I am doing some work on a combined fire-fighting/domestic pump house for a small community.

A couple things look odd to me.

1. They have a 12-inch flanged basket strainer after the pump discharge just before the mains. I was under the impression that any devices or fittings between pump discharge and need to be listed for fire protection use.
   
2. Instead of a jockey pump, they have three potable water pumps which run all the time pushing potable water to the mains. The primary fire pump automatically operates when the pressure drops to 4.5 bar and the backup pump at 2.3 bar.
   

There seem to be two deviations from NFPA standards here:

First, the jockey pump should be small , so that in case of fire it is the fire pump taking the load, and second, the starting sequence requires the jockey pump to start above the fire pump churn, the first fire pump a little lower and so on.

Is there any exception for such combined domestic/fire protection systems in the NFPA line of standards?

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What is the best procedure to use when testing a 3,500 gallon diesel fire pump that is equipped with a throttling/pressure governor installed on it?

My graph was well below the rated curve at 50% and 100%, but the governor seemed to disengage at 150% flow and my numbers exceeded the rated curve when we pushed this much water.

I did not attempt to change the controller settings or unplug the device (if that's even possible) to disengage the forced idle at 50% or 100% but insurance isn't "buying" that the pump didn't fail. These pumps aren't more than 5 years old and are ran on a tight schedule once a week (by the way).

Maintenance thinks it'll lead to faster wear and tear on the motor and I agree. All I could really do was state the facts and hope I don't have to go back out there and do the test again.

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We have two fire pumps on a project which are to be connected to one emergency generator. One is a primary pump, the other is a backup.

Will these ever run simultaneously?

The Electrical Engineer on the project is concerned about running supply for both pumps simultaneously and overburdening the generator. 

Is there an NFPA limitation for this, or requirement either way?

Thanks in advance.

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Is there any NFPA provision for forbidding a fire pump to start in the event a water storage tank has a water level that is too low?

I'm wondering what might happen if the water storage gets down to ~25% of the design level, or lower, and the potential need to shutdown the pump before it runs dry. 

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I live in a province in Canada with its own building code version and recently had a project for a very small, single-story building - an industrial class with an incinerator.

We were originally told that the building needed to be sprinklered so we designed a system for it. Since the system will cost a lot of money, the owners have hired a code consultant that concluded that the building does not need to be sprinklered as there is no requirement to sprinkler a single-story very small industrial building by the building code.

They make the argument that standards like NFPA 82 & NFPA 20 (for fire pumps) pertain to the equipment but not the building as those aspects are covered by the building code. They also mention this usage has been called into question and accepted in other Canadian provinces with similar code structures.

Noting that this argument is not specific to the incinerator or NFPA 82 but any equipment or room covered by an NFPA standard, I'm wondering if anyone has heard a similar argument or has other experience in another jurisdiction.

Does the usage here drive a requirement for fire sprinkler protection?

Is this the correct approach here?

Thanks in advance.

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Are there any good practices or other viable options allowed by NFPA 20 (other than a Pressure Limiting Driver) to limit the fire pump discharge pressure to at churn to 175psi when there is a high static pressure on the water supply?

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We are bidding a job that may possibly need a 1,250 gpm rated fire pump due to not enough flow from the city. Our test was 43 psi static, 35 psi residual at 872 gpm. We will need to include a ground suction tank.

How do I correctly include or simulate a ground suction tank in my hydraulic calculations?

We use the Sigma Hydraulic Calculation program.

Thanks in advance.

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Is there a code or standard that specifies floor clearance in front of a fire pump controller cabinet?

I am installing a fire pump in an existing building which has a controller with a transfer switch. Of course the fire pump room size presents clearance issues.

I have clearances I need for sprinkler pipe, but I do not know the working clearances required in front of the cabinets. 

I do have door swing clearance, but was wondering about a working clearance. Thanks in advance.

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We have a two-zone fire sprinkler system, one is wet, the other is dry-pipe. There are no inside hose valves, just a small NFPA 13 building.

Does the fire pump size need to accommodate hose allowances?

The sprinkler calculations have no inside hose allowance. We would typically apply the hose allowance at the city tap, which would be upstream of the fire pump. 

Thanks in advance.

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Does a diesel-powered fire pump require a full flow relief valve to prevent over pressurization due to a RPM governor failure?

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Under NFPA 20, Section 4.20.7.1: 

The circulating relief valve shall actuate below the opening set point of the pressure relief valve to ensure cooling of the pump during churn operation.

NFPA 20 Handbook:
​
The pressure setting of the circulation relief valve should be well below the pressure relief valve setting but above the maximum suction pressure.

Based on this, how do I properly specify the circulation relief valve setting that is installed on the pressure relief valve discharge line if the pressure relief valve set point is 175 psi?

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When doing an annual test today for large fire pumps with a combined test header, I was told that most inspectors throttle and send water to the pitot gauges by using the butterfly valve inside the pump room and keeping the control valves wide open outside on the test header.

I disagreed with this approach, as my mentor in the industry taught me to first charge the test header and then get your pressures by opening each outside control valve individually to get your pressures. He said this is so that you don't burn up the rubber on the inside test header (normally-closed) butterfly valve. He said it happened to him in the past and then the building owner is left with a leaking test header control valve and the danger and costliness of a test header full of water.

Is there a correct way (by code) to get your pitot reading off the hose monsters outside (what I mainly using) or is charging water one way or the other simply a matter of preference?

I hope this makes sense.

I understand some test header control valves are OS&Y but most all the outside components I come across are the test hose connections that open and close via the gate valve.

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Is there a minimum distance requirement between a unit heater and a diesel fuel tank within a fire pump room?

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There's a project in our jurisdiction that is a warehouse with a detached fire pump building.

