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Is it mandatory to install a strainer at the suction pipe of a fire pump?
Or are there specific criteria in NFPA for horizontal centrifugal pumps to determine under what circumstances a strainer may not be required at the suction pipe? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe
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Diesel fuel tank - how low should I allow the diesel fuel level to drop before I fill the tank with diesel fuel for a fire pump?
Should I add diesel fuel when the fuel gauge drops to 3/4 full, 2/3 full, or 1/2 full? Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe I'm designing a 13R system. The building currently has a 3/4" domestic water service. The building is in a location that would make installing a new (larger) service a logistical nightmare.
Is it allowed to connect the 3/4" existing supply to a water storage tank (sized per system/domestic demand) in the basement, then build a residential riser from that? If this is allowed, do I only take my calculations back to the storage tank? Do you foresee other problems with this? Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Pipe Stands and Bracing I have a 12" fire pump that feeds the "U Turn" in the attached picture. Insurance company is adamant more bracing is needed. My question is what size pipe stands are required for 12", and do I need more lateral bracing for the surge if the fire pump runs? All I can find in NFPA 13 only addresses up to 10". Any thoughts or ideas on codes I may be missing would be appreciated. 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 We have a 119-gallon double-wall fuel tank for our diesel fire pump.
Our tank rep believes we only need (2) vents total: (1) an emergency vent for the interstitial space and (1) a combined normal/emergency vent for the primary tank. We have received pushback that we need (3) vents: (1) normal for the primary tank, (1) emergency for the primary tank, and (1) emergency for the interstitial space. We are having difficulties finding any requirements either allowing or not the combination of the emergency and normal vent lines of the primary tank (NFPA, building code, or UL 142). Do any of you know if the combination of these vents is typically allowed? What do you typically see for the venting of a diesel fire pump fuel tank? Note, this job does fall under 2022 California Building Code, but I am still interested in what is common even outside of California. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe In reviewing the top articles from 2024, I re-read #11 regarding forward flow. As an AHJ, this is something we have been focusing on for the last four years and have uncovered multiple water supply issues.
My question is related to NFPA 13 and the 2-1/2” hose valve that is required for every 250 gpm (950 L/min) of system demand. From the fire suppression side, we usually generalize that a 2-1/2” hose valve can only flow 250 gpm. However, in our forward flow testing and research, we have found that a 2-1/2” hose valve off a main riser can actually flow almost 600 gpm. So my question to the forum technical design experts is, if we are getting an adequate gpm flow for system demand from the pitot reading, do we really need to flow a hose valve for every 250gpm of system demand? In other words, if system demand is 450 gpm and we are getting that from a single 2-1/2” hose valve, is that accurate and acceptable? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Is it required by IBC or NFPA 13 to have a detached fire pump room or shelter to be protected by the sprinkler system as long as the fire pump serves the sprinkler protected building?
Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe I have a project where the Specifying Engineer has noted to have a small hose connection for periodic (maybe every 6 months) building maintenance use to wash down a water intake filter.
They have specified that it be fed from the jockey pump upstream of the jockey discharge check valve and connection to the fire pump connection, so it would seem that it would not really affect the fire protection system or fire pump discharge. However, I don't think it is a good idea, and I think a separate pump for building maintenance should be provided. Looking to see if there is any code reference I can use for backup as common sense doesn't always work or maybe I am wrong. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe When doing Calculations for a building that has a fire pump that is fed by an above-ground water tank, what do I use for available supply?
The fire Pump is 75 psi at 1,500 gpm. City water refills the water tank. City water is 104 psi static, 81 residual at 1,453 gpm flow. Do I factor in the tank by figuring the pressure created by elevation, or do I bypass the tank and use the city pressure in combination with the fire pump? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Is a flow switch required on the discharge side of the fire pump on the pipe before it exits the pump room?
We have an approved job that does not have a flow switch, and the fire marshal is requiring one. Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe I am working on a fire pump station project.
As the water tank ( 2 x 50,000 gal) is dedicated to the fire pumps only, a possible stagnation is expected, and hence, a recirculation pump for the tanks will be the best solution. I saw in many forums or searches that an 8-hour refill needs to be incorporated for the pump sizing, however, I couldn't find anything solid on NFPA 22 documents regarding recirculation. Can someone direct me to the NFPA reference for the recirculation requirements? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Can a wafer check or grooved check valve be installed directly on a fire pump discharge flange?
I've found they affect the pump performance by 3 to 8 psi. When testing we found this true and moved it by a foot. The pump didn’t hit its curve and was fairly new. Shouldn’t NFPA 20 or manufacturers be aware of this? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Has anyone here ever done a green points calculation for the benefit of having a flow meter on a fire pump and rat racing back to suction rather than waste?
