5: Roofs," in Home Builder's Guide to Construction in Wildfire Zones (Washington, D.C.: Government Printing Office, 2008).

12 FEMA.

13 FEMA.

14 Stephen L. Quarles et al., 2010, "Home Survival in Wildfire-Prone Areas: Building Materials and Design Considerations," ANR Publication, no. 8393 (2010): 1-22, https://anrcatalog.ucanr.edu/pdf/8393.pdf.

15 FEMA, "Technical Fact Sheet No. 5: Roofs."

16 FEMA.

17 Quarles et al., "Home Survival in Wildfire-Prone Areas: Building Materials and Design Considerations."

18 FEMA, "Technical Fact Sheet No. 5: Roofs."

19 FEMA.

• Replace any damaged, broken, or missing pieces or sections.
• Remove litter and other vegetation debris on roof annually before core fire season.
• Replace roof with Class A rated roofing material. Note: Class A covering alone is not enough, the entire roof system should be considered to include underlayment and any other components that impact wildfire vulnerability.
• Refer to Typical Design, Vulnerability and Mitigation Considerations for additional mitigation options.
• For tile roofs, bird-stop or mortar open ends of tiles at the roof eaves, roof edge, hips, and ridges to reduce vulnerability to ember ignition.²⁰
• For tile roofs, install metal flashing under tiles at roof valleys. For profiled tile, lead or flexible flashing should be installed (as recommended by the manufacturer).
• Replace roof coverings before significant deterioration due to exposure to weathering.

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20 FEMA, "Technical Fact Sheet No. 5: Roofs," in Home Builder's Guide to Construction in Wildfire Zones (Washington, D.C.: Government Printing Office, 2008).

NFPA Assessing Structure Ignition Potential from Wildfire

• Fire testing does not account for weathering of materials prior to fire exposure.
• ASTM E108 is an exterior fire exposure based on a piloted ignition scenario. This may not be reflective of anticipated fire exposures for wildfire conditions (e.g., embers, large radiative exposure from wildfire flaming, direct flame impingement, heat release rates characteristic of wildfires).
• Test conditions are often less severe than actual wildfire exposure.
• In some cases, it may be challenging to verify in-the-field if a roof covering is rated to Class A, B, or C. (Professional judgement required).

IBHS Ember Testing: https://ibhs.org/wildfire/building-vulnerability-to-ember-exposure/
IBHS Preparedness: https://disastersafety.org/wp-content/uploads/2021/08/WFR-Home-Preparedness-Guide.pdf
FEMA – Home Builder’s Guide to Construction in Wildfire Zones, Technical Fact Sheet No. 5: https://defensiblespace.org/wp-content/uploads/2021/01/FEMA_2008_P-737-Home-Builders-Guide-to-Construction-in-Wildfire-Zones.pdf
University of California, Agriculture and Natural Resources: https://ucanr.edu/sites/fire/Prepare/Building/Roof/
Headwaters: Headwaters Economics – Building a Wildfire-Resistant Home: Codes and Costs

The intrusion of embers through roof vents and chimneys is a major source of vulnerability that can lead to structure ignition during wildfires. The main concern with roof vents and chimneys is that they can provide several openings where windborne embers, convective heat, and radiant heat from wildfires can be blown in or pulled into the structure leading to ignition of interior building contents and other building components. In addition, chimneys can also be a source of embers from fireplaces leading to ignition of vegetation outside. Both inlet and outlet vents are sources of vulnerability, as fire behavior can create reverse flows due to over-pressures that can drive embers and hot gases into a building interior (e.g., attic, crawl space, basements). Debris can also accumulate at vent openings, chimney openings, and around the chimney chase, providing a source of combustible fuels for ignition.

• Chimney: A primarily vertical structure containing one or more flues, for the purpose of carrying gaseous products of combustion and air from a fuel-burning appliance to the outdoor atmosphere.²¹
• Gas Fireplace Chimney: A vertical or horizontal vent designed to release hot air from the gas burning fireplace to the outdoor atmosphere.
• Ember: Small burning or glowing pieces of vegetation or other cellulosic-based material.
• Gable End Vent: A vent located in the gable-end wall, just below the roof ridge to allow flow into and out of attics. Gable-end vents normally have louver blades. This type of vent is commonly metal and normally has an insect screen.²²
• Hip Vent and Ridge Vent: A continuous vent installed along the full length of the hip or ridge of a roof, with the air slots underneath the hip or ridge vents located only at the top portion of the hip or ridge. These vents are typically comprised of metal or plastic and may have internal or external baffle media to minimize the entrance of wind-driven rain or snow.^{23 24}
• Mechanical Exhaust Vents (Whirly birds, Wind Turbines) – Cylindrical dome-shaped vents that sit on the roof of a building and spin in the wind, creating a vacuum that extracts warm air and moisture from the attic. Turbines sit higher above the roof surface, so they stand out more than other exhaust options, but they move air effectively. When there's no wind, their function is similar to that of a static exhaust vent.²⁵
• Powered Exhaust Vent: These types of vents are powered by electric, solar or a combination of both and are either roof-mounted or gable-mounted. Powered vents typically include thermostat control to provide optimum airflow rating.
• Spark Arrestor Cap: A metal assembly at the top of the chimney that prevents embers from leaving the chimney while also preventing embers from entering the chimney in the event of a wildfire.
• Through-roof Vent: A vent that penetrates the roof to allow exfiltration of attic air or connection to an HVAC system. They can also be known as a dormer or eyebrow vent. These types of vents are typically comprised of metal, plastic, or rigid fiberglass.
• Vent: A device or assembly placed in an exterior opening of a building that allows for aeration.

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21 International Code Council, Inc., International Building Code (Country Club Hills, IL: International Code Council, Inc., 2018).

22 FEMA, "Technical Fact Sheet No. 8: Vents," in Home Builder's Guide to Construction in Wildfire Zones (Washington, D.C.: Government Printing Office, 2008).

23 FEMA.

24 Stephen L. Quarles et al., 2010, "Home Survival in Wildfire-Prone Areas: Building Materials and Design Considerations," ANR Publication, no. 8393 (2010): 1-22, https://anrcatalog.ucanr.edu/pdf/8393.pdf.

25 Wendy Helfenbaum, "The Most Common Types of Roof Vents for Attic Ventilation," National Contractors, Inc., accessed April 2022, https://www.nationalcontractors.net/national-news/the-most-common-types-of-roof-vents-for-attic-ventilation.

Currently there isn’t an accepted procedure to evaluate ember intrusion and direct flame impingement of ridge vents.

The ember and direct flame impingement resistance of gable end and other vent mounted on vertical walls is defined by ASTM E2886 Standard Test Method for Evaluating the Ability of Exterior Vents to Resist the Entry of Embers and Direct Flame Impingement. This test standard prescribes two individual methods to evaluate the ability of the vent opening to resist embers and flame. The ability of such vents to completely exclude entry of flames or embers is not evaluated. Roof ridge and off-ridge (field) vents are excluded from this standard. Acceptance criteria are not provided in this standard.²⁶ However, performance criteria are specified in the California Building Code (CBC) Section 706A.2 and NFPA 1144 Section 5.3.3.

Note: Vents that have been included in a roof covering assembly tested per ASTM E108 to achieve a Class A rating have only been tested for whether they contribute to flame spread, failure/detachment from the roof or production of embers. ASTM E108 does not assess if a vent can resist the penetration of embers or direct flames from wildfires.

Factory-built chimneys and fireplaces should be fire-blocked in accordance with UL 103 and UL 127.

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26 ASTM International, "ASTM E2886/E2886M-20 Standard Test Method for Evaluating the Ability of Exterior Vents to Resist the Entry of Embers and Direct Flame Impingement," ASTM International, July 24, 2020, https://www.doi.org/10.1520/E2886_E2886M-20.

27 ASTM International, "ASTM E2912-17 Standard Test Method for Fire Test of Non-Mechanical Fire Dampers Used in Vented Construction," ASTM International, September 20, 2017, https://www.doi.org/10.1520/E2912-17.

28 ASTM International.

• ASTM E2886/E2886M-14 Standard Test Method for Evaluating the ability of Exterior Vents to Resist the Entry of Embers and Direct Flame Impingement:  https://www.astm.org/e2886_e2886m-20.html
• ASTM E2912 Standard Test Method for Fire Test of Non-Mechanical Fire Dampers Used in Vented Construction: https://www.astm.org/e2912-17.html

• International Wildland Urban Interface (IWUI) Code:
  • 504.10 Vents
  • 605 Spark Arresters
• California Building Code (CBC):
  • 706A Vents
  • 718.2.5.1 Factory-Built Chimneys
• NFPA 1144 Standard for Reducing Structure Ignition Hazards from Wildland Fire:
  • 5.3.3 Vent Assemblies
  • 5.8 Chimneys and Flues
• UL 103 Standard for Safety Factory-Built Chimneys
• UL 127 Standard for Safety Factory-Built Fireplaces

Codes and standards will vary depending on location and adoption in individual jurisdictions.

• Check local, county, and state amendments for additional wildfire codes and standards.
• Check local general plan, multi-hazard mitigation plan, or zoning documents for additional requirements.
• IRC (if applicable – check for wildfire amendments).

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29 Fire Safe Marin, "Fire-Resistant Vents," Fire Safe Marin, accessed April 2022, https://firesafemarin.org/harden-your-home/fire-resistant-vents/.

30 FEMA, "Technical Fact Sheet No. 8: Vents," in Home Builder's Guide to Construction in Wildfire Zones (Washington, D.C.: Government Printing Office, 2008).

31 FEMA.

• Debris should be removed from around vents and chimney chases periodically.
  • Wind-blown vegetative debris must be removed from the inlet of all ridge and off-ridge vents, paying particular attention to vents with plastic components. Plastic components are commonly used in ridge vents.³²
• Provide ember resistant vents protected with wire mesh with openings no larger than 1/8”, preferably 1/16”.
  • Common ¼” screens are ineffective and should be replaced.³³
  • Do not use fiberglass or plastic mesh because they can melt and burn.³⁴
• Provide spark arrestor cap on all chimneys.
  • Chimneys serving fireplaces, barbecues, incinerators, or decorative heating appliances in which solid or liquid fuel is used, should be provided with a spark arrestor.³⁵
  • Spark arrestors are required to be constructed of woven or welded wire screening of 12 USA standard gauge wire having openings not exceeding ½”.³⁶
• Avoid using non-wildfire-resistant off-ridge and ridge vents. Of the ridge and off-ridge outlet vent options, the following performed well:³⁷
  • Miami-Dade wind-driven-rain-compliant ridge vent
  • Wildfire-resistant off-ridge vent
  • Turbine (off-ridge) vent with screening attached to the roof sheathing
• Replace non-metal roof vents with corrosion-resistant, metal vents and vent flashing.
• Ensure turbines can spin freely to prevent ember intrusion.
• Specify and install vent openings with a maximum net free area of 144 sq. in.³⁸
• Place all vent openings at least 10' from other buildings or property lines to avoid ignition from embers and hot gases from an adjacent building that has ignited.³⁹
• Refer to Typical Design, Vulnerability and Mitigation Considerations for additional mitigation options.
• Ember and flame-resistant vents have been developed. Vents that comply with the provisions of the California Building Code can be found on the California Office of the State Fire Marshal, Building Materials Listing Program website.

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32 Fire Safe Marin, "Fire-Resistant Vents," Fire Safe Marin, accessed April 2022, https://firesafemarin.org/harden-your-home/fire-resistant-vents/.

33 Fire Safe Marin.

34 Fire Safe Marin.

35 International Code Council, Inc., "2018 International Wildland Urban Interface Code," ICC Digital Codes, August 2017, https://codes.iccsafe.org/content/IWUIC2018/.

36 International Code Council, Inc.

37 Fire Safe Marin, "Fire-Resistant Vents."

38 FEMA, "Technical Fact Sheet No. 8: Vents," in Home Builder's Guide to Construction in Wildfire Zones (Washington, D.C.: Government Printing Office, 2008).

39 FEMA.

NFPA Assessing Structure Ignition Potential from Wildfire

• Fire testing does not account for weathering of materials prior to fire exposure or the impact of general wildfire environmental conditions (e.g., high winds, flying debris, impact from objects).
• ASTM E2886 does not evaluate the ability of vents to completely exclude entry of flames or embers.
• ASTM E2886 does not include roof ridge and off-ridge (field) vents. However, the functional parts of some approved vents have been installed in dormer-style off-ridge vents, and should perform as well in this location as others.
• Most ASTM standards do not provide acceptance criteria. Where information is needed for the Authority Having Jurisdiction, review the report section of the standard where the authors of the standard typically provide key information. Also, review information in the Appendix as this can provide information helpful for determining “acceptance criteria.”
• In most instances, it’s challenging to verify in-the-field if a vent has been fire-tested. (Professional judgement and discussion with the homeowner are required.)
• Air flow calculations may need to be reconsidered or redesign where fire rated vents are installed in existing structures, to ensure sufficient airflow is still satisfied for non-fire purposes.
• There is no accepted procedure to evaluate ember intrusion and direct flame impingement of ridge vents.

IBHS Ember Testing:

• https://ibhs.org/wildfire/building-vulnerability-to-ember-exposure/
• https://ibhs.org/wp-content/uploads/wpmembers/files/Vulnerability-of-Vents-to-Wind-Blown-Embers_IBHS.pdf
• https://www.facebook.com/watch/?v=389602881106017

IBHS Preparedness: https://disastersafety.org/wp-content/uploads/2021/08/WFR-Home-Preparedness-Guide.pdf

FEMA – Home Builder’s Guide to Construction in Wildfire Zones, Technical Fact Sheet No. 8: https://defensiblespace.org/wp-content/uploads/2021/01/FEMA_2008_P-737-Home-Builders-Guide-to-Construction-in-Wildfire-Zones.pdf

University of California: https://ucanr.edu/sites/fire/Prepare/Building/Vents/

In general, joints create gaps in the continuity of a fire rated or fire resistive roof assembly and present a potential avenue for embers, hot gases, or flame to breach the exterior envelope of a rated roof. Joints can also create places for the accumulation of combustible debris that can be easily ignited by embers, hot gases, or direct flaming. Embers can oftentimes accumulate at roof joints, creating a concentrated source of heat. In addition, there is currently no fire test for roof joints to wildfire exposure – embers, direct flaming, or hot gases. This can create a short-circuit of a Class A rated roof assembly. Some joints may not be visible (e.g., between panel joints on the roof deck), therefore making it difficult to verify if appropriate joint protection is provided. However, where joints are visible, it is important to verify that flashing and joint protection are in good condition.

• Joint: The opening in or between adjacent assemblies that is created due to building tolerances or is designed to allow independent movement of the building in any plane caused by thermal, seismic, wind or any other loading.⁴⁰
• Fire-Resistant Joint System: An assemblage of specific materials or products that are designed, tested and fire-resistance rated in accordance with a standard fire test to resist for a prescribed period of time the passage of fire through joints made in or between fire-resistance rated assemblies.⁴¹ (Note: There are currently no fire-resistant joint system tests for wildfire exposures.)
• Roof Ridge: The roof ridge, or ridge of a roof is the horizontal line running the length of the roof where the two roof planes meet. This intersection creates the highest point on a roof, sometimes referred to as the peak.⁴²
• Roof Valley: A roof valley is formed where two roof slopes or plains meet. A valley occurs where two roof plains intersect. Valleys are places where leaves and needles often accumulate and where embers can land.⁴³
• Flashing: A thin metal that is installed at joints to protect against intrusion of unwanted elements such as water and embers.
• Expansion Joint: A physical discontinuity that spans the entire breadth of an element in a building, creating two separate sections of the element instead of one bigger one. They are designed and configured to allow the different building sections to move independently of each other, so the structures don’t become overstressed and crack or break under various loads (e.g., thermal expansion/contraction, moisture-related dimensional change, seismic movement).⁴⁴

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40 International Firestop Council, "Inspection Guidelines: Penetration Firestop Systems and Fire Resistive Joint Systems in Fire Resistance Rated Construction," International Firestop Council, accessed 2022, https://www.firestop.org/inspection-guidelines.

