Fire Pump Test at Discharge Header Versus Roof?

3/31/2021

Hi, all! I came across this forum by accident at the perfect time. I am having a dilemma with the building department.

I am conducting an annual flow test on a 500 gpm (at 100 psi) fire pump from the test header off the pump discharge with the valve closed as to not disturb the system. I achieved 100% and 150% with no issues and the curve was almost identical to the pump's design curve.

The Department of Buildings is rejecting the test because the test was conducted from the discharge manifold. I was trying to avoid flowing from the roof because it's a very high end building and did not want to risk anything. Now, this system has been recently installed and the jockey pump panel is reading 100 psi on the system.

When I tested my pump, it pushed out 168 psi on discharge and 48 psi on suction for a net of 120 psi (the pump is rated at 124 PSI for churn). I can conduct the test from the roof with no issue as long as the building feels comfortable with their storm drain's ability to handle the flow, but I am worried about over-pressurizing the system.

Am I permitted by code to test off the header and not from the roof?

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10 Comments

Dan Wilder

3/31/2021 08:00:25 am

Unless you are testing the Standpipes per 25-19' 6.3.1, there is no requirement to test from the roof if the means are available to test the pump via the test header/flow meter (depending on the cycle). As long as you are complying with 8.3.3.1 for testing through "approved" test devices (valves in/adjacent to the pump room), you are in compliance with 25.

Had the pump shown degradation from the original Cx test curve, I could see the additional test being an option to prove that the pump can still provide the needed flow/pressure for the standpipe without a pump diagnosis.

Glenn Berger

3/31/2021 09:22:18 am

Adding to Dan's comment above - Storm drains are not sized to handle the large amount of water flow from a fire pump test.

There are AHJs that do not trust installed flow meters and want new calibrated meters used or recently calibrated pitots to be used for the tests.

Craig Hanson link

3/31/2021 09:23:39 am

I would ask them to provide the code requirement that has a test from the roof. If they stick to their guns I would have them sign an waiver that they are responsible for any water damage or window washing etc. due to the mandatory test.

Arthur J Tiroly

3/31/2021 09:56:58 am

NFPA 25 requires a standpipe flow test every 5 years from the top or roof.
The system was hydrostatically tested to 200 psi.

A test is a better time to determine that 175 psi on the first floor is not ecxcessive. Pressure at the top will be much less.

Peter

3/31/2021 10:08:53 am

There is nothing to prohibit you from testing the fire pump from the roof (or standpipe hose valves) in NFPA 25. NFPA 25 only requires that the means 'be approved'. Which means, that the AHJ says "yes, that is ok with us". Obviously (to most of us), if there is a test header, that is the preferred means to which you should be discharging water. However, a lot of older buildings do not have test headers installed and there is no retroactive requirement in NFPA 20 or NFPA 25 to install a test header that is not present, but that doesn't appear to be an issue for you as you indicated a test header is present.

When flowing water you need to verify with the owner that the location of the water discharge is acceptable. Storm drains on the roof may not be able to handle the volume of water and dumping water over the side of the building may be undesirable.

In regards to your other question about 'over pressurizing' the building. I've seen this a lot from inspectors. The static pressure on the system should be higher than the flowing pressure of the system. You mentioned the jockey pump gauge is showing 100psi on the system, yet the pump is rated for 124psi. The jockey pump stop setting should be set to 124psi + the minimum suction pressure of city water supply (See NFPA 20, 2016 A14.2.6(4)(a)). So, if the minimum city water supply pressure is 50psi, the jockey pump stop should be 174psi. The jockey pump start should be the stop pressure - 10psi. 174 - 10 = 164psi.

I get that you think you're over pressurizing the system, but you have settings that are not standard practice and they probably should be addressed which I believe is leading you to that conclusion. Keep in mind, that while it is understandable that people don't want to turn the pump on because of the 'damage it may due to the system' the pump is designed to turn on (in most circumstances) automatically, without anyone there to turn the water off if a sprinkler were to activate. Plus you need to have the pump on to perform annual main drain tests of the risers as well as to flow water through the inspector's test valve for alarm devices. You are performing an inspection and test, if you follow the correct procedures and a piece of corroded pipe breaks, it is better to break under circumstances of an inspection than under a real fire situation.