I’ve heard many talk of this and how conscious they are of our effort to save water, but I’m wondering if anyone has ever submitted applications, calculated savings, or presented evidence. I’d also be interested in local or regional purveyor requirements on waste, reclamation, and disposal, if there are any. Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe During a fire event, the pressure in a sprinkler system drops, and the jockey pump starts but cannot make up the pressure loss. Then, the electric fire pump kicks in.
Should the jockey still be running, or stop? Same for electric and diesel: should they operate together if the pressure still goes down and the electric pump cannot make the pressure up? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe To comply with NFPA-20, the fire pump suction must have at least 10 pipe diameters from the pump flange to the elbow or tee. According to Section 4.16.6.3, the pipe can be horizontal or vertical.
Does the vertical pipe have to be at a 90-degree angle, or will a 45-degree angle be acceptable because that's the only way it can be installed? Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Can a fitting (a 90-degree elbow) from a fire ductile iron water line be under the footing, which turns the pipe up into the Fire Pump room?
In other words, the pipe feed comes from a water tank underground, then turns up with a 90 under the building footing and the pipes through the footing. Is this acceptable? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe We have a number of apartment buildings, 4-5 stories in height, with fire pumps serving the standpipes coming towards their end-of-life.
Is there a code requirement to re-evaluate the water supply when replacing a pump in a like-for-like scenario? Of course, this building has no existing fire protection records or placards to reference. Thanks! Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Can a fire pump room, properly built with only a fire pump and domestic water in it, have the fire pump electrical service meter in the fire pump room?
The local utility is permitting it. This specific example has it meeting reliable power, so there is no emergency feed that could be affected by the meter blowing out. If the meter goes, so does the pump power. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Our high-rise facility consists of apartments, condominiums, retail on the bottom floor, restaurant tenants on the top floor, and (3) levels of underground parking. We are 9 stories tall out of the ground.
They have great water pressure at the site with 140 static and 118 residual, flowing about 1,900 GPM, but with our floor-to-floor distances, I cannot get 100 PSI at the top of my standpipes. The building footprint is spread out, so I will need (8) standpipes to cover the hose lay inside the building (fully sprinklered). I'm assuming one 1,000 gpm pump will cover all the standpipe demand. To complicate matters, this is in a seismic area D classification, and with it being a high rise, I am required to have a secondary on-site water supply. The intent was to install an underground tank to supply the fire pump or pumps, if necessary. My thought was to supply water directly from the city main to the tank, and if there is ever a break in the city supply line, the pump would be served from water in the tank, which would have enough capacity to serve the facility for 30 minutes. Is 30 minutes the duration I need? What do you think about how I plan to serve the building? Would that meet the requirement for a secondary water supply? Do I consider the standpipe demand when sizing the underground tank, or just the most demanding area of my sprinklers? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Is an alarm check valve required in a sprinkler system?
Is there an alternative to an alarm check valve? Are there any restrictions on where the alarm check valve is required to be (i.e., inside or outside of a fire pump room)? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe NFPA 20 is pretty clear on the orientation of the eccentric reducer on the suction (upstream) side of a fire pump.
But the diagrams seem to suggest that the diagonal slope (not the flat side) of the eccentric reducer is always on the bottom. Is this true even when the supply is being fed from above? For instance, we often have a stub into a fire pump room from the floor, then a vertical backflow preventer, then the feed comes vertically-down and to the fire pump. Which way is correct for the eccentric reducer when the feed is from above? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe We have a low-rise building with a manual wet standpipe and a sprinkler system. One combination riser is 6-inch and the other is 4-inch. Standpipes will be Class I.
The calculated sprinkler demand is 195 gpm (Light Hazard). My total manual wet standpipe system demand will be 750 gpm (500 gpm first riser + 250 gpm second riser). Does my fire pump need to accommodate the 750 gpm of the manual standpipe system, since they're interconnected? I know the fire department will handle the standpipe demand, but does the flow rating for the fire pump need to accommodate 750 gpm? I've searched but haven't found specific code references in NFPA 13 or 20 to address this sizing. Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe We have a project where the owner just wants to manually turn a switch to transfer from main power to backup power for a fire pump instead of having an Automatic Transfer Switch.
Wouldn't this be considered manual activation under NFPA 20, and not be allowed? I would think this arrangement isn't allowed because that's not automatic transfer. Thanks in advance for your input. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe I have seen this method of arranging fire suppression components (see attached schematic) several times where I live. The attached is a partial re-creation of the fire water entry schematic for a high-rise building with a fire pump. The system has low and high pressure zones. The underground parking dry systems are served by the municipal water directly, and the standpipes and aboveground sprinklers are fed by the pump.  Questions: 1. Can you have a FDC serving the low pressure zones as shown on the suction side of the pump per NFPA-14 6.4.3.1? 2. If not, how should the schematic be arranged instead? 3. What could happen if the Low Pressure FDC were pressurized as shown? This project was built under the 2013 editions of NFPA-13, 14, and 20. I am asking because I am beginning design of a sprinkler system for a 22 story high-rise. Thanks for your help. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe |
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