Instrument Air Consumption 2

[mwheeler]

Are there any new "rules of thumb" for calculating instrument air consumption for compressor sizing?
I have always used 0.5 to 1.0 scfm per user plus a margin but, in modern plants, the majority of steady state consumers are smart positioners that use about 0.2 scfm. Any advise?

 

[ICman]

I used to use 0.5 - 1.0 SCFM, but now look at 0.5 for all users. This includes a substantial safety margin, however, so you have to keep that in mind.

Look especially for those users that require gobs of air, usually periodically. Starting air for motors, compressors, etc. is often missed. Also, anything that may be purged.

Will the air be used for maintenance purposes? Things like blow guns, valve testing, etc. can tax your supply.

Hope this helps.

. . . Steve