Gas Correction Factors for Vacuum Pressure Gauges

Vacuum pressure gauges will typically arrive from a manufacturer calibrated for nitrogen; for other gases, to avoid potentially significant measurement errors, a correction factor must be used to convert ‘measured’ or ‘indicated’ pressure to ‘true’ pressure. The correction factors used are influenced by a large number of factors and these vary with gauge type. In this article the factors leading to varying gauge sensitivity with different gases are examined and values for correction factors provided by manufacturers and in literature are presented.