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I have a small 580 sq. ft. attic, fed by a dry system, next to a wet system in a retail outlet mall. They are 2 separate systems at the valve assembly. The ceiling for the dry system is 10-ft higher than the wet system.
Would a phantom flow be required here? If so, would it be added at the valve assembly, where they meet? Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe
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We are working on hydraulic calculations for a military hangar, and we are referencing UFC 4-211-01, which calls for the design area to be 0.20 over 5000 sqft.
The hangar is 60 feet tall at its peak. To prevent overflow, we are proposing K5.6 sprinklers for the area. Are K5.6 sprinklers allowed, or does UFC 3-600-01 apply where buildings 45-ft up to 60-ft would require minimum K11.2 sprinklers? The area is overflowing by around 600 gpm. Any advice on this would be helpful. Thanks. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe For forward-flow test connections, is a 4-ft length of pipe inside the heated space required?
NFPA 13 Section 16.10.4.9 would require this of any main drain test connection. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe I am designing a wet pipe fire sprinkler system in a one story Group B occupancy (16-ft high). The building is about 90,000 sqft in area. The building will be fully sprinklered with two zone control valve assemblies.
The fire department is asking to add fire hose valve cabinets as the interior remote areas of the building are more than 130 feet from an exterior door, only citing that its required by IBC 2021. Is this correct? I can't find this requirement. Any help is appreciated. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe For a fire sprinkler system, if you have a loop running around a typical hip-roof attic, and you have a center riser, can you tie it into the loop in two locations?
NFPA 13 doesn't really discuss when a looped system turns into a gridded system. None of the branch lines would be connected, so in my opinion this would be acceptable as long as you meet the discharge time through the remote inspector's test connection. What are your thoughts? Is this a gridded or double-loop systems? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe What is the industry standard or method used for determining the design area size in order to do the hydraulic calculations for Window Sprinklers in terms of the "Adjacent Sprinklers?"
What is the definition of "Adjacent Sprinklers?" Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe When dealing with combustible soffits, what are the conditions where a soffit is big enough to warrant a sprinkler inside?
In our case, we have wood constructed soffits with sprinkler protection below and adjacent to the soffit. Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe For NFPA 13D and a single family home of 1,000 sq ft, what is the optimal k-factor I should be considering?
In this particular project, we don't have a city water supply but we do have a good well. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe How would you recommend protecting a dry room for battery operations, such as battery testing or packaging?
I've been designing these with dry systems but was curious if there are any codes to omit sprinklers, or if anyone uses clean agent systems? If you use something alternatively, why do you go that direction? Moderator's Note: Dry Rooms for batteries have less moisture to avoid corrosion and any chemical reaction for the batteries, which would degrade or reduce performance. Very low moisture is the key for a dry room for batteries. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe I have a sprinkler system in a 75,000 sqft self-storage facility. There are upright sprinklers that are within 2" of a vertical support Unistrut that is used to separate storage spaces. Would this be considered obstructed? What is the code-basis for evaluating a vertical obstruction like this?  If a duct detector is installed, and the mechanical unit has a capacity of less than 2,000 CFM, it is required by code for the duct detector to be connected to the fire alarm panel?
Alternatively, removing the detectors can be considered in this situation. Looking for relevant code and standard basis. We're under the 2021 IFC, 2021 IBC, and 2019 NFPA 72. Thank you! Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Does anybody have experience with locating diesel fire pump fuel tanks in exterior locations where the local ambient temperature can drop to below freezing point?
We have an unavoidable situation where we have to locate the fuel tank outside the pump room and we're hoping not to have to build a heated enclosure. NFPA 20 seems to require a heated enclosure, but FM not so much. I am aware that condensation and fuel deterioration are issues to be dealt with, but I was thinking maybe good quality thermal lag of the tank and feed/return fuel piping may be sufficient with just a roof structure above the fuel tank. What are your thoughts on this? any thanks in advance for your thoughts and advice Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe I have a 35' tall, 79,103 ft², non-combustible building, which is a cooler in a cheese factory. There are two dry systems at the ceiling uses CMDA heads. There are single and double row racks throughout the cooler. The top of the rack 22' top of storage is roughly 26'. The racks have a single layer of 5.6K in-rack sprinklers at the top of the 3rd level. There are 5 levels of storage, which includes the storage setting on top of the racks. The in-rack sprinklers have their own valve at the riser. It is a Class II commodity to 30'. The original design was done years ago and my question is not about the original design. In a single portion of the cooler the owner is taking a 32' section of the existing racking out and installing new racking. The new racking will have the same amount of levels. The bottom 3 levels will have a "cooling cell," one on each level.  I have never heard of a cooling cell on a rack like this. Not sure what the cooling cell is made of. Does a cooling cell increase the protection level from Class II? If so, how much would it change the commodity classification? Does NFPA 13 even address something like this? My assumption is that it will increase the hazard and call for greater level of protection. I have asked for the data sheet for the cooling cell and hope that it gives direction for fire sprinkler coverage. I have attached a picture, which really doesn't give a lot of information. Has anyone run into this before? Thank you! Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe My jurisdiction (I am the AHJ) has had several buildings built with private hydrants supplying the sprinkler system where the main comes into the building, through the RPZ, feeds the sprinkler system/standpipes, and leaves the building and feeds the hydrant(s).  This has always seemed counterintuitive to me, at best. I feel we are "robbing Peter to pay Paul" and have wondered if this arrangement will adequately supply the sprinkler system when we (FD) pull water from the hydrant and pump it back into the FDC.
