Use the following equation: Fstd.= Volume Flow * (Pactual * Tstandard)/(Pstd. * Tactual) Where: Fstd.: Flow in sccm (or sccs) Volume Flow: cc/min (or cc/sec) Pactual: Actual Pressure as Absolute Pressure units (e.g: psia, Kpa-Absolute) Pstd.: Your standard barometric pressure e.g: 14.695 psia Tactual: Actual temperature in absolute units (Kelvin or Rankin) Tstd.: Your standard temperature (e.g 428° R =68° F, 293° K=20° C). For many leak test applications, we assume that Tactual = Tstd. and the conversion then becomes: Fstd. = Volume Flow * (Pactual/Pstd.) ATC's Intelleigent Gas Leak and Flow sensors provides both measurement units, using actual pressure and temperature measurements that are part of our sensor.