Fire fighting pump for hose reel systems

[davidddd]

hi,
The conditions are as follows:
-I just want to supply water for class I & III hose cabinets, there is not a sprinkler system.

-I calculate the required pressure by myself, only tell me the nominal flow capacity of the pump (gpm) and I guess a fire pump can supply up to 140% of its nominal capacity

-Condition: ordinary hazard group II

-Consider the pump is going to furnish 10 hose cabinets

I guess the required flow is 250 gpm, but I'm not sure, am I right?

Which pump do you recommend for this system?

 

[cdafd]

Look at nfpa 14

Your flow is wrong

 

[SprinklerDesigner2]

You are going to need a bigger pump.

5-9.1.1* Minimum Flow Rate.

For Class I and Class III systems, the minimum flow rate for the hydraulically most remote standpipe shall be 500 gpm (1893 L/min). The minimum flow rate for additional standpipes shall be 250 gpm (946 L/min) per standpipe, with the total not to exceed 1250 gpm (4731 L/min). For combined systems, see 5-9.1.3.

Exception: When the floor area exceeds 80,000 ft2 (7432 m2), the second most remote standpipe shall be designed to accommodate 500 gpm (1893 L/min).

You will need 1,250 gpm and lacking sprinklers 100 psi will be required at the top outlet. Depending on the height of the standpipe you might not be able to use a 1,000 gpm pump if the building has any appreciable height. It may be possible to use a 1,000 gpm pump in a four story building but, again depending on the curve it might, not work in an eight or ten story building. In any event 1,000 gpm would be the smallest you could use.

You can also use any point on a pump curve out to 150%.

 

[davidddd]

Thanks for your answers,
The reason I thought 250gpm is enough was because of Table 11.2.3.1.1 in NFPA 13-2002, which states the total combined inside and outside hose (gpm) for a ordinary hazard is 250.

So, installing sprinkler system usually reduces the total required flow?
What if the building is partially protected by sprinklers, how does the required flow change? For example, consider in a building only garages
are protected by sprinklers but the office areas are unsprinklered.

 

[cdafd]

A standpipe system is designed to nfpa 14. Not nfpa 13

 

[stookeyfpe]

Since this appears to be an open parking garage, have you considered applying Section 9.1.4 and avoiding the fire pump:

Where fire department pumpers cannot supply the required system demand through a fire department connection, an auxiliary water supply consisting of high-level water storage with additional pumping equipment or other means acceptable to the AHJ shall be provided.