FPEeXTRA Issue 70

When the Rubber (Standard) Meets the Road (Field): A Deep Dive into Firestopping Special Inspections

By: Jeffrey M. Amato, PE

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Understanding and interpreting building codes that address all aspects of construction can be a daunting task in and of itself. The fact that these codes reference hundreds of inspection and testing standards for various aspects of design and construction makes this effort more challenging. These standards allow consistent inspection, testing, and evaluation of materials, systems, and assemblies to provide specific fire performance aspects, such as an hourly fire-resistance rating or flame spread index. The construction industry creates standards with the best of intentions; to provide insight into the minute details of design and construction and inspection and testing. Unfortunately, there are times when codes and standards fall short of bridging the gap between the theoretical and the practical.

Numerous structural failures, many due to fires, occurred during the 1970s and 1980s, which resulted in personal tragedies and property damage. Authorities determined that most failures were due to a lack of adequate construction assessments, and model codes were encouraged to require certain inspections. The is the model building code for most jurisdictions, including New York City. According to International Building Code (IBC) [1], quality assurance measures that verify the proper assembly of structural components and the suitability of the installed materials are intended to ensure a building that, once constructed, complies with the minimum structural and fire-resistance code requirements as well as the approved design. As adopted by the local jurisdiction, the building code identifies areas of building construction that require special inspections and minimum qualifications to perform inspections.

Passive fire protection plays a vital, albeit sometimes overlooked, role in fire protection along with active protection such as fire detection and suppression. A fire-resistance-rated assembly is only as strong as its weakest link. Often its weakest link is its penetrations and joints. Firestopping is not just the mundane task of filling an opening in an assembly, commonly referred to by contractors as “red it up.” There are various materials to choose from in numerous listed systems. Firestopping materials started primarily as a caulk but have evolved to include sprays, blocks, pillows, composite sheets, pre-formed devices, sleeves, putties, foams, etc. Each firestop manufacturer has its products listed as part of a tested assembly.

The use of an “approved” product does not necessarily ensure the minimum fire performance is achieved. Technicians must install the proper products in accordance with the approved design listing. This ensures it will achieve the desired fire performance, especially with systems or assemblies incorporating multiple components.

Firestop Ratings

To help prevent the spread of fire or smoke within a building, certain walls, floors, and joint assemblies are required to meet a specified fire-resistance rating – the period during which a building component has been tested to confine a fire and/or continue to perform a structural function. Firestop systems may be required to achieve a rating and duration depending upon the project specifications for a given assembly.

There are various firestop ratings, including flame (F), temperature (T), leakage (L), and water (W). The F-Rating indicates the duration a firestop system will successfully prevent the ­passage of fire. The T-Rating is a measure of the thermal conductivity of a firestop system. The L Rating is used as an indication of smoke resistance, and the W Rating is an indication of short-term water resistance. To achieve a rating, the firestop assembly must remain in place for the duration of the test. Further, it must withstand the hose stream such that there is no water projection beyond the unexposed side.

To achieve an F-Rating, no flame may pass through the firestop assembly or any unexposed materials. An assembly with a T-Rating must meet the criteria for an F Rating, in addition to a temperature limit of 325⁰ F above the ambient on the unexposed side of the assembly. An L-Rating is a measurement of the air or smoke the firestop system allows through the assembly at ambient temperature and 400⁰ F. To qualify as a Class 1 W-Rated system, the firestop assembly must withstand a 3-ft head of water for 72 hours with no leakage.

Firestop through-penetration assemblies are evaluated based on ASTM E814, Standard Test Method for Fire Tests of Penetration Firestop Systems. [2] This test standard is relative to [3]. UL has a similar standard, UL 1479, entitled Fire Tests of Through-Penetration Firestops. Unlike ASTM E814, UL 1479 [4] includes two optional test protocols ­for evaluating air leakage (L-Rating) and water resistance (W-Rating). The IBC refers to both UL 1479 and ASTM E814.

In addition to an hourly rating achieved by a fire test and hose stream test, firestop joint systems are typically rated for a nominal joint width and the movement capabilities as a percentage of compression or extension from this resting position. Firestop joint systems are subjected to cyclical movement prior to the fire test to evaluate the ability of the system to accommodate movement due to thermal expansion, wind, or seismic conditions. Class I Movement Capabilities (Thermal) criteria consist of 1 cycle per minute for 500 cycles. The Class II Movement Capabilities (Windsway) criteria consist of 10 cycles per minute for 500 cycles. Class III Movement Capabilities (Seismic) criteria consist of 30 cycles per minute for 100 cycles.

