Fire pump testing - how might one do the attached example with a PRV? 3

[ContractorDave]

Hello

I'm doing ITMs on a mine site. There's a fire pump module / trailer with two 2000 gpm pumps fed from tank supplies. I drew up a rather corny looking iso with one system represented. There's a flow meter test loop on the system but there's also a PRV loop that does not have isolation valves. The PRV's are the Watts 116FM. Attached is the iso and hopefully I can attach the pdf I found on line for the PRV but it sure doesn't tell you much.

Does anyone have any thoughts on how to proceed under these circumstances? How might you lock down that PRV so it doesn't affect your flow rates or how might you otherwise account for it?

Thx
Dave

 

[Sprinklerfitter]

Dave,

I agree with your assesment with regards to an inspector's responsibilities while performing an annual performance test on a fire pump or any fire sprinkler devices for that matter.

NFPA 25HB 2010 states:

The contract with a fire protection contractor to perform the inspection, testing, and maintenance of a waterbased fire protection system is not an insurance policy or an engineering evaluation. If the property owner is ever uncertain whether the fire protection system as installed will provide the minimum protection required by the applicable codes, the owner should contact a fire protection engineer or qualified contractor to perform an analysis of the building, the building occupancy, the commodity classification of any storage present, the system design criteria, and the water supply.

The inspection and testing of a fire protection system in accordance with NFPA 25 is not equivalent to any of the following:

1. An engineering or AHJ review or evaluation of the
adequacy of the system to control or extinguish a fire
in the protected occupancy
2. An engineering or AHJ review or evaluation of the
adequacy of the water supply, including water tanks
and fire pumps, to provide the necessary waterflow
and pressure needed to meet the fire protection system
demand as designed
3. An engineering or AHJ review or evaluation of the
hazards present in the facility to determine the required
system criteria for minimum protection levels
4. An engineering or AHJ review, evaluation, acceptance,
inspection, or test of the fire protection system to determine
whether the system was designed and installed in
accordance with the applicable installation standard,
including NFPA 13, 13R, 14, 15, 16, 20, 22, and 214
5. An engineering or AHJ review or evaluation of all
areas of the facilities to determine whether all areas of
the facility are protected in accordance with the original
applicable installation standard

The NFPA Technical Committee on Inspection, Testing, and Maintenance of Water-Based Systems has made it clear that the role of the inspector performing inspection and testing activities in accordance with NFPA 25 is not that of a fire protection engineer or an AHJ. The inspector is not required to be a fire protection engineer, nor is the inspector required to have detailed knowledge of the fire protection system installation requirements in the applicable NFPA standards. Therefore, when property owners contract with a fire protection contractor, they should not expect the inspector to provide an engineering analysis detailing the adequacy of the system design when compared to the hazard, or evaluate the accuracy and completeness of the installation.

The inspector is not required to perform the following
functions:
? Review the design criteria for the system to determine
whether it is adequate for the commodity or hazard
? Review the installation shop drawing to make sure all
pipes are correctly sized and the sprinklers are the correct
type, orifice size, and temperature rating
? Perform a water supply analysis to determine whether
the water supply is sufficient to provide the required
gallons per minute at the required pounds per square
inch for the system
? Perform a complete building inspection to determine
whether closets, blind spaces, attics, crawl spaces, and
all other special building features are adequately protected
in accordance with the version of the installation
standard in force at the time of the installation
? Recognize that storage commodities and/or arrangements
are different from those anticipated when the
system was designed and installed
? Research the installation contract files to determine
whether special requirements were required by the AHJ

See item 2 under equivalencies above!!

Thanks

Jamey

 

[ContractorDave]

Very concise Jamey

One star for you!

D

 

[LCREP]

Dave,

Why not add one more curve to your graph. Add the minimum pump performance as per NFPA 25, 2008 ED. See 8.3.5.3 (2) below. If you plot a graph with 95% of the pressure readings at the name plate rating. Based on your pump they would be 110psi=104.5psi, 100psi=95psi, 93psi=88.35psi.

You now have a line that is very easy to see if the pump is "acceptable" or not. We use this and it works great trying to explain why the pump has a problem to someone that knows nothing about pumps. Easy to say see the red line, this is what the pump did. See the black line this is the minimum NFPA 25 curve. Can you see how the red line is way below the black line? If you know nothing about fire pump you can see the difference.

Yes you can post at the 911 site, it does not matter to me, not my site.

8.3.5.3 The fire pump assembly shall be considered acceptable
if either of the following conditions is shown during the
test:
(1)*The test is no less than 95 percent of the pressure at rated
flow and rated speed of the initial unadjusted field acceptance
test curve, provided that the original acceptance
test curve matches the original certified pump curve by
using theoretical factors.
(2) The fire pump is no less than 95 percent of the performance
characteristics as indicated on the pump nameplate.
8.3.5.4* Degradation in excess of 5 percent of the pressure of
the initial unadjusted acceptance test curve or nameplate shall
require an investigation to reveal the cause of degraded performance.

****************************************
Fire Sprinklers Save Firefighters’ Lives Too!

 

[ContractorDave]

Tom

What would be your first course of action if "The fire pump is no less than 95 percent of the performance
characteristics as indicated on the pump nameplate.
8.3.5.4* Degradation in excess of 5 percent of the pressure of
the initial unadjusted acceptance test curve or nameplate shall
require an investigation to reveal the cause of degraded performance."

You would presumably inform the client that he is required to have an investigation done ... and then what? Would you do this investigation, pull the pump apart yourself? I might do such a thing if it's a centrifugal pump because I'm fairly familiar with the internals, but not say a VT. Up here where I am, a mechanic who might do this sort of thing on a fire pump is unheard of.

Dave

 

[LCREP]

Dave,

You said
Hence, why would I use the combined curve? Does it not speak more to the design of the system than the performance of the fire pump I am inspecting?

Why because as I said above, the pump and the system demand go together, they both need to work to extinguish the fire.

Here is an experience I had.

I reviewed a fire pump test and noted the pump was working fine met all NFPA 25 points. BUT the pump discharge pressure was short 12 psi of the sprinkler system demand. This was a 1 million sq. ft. tire warehouse. We reviewed all valves on site and were found to be open. Water department looked at the valves on the city system and found 3 closed. They were closed to isolate a water main break some 2 years ago. They were reopened, test the fire pump again, got the 12 psi plus another 5 psi safety cushion, everything is good again.


Got one going on right now. The pump is below the NFPA 25 minimum curve by 5 psi. Been this way for 3 years in a row. BUT when I do a combined curve we have 10psi more then we need to meet the sprinkler demand. So if we have a fire today I know I will have a sprinkler system that will work because it has an adequate water supply.

To sum up why do it it gives you more options and helps the customer prioritize what and when things need to get done.



****************************************
Fire Sprinklers Save Firefighters’ Lives Too!

 

[LCREP]

Dave,

I was typing the above reply and did not see your question on what to do if below 95%.

Well I work for an insurance company so I do not touch anything. BUT I would recommend they contact the fire pump mfg and have them look at the test results and look at the pump. Yes pull it apart to see what is wrong. I would also look at the past 3 years worth of fire pump tests to determine IF this just happen or has it been like this all the time.

A rock, wear ring going, etc can cause the reduced performance.

Tom



****************************************
Fire Sprinklers Save Firefighters’ Lives Too!