41 International Firestop Council.

42 Owens Corning, "The Anatomy of a Roof," Owens Corning, accessed 2022, https://www.owenscorning.com/en-us/roofing/tools/the-anatomy-of-a-roof.

43 University of California, Agriculture and Natural Resources, "Roof," Fire in California, accessed May 2022, https://ucanr.edu/sites/fire/Prepare/Building/Roof/.

44 Roof Online Staff, "Roof Expansion Joints Explained," Roof Help, October 8, 2022, https://roofonline.com/roof-components/expansion-joints/.

Currently, there is no fire test standard to evaluate ember intrusion, direct flame impingement or thermal transmission of heat via convection or radiation from wildfires for joint systems (roof joints or otherwise). Fire rated joints are necessary to maintain a roof system’s fire rating, integrity and continuity to wildfire exposure. While a variety of fire tests exist for joints in interior building fire exposures (e.g., ASTM E1966 or UL 2079), none are applicable to the fire conditions presented by wildfires. A range of joint systems (e.g., static joints, movement joints) and joint conditions (e.g., chimney-to-roof, vent-to-roof, skylight-to-roof, roof panel-to-roof panel, edge-of-roof joint, roof expansion joints) for exterior wildfire exposures are still needed.

Currently, there is no fire test standard to evaluate ember intrusion, direct flame impingement or thermal transmission of heat via convection or radiation from wildfires for joint systems (roof joints or otherwise).

• International Wildland Urban Interface (IWUI) Code: No explicit requirements
• California Building Code (CBC): No explicit requirements
• NFPA 1144 Standard for Reducing Structure Ignition Hazards from Wildland Fire: No explicit requirements

Codes and standards will vary depending on location and adoption in individual jurisdictions.

• Check local, county, and state amendments for additional wildfire codes and standards.
• Check local general plan, multi-hazard mitigation plan, or zoning documents for any additional requirements.
• IRC (if applicable – check for wildfire amendments).

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45 Roof Online Staff, "Roof Expansion Joints Explained," Roof Help, October 8, 2022, https://roofonline.com/roof-components/expansion-joints/.

46 Roof Online Staff.

47 University of California, Agriculture and Natural Resources, "Roof," Fire in California, accessed May 2022, https://ucanr.edu/sites/fire/Prepare/Building/Roof/.

48 University of California, Agriculture and Natural Resources.

49 University of California, Agriculture and Natural Resources.

50 Division of Agriculture and Natural Resources, University of California, "Skylights," Homeowner's Wildfire Mitigation Guide, accessed April 2022, https://ucanr.edu/sites/Wildfire/Roof/Skylights/.

• Debris should be removed from around all joints created at the roof (e.g., expansion joints, vents/chimney-to-roof joints).
• Noncombustible materials (e.g., mineral) in lieu of combustible materials should be provided to fill expansion joints.
• Fire-resistant sealants should be provided in lieu of non-fire rated caulking.
• Metal flashing should be installed at vent-, chimney- and skylight-roof joints to limit ember penetration or direct flame infiltrating the roof substrate. Where the roof underlayment is combustible, refer to appropriate protection measures in the roof construction/covering section for detailing.
• Refer to Typical Design, Vulnerability and Mitigation Considerations for additional mitigation options.

NFPA Assessing Structure Ignition Potential from Wildfire

• Currently, there is no fire test standard to evaluate ember intrusion, direct flame impingement or thermal transmission of heat via convection or radiation from wildfires for joint systems (roof joints or otherwise).
• It is unclear how susceptible various roof-joints are to wildfire exposures.

• University of California, Agriculture and Natural Resources:  https://ucanr.edu/sites/fire/Prepare/Building/Roof/
• General roof expansion joint references:
  • National Research Council (NRC) –Built-up Roof joints:  https://nrc-publications.canada.ca/eng/view/ft/?id=ccde0331-086c-41a9- 8fff-7b82e29f8144
  • Brick Industry Association – Brick Join: https://www.gobrick.com/docs/default-source/read-research-documents/technicalnotes/18a-accommodating-expansion-of-brickwork.pdf
  • Copper Development Association – Roof-to-Wall: https://www.copper.org/applications/architecture/arch_dhb/arch-details/building_expansion/roof_edges.html
  • AISC – Basic construction details (Non-Fire): https://www.aisc.org/globalassets/modern-steel/archives/2005/04/2005v04_expansion_joints.pdf

The roof edge is a portion of a structure that is highly vulnerable to wildfires and other sources of ignition. As gutters are typically located at the roof edge, a debris filled rain gutter can present a fuel source where embers can collect during a wildfire, creating an ignition source near the roof edge. Gaps between the roof covering and underlayment at the roof edge can create a source of weakness for embers to enter the structure. Roof edges can also be exposed to direct flame impingement and high temperatures where surrounding vegetation is in proximity or directly touching the roof edge.

• Metal drip edge: Metal flashing installed at the edge of the roof designed to keep water or embers away from the fascia board.
• Fascia or gutter boards: Vertical roof trim located along the perimeter of a building, usually below the roof level, to cover the rafter tails at the eaves and to seal off the top of the siding along the rake.⁵¹

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51 Owens Corning, "The Anatomy of a Roof," Owens Corning, accessed 2022, https://www.owenscorning.com/en-us/roofing/tools/the-anatomy-of-a-roof.

Currently, there are no fire rated assemblies for roof edge detailing.

Currently, there is no fire test standard to evaluate ember intrusion, direct flame impingement or thermal transmission of heat via convection or radiation from wildfires to roof joints such as the roof edge.

• International Wildland Urban Interface (IWUI) Code: No explicit requirements
• California Building Code (CBC): No explicit requirements
• NFPA 1144 Standard for Reducing Structure Ignition Hazards from Wildland Fire: 5.3.7 Roof Design and Materials

Codes and standards will vary depending on location and adoption in individual jurisdictions.

• Check local, county, and state amendments for additional wildfire codes and standards.
• Check local general plan, multi-hazard mitigation plan, or zoning documents for any additional requirements.
• IRC (if applicable – check for wildfire amendments).

• Install a metal drip edge or flashing to seal off the roof edge to minimize ember entry to the attic via materials burning in a rain gutter or wind-blown embers impinging on the area at the edge of the roof.⁵²
• Replace any damaged, broken, or missing pieces or sections of roof at the roof edge.
• Remove litter and other vegetation debris at the roof edge and in gutters annually before core fire season.
• For profiled tile roofs, bird-stop or mortar open ends of tiles at the roof edges to reduce vulnerability to ember ignition.
• For tile roofs, install metal flashing under tiles at roof edge. For profiled tile, lead or flexible flashing can be installed (as recommended by the manufacturer).⁵³ Where underlayment is combustible provide an additional fire-resistant underlayment between the roof covering and underlayment.
• Replace roof coverings and underlayment at roof edge before significant deterioration with age and exposure to weathering.
• Trim back vegetation touching, overhanging, or in close proximity to the roof edge.
• Refer to Typical Design, Vulnerability and Mitigation Considerations for additional mitigation options.

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52 University of California, Agriculture and Natural Resources, "Roof," Fire in California, accessed May 2022, https://ucanr.edu/sites/fire/Prepare/Building/Roof/.

53 FEMA, "Technical Fact Sheet No. 5: Roofs," in Home Builder's Guide to Construction in Wildfire Zones (Washington, D.C.: Government Printing Office, 2008).

NFPA Assessing Structure Ignition Potential from Wildfire

• Currently, there is no fire test standard to evaluate ember intrusion, direct flame impingement or thermal transmission of heat via convection or radiation from wildfires at the roof edge. The roof edge includes the underlayment, sheathing, fascia, and gutter and how these systems interact.
• As there are no fire testing for roof edges, it is unclear how weathering of materials prior to fire exposure or the impact of general wildfire environmental conditions (e.g., high winds, flying debris, impact from objects) will impact performance over time.

• University of California, Agriculture and Natural Resources: https://ucanr.edu/sites/fire/Prepare/Building/Roof/
• FEMA – Home Builder’s Guide to Construction in Wildfire Zones – Technical Fact Sheet No. 5: https://defensiblespace.org/wp-content/uploads/2021/01/FEMA_2008_P-737-Home-Builders-Guide-to-Construction-in-Wildfire-Zones.pdf 

Combustible debris such as leaves and pine needles can accumulate in gutters, especially from nearby or overhanging trees. Due to difficulty in accessing upper stories of a home, gutters two and three floors high are even more problematic since they will be difficult to clean out on a regular basis. If ignited, combustible debris in the gutter will expose the edge of the roof covering, typically the fascia and or roof sheathing. Depending on the condition of the wood and presence (or absence) of metal flashing at the edge of the roof, debris in the gutter may make it easier for fire to enter the attic.⁵⁴ In addition, the material of the gutter is a concern. Many gutters are constructed of plastic. Plastic gutters are typically composed of polyvinyl chloride (PVC) and can melt and fall to the ground. While PVC will self-extinguish once the debris around and in it burns out (the chlorine acts as a fire retardant), the fact that the gutter may contain burning debris as it collapses creates another mechanism for spread fire along the façade of the building or to combustible fuel beds below.

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54 Fire Safe Marin, "Fire-Resistant Gutters," Fire Safe Marin, accessed April 2022, https://firesafemarin.org/harden-your-home/fire-resistant-gutters/.

• Gutters: A shallow trough fixed beneath the edge of a roof to catch and direct rainwater.
• Fascia or gutter boards: Vertical roof trim located along the perimeter of a building, usually below the roof level, to cover the rafter tails at the eaves and to seal off the top of the siding along the rake.⁵⁵
• Gutter guard: Gutter guard is a generic term used to describe anything that goes over gutters to limit the accumulation of vegetative debris (e.g., leaves, needles, twigs) in the gutter. There are a range of gutter guards including brush inserts, foam inserts, DIY screen, micro-mesh, hood, etc. Gutter guards can be combustible or noncombustible. Noncombustible options should be used.

---

55 Exterior Building Solutions, "Roofing Terms," Exterior Building Solutions, accessed April 2022, https://www.exteriorbuildingsolutions.com/resources/roofing-terms/.

Currently there isn't an accepted procedure to evaluate the fire performance of gutters to ember exposure, radiant heat, convective heat, or direct flame impingement due to wildfires. Therefore, there are no fire rated assemblies.

Currently, there is no fire test standard to evaluate ember exposure, direct flame impingement or thermal transmission of heat via convection or radiation from wildfires to evaluate the effectiveness of gutter covers and gutter cover devices.

• 2021 International Wildland Urban Interface (IWUI) Code: Section 505.4 Gutters and Downspouts
• 2019 California Building Code (CBC):
  • Section 1502.4 Gutters
  • Chapter 7A Materials and Construction Methods for Exterior Wildfire Exposure
• 2018 NFPA 1144 Standard for Reducing Structure Ignition Hazards from Wildland Fire: Section 5.3.2

• Codes and standards will vary depending on location and adoption in individual jurisdictions.
• Check local general plan, multi-hazard mitigation plan, or zoning documents for any additional requirements.
• IRC (if applicable – check for wildfire amendments).

• Clean out debris from gutters, regularly, especially during fire season.
• Install metal flashing at the roof edge to provide additional protection to the roof edge.²⁹
• Install noncombustible gutters over plastic gutters in fire hazard areas.
• Install noncombustible gutter guards or covers to minimize the amount debris that may enter.
• Inspect gutter guards regularly to assure that they have not become dislodged.
• Refer to Typical Design, Vulnerability and Mitigation Considerations for additional mitigation options.

---

56 Fire Safe Marin, "Fire-Resistant Gutters," Fire Safe Marin, accessed April 2022, https://firesafemarin.org/harden-your-home/fire-resistant-gutters/.

NFPA Assessing Structure Ignition Potential from Wildfire

• Observations have been made that metal drip edge is effective against ignition of the structure if there is debris in the gutter, but further testing is needed to evaluate its performance.
• There are no fire test standards to evaluate the performance of gutters when exposed to wildfire conditions.
• Little to no fire testing has been conducted to obtain the rate of fire spread from the gutter to the structure if vinyl or plastic gutters are installed.
• Little to no fire testing has been conducted to find if plastic or vinyl gutters will propagate from embers if there is no combustible debris in the gutter.

• Fire Safe Marin, Gutters: https://firesafemarin.org/harden-your-home/fire-resistant-gutters/
• Ready For Wildfire, Gutters: https://www.readyforwildfire.org/cf-action/home-hardening-gutter/

Residential panel installations are a relatively new technology and building component/feature that has evolved significantly since 2014. While there have been significant strides in understanding fire hazards and risks from these systems and how to effectively design to mitigate those risks, little research and design standards have been undertaken to specifically address wildfire exposures and the associated risks that contribute to home ignition, fire load or firefighter safety during wildfire operations.
General concerns include:

• Rooftop placement is isolated from routine occupant awareness, fixed fire protection systems and detection features. These factors result in potential accumulation of debris, delayed fire detection and no fire protection.
• Combustible portions of the module and other components provide fuel to support a fire and can reflect heat from a fire towards the roof, contributing to combustion and burn-rate.
• Defensive fire service actions have been found to have reduced impact as photovoltaic (PV) panels conceal and shield fire below. Fire service must take additional precautions when approaching a structure that includes rooftop solar installation, as power generated by the panels cannot be turned off. Fire service may not identify presence of PV panels if not visible from ground-level.
• In general, there is limited data on how PV systems behave under wildfire exposure. There is potential for these systems to contribute to a wildfire event during substantial exposure, based on the materials used and their constant energization when exposed to light. Rooftop PV systems may include penetrations for building service which may compromise the continuity and integrity of the building envelope, potentially leading to early failure during wildfire exposure.

• Photovoltaic (PV) module: An environmentally protected planar assembly of solar cells, optics, and ancillary parts, such as interconnections, terminals, (and protective devices such as diodes) intended to generate direct current power under unconcentrated sunlight. The structural (load carrying) member of a module can either be the top layer (superstrate) or the back layer (substrate).⁵⁷
• PV panel: This is the technical term for a solar panel, often used interchangeably with PV module (especially in one-module systems), but more accurately used to refer to a physically connected collection of modules (i.e., a laminate string of modules used to achieve a required voltage and current). A collection of photo-voltaic modules mechanically fastened together, wired, and designed to provide a field-installable unit.⁵⁸
• PV system: A complete set of components for converting sunlight into electricity by the photovoltaic process, including the array, rack support system, and balance of system components.⁵⁹
• Photovoltaic-thermal (PV/T) system: A photovoltaic system that, in addition to converting sunlight into electricity, collects residual heat energy and delivers both heat and electricity in usable form. Also called a total energy system or solar thermal system.
• Solar panel: Synonymous with PV panel.

---

57 National Fire Protection Association, National Electrical Code (Quincy, MA: NFPA, 2016).

58 National Fire Protection Association.

59 National Fire Protection Association.

PV systems (PV modules with mounting systems) are available with Class A, B, and C ratings. Classification of roof mounted PV systems is based on UL 1703 (PV Modules) and UL 2703 (PV mounting systems). The combination of roof mounted solar modules and racking components is required to be considered as a system. The system is required to meet or exceed the fire classification of the roof assembly on which they are mounted. PV modules are also categorized by roof slopes they are tested for.

UL 1703 also assigns module types that are based on panel construction and fire performance. There are 33 total module types used by UL 1703, defined based on panel material/thickens, encapsulation method, substrate material/thickness, frame, and fire test performance for external fire exposure. Under the current standard, the use of module types is optional.

• ASTM E108 – Standard Test Methods for Fire Tests of Roof Coverings: https://www.astm.org/e0108-20a.html
• UL 790 Fire Test of Roof Coverings:  https://standardscatalog.ul.com/ProductDetail.aspx?productId=UL790
• UL 1703 Standard for Flat-Plate Photovoltaic Modules and Panels:  https://standardscatalog.ul.com/ProductDetail.aspx?productId=UL1703
• UL 2703 Mounting Systems, Mounting Devices, Clamping/Retention Devices, and Ground Lugs for Use with Flat-Plate Photovoltaic Modules and Panels:  https://standardscatalog.ul.com/ProductDetail.aspx?productId=UL2703
• ASTM E2908 Standard Guide for Fire Prevention for Photovoltaic Panels, Modules, and Systems: https://www.astm.org/e2908- 12r18.html
• Note: There are currently no fire test standards for solar panels exposed to wildfires.

