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
19 Comments
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 I have a project with Miscellaneous Storage of Class I commodities up to 12'-0" and Group A plastics up to 5'-0".
The water supply is a tank fed from a well. Based on NFPA 13-2016 Table 13.2.1, I designed to Ordinary Hazard Group 2 with a 90 minute duration of available water. My original demand was 57 psi at 385 gpm. Our pump supplier provided a vertical in-line pump rated to 80 psi 400 gpm. The client is now unhappy about the volume of water being required so they are removing the Group A plastics from their building so we can calculate to OH I with the new demand being 41.5 psi at 304 gpm. We have already installed most of the system and the pump is ready to be delivered soon. Is it okay to have an oversized pump? Can it be limited to a smaller flow to accommodate the new demand? My worry is that it will flow at the rated capacity and if we are sizing our tanks 10,000 gallons less than originally planned we would run out of water. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe We have a building with an Extra Hazard Group 1 in a fairly rural location. We have an Electric, Diesel and Jockey (electric) pump system.
We had our diesel go out, sent away for repairs. What are the requirements for just having just electric in place? My concern is is the fire department cuts power if they come on site for industrial fire, or lose power due to weather, then we would have no suppression in service. The fire department can provide 1,500 gpm at 100 psi from a Type 1 engine through the FDC, (so 750 gallons). We have a pond to draft from. What would be the considerations? Amount of water available? In the event of power loss, the size of the FDC versus the size of the riser (a 6-8" dry pipe valve)? What would realistic attack line demand be for a hydrant/hose line? Can you think of anything else I'm not thinking of? Thanks in advance for the help! Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Can a flow meter be installed in test header piping?
This is the first time I've ever seen this installation. Thanks. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Is there a specific location requirement for a fire pump test header? NFPA 20 states that the header must be installed on the exterior wall, and outside the fire pump room. Does this mean that the test header cannot be installed in the fire pump room? Additionally, can the test header be directly connected to the pump discharge flange as shown in this photo? I have never seen this type of installation before. Thanks in advance.
Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe When is a fire pump pressure relief valve required?
Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe We have a case where two (2) x 2,000 gpm existing electric fire pumps (primary duty pumps) are available.
Now, the system design demand is increasing from 4,000 gpm to 12,000 gpm due to a scope change, so we are bringing in new electric fire pumps (as primary/duty) to meet the higher demand. All new fire pumps could be either four (4) x 2,000 gpm or two (2) x 4,000 gpm towards meeting the 12,000 gpm system capacity. All performance test curves are checked for all existing fire pumps; they are almost new and meeting the required residual pressure at 2,000 gpm and their performance is close to matching the original equipment manufacturer curves; so these existing pumps need to be retained. Now we do have space constraints, so we'd like to use the two (2) x 4,000 gpm pumps, and their pressure characteristics would be the same as the existing pumps. Would NFPA 13/20 (and any other relevant NFPA standard here) permit two different pump capacities for the system? Would having different pump capacities be concerning, or cause issues? Is there anything else we should be considering here regarding the capacities? Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe I have a unique quandary that I haven't run into before. We have an overperforming fire pump.
It was factory tested, we have a factory performance curve of 68 psi churn, 52 psi at 500 gpm (100%), and 35 psi at 750 gpm (150%). Once it was field installed, we were 1-3 psi over on Churn, 50%, and 100%, but +10 psi on the 150%. We had a net pressure of 45 psi at the 150% test when, based on the factory curve, the net should have been 35 psi. We checked the nameplate for the match, nameplate for the expected pressure at 150%; they all match. The supply for the test in the field got pretty low (about 25 psi suction at 150% flow). The only unique thing I can see about this setup is that we have a very tight room and had to meet a military spec to flow through the flowmeter and both run outside as well as back to the recirculation. As a result, the path from the pump discharge to the outside has to navigate through nine (9) elbows in order to get enough clearance upstream and downstream for the flowmeter in this very tiny pump room. Could a test header with that many bends be affecting the net pressure on the 150% test? Is this considered a failure? As this is military, it'll be by the book and I'm concerned that an overperforming pump might set up future tests for failure if I can't identify why it would be overperforming at the 150%. Thanks in advance! Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe We have a project and have gotten into an internal debate. The project has four diesel fire pumps in one pump house.