Firestop joint assemblies are evaluated based on [5] and UL 2079 Standard for Safety Tests for Fire Resistance of Building Joint Systems. [6] Under the specified test conditions, these test methods evaluate the ability of a fire-resistive joint system to undergo movement without reducing the fire rating of the adjacent fire separating elements and the duration for which test specimens will contain a fire and retain their integrity during a predetermined test exposure. The IBC references both ASTM E1966 and UL 2079.

Firestop Inspection Requirements

Local jurisdictions adopt or amend model code provisions that specify required special inspections. For example, formerly known as controlled inspections in New York City, IBC Chapter 17 identifies special inspections required for various building components, such as structural steel, concrete, masonry, seismic bracing, smoke control systems, fire-resistant structural coatings, fire-resistant penetrations, and joints, etc. Special inspections are intended to ensure the quality, workmanship, and requirements for materials of construction are up to par.

IBC 2018 Section 1705.17 requires special inspections of firestopping in high-rise buildings or in buildings assigned to Risk Category III or IV as defined in IBC Section 1604.5. IBC Sections 714 and 715 contain provisions that govern the materials and methods of construction to protect penetrations and joints, respectively. The IBC does not include criteria for special inspections of firestopping. Instead, it refers to The ASTM International (ASTM) standards for special inspection criteria. ASTM E2174 is the Standard Practice for On-Site Inspection of Installed Firestops (through penetrations), [7] and ASTM E2393 is the Standard Practice for On-Site Inspection of Installed Fire-Resistive Joint Systems and Perimeter Fire Barriers. [8]

For through-penetration firestop systems, the inspection frequency will depend on the method of inspection and the scope of the project, per ASTM E2174. During installation, the inspector must be on-site and randomly witness a minimum of 10% of each type of fire stop installed. The other option is to conduct a post-installation inspection, which will require destructive verification and repair of the fire stop. A minimum of 2%, but not less than one, of each type of firestop, shall be destructively inspected per floor or area. A floor is divided into 10,000 ft2 areas when it exceeds that square footage.  

Any through-penetration firestop that does not comply with the approved project submittals will require remediation and subsequent reinspection of that installation plus one additional inspection of the number specified of that type of firestop. If non-compliance occurs on 10% or more of a type of firestop installation, then inspecting this type of firestop shall cease. The installer must review their work, repair, or replace those types of fire stops within the area before the special inspector resuming their inspections.

Similarly, for control joint firestop systems, inspection frequency will depend on the method of inspection and the scope of the project. During installation, the inspector must be on site and randomly witness a minimum of 5% of total linear feet of each type of fire-resistive joint system being installed. Alternatively, the inspector must conduct a post-installation inspection, which will consist of a minimum of one destructive verification (and subsequent repair) per type of firestop joint system per 500 linear feet.

Any fire-resistive joint system that does not comply with the approved project submittals will require repair or replacement and reinspection of that fire-resistive joint system. Subsequently, an additional inspection of the percentage or number specified for that type of fire-resistive joint system is required. If non-compliance occurs on 10% or more of the quantity of like fire-resistive joint systems, an inspection of those fire-resistive joint systems shall cease. As with through penetrations, the installer must review their work and repair or replace those types of fire resistive joint systems within the area before the special inspector resuming their inspections.

Firestop Inspector and Installer Training and Certifications

The IBC does not specify the minimum experience required to perform special inspections but instead defers to the Authority Having Jurisdiction (AHJ). IBC 2018 Section 1704.2.1 requires approved agencies to demonstrate competence and relevant experience or training of the special inspectors who will perform inspections to the building official. The registered design professional and engineers of record of the project are also permitted to act as an approved agency. Their personnel are permitted to act as special inspectors for the work designed by them, provided they qualify as special inspectors.

Local jurisdictions may have additional requirements. For instance, New York City identifies special inspector qualifications in Appendix A of The New York City Building Code (NYCBC). Most special inspections require the primary inspector or inspection supervisor to have a PE or RA and at least one year of relevant experience. For many special inspections, supplemental inspectors are typically required to have a bachelor’s degree in architecture or engineering and relevant experience or accredited certification. Since there is not a recognized ICC fire-stopping special inspections training or certification, the minimum criteria for a supplemental firestop inspector are either a bachelor’s degree in architecture or engineering and with two years of relevant experience or a technician with three years of relevant experience.