• International Wildland Urban Interface (IWUI) Code: Section 504.2 Roof Assembly
• California Building Code (CBC): Chapter 7A, Section 705A.2 Roof Coverings
• NFPA 1144 Standard for Reducing Structure Ignition Hazards from Wildland Fire: Section 25.3 Roof Design and Materials
• Note: There are currently no codes or standards for solar panels exposed to wildfires.

Codes and standards will vary depending on location and adoption in individual jurisdictions.

• Check local, county, and state amendments for additional wildfire codes and standards.
• Check local general plan, multi-hazard mitigation plan, or zoning documents for any additional requirements.
• IRC (if applicable – check for wildfire amendments).

• Install Class A rated panels for the greatest protection.
• Maintain the panels free of debris and damage. This includes providing sufficient clearance between the panels and roof for clearing debris and inspecting the underside for damage.
• Install invertor and energy storage components within the building to minimize ignition hazards. These elements should not be installed outside within 5’ of exterior walls.
• Refer to Typical Design, Vulnerability and Mitigation Considerations for additional mitigation options.

NFPA Assessing Structure Ignition Potential from Wildfire:

• There is limited information available on how solar panels behave in a wildfire event, as this is dependent on the module, mounting hardware and roof as a system. Actual performance of a rack-mounted PV system exposed to fire or flame is strongly dependent on the mounting geometry of the PV array and properties of the components that make up the specific PV module type.⁶⁰
• Fire classification requirements were updated in 2014 (UL 1703) with substantial focus on fire performance considerations. Since the PV systems field continues to be an innovative field, technology and requirements will continue to evolve.
• Improper design, installation or components can cause hot spots and/or electrical failures that can lead to ignition of the system and adjacent materials during high load. Self-installed systems can significantly increase the risk of fire. PV system installation must be appropriately design and installed using classified and listed products;. Compliant PV systems have a very low incident rate of ignition.
• Roof attachments and methods must be compatible with the roof system and use appropriate precautions. Incorrect attachment methods can compromise fire performance, waterproofing ability, and in extreme cases, structural performance.
• Battery and inverter equipment locations do not typically consider exterior exposure risks and may be located on the building exterior.

---

60 Larry Sherwood et al., Fire Classification Rating Testing of Stand-Off Mounted Photovoltaic Modules and Systems (Solar America Board for Codes and Standards, 2013).

• FEMA: https://www.fema.gov/sites/default/files/2020-08/fema_p_737_0.pdf
• SFPE: https://www.sfpe.org/home?page=FPE_ET_Issue_99
• Solar ABCs / UL:
  • http://www.solarabcs.org/about/publications/reports/flammability-testing/pdfs/SolarABCs-36-2013-1.pdf
  • http://www.solarabcs.org/about/publications/reports/flammability-testing/pdfs/Flammability_Interimreport.pdf

Skylights can compromise a home’s ability to survive a wildfire when precautions are not taken to minimize the potential for them being an entry point for embers and/or flames. During a wildfire, a skylight can be compromised due to extended radiant heat exposure or to flames when embers have ignited vegetative debris on top or next to the skylight. Most guidance recommends using a flat glass skylight rather than a plastic dome style because the plastic is combustible. However, there are situations based on the slope of the roof where flat glass could become more vulnerable.⁶¹

• Vegetative debris can more easily land and stay on a low slope roof leading to increased risks.
• Typical flame temperatures from wind-blown ember ignition of debris would be high enough to break even tempered glass.⁶²

---

61 National Fire Protection Association, "Wildfire Research Fact Sheet: Skylights," NFPA.org, accessed April 2022, https://www.nfpa.org/-/media/Files/Firewise/Fact-sheets/FirewiseFactSheetsSkylights.ashx</>.

62 National Fire Protection Association.

• Unit skylight: A factory-assembled, glazed, fenestration unit, containing one panel of glazing material that allows for natural lighting through an opening in the roof assembly while preserving the weather-resistant barrier of the roof.⁶³
• Skylights and sloped glazing: Glass or other transparent or translucent glazing material installed at a slope of 15 degrees or more from vertical. Unit skylights, tubular daylighting devices, glazing materials, solariums, sunrooms, roofs, and sloped walls are included in this definition.⁶⁴

---

63 International Code Council, Inc., International Building Code (Country Club Hills, IL: International Code Council, Inc., 2018).

64 International Code Council, Inc.

Skylights can comply with several different requirements to resist the effects of fire. Applicable options are as follows:

• Be constructed of multi-pane glazing with a tempered pane⁶⁵
• Be constructed of glass block units⁶⁶
• Be comprised of fire rated glazing per ASTM E119
• Have a fire-resistance rating of not less than 20 minutes when tested in accordance with NFPA 257

---

65 Division of Agriculture and Natural Resources, University of California, "Skylights," Homeowner's Wildfire Mitigation Guide, accessed April 2022, https://ucanr.edu/sites/Wildfire/Roof/Skylights/.

66 Rodolfo Uribe, Factors Leading to Structure Loss on the Thomas Fire (San Luis Obispo: California Polytechnic Institute, 2021), https://digitalcommons.calpoly.edu/theses/2341/.

• ASTM E119 Standard Test Methods for Fire Tests of Building Construction and Materials: https://www.astm.org/e0119-20.html
• NFPA 257 Standard on Fire Test for Window and Glass Block Assemblies

• International Wildland Urban Interface (IWUI) Code: Sections 504.8, 505.8 Exterior Glazing
• California Building Code (CBC):
  • 708A Exterior Windows, Skylights, and Doors
  • 202 Definitions
• NFPA 1144 Standard for Reducing Structure Ignition Hazards from Wildland Fire:5.7 Exterior Openings
• ASCE 7-05 American Society of Civil Engineers Standard: Windborne debris criteria

Codes and standards will vary depending on location and adoption in individual jurisdictions.

• Check local, county, and state amendments for additional wildfire codes and standards.
• Check local general plan, multi-hazard mitigation plan, or zoning documents for any additional requirements.
• IRC (if applicable – check for wildfire amendments)

---

67 National Fire Protection Association, "Wildfire Research Fact Sheet: Skylights," NFPA.org, accessed April 2022, https://www.nfpa.org/-/media/Files/Firewise/Fact-sheets/FirewiseFactSheetsSkylights.ashx.

68 FEMA, "Technical Fact Sheet No. 10: Windows and Skylights," in Home Builder's Guide to Construction in Wildfire Zones (Washington, D.C.: Government Printing Office, 2008).

69 FEMA.

70 FEMA.

71 FEMA.

72 FEMA.

73 FEMA.

• Opt for flat / tempered glass skylights. Debris can accumulate at roof-to-skylight intersections. If ignited by embers, flames can potentially wrap around and impinge upon the top surface of the skylight.
• Regularly inspect your roof for debris accumulation on and around skylights. Debris is more likely to accumulate on top of a skylight installed on a flat roof.⁷⁴
• A variety of products are available for glazing in skylights. Glazing can be in a single- or multi-paned configuration. If plastic skylights are installed, it is recommended that they are replaced with laminated glass, tempered glass, glass with a low-emissivity, fiberglass-reinforced translucent glazing, and/or insulated glazing units.  Glazing products that are not recommended are annealed glass, ceramic glass, and plastic glazing.⁷⁵
• Refer to Typical Design, Vulnerability and Mitigation Considerations for additional mitigation options.

---

74 Insurance Institute for Business & Home Safety, "Protect Your Property from Wildfire: California Edition," Northstar Community Services District, accessed April 2022, https://www.northstarcsd.org/media/Fire/Prevention/Defensible%20Space/WF_California_Northstar.pdf.

75 FEMA, "Technical Fact Sheet No. 10: Windows and Skylights," in Home Builder's Guide to Construction in Wildfire Zones (Washington, D.C.: Government Printing Office, 2008).

NFPA Assessing Structure Ignition Potential from Wildfire

• University of California – Homeowner’s Wildfire Mitigation Guide, Skylights: https://ucanr.edu/sites/Wildfire/Roof/Skylights/
• FEMA – Home Builder’s Guide to Construction in Wildfire Zones, Technical Fact Sheet No. 10: FEMA – Home Builder’s Guide to Construction in Wildfire Zones, Technical Fact Sheet No. 10: https://defensiblespace.org/wp-content/uploads/2021/01/FEMA_2008_P-737-Home-Builders-Guide-to-Construction-in-Wildfire-Zones.pdf

Eaves are located at the down-slope edge of a sloped roof and serve as the transition between the roof and fascia/wall. Under-eave areas are vulnerable to damage from wildfires. Once an eave, overhang, or soffit has ignited, fire can spread from the under-eave area onto the roof, into the attic, or onto and through the exterior wall.⁷⁶ Metal soffit panels conduct heat and can distort and allow the passage of embers and hot gases. Untreated wood soffit panels can ignite, and vinyl panels can melt and fall away.⁷⁷

• Windborne embers, convective heat and radiant heat can be trapped under overhangs and in the upper portion of exterior walls.⁷⁸
• Typical construction materials for eaves, overhangs, and soffits are not fire-resistant, and therefore, are susceptible to ignition by embers and hot gases.⁷⁹
• Soffits normally have vents as part of the attic ventilation system. Unprotected vents can allow embers and hot gases to enter the attic.⁸⁰
• Depending on how the under-eave area is constructed (i.e., “soffitted” or “open-eave”) there will be different vulnerabilities from flame contact exposures, ember accumulation, as well as different weaknesses for vents.

---

76 FEMA, "Technical Fact Sheet No. 6: Eaves, Overhangs, and Soffits," in Home Builder's Guide to Construction in Wildfire Zones (Washington, D.C.: Government Printing Office, 2008).

77 Fire Safe Marin, "Fire - Resistant Soffits &amp; Eaves," Fire Safe Marin, accessed April 2022, https://firesafemarin.org/harden-your-home/fire - resistant-soffits-eaves/.

78 FEMA, "Technical Fact Sheet No. 6: Eaves, Overhangs, and Soffits."

79 Fire Safe Marin, "Fire - Resistant Soffits &amp; Eaves.”

80 FEMA, "Technical Fact Sheet No. 6: Eaves, Overhangs, and Soffits."

• Boxed-in eave: An overhang with a soffit that closes and finishes the underside of the eaves.
• Fascia or gutter boards: Vertical roof trim located along the perimeter of a building, usually below the roof level, to cover the rafter tails at the eaves and to seal off the top of the siding along the rake.⁸¹
• Open eave: Design where the roof rafters extend beyond the exterior wall and visible. Blocking is used to fill the space between the top of the exterior wall and the roof sheathing.⁸²
• Soffit: Encloses the underside of roof overhangs.

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81 Exterior Building Solutions, "Roofing Terms," Exterior Building Solutions, accessed April 2022, https://www.exteriorbuildingsolutions. com/resources/roofing - terms/.

82 Division of Agriculture and Natural Resources, University of California, "Eaves," Homeowner's Wildfire Mitigation Guide, accessed April 2022, https://ucanr.edu/sites/Wildfire/Side_of_House/Eaves/.

Currently there isn't an accepted procedure to evaluate ember intrusion of eaves, soffits, or overhangs that results in the designation of a fire rating. Fire test standards that detail tests to evaluate resistance of fire penetration and direct flame impingement of eaves, overhangs, and other projections, as well as tests to evaluate ember/flame resistance of vents, exist and are listed below. Soffits may be included in assemblies that receive fire resistance ratings, but the soffit itself does not.

• ASTM E2886 Standard Test Method for Evaluating the Ability of Exterior Vents to Resist the Entry of Embers and Direct Flame Impingement: https://www.astm.org/e2886_e2886m-20.html
• ASTM E2957 Standard Test Method for Resistance to Wildfire Penetration of Eaves, Soffits, and Other Projections: https://www.astm.org/e2957-17.html
• SFM Standard 12-7A-3 Materials and Construction Methods for Exterior Wildfire Exposure: Horizontal Projection Underside: https://www.hcd.ca.gov/building-standards/state-housing-law/wildland-urban-interface/docs/2010-part-2-cbc-ch7a.pdf

• International Wildland Urban Interface (IWUI) Code:
  • IWUIC 2021 Sections 504.3, 505.3 Protection of Eaves
  • Sections 504.10.1, 505.10.1: Vent locations
• International Building Code (IBC), 2021: Section 705: Exterior Walls
• California Building Code (CBC), 2019:5 Enclosed Roof Eaves and Roof Eave Soffits
• NFPA 1144 Standard for Reducing Structure Ignition Hazards from Wildland Fire, 2018: 3 Roof Design and Materials

Codes and standards will vary depending on location and adoption in individual jurisdictions.

• Check local, county, and state amendments for additional wildfire codes and standards.
• Check local general plan, multi-hazard mitigation plan, or zoning documents for any additional requirements.
• IRC (if applicable – check for wildfire amendments).

• Enclose open overhangs with soffits that have a minimum one-hour fire-resistance rating to prevent embers and hot gases from contacting the joists, rafters or trusses, or the underside of the roof decking.⁸³
• Where possible, replace open eaves with soffited eaves.
• Use flat, horizontal soffits instead of attaching the soffits to the sloped joists, which creates sloped soffits. A flat soffit reduces the potential for entrapment of embers and hot gases.⁸⁴
• For the fascia, use noncombustible or fire-resistant materials (e.g., fire-retardant-treated lumber, fiber-cement board, etc.)⁸⁵
• Evaluate the fire-resistance of existing soffits and replace soffits that are not fire-resistant according to the guidance provided in FEMA Technical Fact Sheet No.8 located within The Home Builder’s Guide to Construction in Wildfire Zones.⁸⁶
• In very high Fire Severity Zones, install exterior 5/8” fire-resistant gypsum board between the existing and new soffit materials for enhanced fire resistance.⁸⁷
• If the fascia is combustible, cover the fascia board with a noncombustible or fire-resistant material like fire-retardant-treated lumber, fiber-cement board, etc.⁸⁸
• Fill joints and gaps with fire rated caulking and other appropriate firestopping materials.
• Do not store firewood, construction materials or other combustible materials under any overhang.
• Avoid planting combustible vegetation under eaves and overhangs.
• Refer to Typical Design, Vulnerability and Mitigation Considerations for additional mitigation options.

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83 Fire Safe Marin, "Fire - Resistant Soffits &amp; Eaves," Fire Safe Marin, accessed April 2022, https://firesafemarin.org/harden-your-home/fire-resistant-soffits-eaves/.

84 FEMA, "Technical Fact Sheet No. 6: Eaves, Overhangs, and Soffits," in Home Builder's Guide to Construction in Wildfire Zones (Washington, D.C.: Government Printing Office, 2008).

85 FEMA.

86 FEMA.

87 FEMA.

88 FEMA.

NFPA Assessing Structure Ignition Potential from Wildfire

• Fire testing does not account for weathering of materials prior to fire exposure or the impact of general wildfire environmental conditions (e.g., high winds, flying debris, impact from objects).
• “Ignition-resistant” eaves and soffits that have been tested against criteria from SFM Standard 12-7A-3 may be difficult to verify in-field.
• “Ignition-resistant” is not a widely used term when referencing fire resistance of eaves, overhangs, and soffits. The term is only used in some local jurisdictions and does not exist in ICC or NFPA codes.
• Incorrect language is often used when referencing fire-resistance of soffits. The soffit itself does not receive a rating. It must be part of an approved assembly.

• Colorado State Forest Service, FireWise Construction Site Design and Building Materials 2012: https://static.colostate.edu/client-files/csfs/pdfs/firewise-construction2012.pdf
• IBHS Wildfire Home Assessment and Checklist: https://www.iafc.org/docs/default-source/pdf/wildfire-checklist_ibhse1e8b15c78366c709642ff00005f0421.pdf?sfvrsn=5bdedd0d
• FEMA Home Builder’s Guide to Construction in Wildfire Zones: https://defensiblespace.org/wp-content/uploads/2021/01/FEMA_2008_P-737-Home-Builders-Guide-to-Construction-in-Wildfire-Zones.pdf
  • Technical Fact Sheet No. 6
  • Technical Fact SHeet No. 8

Windborne embers, convective heat, and radiant heat can be trapped under overhangs, eaves, and soffits due to unique fire induced flows during wildfire incidents. Eaves, overhangs, and soffits typically have vents as part of the attic ventilation system. If soffit vents are unprotected embers and hot gases can enter the attic or other parts of the structure leading to ignition of interior building contents. Oftentimes, fires that initiate via embers into attics or other concealed spaces can go undetected for long periods of time.

