Converting scfm to lb/hr, which density should I use?

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SUMMARY

To convert cubic feet per minute (CFM) to pounds per hour (lb/hr), one must use the actual density of the gas at the given conditions. For air at 150°F and 125 psig, the density is 0.61 lb/ft³, while at standard conditions, it is 0.0765 lb/ft³. The conversion process involves multiplying the CFM value by the actual density and then by 60 minutes per hour to obtain lb/hr. Understanding the difference between CFM and standard cubic feet per minute (SCFM) is crucial for accurate conversions.

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Engineers, HVAC professionals, and anyone involved in gas flow calculations or conversions will benefit from this discussion, particularly those working with air density and flow rates in industrial applications.

Frankenstein19
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Homework Statement
If I convert from cfm to scfm, should I use the density of the material at standard conditions or what the conditions the material is actually at?
Relevant Equations
lb/hr = cubic feet/min * 60 min/hr * lb/cubic feet
For air for example at conditions 150 F and 125 psig, density is 0.61lb/ft3

At standard conditions it's 0.0765lb/ft3

If I convert 500 cfm to scfm, does this mean I should multiply by 0.0765lb/ft3*60min/hr to convert to lb/hr?
 
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It is not clear to me what are cfm and scfm, never seen these units (I can guess, but I prefer to be sure).
 
To convert CFM to lb/hr, you multiply by the actual density. To convert lb/hr to scfm, you then divide by the standard density.
 
In general the only invariant thing in such calculations is the mass.
 

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