Lastly, the report you submitted may be the problem. You said that the pump is rated for 500GPM @ 100psi. You developed 500GPM @ 120psi. Having a pump truly generate 20% more than it is rated for at 100% flow would be unlikely.

Franck

3/31/2021 10:34:25 am

I think that the 120 psi is at churn, which would be in line with a 100 psi at nominal flow (120%).
Maybe this need to be clarified.

Regarding the test, it depends on what is the purpose of the test. If the purpose is to test the pump conditions (the aim of the annual flow test per NFPA 25), you did it right.
If the aim is to have an indication of the residual pressure at the roof level when performing the test, then you have to do it at the roof level. But this is not the purpose of the annual flow test.

3/31/2021 10:40:51 am

As clearly indicated by Peter, the Jockey pump setting is not correct.
It should stop at the net pressure delivered by the pump at churn (+170 psi in your case).. And start about 10 psi below the stop value to maintain the pressure in the system between 160 and 170 psi.
In addition, your fire pump should start at 7-10 psi below the start of the Jockey pump.
You gave non indication in your post, but in your case, it should be around 150 psi.
I doubt this is the case as you indicated the pressure is maintained at 100 psi.
You were afraid of water damage with overpressure ?
In your case I would be much more afraid of water damage due to water hammer.
If one sprinkler open and the pressure raise immediately from 80-90 psi (starting pressure of your pump) to 170 psi (pressure delivered by your system at limited flow), you need to rely on the quality of your pipe fittings and hangers...

Again, as indicated by Peter, it is alsways better to have a problem when making test/maintenance, and then have time to fix the problem, than during a fire event!

Casey Milhorn

3/31/2021 10:58:45 am

I think everyone covered it pretty well. I would just ask exactly what your scope is for this project. Was it an annual fire pump test only, was it to also provide standpipe testing? Is it time for standpipe testing? It's kind of like being a short order cook. Did the customer order the eggs and bacon, or just the eggs? One of the biggest mistakes companies make is to quote an "NFPA 25 inspection" without specifically saying what they include or don't include. Also very important to clarify if its an annual, semi-annual, quarterly, monthly, or even a 3 year/5 year item, and don't forget the sprinkler testing intervals. So basically if the customer only ordered the eggs but now they need the bacon too, that's extra. The liability, of course, is a lot different between serving breakfast and inspecting life saving equipment. Also, a 120% churn is not out of line too badly, but it's a sign of a pump that is close to maxed out. Probably saved a few hundred $ or so on the pump. Not that there is anything wrong with that, just that there is a time where you really want a lower churn % and other times it doesn't really matter. Great question.

Matt

3/31/2021 12:05:07 pm

TL;DR
- your assumptions regarding using the FPTH are likely correct. - The test header is provided for testing.
- you can't use the test header to test standpipe
- check local requirements
- follow-up with AHJ to see where they're coming from
- Read Peter's post regarding jockey pump set pressures

Explanation:

It's important to understand the why of things...
We run the pump to ensure it is performing adequately year over year. Specifically, to ensure that it can provide enough pressure at a given flow when running at a particular speed. The test header is specifically installed (per NFPA 20) with enough outlets provided to facilitate this testing. In order to do this effectively, its important to have an 'apples to apples' comparison. That is to say - if the pump performance testing during commissioning was conducted from the test header it would not be an effective comparison to perform the annual performance test the following year from the roof - nor is it likely that enough water can even be flowed from this point.

On another note, if they are speaking to standpipe in their comments then it must be tested at the most remote connection, which is in many cases located in a rooftop/penthouse mechanical room. Where I am located, we do have local requirements (which differ from NFPA 25) when it comes to minimum flow/pressure at the remote hose station. So you should delve into what the local requirements are.

If you're unsure, follow up with the AHJ.
As an AHJ myself, I make an extra effort to educate contractors and building owners/stakeholders on what my expectations are and I imagine (but certainly don't speak for them) that many other AHJs would happily do the same. If you can get a code reference then that usually provides a more apt description on what they are referring to and what the expectation might be.

Haven't hit refresh on this page for a bit (stopped for a mandated union lunch break midway through writing) so there's likely many other helpful comments on here. I suggest taking the time as you'll find many excellent and relevant morsels of info.

Good luck!

LAURITZ RASMUSSEN

4/5/2021 02:25:48 pm

I suspect that this is the NYC Building Department. Now all bets are off.

Fire Pump Test at Discharge Header Versus Roof?

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