• Soffit vent: A continuous or intermittent vent installed along a soffit as part of the attic ventilation system of a building.⁸⁹
• Eaves: Eaves are located at the down-slope edge of a sloped roof and serve as the transition between the roof and fascia/wall.⁹⁰
• Overhangs: Overhangs are extensions of the roof beyond the exterior wall (i.e., the joists, rafters, or trusses and the decking they support cantilever past the wall).⁹¹

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89 FEMA, "Technical Fact Sheet No. 6: Eaves, Overhangs, and Soffits," in Home Builder's Guide to Construction in Wildfire Zones (Washington, D.C.: Government Print ing Office, 2008).

90 FEMA.

91 FEMA

The ember and direct flame impingement resistance vents in the under-eave area is defined by ASTM E2886 Standard Test Method for Evaluating the Ability of Exterior Vents to Resist the Entry of Embers and Direct Flame Impingement. This test standard prescribes two individual methods to evaluate the ability of the vent opening to resist embers and flame. The ability of such vents to completely exclude entry of flames or embers is not evaluated. Acceptance criteria are not provided in this standard.⁹²

---

92 ASTM International, "ASTM E2886/E2886M - 20 Standard Test Method for Evaluating the Ability of Exterior Vents to Resist the Entry of Embers and Direct Flame Impingement," ASTM International, July 24, 2020, https://www.doi.org/10.1520/E2886_E2886M-20.

93 ASTM International.

94 ASTM International.

• ASTM E2886/E2886M-14 Standard Test Method for Evaluating the ability of Exterior Vents to Resist the Entry of Embers and Direct Flame Impingement: https://www.astm.org/e2886_e2886m-20.html

• International Wildland Urban Interface (IWUI) Code: Section 504.10, Vents
• California Building Code (CBC): 706A, Vents
• NFPA 1144 Standard for Reducing Structure Ignition Hazards from Wildland Fire:
  • Section 5.7.4, Exterior Openings
  • 5.3.3 for Vents

Codes and standards will vary depending on location and adoption in individual jurisdictions.

• Check local, county, and state amendments for additional wildfire codes and standards.
• Check local general plan, multi-hazard mitigation plan, or zoning documents for any additional requirements.
• IRC (if applicable – check for wildfire amendments).

• Cover existing vents with wire mesh screen having openings with a maximum of 1/8”. Preferably 1/16”. Research has shown that 1/8” mesh screening can still lead to embers with sufficient energy to ignite fine fuels in the attics.
• Install ember resistant vents manufactured with wire mesh screening with a maximum of 1/8”. Preferably 1/16”. Research has shown that 1/8” mesh screening can still lead to embers with sufficient energy to ignite fine fuels in the attics.
• Common 1/4" screens are ineffective and should be replaced. 
• Replace screens that have painted over or detached from the substrate.
• Do not use fiberglass or plastic mesh because they can melt and/or burn.
• Use fire-rated caulking around penetrations to seal openings.
• Protect vents in eaves or cornices with baffles to block embers, backed by 1/16” wire mesh (mesh alone is not enough).⁹⁵
• If possible, move soffit vents away from the exterior wall.
• Refer to Typical Design, Vulnerability and Mitigation Considerations for additional mitigation options.

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95 Fire Safe Marin, "Fire - Resistant Vents," Fire Safe Marin, accessed April 2022,https://firesafemarin.org/harden-your-home/fire-resistant -vents/.

NFPA Assessing Structure Ignition Potential from Wildfire

• Fire testing does not account for weathering of materials prior to fire exposure or the impact of general wildfire environmental conditions (e.g., high winds, flying debris, impact from objects).
• ASTM E2886 does not evaluate the ability of vents to completely exclude entry of flames or embers.
• ASTM E2886 does not provide acceptance criteria.
• In most instances, it’s challenging to verify in-the-field if a vent has been fire-tested. (Professional judgement and discussion with the homeowner are required.)
• Air flow calculations may need to be reconsidered or redesign where fire rated vents are installed in existing structures, to ensure sufficient airflow is still satisfied for non-fire purposes.

• IBHS Ember Testing:
  • https://ibhs.org/wildfire/building-vulnerability-to-ember-exposure/
  • https://ibhs.org/wp-content/uploads/wpmembers/files/Vulnerability-of-Vents-to-Wind-Blown-Embers_IBHS.pdf
  • https://www.facebook.com/watch/?v=389602881106017
• IBHS Preparedness: https://disastersafety.org/wp-content/uploads/2021/08/WFR-Home-Preparedness-Guide.pdf
• FEMA – Home Builder’s Guide to Construction in Wildfire Zones, Technical Fact Sheet No. 5: https://defensiblespace.org/wp-content/uploads/2021/01/FEMA_2008_P-737-Home-Builders-Guide-to-Construction-in-Wildfire-Zones.pdf
• University of California: https://ucanr.edu/sites/fire/Prepare/Building/Vents/

In general, joints and other penetrations create gaps in the continuity of a fire rated or fire resistive roof or wall assembly, providing a potential avenue for embers, hot gases, or flame to breach the exterior envelope of a building. Due to unique fire induced flows at the underside of eaves that can lead to an accumulation of hot gas and embers, head-of-wall to roof joints are particularly vulnerable to ember intrusion and exposure to hot gases. Embers can oftentimes accumulate at head-of-wall to roof joints, creating a concentrated source of heat. For bottom-of-wall to roof joints that may occur in more complex roofs (i.e., high number of vertical-to-horizontal transitions), the concern with hot gases accumulating near the joint are reduced. However, bottom-of-wall to roof joints are more susceptible to direct flaming and ember accumulation from the ignition of debris that typically collected in these locations. In addition, head/bottom-of-wall-to-roof joints are also locations where there can be different fire classification/rating levels and construction materials (which can result in one system being compromised by the other). Lastly, there is currently no fire test for any types of roof joints (including head-of-wall or bottom-of-wall joints to roof) to wildfire exposure – embers, direct flaming, or hot gases. This can create a short-circuit of a Class A rated roof assembly or fire-resistance wall detail.

• Joint: The opening in or between adjacent assemblies that is created due to building tolerances or is designed to allow independent movement of the building in any plane caused by thermal, seismic, wind or any other loading.⁹⁶
• Fire-resistant Joint system: An assemblage of specific materials or products that are designed, tested and fire-resistance rated in accordance with a standard fire test to resist for a prescribed period of time the passage of fire through joints made in or between fire-resistance rated assemblies.⁹⁷ (Note: There are currently no fire-resistant joint system tests for wildfire exposures.)
• Head-of-wall: A head-of-wall joint is the linear gap between the top of a wall assembly and bottom of a floor or roof assembly.⁹⁸
• Bottom-of-wall: A bottom-of-wall joint is the linear gap between the bottom of a wall assembly and top of a roof or floor assembly.
• Flashing: A thin metal that is installed at joints to protect against intrusion of unwanted elements such as water and embers.

---

96 International Firestop Council, "Inspection Guidelines: Penetration Firestop Systems and Fire Resistive Joint Systems in Fire Resistance Rated Construction," International Firestop Council, accessed 2022, https://www.firestop.org/inspection - guidelines.

97 International Firestop Council.

98 Walls & Ceilings, "Firestop Head - of - Wall Joints," Walls & Ceilings, October 1, 2005, https://www.wconline.com/articles/84503-firestop-head-of-wall-joints. 

Currently, there is no fire test standard to evaluate ember intrusion, direct flaming impingement or thermal transmission of heat via convection or radiation from wildfires for joint systems (head-of-wall or bottom-of-wall-to roof joint system). Fire rated joints are necessary to maintain a roof or wall system’s fire rating, integrity and/or continuity to wildfire exposure. While a variety of fire tests exist for joint systems in interior building fire exposures (e.g., ASTM E1966 or UL 2079), none are applicable to the fire conditions presented by wildfires. A range of joint systems (e.g., static joints, movement joints) and joint conditions (e.g., header or top-of-wall, footer, or bottom-of-wall details) for exterior wildfire exposures are still needed.

Currently, there is no fire test standard to evaluate ember intrusion, direct flame impingement or thermal transmission of heat via convection or radiation from wildfires for joint systems.

• International Wildland Urban Interface (IWUI) Code: No explicit requirements
• California Building Code (CBC): No explicit requirements
• NFPA 1144 Standard for Reducing Structure Ignition Hazards from Wildland Fire: No explicit requirement

Codes and standards will vary depending on location and adoption in individual jurisdictions.

• Check local, county, and state amendments for additional wildfire codes and standards.
• Check local general plan, multi-hazard mitigation plan, or zoning documents for any additional requirements.
• IRC (if applicable – check for wildfire amendments)

---

99 University of California, Agriculture and Natural Resources, "Roof," Fire in California, accessed May 2022, https://ucanr.edu/sites/fire/Prepare/Building/Roof/.

• Refer to Typical Design, Vulnerability and Mitigation Considerations for additional mitigation options.
• Debris should be removed from around all joints created at the roof (e.g., expansion joints, vents/chimney-to-roof joints).
• Metal flashing should be installed at bottom-of-wall-to-roof joints to limit ember penetration or direct flame infiltrating the wall or roof substrate. Where the roof or wall underlayment is combustible, refer to appropriate protection measures in the roof and wall construction/covering section for detailing.
• Provide fire-rated caulking in any gaps at the joint between the wall and the top of roof.

NFPA Assessing Structure Ignition Potential from Wildfire

• Currently, there are no fire testing standards to evaluate ember intrusion, direct flame impingement or thermal transmission of heat via convection or radiation from wildfires for joint systems.
• It is unclear how susceptible various head/bottom-of-wall-to-roof joints are to wildfire exposures.

• University of California, Agriculture and Natural Resources – Home Survival in Wildfire-Prone Areas: Building Materials and Design Considerations: https://anrcatalog.ucanr.edu/pdf/8393.pdf

Exterior wall surfaces may provide a means for fire intrusion due to the level of combustibility of the exterior cladding and how the exterior cladding is maintained. A secondary, but direct impact for fire intrusion into a structure through exterior cladding is the method in which the surface was installed and to what degree measures were taken to make a fire brand resistant membrane maintain continuity in ember resistance. Exterior walls often have a sublayer that is of combustible materials which depends on the integrity of the exterior cladding to protect the internal framing of the structure from fire. Small openings or gaps in the siding and trim provide a sufficient entry path or point of receptive ignition that would adversely impact the structure. An often-overlooked area of ember intrusion is the foundation overlap where a gap between the foundation and the siding can provide nesting or retention of embers against a combustible surface, including stucco or masonry cladding.

• Any opening in exterior surfaces provides an entry point for ember intrusion including pet doors, HVAC plumbing, unsealed sill cocks, mail slots, vent stacks for cooking ranges, fireplaces, and wood stoves.
• Combustible items attached to the siding or exterior cladding will impact the integrity of the exterior cladding including plastic conduit for utility access to the structure and ornamental plastic fixtures such as decorative shutters made of plastic.
• Wood cladding may by its nature and method of manufacture may provide significant ember purchase points for windblown embers that may go undetected for long periods of time.
• Exterior cladding of less cell density such as cedar provides rapid pre-heating and propagation of fire across the entire surface and adds to the generation of fire brands.
  Furthermore, current building codes do not require fire resistance ratings for exterior walls for single family residences regardless of fire separation distances to adjacent properties or structures. This presents challenges to limiting structure-to-structure spread in high-density housing.

• Exterior Cladding: The construction material applied over another to provide a skin or layer used to provide a degree of thermal insulation and weather resistance.¹⁰⁰

---

100 T

The fire resistance of external wall assemblies to interior and exterior fire exposures is defined by ASTM E119 or UL 263 Standard Test Methods for Fire Tests of Building Construction and Materials. This test standard is applicable to assemblies of masonry units and to composite assemblies of structural materials for buildings, including loadbearing and other walls and partitions, columns, girders, beams, slabs, and composite slab and beam assemblies for floors and roofs.¹⁰¹

The standard is used to measure and describe the response of materials, products, or assemblies to heat and flame under controlled conditions, but does not by itself incorporate all factors required for fire hazard or fire risk assessment of the materials, products or assemblies under actual fire conditions. This is due to limitations of the size of the specimens tested, size of the furnace, standard fire exposure, etc. However, the test standard is one of the most widely adopted methods for comparing the performance of building construction materials, elements, and assemblies to a standard fire exposure.¹⁰²

The test method includes measurements of exposed and unexposed surface temperature, as well as the ability of an element or assembly to maintain structural stability, integrity and insulation when exposed to a severe, standard fire exposure. The standard fire exposure simulates severe interior building fire conditions during flashover conditions. Depending how the wall assembly performs against the performance criteria for stability, integrity and insulation, the assembly can achieve anywhere from a 30-min, 1-hour, or up to 4-hour fire resistance rating.

---

101 ASTM International, "ASTM E119 - 22 Standard Test Methods for Fire Tests of Building Construction and Materials," ASTM International, October 10, 2022. https://www.doi.org/10.1520/E01 19 - 22.

102 ASTM International.

• ASTM E119 Standard Test Methods for Fire Tests of Building Construction and Materials: https://www.astm.org/e0119-20.html
• SFM Standard 12-7A-5 Materials and Construction Methods for Exterior Wildfire Exposure: Ignition Resistant Material
• UL 263 Fire Tests of Building Construction and Materials: https://global.ihs.com/doc_detail.cfm?document_name=UL%20263&item_s_key=00097028
• ASTM E2707 Standard Test Method for Determining Fire Penetration of Exterior Wall Assemblies Using a Direct Flame Impingement Exposure: https://up.codes/viewer/california/ibc-2018/chapter/new_7A/sfm-materials-and-construction-methods-for-exterior-wildfire-exposure#new_705A
• ASTM E84 Standard Test Methods for Surface Burning Characteristics of Building Materials
• UL 723 Test for Surface Burning Characteristics of Building Materials
• NFPA 268 Standard Test Method for Determining Ignitability of Exterior Wall Assemblies Using a Radiant Heat Energy Source

• 2021 International Wildland Urban Interface (IWUI) Code: Section 504.5, 505.5 Exterior Walls,
• 2021 International Building Code (IBC):
  
  • Section 705 Exterior Walls
  • Section 1402 Performance Requirements
  • Section 1405 Exterior Insulation and Finish Systems
• 2019 California Building Code (CBC): Section 707A.3, Exterior Walls
• 2018 NFPA 1144 Standard for Reducing Structure Ignition Hazards from Wildland Fire:
  • Section 5.6: Exterior Vertical Walls
  • Section 5.7: Exterior Openings

Codes and standards will vary depending on location and adoption in individual jurisdictions.

• Check local, county, and state amendments for additional wildfire codes and standards.
• Check local general plan, multi-hazard mitigation plan, or zoning documents for any additional requirements.
• IRC (if applicable – check for wildfire amendments).

Note: While exterior wall coverings may provide an initial barrier to flames, heat can still pass through the coverings and ignite other components of the exterior wall assembly. It is important to ensure that the exterior wall assembly has been tested against criteria from ASTM E119 or UL 263 for a fire-resistance rating.

---

103 FEMA, "Technical Fact Sheet No. 7: Exterior Walls," in Home Builder's Guide to Construction in Wildfire Zones (Washington, D.C.: Government Printing Office, 2008).

