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I'm having trouble finding code citations for this, but if a single-owner site with multiple buildings (like a transportation authority property that has multiple separate buildings) has a dedicated fire water loop serving the sprinkler and hydrant water for the site, can they provide FDCs where the fire water ties into the municipal water, and not provide FDCs for the individual building sprinklers?
Or is each sprinkler system required to have its own FDC? I would imagine that each building with a sprinkler system would still require an FDC, but I can't really find code language about this specific topic. Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe
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I have a code official who is requiring a full-size water meter on the fire line preceding double check backflow.
The backflow has a 3/4" meter and a small check on it with electronic connection capability for the water department. Are there any applicable code/standard references that mandate this? A 6-inch meter on the fire line would run about $15k. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Is the installation form of the control valve for the hydrant correct/allowed as shown? It is a wet barrel hydrant, and the owner wants to save costs by installing the control valve directly below the hydrant. How should the effective coverage area of the fire hydrant be considered? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe  For a newly built steel smelting plant, how should the layout spacing and protection range of private fire hydrants be considered?
I have checked that NFPA 1 states the maximum spacing for "Buildings Other than Detached One- and Two-Family Dwellings" is no more than 500 feet, but NFPA 850 specifies a maximum spacing of 300 feet. Do both govern? If so, does the more-restrictive one apply? What should be the protection range of each hydrant? Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Do I need a separate 6" fire line to a building sprinkler system, and a second water line for all other uses?
This is for an NFPA 13 system. Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe The IBC section 403.3.3 requires an automatic on-site secondary water supply for high-rise buildings in seismic zone C or greater.
Does NFPA have a similar requirement for on-site water storage in a seismic zone? All I can find are the bracing requirements in NFPA 13, but I am not seeing anything in NFPA 101 or NFPA 5000. Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Our project is a school campus with nine buildings.
The Civil Engineer has designed the underground so that three buildings are controlled from a single PIV and an FDC. Additionally, they want butterfly valves on each fire sprinkler riser. Does shutting off three buildings become an issue, and is this within the NFPA 13 parameters to dictate this one way or another? Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Before people say, "Ask the AHJ," I am him; he is me.
I have an applicant who has combined plots of land with a mid-rise and some detached townhouses. A shared fire line supplies the two structures, but only the mid-rise FACP monitors the supply tamper. The townhouse FACP will not know if the water is off (except for the tampers at the risers within the townhouse). The buildings are owned by the same ownership. They are arguing they are technically meeting IBC 2015 903.4 "Valves controlling the water supply for automatic sprinkler systems, pumps, tanks, water levels, and temperatures, critical air pressures, and waterflow switches on all sprinkler systems shall be electrically supervised by a listed fire alarm control unit." It is being monitored, but the fire marshal and I are of the opinion this doesn't provide monitoring for the townhouse and does not meet the intent of the code. Does anyone have any thoughts on whether a shared line can be monitored by only one building that it serves? 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 In an area subject to freezing, we have a remote FDC that supplies a riser room at the same level. The feed is through underground pipe.
Is the base of the FDC required to have an automatic drain similar to what's at the base of dry barrel fire hydrants? If not, how are these FDC's typically drained after use? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Is there any particular drainage pipe requirements needed for an FDC that makes a U-loop underground?
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 I have a bunch of new houses going in. Some are along an existing street, and some are around a newly formed cul-de-sac.
How do I determine the number of hydrants, how far apart they are, and the maximum distance to any of the homes? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe If I have a fire tap that services multiple buildings, is it required to have a service valve outside the building on each line?
Does each building need to be capable of being isolated in case of service needs without interrupting others? As it is, if one building needs work done to the #1 valve on the backflow then the other buildings will have to lose water during repair. Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe MeyerFire has a great thrust block calculator that appears to match NFPA 13’s annex/appendix exactly. https://www.meyerfire.com/blog/a-new-thrust-block-calculator-part-i How can the thrust block volume fit within the dimensions of the thrust block? The default entries, for example, give a thrust block volume of 57.8 ft³ (NFPA 13 Equation A.6.6.1c), a base height of 2.2 ft, and a base width of 4.27 ft. This meets the bearing area required by the equations. NFPA 13, Figure A.6.6.1(b) gives the angle between the base of the thrust block and the pipe as 45°. This makes the thrust block a pyramid shape but ends with a pipe instead of coming to a tip. The Figure shows both vertical and horizontal angles as 45°, but that wouldn’t work unless the height and width are equal. If 45° is the minimum angle, then the width of 4.27 ft would control the distance from the base of the pyramid to the pipe. If each side has a 45° angle, this distance would be half the width or 2.135 ft. These dimensions can be used with the pyramid volume formula to give another method to check the thrust block volume. The pyramid formula is V = L*W*H/3, which gives a volume of 6.7 ft³. This is very different from the NFPA equation result. Even if the thrust block was poured as a cube, its volume would be V = L*W*H, which is 20 ft³ -- still much smaller than the NFPA value. – I am counting the tip of the pyramid, which is part of the pipe, not the thrust block. It would be more accurate to exclude the tip, lowering the required volume slightly, but it would be harder to calculate. If the pyramid were 57.8 ft³ with a bearing area of 2.2 ft by 4.27 ft, then it would need a distance from the pipe of 18 feet. I think there is something wrong with Equation A.6.6.1c in NFPA 13. It doesn’t make sense that it cancels the thrust force with the weight of the fill material. If you could use some incredibly dense fill material (pretend fantasy fill that is 8670 lb/ft³), then the thrust block volume would be 1 ft³ by that formula, but how is that small thrust block volume going to transfer the thrust forces onto a large enough soil surface?  The weight of the thrust block material should not be related to calculating the volume of fill material required.