During testing, are we allowed to run all four at the same time? Or do we need to run each separately as we do normally to reduce the chance of blowing out a main? Anyone have insight on this? Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Where does NFPA 20's jurisdiction end?
Is it possible to have pressure reducing valves in a suppression system, downstream of a fire pump? NFPA 20 seems to not allow for that, but does NFPA 20 apply downstream? If so, how far? In the standard it says up to a last control valve or something like that - what control valve(s) is it referring to? Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe When would you recommend replacing an existing fire pump?
I am working a project where we are renovating a large hotel and the diesel fire pump in the basement is dated 1994. I am aware there is a lifespan but with proper maintenance they can probably operate just fine for a long time. Is 30 years when you would begin to suggest replacing that piece of equipment? Should I make the suggestion to the client that it is best to replace and have them make the final call? Thank you. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe NFPA 20 dictates the number and size of hose valves according to the pump rating, but is there any specific requirement on how many are to be used during testing?
How is that determined? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Is there any code that sets a specified elevation for the the Fire Pump Test Header above outside grade?
Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Long question - in essence - is Fire Flow considered on top of a flowing sprinkler system?
Recently there was a great discussion on the forum here about whether a water storage tank size needs to include Fire Flow in addition to sprinkler demand. There were some great points made (www.meyerfire.com/daily/must-water-storage-tank-include-site-fire-flow). I have just come upon a project where we do have a municipal water supply, but it tapers off very steeply. The flow test in the area was 52 psi static, 25 psi residual at only 650 gpm. This would put the available Fire Flow around 712 gpm at 20 psi for the site. In order for the AHJ to reduce the required Fire Flow under the IFC, the building(s) nearby need to be sprinkler-protected. This would bring down the Fire Flow requirement to 1,000 gpm at 2-hours, for this setup. The sprinkler system isn't designed yet, but we'd estimate around a 550-650 gpm demand with a fire pump. This gets really interesting based on the prior discussion. When the fire department shows up on site during a fire, and then starts to pull water, is this Fire Flow in addition to the flowing sprinkler system, or considered separate? In other words, is the 1,000 gpm (for 2 hours) for Fire Flow on top of a 600 gpm demand for sprinkler (for 60 minutes)? If the water storage tank needs to meet the demand of the sprinkler and Fire Flow separately, then the calculation comes down to ~300 gpm needed to fill the shortage on Fire Flow, multiplied by 2-hours. That's a tank in the ballpark of 35-40,000 gallons. If the water storage tank needs to meet the Fire Flow as the sprinkler system is operating, that's a flow of around 1,600 gpm to fight a fire. That's as much as ~900 gpm x 2 hours to a ballpark of 100-115,000 gallons. Huge difference. I can't find any relevant code that stipulates one way or another, only that the tank must supply the sources it is connected to. Am I looking at this correctly? I see sprinkler and Fire Flow needing to be met by a tank that they're connected to, but is the Fire Flow robbing the sprinkler system, or vice-versa? Thanks so much for reading. This is obviously TLTHFR (too long, thank-you-for-reading). Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Recently a client determined that they no longer want diesel fire pumps to be provided on their projects. They want electric fire pumps with a diesel generator to ensure reliable power. (Please do not ask why state this desire.)
If a diesel generator is provided strictly for the electric pump assembly, what mechanism do you utilize to turn the generator on when fire pump needs to start up? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe I have a standpipe demand of 750gpm. I am providing a fire pump for the system demand.