• Refer to Typical Design, Vulnerability and Mitigation Considerations for additional mitigation options.
• Maintain an ember-resistance zone for at least 5’ from all exterior walls of the structure. Remove combustibles fuel loads including wood mulch, propane tanks, trash containers, plastic storage bins, BBQs, vegetation of all kinds (if possible, otherwise remove all high fire hazard vegetation).
• Maintain landscaping and general housekeeping within the home ignition zone. Refer to defensible space requirements.
• Consider upgrading the exterior wall cladding to include an 5/8” Type X exterior rated gypsum board between the wall cladding and underlayment.
• Consider upgrading exterior wall to be 1-hour fire rated where the exterior wall is within 30’ of the property line or adjacent structure.
• Apply fire resistive gels to siding to protect from embers, radiant heat, and direct flame contact.
• Utilize sprinkler kits provided by agencies or use home sprinklers systems. This should NOT be considered the main line of defense, as exterior sprinklers systems have no standard fire test, design criteria or performance specifications to have any certainty of its reliability and performance in a wildfire event.
• Block any point which may allow ember penetration to structure.
• Utilize fire resistive wrapping to protect siding from flame impact.

NFPA Assessing Structure Ignition Potential from Wildfire

• Current building codes do not require fire resistance ratings for exterior walls for single family residences regardless of fire separation distances to adjacent properties or structures. While fire separation distances exist in building codes, they are primarily designed for structure-to-structure spread from adjacent properties, they do not explicitly apply to outbuildings for the same property. The underlying basis for the separation distances and ratings are likely valid but need to be specified/confirmed for SFRs and multiple-dwelling units.
• While the standard ASTM E119 fire resistance test is based on interior building fires or structure-to-structure fires, it was not specifically designed to account for the unique aspects of wildfire fire exposures. That is, it does not capture the impact of embers of direct flame impingement. That said, interior building fire exposures are generally more severe to exterior fire exposures, and therefore may provide a reasonable proxy for anticipating a rated-wall assembly’s performance in a wildfire.
• ASTM E119 fire testing does not account for weathering of materials prior to fire exposure. UL 263 has an accelerated weather exposure protocol prior to fire testing.
• In most instances, it’s challenging to verify in-the-field if an exterior wall assemblies fire resistance rating of 1-hour, 2-hour, etc. (Professional judgement required.)

• FEMA – Home Builder’s Guide to Construction in Wildfire Zones, Technical Fact Sheet No. &: https://defensiblespace.org/wp-content/uploads/2021/01/FEMA_2008_P-737-Home-Builders-Guide-to-Construction-in-Wildfire-Zones.pdf
• IBHS – Home Preparedness Guide: https://disastersafety.org/wp-content/uploads/2021/08/WFR-Home-Preparedness-Guide.pdf

Like other exterior openings, doors can compromise a home’s ability to survive a wildfire when precautions are not taken to prevent them from being an entry point for embers and/or flames. During a wildfire, a door can be compromised due to an extended radiant heat exposure from surrounding vegetation or due to flames when embers have ignited vegetative debris near the door.¹⁰⁴  Deteriorating weather stripping and glass panels are the most vulnerable part s of the door. If the weather stripping has deteriorated around the door causing a poor seal, embers and flames can penetrate around the door into the structure. If the glass panels in a door break during a wildfire, embers and flame can easily enter a structure.¹⁰⁵  Similarly, non - fire rated combustible doors and combustible door frames can ignite or fail, leading to ember intrusion and ultimately ignition of other material inside of the structure. Therefore, doors must be able to resist the following exposures:

• A radiant exposure severe enough to break the glass in a door or ignite the door or door frame . Burning vegetation in close proximity to a door could also ignite non - fire rated combustible doors and combustible door frames. ¹⁰⁶
• A flame contact exposure that could result from embers igniting vegetation and/or exterior cladding that burns up to the door(s).¹⁰⁷ 

See window section below for additional guidance on glass panels in doors.

---

104 National Fire Protection Association, "NFPA Wildfire Research Fact Sheet: Exterior Sprinkler Systems," NFPA.org, accessed Apr il 2022, https://www.nfpa.org/ - /media/Files/Firewise/Fact-sheets/FirewiseFactSheetsExteriorSprinklers.ashx.

105 University of California, Agriculture and Natural Resources, "Windows," Mariposa County, accessed April 2022, https://cemarip osa.ucanr.edu/Fire_Information/Wildfire_Preparation/Preparing_Your_Home_599/Windows/.

106 University of California, Agriculture and Natural Resources.

107 University of California, Agriculture and Natural Resources

• Weather strip: A strip of material to cover the joint of a door or window and the sill, casing, or threshold to exclude rain, snow, and cold air.¹⁰⁸
• Sidelite: The side panels on either side of the door. Filled with glass or wood and usually appear in pairs, though can exist solo.

---

108 Merriam - Webster, "Weather Strip," Merriam - Webster.com, accessed 2022, https://www.merriam - webster.com/dictionary/weather%20 strip.

Fire ratings for doors or door assemblies is defined by a number of standards, as follows:

• NFPA 252 Standard Method of Fire Tests of Door Assemblies
• UL 10C Standard for Positive Pressure Fire Tests of Door Assemblies.
• UL 10B Standard Test for Fire Tests of Door Assemblies
• ASTM E152 Standard Methods of Fire Tests of Door Assemblies

These test standards prescribe specific fire and hose stream test procedures for fire door assemblies for determining the degree of fire protection provided by such assemblies in retarding the spread of fire (flame, heat, and hot gases) through door openings in a fire resistive wall when exposed to a severe, standard fire exposure.¹⁰⁹ The standard fire exposure simulates severe interior building fire conditions during flashover conditions. It does not represent the wildfire exposures that may also include embers and direct flame impingement. Depending on how the door assembly performs against the performance criteria defined in the standards, the door can achieve anywhere from a 20-min, 1-hour, or up to 3-hours (typically) fire resistance rating.

---

109 National Fire Protection Association, NFPA 252: Standard Method of Fire Tests of Door Assemblies (Quincy, MA: NFPA, 2017).

• ASTM E119 Standard Test Methods for Fire Tests of Building Construction and Materials: https://www.astm.org/e0119-20.html
• ASTM E152 Standard Methods of Fire Tests of Door Assemblies
• ASTM E2112 Standard Practice for Installation of Exterior Windows, Doors, Skylights:
   https://www.astm.org/e2112-19c.html
• UL 10B Standard Test for Fire Tests of Door Assemblies:
  https://standardscatalog.ul.com/ProductDetail.aspx?UniqueKey=29319
• UL 10C Standard for Positive Pressure Fire Tests of Door Assemblies: https://www.shopulstandards.com/ProductDetail.aspx?UniqueKey=31216
• NFPA 252 Standard Methods of Fire Tests of Door Assemblies

• 2021 International Wildland Urban Interface (IWUI) Code: Chapter 5, Sections 504.9, 505.9 Exterior Doors
• 2019 California Building Code (CBC) and California Residential Code (CRC): Chapter 7A , CBC 708A/CRC R337.8

Codes and standards will vary depending on location and adoption in individual jurisdictions.

• Check local, county, and state amendments for additional wildfire codes and standards.
• Check local general plan, multi-hazard mitigation plan, or zoning documents for any additional requirements.
• IRC (if applicable – check for wildfire amendments)

• Refer to Typical Design, Vulnerability and Mitigation Considerations for additional mitigation options.
• Provide, where possible, ignition resistant or noncombustible framing materials (e.g., metal or metal-clad wood).
• Replace old hollow core doors with solid core or steel doors.
• Consider using tempered glass for sliding glass doors or glass panel inserts, which is stronger than annealed glass and will provide additional protection during a wildfire.¹¹⁰
• Fabricate covers (for example, ½” plywood covers), cut to size and marked so that it can easily be installed over a door prior to evacuation. Shutters or other roll-down devices could also be installed.¹¹¹
• During a wildfire event, make sure all doors remain closed to avoid ember intrusion into structures.
• Manage vegetation and other types of items that could catch fire in the areas nearest to doors. This includes maintaining the surrounding vegetation and using noncombustible mulch and ignition resistant materials for yard and garden structures near doors.¹¹²
• The recommended glazing products for homes in wildfire zones are laminated glass, tempered glass, glass with a low-emissivity, fiberglass-reinforced translucent glazing, and insulated glazing units (IGUs). Glazing products that are not recommended are annealed glass, ceramic glass, and plastic glazing.¹¹³

---

110 Division of Agriculture and Natural Resources, University of California, "Windows," Homeowner's Wildfire Mitigation Guide, accessed April 2022, https://ucanr.edu/sites/Wildfire/Side_of_House/Windows/.

111 Division of Agriculture and Natural Resources, University of California.

112 Fire Safe Marin, "Fire - Resistant Windows," Fire Safe Marin, accessed April 2022, https://firesafemar in.org/harden - your - home/fire - resistant - windows/.

113 FEMA, "Technical Fact Sheet No. 10: Windows and Skylights," in Home Builder's Guide to Construction in Wildfire Zones (Washington, D.C.: Government Printing Office, 2008).

NFPA Assessing Structure Ignition Potential from Wildfire

---

114 Division of Agriculture and Natural Resources, University of California, "Windows," Homeowner's Wildfire Mitigation Guide, accessed April 2022, https://ucanr.edu/sites/Wildfire/Side_of_House/Windows/.

•  https://ucanr.edu/sites/fire/Prepare/Building/Windows/
• Fire Safe Marin - Fire Resistant Windows: https://firesafemarin.org/harden-your-home/fire-resistant-windows/
• IBHS - Creating a Fire Adapted Home: http://www.projectwildfire.org/wp-content/uploads/2016/02/IBHS-Guide-to-Creating-Fire-Adapted-Home.pdf
• Fire Safe San Mateo County - Windows: https://firesafesanmateo.org/preparedness/home-hardening/windows

• Weather Strip:
• Sectional Garage Doors: closes, wheels at the edge of each panel roll inside a vertical track on each side of the door opening. ¹¹⁶

---

115 Merriam - Webster, "Weather Strip," Merriam - Webster.com, accessed 2022, https://www.merriam - webster.com/dictionary/weather%20strip.

116 Debbie Dey, "What are the 6 Types of Garage Doors? (And How to Choose One)," puls, accessed July 2022, https://blog.puls.com/what-are-the-6-types-of-garage-doors.

• ASTM E119 Standard Test Methods for Fire Tests of Building Construction and Materials: https://www.astm.org/e0119-20.html

• International Wildland Urban Interface (IWUI) Code: No explicit requirements
• California Building Code (CBC): No explicit requirements
• NFPA 1144 Standard for Reducing Structure Ignition Hazards from Wildland Fire: No explicit requirements

Codes and standards will vary depending on location and adoption in individual jurisdictions.

• Check local, county, and state amendments for additional wildfire codes and standards.
• Check local general plan, multi - hazard mitigation plan, or zoning documents for any additional requirements.
• IRC (if applicable – check for wildfire amendments).

---

117 Debbie Dey, "What are the 6 Types of Garage Doors? (And How to Choose One)," puls, accessed July 2022, https://blog.puls.com/what-are-the-6-types-of-garage-doors.

• Install ignition resistant or noncombustible framing materials (e.g., metal or metal - clad wood).
• Ensure any weather stripping is in good condition and provides a tight seal.
• .¹¹⁸

---

118 Fire Safe Marin, "Fire - Resistant Windows," Fire Safe Marin, accessed April 2022, https://firesafemarin.org/harden - your - home/fire - resistant - windows/.

NFPA Assessing Structure Ignition Potential from Wildfire

• Field and/or lab research is limited on the performance of garage doors during wildfire events.
• Fire testing of sealants around garage doors for radiant heat, direct flame impingement and/or ember exposure is currently unavailable.
• .

• University of California Fire in California, Windows: https://ucanr.edu/sites/fire/Prepare/Building/Windows/
• Fire Safe Marin, Fire Resistant Windows: https://firesafemarin.org/harden-your-home/fire-resistant-windows/
• IBHS, Creating a Fire Adapted Home: http://www.projectwildfire.org/wp-content/uploads/2016/02/IBHS-Guide-to-Creating-Fire-Adapted-Home.pdf
• Fire Safe San Mateo County, Windows: https://firesafesanmateo.org/preparedness/home-hardening/windows

Windows can compromise a home’s ability to survive a wildfire when precautions are not taken to prevent them from being an entry point for embers and/or flames. During a wildfire, a window can be compromised due to an extended radiant heat exposure from surrounding vegetation or to flames when embers have ignited vegetative debris near the window. The glass is the most vulnerable part of the window. If the glass in a window breaks during a wildfire, embers and flame can easily enter a structure. Similarly, combustible window frames can ignite or fail, leading to ember intrusion and ultimately ignition of other material inside of the structure. Therefore, windows must be able to resist the following exposures:¹¹⁹

• A radiant exposure severe enough to break the glass in a window or ignite the exterior siding directly below it. Burning vegetation in close proximity to a window could also ignite combustible siding.¹²⁰
• A flame contact exposure could result from embers igniting vegetation and/or exterior cladding that burns up to the window(s). ¹²¹
• Glass breakage occurs because of thermally induced strains caused by temperature differences between the shielded glass near the frame edge and the exposed glass away from the frame. This non - uniform heating causes the glass to expand at different rates.¹²² The presence of a rigid frame also restrains the glass from expanding, leading to cracking of the glass. If the temperature differences are large enough, the cracks grow potentially leading to failure of glass and fall out.

---

119 Division of Agriculture and Natural Resources, University of California, "Windows," Homeowner's Wildfire Mitigation Guide, accessed April 2022, https://ucanr.edu/sites/Wildfire/Side_of_House/Windows/.

120 Division of Agriculture and Natural Resources, University of California.

121 Division of Agriculture and Natural Resources, University of California.

122 Division of Agriculture and Natural Resources, University of California.

• Double-Pane Window: Window provided with two panes of glass to slow the heat transfer across the window. This also provides a security factor should one pane break during a fire event.

• Be constructed of multi-pane glazing with a tempered pane¹²³
• Be constructed of glass block units¹²⁴
• Have a fire - resistance rating of not less than 20 minutes when tested in accordance with NFPA 257
• Have a fire - resistance rated glazing with performance tested in accordance with ASTM E119

---

123 Rodolfo Uribe, Factors Leading to Structure Loss on the Thomas Fire (San Luis Obispo: California Polytechnic Institute, 2021) , https://digitalcommons.calpoly.edu/theses/2341/.

124 Uribe.

• ASTM E119 Standard Test Methods for Fire Tests of Building Construction and Materials:
  https://www.astm.org/e0119-20.html
• ASTM E 2112 Standard Practice for Installation of Exterior Windows, Doors, Skylights:
  https://www.astm.org/e2112-19c.html
• UL 263 Fire Tests of Building Construction Materials:
  https://global.ihs.com/doc_detail.cfm?document_name=UL%20263&item_s_key=00097028

• 2018 International Wildland Urban Interface Code (IWUIC) : Chapter 5, Sections 504.8, 505.8 Exterior Glazing
• California Building Code (CBC):
• Chapter 24 Glass and Glazing,
• Chapter 7A of the California Building Code and California Residential Code: CBC 708A/CRC R337.8
• NFPA 257 Standard on Fire Test for Window and Glass Block Assemblies
• NFPA 252 Standard Method of Fire Tests of Door Assemblies
• NFPA 80 Standard for Fire Doors and Other Opening Protectives

Codes and standards will vary depending on location and adoption in individual jurisdictions.

• Check local, county, and state amendments for additional wildfire codes and standards.
• Check Local general plan, multi-hazard mitigation plan, or zoning documents for any additional requirements.
• IRC (if applicable – check for wildfire amendments).

---

125 Fire Safe Marin, "Fire - Resistant Windows," Fire Safe Marin, accessed April 2022, https://firesafemarin.org/harden - your - home/fire - resistant - windows/.

126 Fire Safe Marin.

127 FEMA, "Technical Fact Sheet No. 10: Windows and Skylights," in Home Builder's Guide to Construction in Wildfire Zones (Washington, D.C.: Government Printing Office, 2008).