Another issue I see with the equation is that it is suddenly using T = P*A*sin(theta) while all previous formulas were using T = P*A*sin(theta/2). Why did the angle change for this formula? Thanks in advance for any insight you could shed on the difference in volume versus shape with the NFPA formulas. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe We have a scenario where the fire riser will be installed after the building is completed. If the pipe is located below the pedestrian walkway area, is this required to comply with NFPA 13, 2022, (6.4.2.2.2 In locations where freezing is not a factor, the depth of cover shall not be less than 30 in. (750 mm) below grade to prevent mechanical damage. [24:10.4.2.2.2])? See the attached sketch. If yes, what is the possible solution? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe  Can a 4" pump with 4"-6" discharge fitting be used on a private 10" combination line (fire suppression and hydrants)?
NFPA 24 Section 13.1 states that no line less than 6" shall service a hydrant. But does the fact that NFPA 20 Section 4.16 allows the 4"-6" discharge fitting as part of the pump assembly overrule this? Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Hi all, what is the maximum length of the connection from the hydrant to the fire water main?
NFPA 24 mentions that the minimum size is 6" but couldn't find anything related to the pipe length. Thanks Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Typically when I work on campus/multi-building systems, I am using a single underground main and splitting off to each building. Since you don't have to consider a multiple building fire problem, we have typically worked on the hydraulically most-remote building for underground sizing and use wall PIVs to offer individual building shutoffs, with FDCs on the individual buildings.
I'm getting challenged on "what allows this in code?" It's mostly a question of - where is the limit on how long a loop can be? I'm looking at this from a sprinkler design perspective and whether each individual building's sprinkler system is able to perform hydraulically. Is the limit for the length/layout/sizing of a campus underground loop simply the more demanding of Fire Flow or sprinkler system feeds? Is there a code basis for this? Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe According to NFPA 13 2022 Section 16.9.8.2 it is to our discretion what we consider a location " where they are not subject to mechanical damage?
When installing a Post Indicator Valve, what do you consider "not subject to mechanical damage?" Where is the line drawn, so to speak? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Had a review comment come back and needed to clarify. I have a 14-inch city main with an 8-inch tap to a backflow in a pit. It then runs to four hydrants, and then turns into the building supplying a fire pump. The flow test at the hydrant near the tap (#1 on image below) was 49 psi static, 47 psi residual at 920 gpm. The flow test at a hydrant nearest the building (#2 on image below) was 49 psi static, 39 psi residual at 750 gpm.  The 95 psi @ 1,500 gpm pump in the building is running the underground dry. The plot curve shows 20 psi at 2,100 gpm, however the pump rep said he barely got 500 gpm at 9 pitot and had to shut it down as the gauges went below 20 psi and air was starting to come out of the 2-1/2" hose valves.
This is a mystery to us - we have five different flow tests all ranging from 750 gpm to 1,060 gpm at 40-32 psi residual. Why would the pump be pulling the underground so low? They checked all the valves and rebuilt the backflow in the pit. Water meter is good as well (per the utility department). Looking for suggestions. Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Can a floating dock standpipe with hose valves in the ocean be ran with PVC pipe?
NFPA 307 doesn’t go into detail about materials used but reverts back to NFPA 20, 22 and 24. This is in Florida. The AHJ wants it full of water so I have to issues, it’s too heavy to mount on the side of the dock, it’s not very big and it will be in the water or very close with high tide, so corrosion is inevitable. Is there anything stating Schedule 40 or 80 PVC is listed or acceptable for such use? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe We have a private water main feeding a combined domestic and NFPA 13 system that was specified as C900. They installed SDR21 (6") instead.
They are using the argument that this 200 psi rated pipe will not be subject to the fire system pressure and therefore is ok. I cannot find where this is listed for fire service mains. Any direction? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Would it be possible to replace a Kennedy K-10 dry barrel fire hydrant with a wet barrel fire hydrant if the main valve of the K-10 was left open, and a wet barrel hydrant was then bolted to the standpipe base?
We're in southern California, so we commonly have wet barrel hydrants in the area. Replacing with a wet barrel means we wouldn't have to excavate. The main reason I see is that the drain holes would be left open if the dry barrel main valve is removed. We have been unable to find new main valves for Kennedy K-10 hydrants. Your comments would be greatly appreciated. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Last week someone asked a great question about the limits of where NFPA 20 starts and stops.
In a similar vein, what are the limits of where NFPA 22 and NFPA 24 start and stop for a typical system with a water storage tank, fire pump and private mains? We had a question at work yesterday as to whether NFPA 24 or NFPA 22 applies to pipe before a water storage tank. It'd be helpful for us to understand these limitations in addition to the conversation last week. Thanks in advance! Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe |
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