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Is there an NFPA requirement that mandates sprinkler protection of a generator room that is in a separate technical service building?
If so, what is the hazard classification for the generator room? Is there an equivalent of a 6.5 L/min.m² foam-water system under NFPA-specific requirements? Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe
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For a SCIF, where should the ground wire be bonded?
We have a project where #4 AWG ground wire is to be bonded to sprinkler (water) piping of the penetration, but does that need to occur on the secure side or the unsecured side of a SCIF? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe We are having a debate between our office and the field.
What numbers are we looking for at the initial forward flow test? The office claims we are looking for the full flow possible from the riser testing arrangement, with a minimum flow rate equal to system demand. Pressure is to be noted but not have a requirement. (The pressure is to be noted for future tests to assess system degradation.) The field claims we are looking for Flow and Pressure of the demand of the sprinkler system. Achieve flow and throttle the discharge to achieve the sprinkler system minimum required pressure for system acceptance. NFPA 13, 2019 Edition, Section 16.14.5.1 and A.16.14.5.1 address this "tests at a minimum flow rate of system demand including hose allowance where applicable" and the appendix "this test is only concerned with testing at the proper flow rate." What are your thoughts? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe We are working on a school project that needed a 1,000 gpm fire pump due to three standpipes.
We initially did a hydrant flow test and had a flow of 425 gpm with a static of 55 psi and residual of 50 psi when we started the design. By the time it went out to bid and the contractor performed their own test, they flowed 354 gpm with a static of 55 and a residual of 50. In the first test, we got 1215 gpm at 20 psi, and 1012 gpm in the second test. They went to turn on the pump and were only getting 368 gpm when the building inlet pressure was at 20 psi. We re-did the flow test to see what changed so drastically and again got a static of 51 with residual of 46 at 375 gpm, which would give us 1004 gpm at 20 psi. We have confirmed the two valves between the street and the building are fully open, and we only have about 50 feet of 8” pipe, so the pressure drop to the building is negligible, especially at 368 gpm. We are at a loss for what could be causing such a difference in pressure to the building and such a low flow. Has anyone ever run into an issue like this or have any suggestions of what else we could check out? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe We have a project under NFPA 13 with different hazard classifications on the same floor. I’m designing a sprinkler system using the density/area method.
If different areas on the same floor have different occupancies and contents, for example, an OH1 workshop adjacent to an OH2 storage area, can the boundary between the two hazards be based simply on the different use/occupancy and materials present? Or does NFPA 13 require a specific physical separation or fire-rated compartmentation between them in order to use different hazard classifications? How stringent are these separation requirements? I’m not referring to the Room Design Method. Thanks in advance Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe For those of you who have designed sprinkler systems in old or existing buildings, is there any common rule of thumb for how much the sprinkler count tends to increase because of irregular geometry, existing walls, small rooms, etc.?
In my case, I’m ending up with roughly 20–30% more sprinklers than what I would get from simply dividing the total protected area by the maximum allowable coverage per sprinkler. Does that sound normal for an existing building, or would you consider that excessive? Thanks in advance! Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Regarding NFPA 13 2025, how much polyethylene can you have in a composite container without classifying it as a Group A plastic?
Is it a maximum of 15% of the total weight? This container will store non-combustibles, also on a plastic pallet. I guess if you can classify the container/product as a Class IV, then the classification of the total storage unit will be Cartoned Group A Plastic? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe We installed a basement with pendent sprinklers where the deflector is 1” below the bottom of the wood joist that is 10 inches deep, and the AHJ says that pendent sprinkler heads are not acceptable because heat goes into the bay and delays sprinkler activation.
If the sprinkler is installed 1” below the timber joist, can we consider it as unobstructed construction? If the deflector is installed 11 inches below the roof ceiling and NFPA 13 2019 edition establishes that the distance between the deflector and the ceiling is between 1 and 12 inches for upright and pendent sprinklers, why can we not use pendent sprinklers? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Is my understanding of NFPA 13 (all recent editions) correct in that any ceiling projection down that is over 48" wide must have sprinklers in the lower ceiling/soffit?
The specific scenario: a 5-foot-wide x 25-ft-long gyp board ceiling above a nurses station. The vertical distance between the 2 ceilings is 0'-3". Even with the pendent sprinklers installed in the higher ceiling more than 12" away from the vertical face (which meets other obstruction rules), code tells me sprinklers shall be installed in the 5 ft wide lower ceiling (because it exceeds the 4 ft wide threshold) even though the sprinklers in the higher ceiling are not obstructed. What's your take on this? Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe I've got a question regarding commodity classification in a facility with a sprinkler system designed for Cartoned non-expanded Group A Plastics. The owner wants to store high-weight non-combustibles inside plastic containers, see picture.  The total weight of plastics will not exceed 15% of the total weight.
Is there any chance the storage unit can be treated as a Class 4 commodity and raised to Cartoned Group A Plastics due to the plastic pallet? Or is it necessary to treat the commodity as Exposed Group A Plastics because of the plastic container? Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe I have a project right now that the sprinkler system is being supplied from a tank and pump because the only water available is 25 gpm from a well. The AHJ refuses to allow NFPA 1142 for mobile apparatus to supply fire flow, saying it has to be a "fixed" system. However, he does let me use NFPA 1142 for fire flow rate.
