Fire pump info

[cda]

http://www.plumbingengineer.com/dec_09/fire.php

 

[Insurance Engineer]

Re: Fire pump info

Thanks CDA,

Good stuff I see this one below that a lot of designers and plan reviewers miss. This is a hard one to correct once the pump is installed. :cry:

3. Suction piping. To avoid potential for cavitation, arrange the pump suction to avoid elbows and tees within 10 pipe diameters of the fire pump suction flange. It is acceptable to have an elbow with a centerline plane perpendicular to the horizontal split-case pump shaft, i.e. an elbow turning up or down into the pump, but not right or left into the pump. This is one of the most common errors I see in pump room layout. Also make sure an eccentric reducer is used at the pump suction flange if its diameter is less than the suction pipe.

 

[FyrBldgGuy]

Re: Fire pump info

I would agree this is a good list of common problems. At the present time I am working to resolve two fire pump design issues. One pump is oversized based on an improper original flow test from city water. The intake pressure is higher than calculated resulting in pressures over 250 psi on a system with fittings rated to 175. The entire system has numerous pressure reducing valves that all allow slow bleed across the valves. I hope the system is fixed before it blows.

Another fire pump was not designed for ease of testing, so use of the test header is not permited. The water source is from a cooling water basin that has treated water. Any fire pump test using the header would result in contaminated water going to ground.

 

[Insurance Engineer]

Re: Fire pump info

Another fire pump was not designed for ease of testing, so use of the test header is not permitted. The water source is from a cooling water basin that has treated water. Any fire pump test using the header would result in contaminated water going to ground.

Why not a flow meter on the pump discharge piped back to the water basin? The only thing you need to make sure is the meter is calibrated annually or what ever the meter mfg requires. With this set up you can test the pump and meet both NFPA 20 and 25 and not loose a drop of water.