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Given a concrete water tank for a high rise with relatively short 6" fill lines, 100psi of city pressure, and a nearly flat supply curve, the plumbing engineer has designed an 8" overflow.
He's showing it as an 8" horizontal pipe extending about a foot into the side of the tank with 4" below the bottom of the pipe as the high water level in the tank. I have my doubts, but assuming the 8" pipe can handle the overflow condition, is this an appropriate way to install the pipe inside the tank? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe
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Is an FDC required on a water storage tank meant to service a fire pump to a commercial warehouse when there is already an FDC connection on the discharge side of the pump piping?
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 I have been introduced to a project that involves six underground water storage tanks and an external pump house that will provide fire protection water to a fully sprinklered building.
We have been informed that the sprinkler contractor will be providing the building sprinkler system design, but not the underground storage tank portion of the project. The firm I work for performs a significant amount of fueling and convenience store design work for gas station and convenience store clients, but I am curious whether these water storage tank options are similar in nature to underground fuel storage tanks and their associated pumping equipment? Obviously, the medium is different (water versus fuel), but I am interested in understanding whether there are comparable design considerations, equipment types, or industry standards. Any guidance, resources, or lessons learned would be greatly appreciated. Thank you. 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 Hi, have you encountered cases where the fire pump is more than 100 ft (30 m) away from the water storage tank (underground)?
I know this isn't ideal. What type of pump or setup do you suggest or recommend in this situation? Thank you. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe I have a DoW project with specifications that require the diesel fire pump flow meter to discharge both into the pump suction and through the test header. I don't have experience with this setup; in all my previous projects, the diesel fire pump discharged back to the water tank as well as to the test header. I understand that NFPA 20 allows this arrangement (see attached figure from the 2025 edition), but I'm curious how it works in practice for two main reasons: 1. If we close the tank valve during testing, the pump's suction pipe will receive considerable pressure. Will this repeated pressure adjustment after each test impact the longevity of the soft packing, particularly regarding increased water leakage? 2. How does a diesel fire pump cool its motor if the heat exchanger water isn't returned to the tank with fresh cool water coming in? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe  I am working on a new building in a rural area that will require sprinkler protection. There is no access to a public water supply, only a 30-100 gpm well on site.
Options for fire suppression water include pumping from a large farm pond 150 feet away or installing a 15,000-gallon water storage tank with a pump. Any thoughts on which option is more feasible and cost-effective, or any alternatives we're not considering? This is in a freezing climate. Thank you in advance! Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe I've got a high-rise project in a seismic zone higher than category C. We are required by IBC to have a secondary water supply other than the city supply (IBC 403.3.3). The structural team is pushing to not put the tank on the roof, and our site is extremely limited, so there is discussion about trying to bury the tank.
What pump/tank configurations are available for this situation? I am aware of either a concrete or fiberglass tank with a vertical turbine pump, but can you tie in the city supply to a vertical turbine submerged in a tank? Is there a way to appease this rule other than a secondary fire tank that I'm not thinking of? Thank you in advance for any help. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Is a water storage tank for an NFPA 13 system required to be UL listed, or does it need to simply be NFPA 22 compliant?
I was always taught that a tank had to be at least UL Listed for fire protection, but I have a supplier telling me otherwise, and the price he offers is less than half that of a UL/FM tank. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe My fire department is requesting that a new large development in our district install a more robust water storage tank (20,000 gallons more than required by code, along with a wet hydrant adjacent to the tank).
We will use the extra water for fires in the area. My question is - how can the fire department refill the tank after the nearby fire is under control? Can we require a FDC adjacent to the tank (5"storz connection) so we can refill the water storage tank quickly from FD tankers? There is no public water supply in area-wells only. Thanks! Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Anyone know of an economical way to store 30,000 gallons of Fire Sprinkler water above ground in (2) 15k or (3) 10k poly tanks stored outside in area that can get below 0 degrees in the winter?
1) Can these tanks be insulated? 2) Can these tanks be equipped with immersion heaters? 3) Do these tanks degrade when exposed to the sun? Ideally, we are pushing the client to consider building a structure or Lean-To with some heat to solve all of these questions. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Does NFPA provide guidance on campus-style fire pump design?
Can I provide two water services (one from each building) and serve out to two buildings? NFPA 20 4.9 implies that campus-style designs are acceptable, but I am not seeing any code lines referencing any further requirements for such a design. Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe We have a facility with an NFPA 13 Extra Hazard 1 sprinkler system.
The client's proposed location of the water storage tank is approximately 33-ft (10m) higher than the level of the protected building and around 100-ft (30m) away. The client's proposed pump house is closer to the building, separate from the tank. My question is - is there a maximum length for the suction feed from the tank to the pumphouse under NFPA rules (13, 20, 22)? I would rather locate the pump house next to the tank and run the delivery main to the building. Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe We have a project with a very large Water Storage Tank that requires a 20" suction line from the tank to the suction manifold side of (3) pumps.
Per NFPA 20, at the connection point from the water storage tank to the supply line to the fire pumps as required by NFPA 20 (2019 ed.) 4.16.6.5, where the pump and its suction supply are on separate foundations with rigid interconnecting pipe, the pipe shall be provided with strain relief in Figure A.6.3.1(a). We can find no manufacturer that has a 20" UL/FM strain relief connection. We do, although, have a supplier that makes a 20" Flexible Double Expansion Joint, but not UL/FM Listed. Does anyone know of any other options, or can we just use this flexible expansion joint and get a waiver from the Fire Marshal and EOR? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe How do you determine the effective capacity of a water storage tank for fire protection purposes?
Where are the unusable limits set for the bottom of the tank suction and the top air gap? Is there a mandate for either of these in code or standards? Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Existing remote church with water provided by a storage tank. The church plans on building a separate meeting hall that does not connect to the church. These buildings will be approximately 200 feet apart. This new building will require sprinkler protection.
Is it possible to use the existing storage tank to serve both buildings? The current tank is sized just for one fire area, so it is not for two simultaneous fires. Normally, two separate buildings have two services, but I wonder if there is an exception for storage tanks in remote areas. 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 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 I work for a local fire department that does plan reviews for fire protection systems. We are reviewing a project that requires 40,000 gallons of stored water. They are proposing using multiple fire water tanks and eight 5,000-gallon tanks.
While NFPA does not restrict the use of multiple tanks, I would like to see fewer tanks than eight. I am more inclined to allow two separate tanks at the most. However, I wanted to see what others thought and if there was a standard understanding or practice to number or size of tanks to the total needed water demand. Thanks for any help. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe When sizing an elevated fire water storage tank for the minimum supply duration of a sprinkler system, should non-remote areas (areas closer to the tank) of the system be considered as well?
Since sprinklers closer to the tank would be under higher pressure, they would discharge more water than those in the remote area. Thanks in advance. 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 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 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 If the system demand is 321.5 gpm for an Ordinary Hazard Group 2 system, do you add the 250 gpm hose allowance before or after calculating the 90-minute supply?
For example, 321.5 gpm + 250 gpm = 571.5 gpm x 90 minutes = 51,435 gallons, or, 321.5 gpm x 90 min + 250 gal = 29,185 gallons. Looking for input to order a water storage tank and the owner is disputing the water storage tank size. We told them we would need a 52,000 gallon tank. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe |
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