Other NFPA Standards address fire pump requirements such as 409 and 15 I 
believe as requiring the full satisfaction of the design demand being met with 
the largest (of multiple pumps) being out of service. I've not experienced such 
high flow demands as Q= 7500 outside these Standards.

Mark at Aero
602 820-7894

Sent from my iPhone

On Dec 19, 2017, at 4:05 PM, Cahill, Christopher 
<[email protected]<mailto:[email protected]>> wrote:

So I found this in NFPA 20 - 4.9.1 A centrifugal fire pump for fire protection 
shall be selected so that the greatest single demand for any fire protection 
system connected to the pump is less than or equal to 150 percent of the rated 
capacity (flow) of the pump.

So does that mean if the demand is 1,000 gpm I can’t use 3 - 250 gpm pumps?  
Don’t ask why someone would do that, yes it would be odd.  Think really big 
flows and high pressures where variable flow in reality one might choose to 
split the pumps.

So basically isn’t it demanding a single pump for systems up to 7,500 gpm? 
(assuming a 5,000 gpm pump is the maximum) No option for using 2 - 3,000’s?

Chris Cahill, PE*
Associate Fire Protection Engineer
Burns & McDonnell
Phone:  952.656.3652
Fax:  952.229.2923
[email protected]<mailto:[email protected]>
www.burnsmcd.com<http://www.burnsmcd.com/>
*Registered in: MN

If Americans switched from pounds to kilograms there would be mass confusion.

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