128 FEMA.

129 FEMA.

130 FEMA.

131 FEMA.

132 FEMA.

133 FEMA.

134 FEMA.

• Refer to Typical Design, Vulnerability and Mitigation Considerations for additional mitigation options.
• Install ignition resistant or noncombustible framing materials (e.g., metal or metal-clad wood).
• Replace old single-pane windows with dual-pane windows.
• Close all window during a wildfire or before leaving during evacuation.
• Consider using tempered glass, which is stronger than annealed glass and will provide additional protection during a wildfire.¹³⁵
• Consider using insect screens. Screens fabricated from noncombustible materials are preferred.
• Fabricate covers (for example, 1/2" plywood covers), cut to size and marked so that it can easily be installed over a window prior to evacuation. Shutters or other roll-down devices could also be installed.¹³⁶ 
• Install noncombustible window screens of at least 1/16”.
• Manage vegetation and other types of items that could catch fire in the areas nearest to windows. This includes maintaining the surrounding vegetation and using noncombustible mulch and ignition resistant materials for yard and garden structures near windows.¹³⁷ 
• Exterior shutters can provide protection in a wildfire. Solid metal shutters that are unlikely to ignite or melt are therefor e recommended over wooden or plastic shutters. For enhanced protection, an insulated metal shutter can be designed and fabricated. If the building is located in a windborne debris region within a hurricane - prone region, the shutter should meet the windborne debris criteria in ASCE 7 - 05 . Note that temporary shutters are only effective if the homeowner has sufficient time to put the shutters into place.¹³⁸
• The recommended glazing products for homes in wildfire zones are laminated glass, tempered glass, glass with a low-emissivity, fiberglass-reinforced translucent glazing, and insulated glazing units (IGUs). Glazing products that are not recommended are annealed glass, ceramic glass, and plastic glazing.¹³⁹

---

135 Division of Agriculture and Natural Resources, University of California, "Windows," Homeowner's Wildfire Mitigation Guide, accessed April 2022, https://ucanr.edu/sites/Wildfire/Side_of _House/Windows/.

136 Division of Agriculture and Natural Resources, University of California.

137 Insurance Institute for Business &amp; Home Safety, "Protect Your Property from Wildfire: California Edition," Northstar Community Services District, accessed April 2 022, https://www.northstarcsd.org/media/Fire/Prevention/Defensible%20Space/WF_California_Northstar.pdf.

138 FEMA, "Technical Fact Sheet No. 10: Windows and Skylights," in Home Builder's Guide to Construction in Wildfire Zones (Washington, D.C.: Government Printing Office, 2008).

139 FEMA.

NFPA Assessing Structure Ignition Potential from Wildfire

• Some gels and foams marketed for structure protection during wildfires indicate they will also protect windows, but verification of these claims by an independent source is not currently available.¹⁴⁰ 

---

140 Division of Agriculture and Natural Resources, University of California, "Windows," Homeowner's Wildfire Mitigation Guide, accessed April 2022,https://ucanr.edu/sites/Wildfire/Side_of_House/Windows/.
141 University of California, Agriculture and Natural Resources , "Windows , " Mariposa County , accessed April 2022 , https://cemaripo sa.ucanr.edu/Fire_Information/Wildfire_Preparation/Preparing_Your_Home_599/Windows/.

• University of California Fire in California, Windows: https://ucanr.edu/sites/fire/Prepare/Building/Windows/
• Fire Safe Marin, Fire Resistant Windows: https://firesafemarin.org/harden-your-home/fire-resistant-windows/
• IBHS, Creating a Fire Adapted Home: http://www.projectwildfire.org/wp-content/uploads/2016/02/IBHS-Guide-to-Creating-Fire-Adapted-Home.pdf
• Fire Safe San Mateo County, Windows: https://firesafesanmateo.org/preparedness/home-hardening/windows
• FEMA – Home Builder’s Guide to Construction in Wildfire Zones – Technical Fact Sheet No. 10: https://defensiblespace.org/wp-content/uploads/2021/01/FEMA_2008_P-737-Home-Builders-Guide-to-Construction-in-Wildfire-Zones.pdf

In general, joints create gaps in the continuity of a fire rated or ignition resistant wall assembly, presenting a potential avenue for embers, hot gases, or flames to breach the wall assembly and into the building interior. Joints can also create places f or the accumulation of combustible debris that can be easily ignited by embers, hot gases, or direct flaming. Embers can oftentimes accumulate at windowsills, door framing and at wall - to - wall intersections, creating a concentrated source of heat that may compromise the integrity of the wall, window, or door. In addition, there is currently no fire test for joints in wall assemblies to wildfire exposures – embers, direct flaming, or hot gases. This can create a short - circuit of a fire resistance rated (e.g., 1 - hour, 2 - hour), ignition resistant , or fire resistive exterior wall

• Joint: The opening in or between adjacent assemblies that is created due to building tolerances or is designed to allow independent movement of the building in any plane caused by thermal, seismic, wind or any other loading.¹⁴²
• Fire-Resistant Joint System: An assemblage of specific materials or products that are designed, tested and fire-resistance rated in accordance with a standard fire test to resist for a prescribed period of time the passage of fire through joints made in or between fire-resistance-rated assemblies.¹⁴³ (Note: There are currently no fire-resistant joint system tests for wildfire exposures.)
• Flashing: A thin metal that is installed at joints to protect against intrusion of unwanted elements such as water and embers.
• Expansion Joint: A physical discontinuity that spans the entire breadth of an element in a building, creating two separate sections of the element instead of one bigger one. They are designed and configured to allow the different building sections to move independently of each other, so the structures don’t become overstressed and crack or break¹⁴⁴ under various loads (e.g., thermal expansion/contraction, seismic movement).

---

142 International Code Council, Inc., International Building Code (Country Club Hills, IL: International Code Council, Inc., 2018).

143 International Code Council, Inc.

144 Roof Online Staff, "Roof Expansion Joints Explained," Roof Help, October 8, 2022, https://roofonline.com/roof - components/expansion - joints/.

Currently, there is no fire test standard to evaluate ember intrusion, direct flame impingement , or thermal transmission of heat via convection or radiation from wildfires for joints in wall assemblies. Fire rated joints are necessary in order to maintain a wall assembly’s fire rating, integrity , and continuity to wildfire exposure. While a variety of fire tests exist for joints in interior building fire exposures (e.g., ASTM E1966 or UL 2079), none are explicitly designed for the fire conditions presented by wildfires. A range of joint systems (e.g., static joints, movement joints) and joint conditions (e.g., window - to - wall, door - to - wall, wall - to - wall, expansion joints) for exterior wildfire exposures are still needed.

Currently, there is no fire test standard to evaluate ember intrusion, direct flame impingement, or thermal transmission of heat via convection or radiation from wildfires for joint systems (wall joints or otherwise).

• International Wildland Urban Interface (IWUI) Code: No explicit requirements
• California Building Code (CBC): No explicit requirements
• NFPA 1144 Standard for Reducing Structure Ignition Hazards from Wildland Fire: No explicit requirements

Codes and standards will vary depending on location and adoption in individual jurisdictions.

• Check local, county, and state amendments for additional wildfire codes and standards.
• Local general plan, multi-hazard mitigation plan, or zoning documents for any additional requirements.
• IRC (if applicable – check for wildfire amendments).

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145 University of California, Agriculture and Natural Resources, "Roof," Fire in California, accessed May 2022, https://uc anr.edu/sites/fire/Prepare/Building/Roof/.

146 FEMA, "Technical Fact Sheet No. 7: Exterior Walls," in Home Builder's Guide to Construction in Wildfire Zones (Washington, D. C.: Government Printing Office, 2008).

• Refer to Typical Design, Vulnerability and Mitigation Considerations for additional mitigation options.
• All combustible materials should be cleared away from doors both on the interior and exterior sides.
• Ensure there is no vegetation or other combustible materials within 5' of windows and glass doors.
• Clear debris from windowsills, wall-to-wall joints and other surfaces where combustible debris collects near wall joints.
• Seal any gaps at wall joints with firestopping and through-penetration systems as needed to maintain the continuity of the exterior wall assembly.
• Repair damage to foundation wall and cladding to reduce the accumulation of embers and fire brands between damaged materials.

NFPA Assessing Structure Ignition Potential from Wildfire

• Currently, there is no fire test standard to evaluate ember intrusion, direct flame impingement or thermal transmission of heat via convection or radiation from wildfires for joint systems.
• It is unclear how susceptible various wall joints or functional gaps around doors are to wildfire exposures

• FEMA – Home Builder’s Guide to Construction in Wildfire Zones: https://www.fema.gov/sites/default/files/2020-08/fema_p_737_0.pdf
• IBHS – Home Preparedness Guide: https://disastersafety.org/wp-content/uploads/2021/08/WFR-Home-Preparedness-Guide.pdf

Architectural embellishments are decorative in nature and not part of the engineered structure. In this sense these attachments do not add to the structure stability but can significantly compromise the structure by providing locations for ember accumulation or transfer of heat through connecting methods to the structure itself. In some cases, the architectural features can present a fuel load itself, if comprised of combustible, unprotected materials. Some balconies on buildings are solely architectural embellishments, where they are purely for aesthetics and not load - bearing. (Note: Refer to balcony section for additional information where decorative balconies are provided.)

• Architectural Embellishment: A decorative detail or feature added to the exterior of the building to enhance the aesthetics.
• Ornament: An applied embellishment in various styles that is a distinguishing characteristic of buildings. Ornamentation often occurs on entablatures, columns, and the tops of buildings and around entryways and windows, especially in the form of moldings.¹⁴⁷

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147 Editors of Encyclopedia Britannica, "Ornamentation," Britannica, accessed April 2022, https://www.britannica.com/topic/ornamentation-architecture.

There are currently no fire classifications or ratings for architectural embellishments and ornaments.

Currently, there is no fire test standard to evaluate the performance of architectural embellishments du ring wildfires. There are also no fire tests to assess the contribution of these architectural features to the vulnerability of buildings in wildfire incidents (e.g., if they significantly contribute to building ignition, heat transfer to interior spaces, lead to ignition of exterior walls).

• International Wildland Urban Interface (IWUI) Code: No explicit requirements
• California Building Code (CBC), 2019: Section 710A, Accessory structures
• NFPA 1144 Standard for Reducing Structure Ignition Hazards from Wildland Fire: No explicit requirements

Codes and standards will vary depending on location and adoption in individual jurisdictions.

• Check local, county, and state amendments for additional wildfire codes and standards.
• Local general plan, multi-hazard mitigation plan, or zoning documents for any additional requirements.
• IRC (if applicable – check for wildfire amendments).

• Remove combustibles (e.g., furniture, firewood, BBQs, mulch, non-fire adapted vegetation, ornamental landscaping) from areas under decorative overhangs that could create a localized fire that ignites these decorative features.
• Seal any openings that may allow passage of embers or flame into structure with firestopping and fire caulking.
• Upgrade attachment points of artwork and other decorative panels such that they fixed further away from the exterior wall where embers could collect.
• Consider replacing combustible architectural embellishments with noncombustible materials.

NFPA Assessing Structure Ignition Potential from Wildfire

• There is no fire test standard to evaluate the performance of architectural embellishments during wildfires.
• There are no fire tests to assess the contribution of these architectural features to the vulnerability of buildings in wildfire incidents (e.g., if they significantly contribute to building ignition, heat transfer to interior spaces, lead to ignition of exterior walls)
• There are limited codes and standards on the resiliency of these elements to wildfires.

n/a

Balconies and decks can pose a significant hazard in the event of a wildfire. One of the main concerns associated with balconies and decks is the large surface area they present for collecting embers, leading to ignition of materials located on the balcony/deck or the balcony/deck itself. Similar to eave overhangs, unique fire induced flows can lead to the accumulation of embers and hot gases in the underside of balconies or elevated decks, potentially leading to ignition of the balcony/deck particularly where the framing elements are exposed and of combustible construction. In addition, most homeowners tend to store various types of combustible fuel loads below and on balconies/decks, such as combustible furniture, BBQs, wood piles etc. Balconies/decks can also introduce additional interfaces with the main structure, presenting numerous joints and potential gaps in the continuity of the exterior wall envelope, which may or may not be fire rated.

For decks and other similar features (e.g., stairs) that are at or near grade, these building components are also susceptible to direct flame impingement from surface fuels and other proximate vegetation. Many existing commercial or residential decks are constructed with less expensive, combustible materials such as untreated woods, plastics, and wood-plastic composite products, which are vulnerable to ember and heat exposure in a wildfire event. Decks are often built at the top of a slope, likely in direct line of a wildfire¹⁰⁰. Therefore, building and deck orientation must be considered. Embers and firebrands can easily become trapped under and around the deck/patio. Material selection, orientation, design, storage and landscaping practices around the deck are all critical to reducing the risk of ignition of the deck and the home.

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148 FEMA, "Technical Fact Sheet No. 13: Decks and Other Attached Structures," in Home Builder's Guide to Construction in Wildfire Zones (Washington , D.C.: Government Printing Office, 2008).

• Balcony: A platform enclosed by a wall or balustrade on the outside of a building, with access from an upper-floor window or door.¹⁴⁹
• Deck: A flat surface capable of supporting weight, similar to a floor, but typically constructed outdoors, often elevated from the ground, and usually connected to a building.¹⁵⁰
• Flashing: A sheet of thin, impervious material used to prevent water penetration or seepage into a building and to direct the flow of moisture in walls.¹⁵¹

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149 Education4Each, "Balcony," education4each.com, accessed April 2022, https://education4each.com/balcony/.

150 Prince George's County, MD, "Decks," Prince George's County, MD, accessed April 2022, https://www.prince georgescountymd.gov/2662/Decks.

151 Designing Buildings Ltd, "Flashing in Building Construction," Designing Buildings: The Construction Wiki, May 17, 2022, https ://www.designingbuildings.co.uk/wiki/Flashing_in_building_construction.

As occupiable floor areas, balconies are oftentimes treated as floor assemblies by code.

As such, balconies and their supporting construction can achieve fire-resistance ratings (e.g., 1-hour, 2-hour).

There are currently no fire-rated floor assemblies to a wildfire exposure. That said, most exterior floor spaces requiring a fire-rating are based on interior building fire test standards. The fire resistance of floor assemblies to interior fire exposures is defined by American Society of Testing and Materials ASTM E119 or UL 263 Standard Test Methods for Fire Tests of Building Construction and Materials. This test standard is applicable to assemblies of masonry units and to composite assemblies of structural materials for buildings, including loadbearing walls and partitions, columns, girders, beams, slabs, and composite slab and beam assemblies for floors and roofs.¹⁵²

The standard is used to measure and describe the response of materials, products, or assemblies to heat and flame under controlled conditions, but does not by itself incorporate all factors required for fire hazard or fire risk assessment of the materials, products or assemblies under actual fire conditions. This is due to limitations of the size of the specimens tested, size of the furnace, standard fire exposure, etc. However, the test standard is one of the most widely adopted methods for comparing the performance of building construction materials, elements and assemblies to a standard fire exposure.¹⁵³

The test method includes measurements of exposed and unexposed surface temp erature, as well as the ability of an element or assembly to maintain structural stability, integrity and insulation when exposed to a severe, standard fire exposure. The standard fire exposure simulates severe interior building fire conditions during flas hover conditions. Depending on how the floor assembly performs against the performance criteria for stability, integrity and insulation, the floor can achieve anywhere from a 1 - hour up to a 4 - hour fire resistance rating.

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152 ASTM International, "ASTM E119 - 22 Standard Test Methods for Fire Tests of Building Construction and Materials," ASTM International, October 10, 2022. https: //www.doi.org/10.1520/E0119-22.