They are proposing to feed the controller for the diesel fire pump (in the detached fire pump building) from the service in the main warehouse building.

Are there any relevant fire codes or standards that require the controller to be fed from a separate service?

Or, at least fed from a service that is "dedicated" to the fire pump building?

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We have a newly-installed electric (duty) fire pump, and a back-up diesel fire pump. 

Each pump has a 100% required flow capacity for the system (750 gpm each) for the building.

Is it OK to run the two pumps simultaneously during testing - which would result in a 200% flow?

The diesel pump is only intended to be used during power interruption/worst-case, but not with normal power online.

During testing, we release water in the test line (flow meter) - the pressure went down and triggered the cut-in pressure of both the electric and diesel pump which makes it run simultaneously (electric first, then the diesel a few seconds later).

Does this not have a water hammer effect on the system?

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Working on a project with an underground water storage tank, where the water level is under the pump suction inlet. The pump type is a vertical turbine pump.

Is the a maximum vertical length of suction pipe for this type arrangement?

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Hello everyone -

I have a problem with two identical fire pumps rated at 145 psi at 2,500 gpm.

When testing for 0% flow and 100% flow the pump gives the correct pressure, but, when testing 150% flow the pressure drops dramatically, it has to show 125 psi and the result is 92 psi.

The pumps has a 10-inch flange suction an as NFPA allows it was installed a 10-inch pipe directly to the pipe, no suction reducer, having 16-ft (5 m) long of distance for one pump and 19'-6" (6 m) for another one, the second one with two 45-degree elbows installed more than 10 times the diameter from pump suction.

The tank is 23-ft (7 m), full of water. The test outlet is installed on the other side of the tank, so the flow does not fall over the suction inlets. The antivortex inlet has a plate of 7.5 inches above the floor.

The pump discharge is 10 inch.

The flow meter is 8-inch diameter with 8 diameters before and more than 5 diameters after.

Any idea why the pressure at 150% is so low?

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Happy New Year everyone!

We are upgrading protection for one of our Crude Oil Storage Facilities for a major oil and gas clients in the Middle East region. We have 4,000 gpm diesel driven pumps for fire water use. There are 8-inch pressure relief valves provided, per Section 4.20 of NFPA 20-2019.

Section 4.20.4.1 (Type) reads as "pressure relief valves shall be either a listed spring-loaded or a pilot-operated diaphragm type."

My interpretation of this section is that the listing is required in either of these cases, whether it's spring loaded or pilot operated.

However, it's being challenged by those who are reading word-to-word meaning and saying that the listing requirement is only applicable for spring-loaded, and not for pilot operated relief valves as the sentence is separated by "or" along with the latter "a". If the letter "a" is not there, then I'm convinced with my interpretation that the listing is applicable for both cases.

Also, I checked the handbook but it does not provided any further detail.

Has anyone had any insight/experience as to whether the listed requirement applies to pilot-operated relief valves?

I appreciate any further detail or discussions on the above with reference to code interpretations. Thanks!

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I'm performing a shop drawing review of underground concrete storage tanks, to be used for firefighting.

We have six tanks arranged into two rows of three. 12-inch pipes connect the three tanks per row toegether, and one 12-inch pipe connects the two rows at one end.

It makes a U-shape flow path down one row, and back up the other.

Should two more linking pipes be added to form a complete grid, and allow more paths for water to flow?

Should these linking pipes be provided with vortex plates?

Thanks in advance!

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We have to move pre-action valves for two different pre-action systems from their original location in the fire riser room to another area of a warehouse. The location where they are inteded to be placed is protected by ESFR sprinklers for high-pile storage hazards.

Is there any requirement to place the valves and panel in this location?

Do they have to be placed in a room to avoid mechanical damage, or some type of enclosure?

Can they just be in the warehouse without any code violation (we are under both FM and NFPA suppression standards)?

Thanks in advance.

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Is there a requirement to monitor a fire pump or fire protection sprinkler riser room's temperature with the fire alarm system?

It is clear from NFPA 72 that the device needs to be added to the fire alarm panel if it is present.

NFPA 13, 14, and 20 don't seem to have a need to monitor the room's temperature.

From NFPA 72 (2016 Edition): Section 17.16.5 Room Temperature Supervisory Signal - Initiating Device. A room temperature supervisory device shall indicate a decrease in room temperature to 40 degrees (4.4 C) and its restoration to above 40-degrees (4.4 C).

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We have a project where we're using a vertical turbine fire pump.

NFPA 20 makes reference to a 'water level' at 150% of pump rated capacity. What exactly does this 'water level' mean?

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We have a pump house that is 250-ft away from primary building. I was told that we have to maintain a 42-degree temperature inside the pump house.

Although we are in Jacksonville Florida it still gets down to the mid twenty's here and there.

The doors are in really bad shape and need replaced to hold in the heat.

What are the requirements for replacement doors on a pump house? Do they need to be vented?

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What are time delay intervals associated with a fire pump's energy source transfer?

Is a 2-minute wait time long enough before notating an impairment when the pump doesn't start operating at peak again after shutting down the main power on an annual pump test?

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Hello lovely forum. Recently there was a question on taking the FDC off the fire pump bypass as long as it was downstream of any control valves on the pump bypass.

[Moderator Note: link to that question is here: https://www.meyerfire.com/daily/allowed-to-tap-fdc-into-fire-pump-bypass]

Building off that question, I have seen freestanding fire department connections being feed into an exterior hotbox that has the backflow preventer. This setup is before the feeds enter the building, and before going to a fire pump inside the building (and control valves before the pump).

Is this a violation of code, for having control valves on the FDC line before the valve header?

Thanks for your time.

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