NFPA 13 – Installation of Sprinkler Systems, continues to
evolve with the 2013. During development of the 2013 edition, the
responsible committees addressed 606 proposals and 380 comments. As
usual, the majority of the changes clarify issues, but there have been
some very significant changes. This article will focus primary on
changes that can affect the design of sprinkler systems.
3.3.18 The terms "continuous" and "non-continuous"
have been used for many cycles to describe obstructions and the criteria
to be applied. These terms now have definitions, with "continuous"
being obstructions that affect two or more adjacent sprinklers. Although
typically thought of as a single item, such as a duct, prior editions
did identify in the annex (A.22.214.171.124.1.4) that even if
the obstructions are not connected, but affect adjacent sprinklers, such
as adjacent light fixtures, they are considered "continuous."
7.6 Only listed antifreeze solutions can now be
used, except in listed ESFR sprinklers, where propylene glycol is
permitted. Currently, there are no listed antifreeze products on the
market. Although not an update for NFPA 13, a significant change
occurred in NFPA 25 Inspection, Testing, and Maintenance of Water-based Systems; many existing antifreeze systems will require a risk analysis to remain in service (see http://www.sfpe.org/?page=FPE_ET_Issue_59).
126.96.36.199.1 ESFR sprinklers can be used with solid shelves if in-rack sprinklers are provided.
A.188.8.131.52 Residential sprinklers have always been
allowed to be used in hallways, but restricted to hallways leading only
to dwelling units. Residential sprinklers are now allowed in hallways
leading to residential units and other uses, such as elevator lobbies
and seating areas.
184.108.40.206 There has been past confusion on whether
residential and fast response spray sprinklers could be used within a
single compartment. This was cleaned-up by deleting the legacy reference
to fast response sprinklers.
220.127.116.11.7 The allowance to omit sprinklers when a
space is completely filled with insulation has been revised to permit a 2
inch (50 mm) air gap. This issue was initially added to the 2010
edition but only in 18.104.22.168.17.
22.214.171.124.1 The omission of protection for small
bathrooms, which has been in the standard for all dwelling units for
just over 20 years, is now allowed only for hotels and motels.
126.96.36.199.4 and A.3.3.23 In buildings greater than
two stories, every floor is considered an individual sprinkler system
and must have a floor control valve assembly (with some exceptions).
This assembly is still portrayed only in the Annex and only under the
wet-pipe test connection section.
188.8.131.52.5 Freeze protection can be omitted in areas
that are below 40 ⁰F (4 ⁰C) but should not freeze if a heat loss
calculation by a professional engineer confirms it will not freeze.
184.108.40.206(1) It is explicitly stated that each floor
of a high-rise shall have a waterflow device. Although this has always
been understood, it was not explicitly required by NFPA 13.
220.127.116.11 This will permit shared piping support to
also support systems other than the sprinkler system if the supports are
designed by an engineer.
11.1.7 & 12.1.4 Guidance is provide for High
Volume Low Speed (HVLS) fans. It states that HVLS fans can be used in
buildings protected by either control mode or ESFR systems when the
following is applied:
Fans shall have a maximum diameter of 24 ft (7.3 m).
Fans shall be approximately centered between four adjacent sprinklers.
The minimum vertical clearance to the sprinkler deflector is 3 ft (0.9 m).
Fans shall be interlocked and shut down immediately upon receiving a signal from the alarm system.
18.104.22.168 When using residential sprinklers and
there’s a concealed, combustible space that is unprotected, the 2010
edition required remote area of 3,000 sf (280 m2). This was changed to 8 residential sprinklers so as to mimic the philosophy of doubling the initial size of the remote area.
22.214.171.124 Early Suppression Fast Response (ESFR) and
Control Mode Specific Application (CMSA) sprinklers designed to meet
storage criteria can be used for light or ordinary hazard occupancies.
This was previously permitted only for ordinary hazard occupancies, but
was extended to light hazard in recognition that it makes little sense
to remove these systems when a change of occupancy occurs.