153 ASTM International.

• ASTM E119 Standard Test Methods for Fire Tests of Building Construction and Materials:
  https://www.astm.org/e0119-20.html
• ASTM D2898  Standard Practice for Accelerated Weathering of Fire-Retardant-Treated Wood for Fire Testing:
  https://www.astm.org/d2898-10r17.html
• ASTM D7032  Standard Specification for Establishing Performance Rating for Wood-Plastic Composite and Plastic Lumber Deck Boards, Stair Treads, Guards, and Handrails: https://www.astm.org/d7032-21.html
• ASTM D6662 Standard Specification for Polyolefin-Based Plastic Lumber Decking Boards https://www.astm.org/d6662-17.html
• ASTM E84 Standard Test Method for Surface Burning Characteristics of Building Materials:
  https://www.astm.org/e0084-21a.html
• ASTM E2726 Standard Test Method for Evaluating the Fire Test Response of Deck Structures to Burning Brands
• ASTM E2632 Standard Test Method for Evaluating the Under-Deck Fire Test Response of Deck Materials
• ASTM E2768 Standard Test Method for Extended Duration Surface Burning Characteristics of Building Materials: https://www.astm.org/e2768-11r18.html
• UL 723 Standard for Test for Surface Burning Characteristics of Building Materials https://standardscatalog.ul.com/ProductDetail.aspx?productId=UL723
• SFM Standard 12-7A-4, Decking: A two-part test consisting of a heat release rate (Part A) deck assembly combustion test with an under deck exposure of 80 kW intensity direct flame for a 3-minute duration, and a (Part B) sustained deck assembly combustion test consisting of a deck upper surface burning ember exposure with a 12 mph wind for 40 minutes.
• SFM Standard 12-7A-4A Decking Alternate Method A: A heat release rate deck assembly combustion test with an under-deck exposure of 80 kW intensity direct flame for a 3-minute duration.
• SFM Standard 12-7A-5 Ignition-resistant Material: A generic building material surface burning flame spread test standard consisting of an extended 30-minute ASTM E84 or UL 723 test method as issued for fire-retardant-treated wood.

• International Wildland Urban Interface (IWUI) Code, 2021 –
• 504.6 & 505.6: Underfloor enclosure;
• 504.7 & 505.7: Appendages and Projections;
• California Building Code (CBC), 2019 –  
• Section 707A.7: Floor projection;
• 707A.8: Underfloor protection; 709A: Decking
• 709A: Decking
• NFPA 1144 Standard for Reducing Structure Ignition Hazards from Wildland Fire, 2018:
• Section 5.4: Overhanging Projections
•  A structural assessment rating form and guide included in Appendix A provides an assessment of siding and deck building construction material.

Codes and standards will vary depending on location and adoption in individual jurisdictions

• Check local, county, and state amendments for additional wildfire codes and standards.
• Local general plan, multi-hazard mitigation plan, or zoning documents for any additional requirements.
• IRC (if applicable – check for wildfire amendments).

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154 FEMA, "Technical Fact Sheet No. 13: Decks and Other Attached Structures," in Home Builder's Guide to Construction in Wildfire Zones (Washington, D.C.: Government Printing Office, 2008).

155 FEMA.

• For exposed undersides of balconies and decks of combustible construction, consider enclosing to grade (with solid fire-resistant materials or 1/16” screening) or replacing structural supports and exposed underside of the balcony or deck with (1) noncombustible material, (2) ignition-resistant material, (3) one layer of 5/8" Type X gypsum sheathing applied behind an exterior covering on the underside of the balcony or deck (4) the exterior portion of a 1-hour fire resistive exterior wall assembly applied to the underside of the balcony or deck. Note: Heavy timber supporting elements do not require protection.¹⁵⁶
• Provide a fire resistive coating over wood surfaces and elements to enhance fire resistive characteristics, apply at cycles recommended by manufacturer. Alternatively replace with fire-retardant treated wood.
• Create an ember-resistant zone (0-5ft) around and under the deck, and make sure that all combustible items are removed from underneath and around the deck (this is especially important to maintain where a deck overhangs a slope). Lay weed barrier or gravel under and around the deck to prevent vegetation from growing under or near the deck.
• Replace combustible furniture with noncombustible materials, where kept on or under balconies or decks.
• At the connection point of decks and balconies to the main structure, consider installing metal flashing on ledger boards that are attached without gaps to create a barrier to embers and prevent water from penetrating. Seal any gaps and joints with appropriate. ¹⁵⁷
• Change any electrical fixture or box cover that is plastic with metal fixtures/covers.
• Repair damage to deck/ patio construction before they lose their fire-resistance, and to reduce the accumulation of embers and firebrands between damaged deck boards.
• Deck clearance: Keep the deck clear of debris, vegetation, combustible materials, (e.g., seat cushions, straw mats, rugs, pine needles, firewood, etc.). Remove needles and leaf litter from deck board gaps and the deck-to-house connection where embers may easily accumulate.
• Alternative Retrofit examples:
  • If a deck is made of combustible decking materials, replace the board closest to the home with a noncombustible material.¹⁵⁸
  • Replace dimensional timber railings with railings constructed of fire-resistant materials such as metal, tempered glass, cables, or 3" nominal thickness fire-retardant-treated wood.¹⁵⁹
  • When the deck, balcony, stairs, or ramp can accommodate or be reinforced to accommodate additional load, install brick or concrete pavers and a suitable drainage mat over the existing decking.¹⁶⁰
  • Attach a corrosion-resistant metal flashing strip or noncombustible siding between the top of the deck, extending up the exterior combustible siding (minimum of 6 inches).¹⁶¹

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156 International Code Council, Inc., "2022 California Building Code," ICC Digital Codes, July 2022, https://codes.iccsafe.org/content/CABC2022P1/copyright.

157 FEMA, "Technical Fact Sheet No. 13: Decks and Other Attached Structures," in Home Builder's Guide to Construction in Wildfire Zones (Washington, D.C.: Government Printing Office, 2008).

158 FEMA.

159 FEMA.

160 FEMA.

161 FEMA.

NFPA Assessing Structure Ignition Potential from Wildfire

• Wildfire building codes and standards do not provide a clear definition or distinction for balconies and decks. It is unclear which provisions are applicable.
• There is no prioritized list of retrofit ideas which include the most effective methods to improve the fire resistance of existing decking.

• FEMA – Home Builder’s Guide to Construction in Wildfire Zones: https://defensiblespace.org/wp-content/uploads/2021/01/FEMA_2008_P-737-Home-Builders-Guide-to-Construction-in-Wildfire-Zones.pdf
• IBHS:
  • https://disastersafety.org/wp-content/uploads/2021/08/WFR-Home-Preparedness-Guide.pdf
  • https://disastersafety.org/wp-content/uploads/2019/03/Wildfire-Retrofit-Guide-California_IBHS.pdf
• UC Extension, Agriculture, Biotechnology & Natural Resources
  • http://www.readyforwildfire.org/wp-content/uploads/Wildfire_Home_Retrfit_Guide-1.26.21.pdf
  • https://ucanr.edu/sites/fire/Prepare/Building/Deck/
• Fine Home Building – https://www.finehomebuilding.com/membership/pdf/9390/021s41055.pdf

The intrusion of embers through crawl space or basement vents is a major vulnerability that can lead to structure ignition du ring wildfires. The main concern with crawl space/basement vents is that they can provide several openings where windborne embers, convective heat, and radiant heat from wildfires (particularly surface fuels) can be blown in or pulled into the structure leading to ignition of interior building contents and other building components. Both vent inlets and outlets are sources of vulnerab ility, as fire behavior can create reverse flows due to over - pressures further driving embers and hot gases into a building interior. Debris can also accumulate at crawl space/basement v ent openings, providing a source of combustible fuels for ignition

• Crawl Space: An unoccupied, unfinished, narrow space within a building, between the ground and the first (or ground) floor. The crawl space is so named because there is typically only enough room to crawl rather than stand (about 3 ’ to 5 ’ ).¹⁶²
• Crawl Space Vents: Active or passive openings or vents through foundation walls or exterior walls providing aeration of the under - floor space between the bottom of the floor joists and the earth under a building (except space occupied by a basement).¹⁶³
• Ember: Small burning or glowing pieces of vegetation or other cellulosic - based material.
• Vent: A device or assembly placed in an exterior opening of a building that allows for aeration.

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162 Wikimedia Foundation, Inc., “Crawl Space,” Wikipedia, accessed December 28, 2022, https://en.wikipedia.org/wiki/Crawl_space.

163 International Code Council, Inc., International Residential Code (Country Club Hills, IL: International Code Council, Inc., 2018).

The ember and direct flame impinge ment resistance of vents mounted on vertical walls is defined by ASTM E2886 Standard Test Method for Evaluating the Ability of Exterior Vents to Resist the Entry of Embers and Direct Flame Impingement. This test standard prescribes two individual methods t o evaluate the ability of the vent opening to resist embers and flame. The ability of such vents to completely exclude entry of flames or embers is not evaluated. Acceptance criteria are not provided in this standard.¹⁶⁴ However, performance criteria are specified in the California Building Code (CBC) Section 706A.2 and NFPA 1144 Section 5.3.3.

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164 ASTM International, "ASTM E2886/E2886M-20 Standard Test Method for Evaluating the Ability of Exterior Vents to Resist the Entry of Embers and Direct Flame Impingement," ASTM International, July 24, 2020, https://www.doi.org/10.1520/E2886_E2886M-20.

165 National Fire Protection Association, NFPA 1144 Reducing Structure Ignition Hazards from Wildland Fire (Quincy MA: NFPA, 2017).

166 National Fire Protection Association.

167 ASTM International, "ASTM E2912-17 Standard Test Method for Fire Test of Non-Mechanical Fire Dampers Used in Vented Construction."

• ASTM E2886/E2886M - 14 Standard Test Method for Evaluating the ability of Exterior Vents to Resist the Entry of Embers and Direct Flame Impingement: https://www.astm.org/e2886_e2886m-20.html
• ASTM E2912 Standard Test Method for Fire Test of Non - Mechanical Fire Dampers Used in Vented Construction: https://www.techstreet.com/standards/astm-e2886-e2886m-20?product_id=2198686

• International Wildland Urban Interface (IWUI) Code, 2021 : 504.10 Vents
• California Building Code (CBC): 706A Vents
• NFPA 1144 Standard for Reducing Structure Ignition Hazards from Wildland Fire: 5.3.3 Vent Assemblies

Codes and standards will vary depending on location and adoption in individual jurisdictions.

• Check local, county, and state amendments for additional wildfire codes and standards.
• Check local general plan, multi - hazard mitigation plan, or zoning documents for any additional requirements.
• IRC (if applicable – check for wildfire amendments).

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168 International Code Council, Inc., International Residential Code (Country Club Hills, IL: International Code Council, Inc., 2018).

• Common 1/4" screens are ineffective and should be replaced.
• Install vents that are listed to ASTM E2886.
• Cover existing vents with wire mesh screen having openings with a maximum of 1/8”. Preferably 1/16”. Research has shown that 1/8” mesh screening can still lead to embers with sufficient energy to ignite fine fuels in the attics.
• Replace screens that have painted over or detached from the substrate.
• Vent and covering materials used shall be noncombustible, and corrosion resistant. Do not use fiberglass or plastic mesh because they can melt and burn.¹⁶⁹
• Use fire - rated caulking around penetrations to seal openings.
• Inspect and maintain vegetation in the vicinity of crawl space vents.¹⁷⁰ Remove combustible fuel loads including vegetation within 0 - 5' of building perimeter.¹⁷¹
• Clean vents on a regular basis to minimize buildup of debris in the mesh.¹⁷²
• Remove debris that accumulates near crawlspace or basement vents.¹⁷³
• Consider making vent covers that can be installed prior to the approach of a wildfire (and removed after the wildfire has passed).¹⁷⁴
• Refer to Typical Design, Vulnerability and Mitigation Considerations for additional mitigation options.

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169 Fire Safe Marin, "Fire-Resistant Vents," Fire Safe Marin, accessed April 2022, https://firesafemarin.org/harden-your-home/fire-resistant-vents/.

170 Division of Agriculture and Natural Resources, University of California, "Vents," Homeowner's Wildfire Mitigation Guide, accessed April 2022, https://ucanr.edu/sites/Wildfire/Vents/.

171 National Fire Protection Association, "NFPA Wildfire Research Fact Sheet: Exterior Sprinkler Systems," NFPA.org, accessed April 2022, https://www.nfpa.org/-/media/Files/Firewise/Fact-sheets/FirewiseFactSheetsExteriorSprinklers.ashx.

172 Fire Safe Marin, "Fire-Resistant Vents."

173 Fire Safe Marin.

174 Fire Safe Marin.

NFPA Certified Wildfire Mitigation Specialist (CWMS) Certification

• Fire testing does not account for weathering of materials prior to fire exposure or the impact of general wildfire environmental conditions (e.g., high winds, flying debris, impact from objects).
• ASTM E2886 does not evaluate the ability of vents to completely exclude entry of flames or embers.¹⁷⁵
• In most instances, it’s challenging to verify in-the-field if a vent has been fire-tested. (Professional judgement and discussion with the homeowner are required.)
• Air flow calculations may need to be reconsidered or redesign where fire rated v ents are installed in existing structures, to ensure sufficient airflow is still satisfied for non - fire purposes.

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175 ASTM International, "ASTM E2886/E2886M-20 Standard Test Method for Evaluating the Ability of Exterior Vents to Resist the Entry of Embers and Direct Flame Impingement," ASTM International, July 24, 2020, https://www.doi.org.10.1520/E2886_E2886M-20.

• FEMA – Home Builder’s Guide to Construction in Wildfire Zones: https://defensiblespace.org/wp-content/uploads/2021/01/FEMA_2008_P-737-Home-Builders-Guide-to-Construction-in-Wildfire-Zones.pdf

The design of the well creates deep corners with the exterior wall which encourages dry leaves, pine needles, and other combustible litter or debris to gather. Debris ignition would present a source of flame exposure to the structure, particularly at the window opening it surrounds. The configuration of these wells creates a hazardous condition where those combustible materials that have collected will be directly adjacent to the window and frame which already experience their own vulnerabilities.

• Window / lightwell: : U-shaped, ribbed metal or plastic product designed to fit around basement windows, providing a space between the window and the surrounding earth to allow light into sub-grade structures. More notably, a window well can prevent water damage to a basement while also providing a route from an emergency escape and rescue opening with a finished sill height below the adjacent ground level during an emergency.^176,177
• Window /lightwell covers: A physical barrier between the well and the ground elements to prevent debris build-up in the well. The covering can be constructed of mesh, plastic bubble covers, grill-type, etc. Covers are also provided to prevent injuries from falls and to discourage children and animals from entering the wells and becoming injured or trapped.¹⁷⁸
• Defensible space: The selection, location, grouping, and maintenance of vegetation on the property in such a manner that the opportunity for a fire to burn directly to a structure is minimized.¹⁷⁹

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176 Square One, "Window Wells," Square One, September 12, 2022, https://www.squareone.ca/resource-centres/getting-to-know-your-home/window-wells.

177 International Code Council, Inc., International Residential Code (Country Club Hills, IL: International Code Council, Inc., 2018.

178 Square One, "Window Wells."

179 University of California, Agriculture and Natural Resources, "Defensible Space," Fire in California, accessed April 2022, https://ucanr.edu/sites/fire/Prepare/Landscaping/DefensibleSpace/.

No standard or tested assemblies exist for lightwells installed in the Wildland Urban Interface.

None

There are currently no requirements in adopted codes and standards that address window/lightwells.

Codes and standards will vary depending on location and adoption in individual jurisdictions.

• Check local, county, and state amendments for additional wildfire codes and standards
• Check local general plan, multi-hazard mitigation plan, or zoning documents for any additional requirements.
• IRC (if applicable – check for wildfire amendments)

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180 International Code Council, Inc., International Residential Code (Country Club Hills, IL: International Code Council, Inc., 2018).

• Replace combustible lightwells and associated combustible covers (e.g., polycarbonate plastic or fiber glass) with noncombustible materials.
• Maintain areas in and around lightwells to be clear of debris, and combustible materials.
• Do not store combustible items, such as firewood, in a lightwell.
• Provide a lightwell cover, constructed of noncombustible material to limit build-up of debris in the lightwell.
• Where a mesh cover is provided, clean vents on a regular basis to minimize buildup of debris in the mesh.
• Provide a minimum of 6” noncombustible vertical separation between the bottom of the lightwell and the siding/exterior wall.
• Refer to Typical Design, Vulnerability and Mitigation Considerations for additional mitigation options.

• NFPA Certified Wildfire Mitigation Specialist (CWMS) Certification
• NFPA Assessing Structure Ignition Potential from Wildfire

• No codes or standards related to the appropriate design, installation, and material selection of lightwells in the Wildland Urban Interface.
• Wildfire home hardening guidance does not mention material selection or design of lightwells.
• Manufacturers do not have specific guidance for homeowners installing lightwells on their property in the Wildland Urban Interface.
• No research has been conducted related to lightwell performance and impact in a wildfire.

