Fire Fighting System Design

[vp1959]

Dear Sir,

Hi Designers/ experts in Fire Fighting System

The Fire Fighting System installed for a Construction Equipment Showroom, Spare Parts Store and Workshop facilities spread in an area of 7,500sq.m is provided with:
1) 2x electric driven fire pumps each rated for 1,000GPM/ 94kW
2) 1x electric driven jockey pump rated for 100GPM/ 15kW
3) All above three pumps are feeding from the emergency switchboard fed from main power and emergency generator power through the ATS
4) About 200 sprinkler heads and 10 fire hydrant outlets

Kindly advice the following taking into consideration of codes, industrial practices, reliability, easy for maintenance, etc.
1) What can be the maximum capacity of jockey pump in relation to the main fire pumps? The existing jockey pump is about 10% of the main fire pumps and it is short cycling probably due to pressure surge in auto mode
2) Is it advisable to have two smaller jockey pumps instead of one for having backup (In case one is down for service or repair the other can be used)?
3) Is it permitted to feed all pumps from the same switchboard?
4) Is it permitted to locate all three pumps in one room (confined/ underground room)

Appreciate valuable response

Regards

Prakash

 

[3cio]

Hi!

1. As mentioned in NFPA 20 handbook, we could take a rule of thumb of 1% of FP capacity. Sometimes, we calculate for the leakage rate if we have a large underground system or we select it as a one sprinkler flow. Whichever is higher.

2. There is no requirement of providing two jockey pump in the system as per NFPA-20.

3. I think we could feed that in the same switchboard. but you must consult the AHJ regarding this. as per my exp., the main FP switchboard is separate from na back up FP per the requirement of AHJ in our area.

4. yes. Typically all the pumps should be in the same area.

hope it helps,