12.8.6 Hose stream and duration has been expanded
and is summarized by sprinkler type and size of remote area for CMDA
sprinklers and by storage height for CMSA and ESFR sprinklers. The
information was consolidated from chapters 12, 14, 15, 16, and 17. It
now better reflects the expected performance of each system. For
instance, previously chapter 16 required a 2 hour duration for both
systems with a remote area of 25 or 30 sprinklers. The new duration for a
30 sprinkler design is now 2.5 hrs. The revision also addresses smaller
areas, such as 1,200 sf (110 m2) for CMDA and fewer than 15
CMSA sprinklers that would apply using the room design method. For
example, a CMSA design with less than 15 sprinkler now has a demand of
250 gpm (960 l) with a 60 minute duration.
126.96.36.199 The protection of exposed, unexpanded Group
A plastics when using spray sprinklers for rack storage up to 25 ft
(7.6 m) was previously permitted only for cartoned commodities. This
restriction did not apply to multiple row racks over 25 ft (7.6 m),
which created confusion. This has been clarified, and new sections were
added providing the needed criteria. It is interesting that the source
this data was derived from was not used to also provide criteria for
exposed expanded Group A plastics. That topic is the subject of a
project within the Fire Protection Research Foundation.
New Chap. 21 Although this section’s title indicates
it applies to alternative sprinkler designs for storage, it’s really
just explicit guidance to the manufacturers and testing laboratories for
developing guidance for specially listed sprinklers. It does, though,
provide useful information for those pursuing an equivalency approach.
Deleted old 188.8.131.52.4.1 When performing hydraulic
calculations for ESFR systems and sprinklers that are located beneath
obstructions, it is no longer required to include up to two additional
184.108.40.206.1.4 & .5 How to hydraulically calculate
small systems when they are less than the minimum required area (such
as preaction systems for computer rooms and dry pipe or antifreeze
system for loading docks) is now addressed. One effectively adds the
additional water flow required for the full area based on the
area/density curves without accounting for any discharge overage nor
hose stream demand and adds it to the point of connection of the most
remote branch line.
Table 220.127.116.11.1 Historically, galvanized steel pipe
for dry pipe systems has been assigned a C-value of 120. The C-value
has been reduced to 100.
18.104.22.168 A combined supply main can now be 4” (100
mm) instead of 6” (150 mm) without adding domestic demand to the
hydraulic calculation. New annex text also confirms that the reason that
the calculation for the larger pipe could ignore the domestic demand is
that it is such a small fraction of the total flow that it doesn’t make
a significant difference in the results. Unfortunately, the annex adds
the ambiguous statement that if the domestic demand is considerable, it
should be added to the calculation for 4" (100 mm) pipe.
22.214.171.124 As a result of a problem with a previously
marketed additive, biocides or corrosion inhibitors must be be
compatible with system components and each other (since they are
typically combined). The whole issue of compatibility is in a state of
flux so there may be additional changes next cycle.
Roland Huggins is with the American Fire Sprinkler Association
2nd Quarter 2012 - Challenges for the Fire Sprinkler Industry -- Kenneth E. Isman, P.E., FSFPE
There are a number of challenges that face people in the fire sprinkler
industry. Many of these challenges are associated with the design of
fire sprinkler systems. However, there are other important challenges
facing the sprinkler industry that are of interest to fire protection
engineers, but could not be classified as "design" issues. This article
outlines challenges in the design, standards, specifications,
maintenance and education arenas and will suggest methods of dealing
with these challenges. READ MORE
2nd Quarter 2012 - NFPA 13 Sprinkler System Design Density Curves – Where Did They Come From? – Garner A. Palenske, P.E.
Density curves first appeared in the 1972 edition of NFPA 13. Garner
Palenske explores the history/rationale behind the formulas and
questions the role they have played in the performance of automatic
sprinklers over time. It has yet to be determined, Palenske concludes,
whether the outstanding performance of sprinklers is a measure of the
adequacy of the area/density curves — or a function of the conservative
nature of sprinkler design as a whole. READ MORE
4th Quarter 2010 - NFPA Issues Alerts on Antifreeze in Residential Sprinkler Systems
The National Fire Protection Association (NFPA) Standards Council has
banned the use of antifreeze solution in residential fire sprinkler
systems for new construction until further action by NFPA consensus
standards committees, and NFPA has issued a follow-up to its July 2010
safety alert to provide updated guidance on the use of antifreeze in
residential fire sprinkler systems. READ MORE
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