ASTM E2174 and E2393 also contain qualification requirements for firestop inspectors. The inspector shall have a minimum of two years’ experience in construction field inspections and have education, credentials, and experience acceptable to the Authorizing Authority or be a quality assurance agency accredited by the AHJ. Ultimately, an inspector shall be acceptable to the AHJ. The inspector shall also be completely independent of and divested from the installer, contractor, manufacturer, or supplier of any material being inspected.

The Firestop Contractors International Association (FCIA) is a trade association of firestop contractors, inspection agencies, and manufacturers dedicated to the creation, installation, inspection, and maintenance of firestop systems. The International Firestop Council (IFC) is a nonprofit association of manufacturers, distributors, installers, inspectors, and other key stakeholders interested in passive fire protection materials and systems. While both the FCIA and IFC offer educational programs and certifications for installers, inspectors, and AHJs, they are not recognized by the ICC. Additionally, FM Global has developed a standard for the approval of firestop contractors (FM 4991), and Underwriters Laboratories created a UL Qualified Firestop Contractor Program. Similarly, manufacturers produce training and certifications for contractors.

Concerns with Standards

As of now, ASTM E2174 and E2393 do not clearly define what a “type” of firestop system is, which fosters ambiguity when determining the minimum quantity of inspections. The type of firestop could be interpreted as a penetration or joint or by the rated assembly material of the penetration or joint, such as gypsum or masonry. Or perhaps a type of firestop is defined by the firestopping material utilized in the detail. A conservative approach to meeting ASTM testing frequency requirements would be to consider each firestopping detail a type of firestop installation. Breaking out each firestop detail by contractor or installer would further increase the testing frequency. Defining a firestop type can significantly impact the minimum number of required inspections since there is not just a percentage threshold but a minimum of one assessment for each type of system. The definition can also have a considerable impact on determining failed tests, repairs, and reinspection. The percentages within each type of firestop system can vary depending upon how the types are defined.

A formal response was not provided when reaching out to ASTM regarding a type of firestop. This may be due to the significant implications of defining the type of firestop system on special inspections. Rather, ASTM referred us to the Executive Director of FCIA, who serves as the technical contact for ASTM E2174 and E2393. FCIA recommends that the type of firestop be defined by the listed firestop system for each firestop installation contractor. Based on this, each contractor using the same firestop system would be subjected to the 2% destructive testing or 10% witnessed installation. If the type of firestop was only broken out by the listed system and not by the firestop installation contractor, the potential for not inspecting any of certain contractors’ installations exists.

To determine a percentage of a particular type of firestop, it is necessary to know the quantity, or approximate total, of installations. Advancements in AutoCAD and Revit can help identify the total number of penetrations or linear feet of joints. However, it is not feasible to approximate a quantity of a specific type of firestop installations in the design phase. Unique field conditions arise, and new listed firestop systems or engineering judgments must address these conditions. Understandably, a firestop type needs to be clearly defined first. Once established, the total number of each type should be counted during construction or accurately approximated to ensure the minimum required percentage of inspections is achieved. This can be done by assigning a number to each penetration or joint and tracking it on a drawing while verifying testing percentages using software such as Excel.  Some manufacturers have developed firestop installation software programs that can be used to track installation date, material, assembly numbers, photos, etc. However, this software is proprietary and, therefore, cannot be used in conjunction with other manufacturers' materials and listings.

Whether the inspector is witnessing firestopping installations or destructively testing, there is an inherent issue with random sampling. The ASTM standards indicate a minimum percentage of tests for each type of system or tests per linear feet of a joint, however, identifying the testing locations can directly correlate to the results of the test. Whether it be safety concerns, access or other issues, it is human nature to choose locations that are easily accessible. Areas that are easily accessible are more visible and more likely to be firestopped in accordance with approved details as opposed to areas that are more difficult to access. Test locations can vary significantly depending on the inspector as well as test results.

Destructive testing is an acceptable method to perform firestopping special inspections. However, there are components of firestop assemblies that may not be verified with destructive testing. First, the materials utilized may not be easily identified. Without intricate knowledge of firestopping, it can be challenging to decipher similar firestop materials from different manufacturers. Not all firestop caulks or sealants are red; other colors are available. Job site purchase orders or delivery lists can help document, but there is no way of knowing for certain the materials used without witnessing the installation.

