Estimating system water volume

[chaz12]

Are there any rules of thumb that would allow a consulting engineer to estimate the water volume in a preaction sprinkler system before the actual system layout is designed by the sprinkler contractor. I need an estimate to define the HP of the air compressor for the system

Thanks

Chaz12

 

[SprinklerDesigner2]

There isn't much to go on it all depends on the size of the system, the water supply and hazard which has all to do with size of pipe.

On a double interlocked system

http://www.vikinggroupinc.com/databook/preaction/070789.pdf

you are supposed to maintain 50 psi for water pressure to 175 psi.

I looked at a system I did; .30/2000 with a water supply of 70, 50 and 1200 and came up with 719 gallons over40,000 sq. ft. for 0.018 gallons per sq. ft..

A 10,000 sq. ft. system would have around 180 gallons based on the last system I did.

For you, me not knowing particulars, this information is all but useless but maybe it will give some sort of an idea.

Sorry I couldn't be more specific.

 

[chaz12]

Thank you, sir. Your post was helpful. Our system is single interlock and I have read that 20 psi in the system is normal. Our hazard is O2 and our pressure may be a little better: 82 static, 68 residual, at 1150 gallons.

But the compressors I looked at on the Viking site show that any volume over 300 gallons gets into a horsepower larger than 1/2. So I am going to tell the electrical engineer to provide a voltage higher than 120.

Thanks again.

Chaz12