• NFPA 1144 Standard for Reducing Structure Ignition Hazards from Wildland Fire: 6.4. Exterior vertical walls
• FEMA – Home Builder’s Guide to Construction in Wildfire Zones: https://defensiblespace.org/wp-content/uploads/2021/01/FEMA_2008_P-737-Home-Builders-Guide-to-Construction-in-Wildfire-Zones.pdf

The foundation of a building is often the first area to meet a spreading wildfire, as it the closest part of the structure to the ground. Debris can easily accumulate at the base of the foundation, which can be ignited by embers and surface fuels fires. These embers can ignite combustible foundation, siding, and penetrate crawlspace vents and breach basement windows.¹⁸¹ Where the underside of the first floor is supported by pile or piers of combustible construction (i.e., timber), direct flaming impingement and/or embers could ignite the structure and lead to structural instability and damage.

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181 FEMA, "Technical Fact Sheet No. 12: Foundations," in Home Builder's Guide to Construction in Wildfire Zones (Washington, D.C.: Government Printing Office, 2008).

• Basement foundation: : Full basement foundations cover the building’s perimeter and are typically constructed of poured concreted walls and footing approximately 6 – 8’ below ground level. Full basements can either be finished or unfinished. Finished basements are insulated and installed with drywall and flooring, providing living and storage space. Unfinished basements are usually not insulated, and their walls and floors are left bare.¹⁸²
• Crawl space foundation: Crawl space foundations are elevated several feet off footings, leaving a small, protected space (usually 3’ or 4’) between the ground and base of the building. The foundation walls are built partially underground and shorter than basement foundation walls.¹⁸³ They are shallower than full basements.
• Open foundations (e.g., pier & pilings, post, caissons, or stilts foundation): A foundation that includes openings beneath the structure, such as an open crawl space or similar open areas below the ground floor construction. They typically stand several feet above the ground.
• Shallow foundation: An enlarged base (in the plan area) for the support of the columns or walls of the superstructure in order to spread the stresses of the columns or walls onto a wider founding stratum without failure.¹⁸⁴ Shallow foundations can further be categorized as raft, mat, or slab-on-grade foundations and are useful in controlling differential settlement over low-bearing capacity soil.
• Wall footing: A wall footing is a continuous strip of concrete that serves to spread the weight of a load-bearing wall across an area of soil.¹⁸⁵

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182 MT Copeland Technologies, Inc., "3 Types of Basement Foundations to Know," MT Copeland, December 17, 2021, https://mtcopeland.com/blog/3-types-of-basement-foundations-to-know/.

183 MT Copeland Technologies, Inc.

184 Yung Ming Cheng, Chi Wai Law, and Leilei Liu, Analysis, Design and Construction of Foundations (Boca Raton: CRC Press, 2021).

185 Edward Allen and Joseph Iano, Fundamentals of Building Construction: Materials and Methods. (Hoboken NJ: John Wiley & Sons, 2009).

The fire resistance rating of foundation structural elements is determined by the construction type of the building.

The fire resistance of structural elements and systems is defined by ASTM E119 or UL 263 Standard Test Methods for Fire Tests of Building Construction and Materials.  This test standard is applicable to assemblies of masonry units and to composite assemblies of structural materials for buildings, including loadbearing walls and partitions, columns, girders, beams, slabs, and composite slab and beam assemblies for floors and roofs (inclusive of foundations).¹⁸⁶

The standard is used to measure and describe the response of materials, products, or assemblies to heat and flame under controlled conditions, but does not by itself incorporate all factors required for fire hazard or fire risk assessment of the materials, products, or assemblies under actual fire conditions.¹⁸⁷ This is due to limitations of the size of the specimens tested, size of the furnace, standard fire exposure, etc. However, the test standard is one of the most widely adopted methods for comparing the performance of building construction materials, elements, and assemblies to a standard fire exposure.

The test method includes measurements of exposed and unexposed surface temperature, as well as the ability of an element or assembly to maintain structural stability, integrity, and insulation when exposed to a severe, standard fire exposure. The standard fire exposure simulates severe interior building fire conditions during flashover conditions. Depending on how the floor assembly performs against the performance criteria for stability, integrity, and insulation, the structural element can achieve anywhere from a 1-hour up to a 4-hour fire resistance rating.

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186 ASTM International, "ASTM E119-22 Standard Test Methods for Fire Tests of Building Construction and Materials," ASTM International, October 10, 2022. https://www.doi.org/10.1520/E0119-22.

187 ASTM International.

188 ASTM International.

• ASTM E119 Standard Test Methods for Fire Tests of Building Construction and Materials: https://www.astm.org/e0119-20.html
• UL 263 Fire Tests of Building Construction and Materials: https://global.ihs.com/doc_detail.cfm?document_name=UL%20263&item_s_key=00097028

• International Wildland Urban Interface (IWUI) Code, 2021: No explicit requirements.
• California Building Code (CBC), 2019:
  • Section 707A.3.2 Extent of exterior wall covering shall extend from the top of the foundation to the roof.
  • Section 602 Construction Classification.
  • Section 703 Fire Resistance Ratings and Fire Tests.
• NFPA 1144 Standard for Reducing Structure Ignition Hazards from Wildland Fire: 5.6.4 Exterior vertical walls.

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189 Austin Werner, "Slab vs. Crawl Space Foundations: Pros, Cons, & Repair Methods," June 10, 2022, https://www.therealsealllc.com/blog/slab-vs-crawl-space-foundations-pros-cons-and-repair-methods-2/.

190 Lee Wallender, "Crawl Space Ventilation and Vent Basics," the spruce, February 23, 2022, https://www.thespruce.com/crawlspace-ventilation-requirements-1821946.

191 FEMA, "Technical Fact Sheet No. 12: Foundations," in Home Builder's Guide to Construction in Wildfire Zones (Washington, D.C.: Government Printing Office, 2008).

192 Lee Wallender, "House Foundation Types, Uses, and Pros and Cons."

193 FEMA, "Technical Fact Sheet No. 12: Foundations."

194 FEMA.

195 FEMA.

• Refer to Typical Design, Vulnerability and Mitigation Considerations for additional mitigation options.
• Where possible, provide at least 6” vertical clearance of noncombustible materials along the exterior wall from the ground to the siding.
• Maintain a 5’ ember resistant zone around the building by clearing debris, dead vegetation, and any combustible items within this zone.
• Repair damage to foundation and fill in any gaps at joints with firestopping to minimize embers intrusion.
• Where an existing building has an open foundation:
  • Where possible, open foundations should be enclosed to remove the opportunity for debris, vegetation, and combustible items from accumulating under the building.
  • Remove any combustible items under the structure, and keep it clear of debris, vegetation, and storage.
  • Protect the underside of the floor structure and supporting structure with fire-rated, noncombustible, or fire-resistant materials.
  • Provide noncombustible skirting to help reduce the accumulation of debris under the building (1/16” wire mesh).

None

• Minimal guidance related to the design, material selection and maintenance of foundation walls in the Wildland Urban Interface.
• Minimal guidance related to mitigation options for open foundation configurations in the Wildland Urban Interface.

• FEMA – Home Builder’s Guide to Construction in Wildfire Zones: https://defensiblespace.org/wp-content/uploads/2021/01/FEMA_2008_P-737-Home-Builders-Guide-to-Construction-in-Wildfire-Zones.pdf
  • Fact Sheet #7, Exterior Walls, for guidance on walls and wall coverings.
  • Fact Sheet #8, Vents, for guidance on crawlspace vents.
  • Fact Sheet #10, Windows and Skylights, for guidance on windows.
• UC Extension, Agriculture, Biotechnology & Natural Resources:
  • http://www.readyforwildfire.org/wp-content/uploads/Wildfire_Home_Retrfit_Guide-1.26.21.pdf

Fences can become hazardous in the event of a wildfire, particularly if they connect directly to a structure. Typical wooden post-and-board fences particularly when old and weather beaten can provide a “wick” leading directly to the structure. The bottom of fences collect debris that, when combined with combustible fencing, can become a fuel source to carry fire directly to the structure and ignite the building through radiant heat, convective heat, or direct flame contact.¹⁹⁶ Since fences are often just below the eaves of a house, there is the potential to carry the fire up to the eaves and thus to the roof. Additionally, fences can also create access problems for fire crews trying to enter a yard during an emergency.

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196 FEMA, "Technical Fact Sheet No. 12: Foundations," in Home Builder's Guide to Construction in Wildfire Zones (Washington, D.C.: Government Printing Office, 2008).

• Non-combustible: In building construction material, non-combustible means one of the following:
  • Material of which no part will ignite and burn when subjected to fire. Any material passing ASTM E136 will be considered non-combustible¹⁹⁷
  • Material having a structural base of noncombustible material as defined above, with a surfacing material not over 1/8-inch thick which has a flame-spread index of 50 or less¹⁹⁸

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197 Stephen L. Quarles, "Fire Ratings for Construction Materials," Surviving Wildfire, August 27, 2019, https://surviving-wildfire.extension.org/fire-ratings-for-construction-materials/.

198 Quarles.

None

There are no test standards for fencing assemblies.

• International Wildland Urban Interface (IWUI) Code, 2021: No explicit requirements
• California Building Code (CBC), 2019: No explicit requirements
• NFPA 1144 Standard for Reducing Structure Ignition Hazards from Wildland Fire: Section 5.6.3 Appendages and projections

Codes and standards will vary depending on location and adoption in individual jurisdictions.

• Check local, county, and state amendments for additional wildfire codes and standards.
• Check local general plan, multi-hazard mitigation plan, or zoning documents for any additional requirements.
• IRC (if applicable – check for wildfire amendments).

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198 FEMA, "Technical Fact Sheet No. 14: Landscape Fences and Walls," in Home Builder's Guide to Construction in Wildfire Zones (Washington, D.C.: Government Printing Office, 2008.

200 FEMA.

201 FEMA.

202 FEMA.

• If practical, replace combustible fences using noncombustible (i.e., masonry, metal) or ignition-resistant materials (i.e., fire retardant treated lumber for exterior exposure or thicker dimension lumber).
• If existing wood fences cannot be fully replaced, replace the portion of the fence within 5 ft from the building with noncombustible materials (e.g., a metal gate that is attached to the fence on one side and to the exterior siding on the other side).
• Remove combustible materials such as trash bins, firewood, mulch, or other combustible materials against the fence. Ensure that all combustible components are at least 5’ from the building to prevent heat and flames from igniting the building.²⁰³
• Remove combustible mulch near fences and replace with noncombustible mulch, gravel, or other similar material.
• Remove debris and dead vegetation at the bottom of fences.
• Remove plants where the fence is being used as a trellis as it creates and traps ignitable vegetative debris.
• Ensure the fence or gate is not an access problem for fire crews.
• Maintain physical condition of fence and replace any damaged, deteriorated components.

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203 FEMA, "Technical Fact Sheet No. 14: Landscape Fences and Walls," in Home Builder's Guide to Construction in Wildfire Zones (Washington, D.C.: Government Printing Office, 2008.

NFPA Certified Wildfire Mitigation Specialist (CWMS) Certification

• Fire testing and standards do not exist for fencing installed in the Wildland Urban Interface.
• Design and installation guidelines do not exist for fencing in the Wildland Urban Interface.

• FEMA – Home Builder’s Guide to Construction in Wildfire Zones, Technical Fact Sheet No. 14: https://defensiblespace.org/wp-content/uploads/2021/01/FEMA_2008_P-737-Home-Builders-Guide-to-Construction-in-Wildfire-Zones.pdf
• NIST:
  • Knocking Down Fences for Fire Research: https://www.nist.gov/blogs/taking-measure/knocking-down-fences-fire-research
  • Structure Vulnerability to Firebrands from Fences and Mulch: https://www.nist.gov/publications/structure-vulnerability-firebrands-fences-and-mulch
  • Effects of Wind Speed and Angle on Fire Spread along Privacy Fences: https://www.nist.gov/publications/effects-wind-speed-and-angle-fire-spread-along-privacy-fences

Attachments directly protruding from the façade of the building, such as window awnings, shades, patio covers, and canopies can pose a significant hazard in the event of a wildfire. These components are susceptible to both direct flame exposure and firebrand accumulation, and if combustible, can become a fuel source to carry fire directly to the structure. Awnings are oftentimes comprised of fabric or other such lightweight material that can become readily ignited providing a direct flame impingement on the structure.  Material selection, design, and debris clearance of these are attachments are critical to mitigation the impact of wildfire.

• Awnings: A sheet of canvas or other material stretched on a frame and used to keep the sun or rain off a storefront, window, doorway, or deck.²⁰⁴
• Canopy: Any fixed structure, framework, appendage, appurtenance, shelter, or shade, without enclosing walls, covered with canvas, cloth, galvanized iron, aluminum, approved slow-burning plastic or similar material erected, constructed, or maintained at or over the entrance way to a building or place of business within a building, and extending over any public street or sidewalk supported by an individual framework from the ground except such projections from buildings.²⁰⁵

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204 Oxford University Press, "Awnings," Oxford Languages, accessed April 2022, https://languages.oup.com/google-dictionary-en/.

205 International Code Council, Inc., "2022 California Building Code," ICC Digital Codes, July 2022, https://codes.iccsafe.org/content/CABC2022P1/copyright.

• The International Building Code (IBC) provides several requirements for the fire-resistant design and construction awnings and canopies in Section 3105.
• The frames supporting awnings can be rated to achieve a 1-hour fire resistance rating per ASTM E119.
• The materials of awnings and canopies can be classified based on their performance to NFPA 701, or their flame spread index per ASTM E84 or UL 723 or performance to NFPA 286.

Note: There is no wildfire specific fire classification or rating.

• ASTM E119 Standard Test Methods for Fire Tests of Building Construction and Materials: https://www.astm.org/e0119-20.html
• UL 263 Fire Tests of Building Construction and Materials: https://global.ihs.com/doc_detail.cfm?document_name=UL%20263&item_s_key=00097028
• ASTM E84 Standard Test Methods for Surface Burning Characteristics of Building Materials
• UL 723 Test for Surface Burning Characteristics of Building Materials
• NFPA 268 Standard Test Method for Determining Ignitability of Exterior Wall Assemblies Using a Radiant Heat Energy Source
• NFPA 701 Standard Methods of Fire Tests for Flame Propagation of Textiles and Films:
• Currently, there are no wildfire specific fire test standards to assess the performance of awnings, covers, or shades to embers.

• International Building Code (IBC), 2021: Section 3105 Awnings and canopies
• International Wildland Urban Interface (IWUI) Code, 2021: No explicit requirements
• California Building Code (CBC), 2019: No explicit WUI requirements. Section 3105 Awnings and Canopies
• NFPA 1144 Standard for Reducing Structure Ignition Hazards from Wildland Fire: No explicit requirements

• Attached canopies/awnings can either be attached to a building or can also be mounted on the ground by the support of posts. Retractable canopies are popular for their space-saving solution.
• Freestanding, portable, umbrella shades may also be used.
• Material selection: Awnings or canopies are typically constructed of fabric, wood, polycarbonate, or metal.
• Combustible materials: Fabrics, including canvas, vinyl and acrylic are typically the cheaper option, with easier installation. In addition, wood or polycarbonate materials may be used. These materials are combustible and should be avoided in the wildland urban interface.
• Noncombustible or ignition resistant materials: Metals including aluminum, steel and copper provide a more durable option. Due to the weight of the components, it is typically more costly, and requires professional installation. Metal coverings are suggested in the wildland urban interface.

• Ensure awnings and canopy materials consist of Class A flame spread per ASTM E84 or satisfy other alternative specified in Section 3105 of the IBC.
• Keep all awnings and canopies clear of debris and vegetation. Remove needles and leaf litter accumulation on or around the covering or retractable mechanism.
• Repair damage to awnings and canopies to reduce the accumulation of embers and firebrands between damaged materials.
• Where any gaps or holes are presented at the attachment points to the structure, provide with appropriate firestopping and fire caulking.

NFPA Certified Wildfire Mitigation Specialist (CWMS) Certification

• Currently, there are no wildfire specific fire test standards to assess the performance of awnings, covers or shades to embers.
• The contribution of awnings and canopies to the vulnerability of homes to wildfire threats is uncertain.

None