Many firestopping joints and thru penetration assemblies utilize mineral wool in conjunction with a firestopping product. Generally, a minimum 4 pounds per cubic foot density mineral wool is required in firestopping applications. Once mineral wool is compressed and installed, it can be difficult to differentiate between the type of mineral wool and its density. A minimum compression of 33% or 50% is typically required when used in firestopping joint assemblies. The exact compression of mineral wool can only be confirmed by witnessing the installation. At best, destructive testing can allow for an approximate percentage of compression by an inspector with a good understanding of firestopping installations.

Additionally, there is no way of confirming the expiration date of the product. Manufacturers typically print the materials’ production date or expiration date on the product, either as a date or a coded batch number. Again, job site purchase orders or deliver lists may include this information but it cannot be known for certain without witnessing the actual material being installed. Lastly, manufacturer requirements for material storage and application, such as temperature, cannot be verified with destructive testing. Experience and materials knowledge can help minimize the impact of these unknowns but  cannot eliminate them without direct control over the entire firestop system installation process. These are items to consider when deciding on the firestop inspection and testing method.


Codes and standards are regularly updated to address advancements in technology or necessary modifications. There is a need for clarifications to ASTM E2174 and E2393 to address the issues identified above. With clearly defined inspection and testing requirements and less room for interpretation, an inspector has the ammunition needed when encountering opposition from an installer, general contractor, or owner. When the quantity of each type of firestop system is counted or accurately approximated, the minimum required percentage of inspections can be verified.

Firestop inspections and percentages should then be tracked using programs such as Excel and shared with the general contractor, installer, and Authority Having Jurisdiction (AHJ) to provide transparency in the inspection process. Some firestop manufacturers also offer proprietary software compatible with Revit and AutoCAD to identify conflicts between fire-rated barriers and penetrating items while providing recommendations for firestop products and UL systems or automated applications for engineering judgments. This software integrates firestop information and objects in your BIM software to assist with renovations and maintenance throughout the life of the property. While this may not be useful in buildings utilizing material and details from multiple manufacturers, it is something engineers, architects, or owners should consider during design.

Destructive testing is also not intended to be the sole method of inspection employed at the conclusion of construction. For example, penetrations and joints are often hidden within walls or above ceilings, which are only accessible during construction. There is a clear need for hold points during construction, particularly prior to closing walls or ceilings, which should be mutually agreed upon, as outlined in the applicable ASTM standards. This challenge requires coordination between the general contractor, installers, inspectors, and/or AHJ at the project's onset. And while it is not necessary for the inspector to meet the minimum required percentage of inspections solely by witnessing installations, it is recommended that at least one of each type of installation by each installer is witnessed in addition to any destructive testing. This allows the inspector to verify the material and observe the contractors’ installation method, particularly with some more intricate details – something to consider for the next edition of ASTM E2174 and E2393 Standards.

As projects and field conditions become more complex, firestopping materials and installation details become more intricate and elaborate. New firestopping products and listed assemblies are developed regularly. Attention to detail by the trades is critical to ensuring the system is installed correctly and will provide the required level of performance. Although manufacturers have thousands of tested and listed firestop assemblies, they do not always account for unique field conditions. Subsequently, engineering judgments are often required where no listed firestopping details exist. It is not uncommon for projects to have hundreds, if not thousands, of different firestop assemblies and engineering judgments. The ICC has recognized the need for special inspections of firestopping on specific projects. As the complexity of the industry increases, there is a growing need for a recognized firestopping inspector training and certification.

JEFFREY M. AMATO, PE is with Jensen Hughes



International Code Council, International Building Code (IBC), Washington, DC, 2021.


ASTM, ASTM E814, Standard Test Method for Fire Tests of Penetration Firestop Systems., West Conshohocken, PA, 2017.


ASTM, ASTM E119, Standard Test Methods for Fire Tests of Building Construction and Materials, West Conshohocken, PA, 2020.


UL, UL 1479 Standard for Fire Tests of Through-Penetration Firestops, Northbrook, IL, 2015.


ASTM, ASTM E1966 Standard Test Method for Fire-Resistive Joint Systems, West Conshohocken, PA, 2019.


UL, UL 2079 Standard for Safety Tests for Fire Resistance of Building Joint Systems, Northbrook, IL, 2020.


ASTM, ASTM E2174, Standard Practice for On-Site Inspection of Installed Firestops, West Conshohocken, PA, 2020.


ASTM, ASTM E2393, Standard Practice for On-Site Inspection of Installed Fire-Resistive Joint Systems and Perimeter Fire Barriers, West Conshohocken, PA, 2020.