Air compressor to fill 3.5 cubic metres to 100kPa in 5 mins

[tabletop]

Hello,

After repair work to fire protection pipe work we would like our techs to use a portable compressor to pressure test the system with about 100kPa of air before re-charging with water. It should be a quick indicator of ends accidently left open and large audible leaks.

The pipe work installations are around 3.5 cubic meters(120 cubic feet) in volume. Using a standard workshop compressor it takes too long. Is there a single phase compressor more suitable for this application that could get to about 100kPa in about 5 minutes or less?

 

[trashcanman]

If you are in TX, the "techs" must be licensed in Fire Protection before they can legally touch your system. I am not sure about other states.

Second, NFPA 13, 10.10.2.2.1 states that the entire system shall be hydrostatically tested to 200 psi for 2 hrs.

If cold weather prevents a hydrostatic test, 24.2.2 allows a interim air test, but the hydrostatic test is still eventually required.

I recommend checking with the local AHJ about this "test".

 

[TenPenny]

NFPA aside, I ran a quick set of numbers, and a 10 cfm compressor should be able to do this in 11 minutes, if I ran the nubmers correctly.

http://www.abac-support.co.uk/Calculator_PumpUp.htm

Is but one of many pumpup calculators for compressed air.

 

[BigInch]

Why not just carry a couple of cylinders of compressed air? No dragging a compressor around. Looking for extension cords, power outlets, etc. 2 std. scuba tanks will do nicely. Maybe you could fill them in your shop.

http://virtualpipeline.spaces.msn.com

"What gets us into trouble is not what we don't know, its what we know for sure" - Mark Twain

 

[tabletop]

trashcanman,
Yes, it is a licenced fire protection service company doing the work.

TenPenny,
Thanks, I did search for a simple online calculator before posting with no luck. Unfortunately I dont have the required excel applet so your's dosnt work for me. Do you have another? I'd like to play with the numbers to get that time down.

Biginch,
Pre compressed air, a top idea. With that in mind...

Say my cylinder is .03 cubic meter volume and it was pre compressed to 1000kPa. If I connect it to the insallation which is 3.5 cubic meters (atmospheric pressure) what is the resulting pressure?

or better yet, if anyone could point me to the relevant formula...

 

[BigInch]

That 0.03 m3 cylinder is too small and at very low pressure.

check this table. Shows what pressures you need for a 1 m3 tank volume.

http://www.cp-industries.com/Compressability.htm

You'll need something about the size of 1.5 std scuba tanks (they're usually somewhere around 130-150 Barg)

Here's some more tank ideas,

http://www.bauerpaintball.com/downloads/pdf/Storage Brochure 2005.pdf

http://virtualpipeline.spaces.msn.com

"What gets us into trouble is not what we don't know, its what we know for sure" - Mark Twain