I've added an additional 30,000 gallons to the tank for the 250 gpm fire flow for 2 hours. The AHJ just says to add a connection to the tank so the fire department can pull directly from the tank. The problem I'm running into is how can I be sure the fire department only uses 250 gpm so they don't rob the sprinkler system of any water? I don't have any experience doing this. Any advice or guidance you could provide would be greatly appreciated. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Are sprinklers required in a noncombustible concealed space that contains combustible insulation?
I have a contractor who is trying to use polyurethane spray foam insulation in a noncombustible concealed space above a ceiling. It is an NFPA 13 system and they do not want to sprinkler it. To my knowledge, this spray foam insulation is combustible, and by filling a noncombustible space with it, it will need sprinklers. They are trying to propose intumescent paint, but I don't believe that changes anything for them. Do you all know of any applicable exceptions in this situation or if they don't need sprinklers? I think 9.2.1.13 is the only relevant section from 13, but I am having trouble finding whether this foam exceeds the 1,000BTU per square foot. Thank you. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Is there an easy way for AHJ inspectors to tell the difference between a flexible coupling and a regular coupling?
Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe A project we're looking at has a hydrant network that connects to fire sprinkler systems and hydrants.
What would be the process we'd need to consider for the water supply (fire pump and tank capacities)? How does the greatest sprinkler system demand (possibly with hose allowance) relate to the hydrant demand? Are they additive? Not all buildings could have sprinkler systems in the future, so we're questioning the relationship between sprinklered building system demands and the fire hydrant demand. Thanks for your input. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe When would we be permitted to remove a check valve from a zone control valve?
Like, what are the requirements for needing it one way or another? Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe I have a CMDA wet system, protecting solid-piled Group A Plastics storage. The storage height will be under 12 feet.
Under Section 21.3.3(a), I have been led to the density of 0.60 gpm/sqft in Column C, over a remote area of 2,500 sqft. The 2,500 sqft remote area is what's getting me; it seems cut and dry that in my situation, I am stuck there unless I have a closed storage array. I wanted to verify against other people's interpretations: are there any other ways I am missing that would allow the area to be brought down to 2,000 sqft? I primarily ask because I have seen other systems in the field with areas of 2,000 with densities 0.40, 0.50, 0.60, and I'm unsure of how those systems have gotten to that point with the current codes. For clarity, I am using the 2022 edition of NFPA 13. Any input would be appreciated. Thanks. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Does anyone know any background on the changes to Factory Mutual Data Sheet 8-9, Table 1?
The table used to use a set of formulas for all designs, which would apply a shape factor of 1.2 or 1.4 depending on ceiling construction/slope. It appears to have been updated in July of 2025, with changes being brought in that would allow 12 sprinkler designs to be calculated on the basis of 3 heads on 4 branch lines rather than using the old formulas, which, based on minimum spacing, was not possible for this to occur. There are no comments in the back or anything on FM’s website linked to testing that supports that change; any help would be appreciated. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe In an open, fully sprinklered building, can 50% of the floor area be protected by an automatic wet system, while the remaining 50% is protected by a pre-action system?
There is no wall separating the two areas. Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe For an exposed exterior riser on a wet system, is insulation or mechanical protection required? If so, what type of insulation is best? This is in the Orlando, FL area. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe  There's an existing system in a warehouse with a pump. It's a grid system with an 8" main and 1" 17k ESFR sprinklers.
The main is in a 3' wide inaccessible "hallway". They added office space that will require 15 heads. There's a 4" floater main nearby. Can I connect to the 4" main to feed the added sprinklers? What do I need to consider in doing so? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe I am designing a 25.2k ESFR system in warehouse with purlins set on tapered beams with about 8" wide flanges spaced 20' on center. The last beam in the project area runs 1'-5" off the wall creating a small beam pocket along the length of the wall. Current head spacing is 10'x10', and 18" below ceiling. The sprinklers adjacent to the beam are 3'-10" from centerline, or 5'-3" from the wall. This would require heads within the beam pocket, but the clearance between the wall and beam would obstruct sprinkler discharge. Are there any special exceptions that would allow heads to be omitted from the pocket? Or how could I approach this condition differently to meet code? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe    I have a retrofit application where the sprinkler system needs to be supported from Pyro-Bloc, as that is what is making up the structure of the floor above. NFPA-13 (2022) does not allow the use of toggles (that's what the plumbers and mechanical contractors are using), and the material is too brittle to use drop-ins or expanding anchors.
Any recommendations on how to support the piping? This is specifically 2" and larger. Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Is there any relevant code or standard that restricts the use of flexible sprinkler armovers above hard ceilings?
Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Hello, Following FM DS 2-0 §2.5.4.5.3.3 - if two or more objects are considered a “grouped object”, their overall width is the collective sum of each of the objects that make-up the grouped object; the open spaces between them do not need to be included in the calculation.
Is there an equivalent in NFPA or do I need to take into account the open spaces if my project is in NFPA 13? Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe We have a car dealership with tire storage on rolling racks on fixed rails similar to file storage systems. The tires are on tread and stacked 3 tires high.
Would this be designed as open portable racks or should I be considering a higher density for when the racks are all pushed together? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe |
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