Should I be selecting a 750 gpm pump or a 1000 gpm pump, based on adding a safety factor (or other reasoning)? My sprinkler demand is less than 750 gpm so I would only need to provide the 750 gpm for the standpipes. Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe I am currently evaluating a 7-story building that is being partially renovated and has an existing standpipe system (2 standpipes), but no sprinklers. My scope was to add sprinklers to the renovated areas, creating a partially sprinklered building.
The lack of pressure is leading the AHJ to require a fire pump due the 100 psi required for the standpipe system. While the standpipe requires the fire pump, hydrant flow tests indicate that there may be sufficient pressure to supply a sprinkler system. My question is two-fold. Is there really such a thing as a non-combined sprinkler/standpipe system where they are both required? They both get their water supply from the same source. Also, can I evaluate supplying the sprinkler system through a separate riser that tees off before the fire pump, while the fire pump supplies only the standpipe, significantly reducing the size of the pump? The pump would be sized for 750 gpm total, 500 gpm @ 100 psi to the remote hose connections, and 250 gpm to the second standpipe. What would that sprinkler calculation look like? Would the sprinkler calculation remove the hose stream allowance and replace it with the 750 gpm to consider the flow to the pump/standpipes? The flow potential is there based on the hydrant flow test just not the pressure for the standpipes (and it's close for sprinklers). I'm just wondering if I can give the client and rest of the design team options. Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Architect here with a fire code question. We have a fully sprinklered building (ESFR), of Type II-B, tilt concrete construction.
The fire pump room is located on an exterior wall, and the only door into the pump room is from the exterior. We have 1-hr rated construction separating the fire pump room from the rest of the building. The fire marshal is telling us that the exterior wall and door also have to be rated. I responded by pointing out the fire pump is required to be protected from the surrounding building, and that it does not need to be protected from the exterior, so exterior wall and door should not have to be rated. Fire marshal disagrees and pointed to NFPA 20 4.14.1.1.2. That section does not specifically state that separation is required from the rest of the building, although Section 4.14.1.1.1 right before it does make that distinction, just like IBC/IFC do. We have solid concrete walls that are inherently fire rated construction, so typically I would just say ok and label them rated. The issue is we are required to have ventilation in the pump room per NFPA 20, so we have a makeup air louver in the exterior wall. If we rate the wall, then my understanding is we will have to put a fire/smoke damper on that louver, which is added cost and unnecessary in my opinion. Is your understanding that all walls have to be rated as the fire marshal is saying, or just the walls between pump room and rest of building? I've done many buildings of this type in multiple states and this is the first time I've been told this. I'd appreciate your insight, thanks. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe We have a fire pump room with three 75 HP main pumps that operate sequentially depending on the flow required.
Can we install all 3 controllers within a single enclosure? If not, what standard, code forbids this? Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe I recently obtained an annual full flow fire pump flow test data via hose monsters and pitotless nozzles to open atmosphere.
I am attempting to develop a graph from scratch in Excel for the fire pump curve or honestly, find one that is already built on line where I can plug in each data point for the Actual results (Churn, 100%, and 150%) and Theoretical/Design (Churn, 100% and 150%). Does anyone know of such available graphs or advice on steps to develop in Excel (or a different program)? Thank you in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe We have an underground water storage tank (concrete) with two compartments; Tank 1 and Tank 2. Our fire pumps are vertical turbine type: 1 duty and 1 back-up. Both suctions of each fire pump are located only at Tank 1.
Is this code compliant? Or shall we relocate the suction of the back-up fire pump into the Tank 2? Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe What does "listed for fire protection use" actually mean?
The Department of Defense specifications Section 21 13 13 calls for backflow preventers to be "listed for fire protection use". From what I have found, there is no such specific listing. Has anyone else heard of this? Thank you for your input. During fire pump testing, for the churn test, should the system valve (on discharge side of course) be open or closed?
I lean towards it being open, as I would rather know the weak point during a test than during an actual fire event. Here's my pro/con list to keeping the valve open: Pros (keeping valve open)
Cons (keeping it open)
Thanks in advance! Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Does a double wall diesel tank require a reservoir?
Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe |
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