Per our state law, private hydrants have to be "protected" with a backflow. Is this configuration code compliant, and if not, what is a solution? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe February flew by! Thank you to our Top February Contributors for sharing their expertise.
What specific criteria or code references determine whether a standpipe system is classified as 'separated' rather than 'combined'?
I've seen AHJs state that even though the sprinkler system and the standpipe have separate vertical riser assemblies (control valve, check valve, and supervision), they are fed from the same underground supply (one underground service main) and will still be considered combined. We are working on a project where the AHJ has deemed the building 'partially sprinklered,' requiring the standpipe to be upgraded from 4" to 6" (which would necessitate a pump) but only if it is a combined system. We are looking for clarification or language that supports the distinction between a combined and a separated standpipe system to explore options that may avoid the need for a pump. Additionally, does anyone have thoughts on how we might be able to keep the standpipe at 4" or explore alternative approaches to avoid the pump requirement? Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe I have a dry pipe system in which all test connections have an auxiliary drain except one. That one test connection is the farthest and highest connection, which is then piped down to ground level.
At ground level, the test valve is in a heated room and drains out through the wall. That pipe was filled with water (we don't know why) right to the top of the attic, froze, and burst an elbow. Should this test connection have had an auxiliary drain where the maintenance person checking for condensate and all other test connections likely would have found the filled test connection? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe What is the NFPA Commodity Classification for fruit in plastic bins (for example, cherries, floor-stacked 20 ft. high)? The bins are open on top with holes for drainage and are full of cherries. Do the bins make this Class I a Class IV or Group A plastic instead?  Where are we with the newest clean agents?
I'm running into an interesting scenario where the discussion of the phasing out by 3M of the NOVEC 1230 agent is coming up. I mentioned the competitors to NOVEC 1230 that we're aware of - FK-5-1-12 but they are interested in the next-gen stuff because they don't want to have to redo anything in the near future. Does anyone have any experience with the Fluoro-K or any other newer, lesser used in the past but now have to look into agents? I'm aware of Victaulic's Vortex and CO₂ options, but I'm asking about chemical agents. I look forward to hearing your thoughts and experience. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Can the Quick Response Reduction be used for an above-ceiling calculation for upright heads in an interstitial combustible space?
The combustible roof deck is approximately 13'-0 above the finish floor with a ceiling of 9'-0" below. Assuming the space from the roof deck to the ceiling is 4'-0", this allows a maximum 40% reduction. Or does the calculation need to go to the finished floor for a -3 x 13/2 + 55 for a 35.5% reduction? Which is correct? Is the ceiling, in this case, the floor with only 4'-0" elevation for applying the reduction in the interstitial space, allowing the full 40% reduction? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Is the additional flow described by NFPA 13 27.2.4.2.5 (2019) based on the original minimum design area or the minimum area after modifications?
Say I have a light hazard system with low ceilings. The default minimum area is 1,500 sqft but is reduced to 900 per Section 19.3.3.2.3.1. The calculation on the sprinklers in that 900 sqft area results in 128 gpm total flow (not including the hose allowance). If the additional flow in 27.2.4.2.5 is based on the original 1,500 sqft, then I would need to add 22 gpm of extra flow on the main to get the minimum of 150 gpm running through the main. If the additional flow is based on the 900, then I'm already meeting the requirement of 90 gpm, and I can ignore the additional flow requirement. Similarly, we start at 1500 sqft in a dry attic system, but it needs to be increased to 2,535 sqft minimum due to the dry system and sloped ceiling. Will the minimum flow as per 27.2.4.2.5 be 150 gpm or 254 gpm? This sometimes comes up when using specialty attic sprinklers, which allow for fewer operating sprinklers in the calculation. It comes down to the definition of "minimum design area". Is this the original minimum area, or the modified minimum area? In my designs I've been defaulting to the larger of the two demands to be conservative, but what is the actual intent of this clause? I haven't found any discussions relating to the changing of the minimum design area. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe NFPA 13 is clear about a limit of 10 feet under a building before pipe needs to turn up and into a building (with exceptions for trenching).
What about pipe exposed within a basement? Is there a limit to how far an underground service can run exposed within the building before the system riser? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Has anyone ever used a slosh damper water tank on a roof as part of the fire reserve for the building?
The project is located in NYC. If so, are there any special requirements that need to be adhered to? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe We have an exterior elevator on a two-story building, required by ADA.
The required smoke detector outside the elevator door, installed under the soffit overhang, will quickly fill with dust/dirt. Any thoughts about using a heat detector at this spot that ties into the elevator recall requirement? I am the AHJ. Thank you. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Best Practice suggests that a single FDC supply all fire sprinkler systems in a building, so no matter which FDC the fire department pumps into, all of the systems would be supplemented.
Is there a requirement in any code (except local, village, state amendments, etc.) that requires a fire department connection to connect to all systems? Or, can each system have its own FDC, provided it's properly labeled as to what system(s) are being pressurized by that particular FDC? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe |
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