Specific Gravity of Gas

Specific gravity of gas, abbreviated as \(SG_g\), a dimensionless number, is the ratio of the density of the gas to the density of air at a standard pressure and temperature.

 

Specific Gravity of Gas formula
\(\large{ SG_g = \frac{\rho_g}{\rho_a}  }\)
Symbol	English	Metric
\(\large{ SG_g }\) = specific gravity of gas (air = 1.0)	\(\large{dimensionless}\)
\(\large{ \rho_a }\) = density of air	\(\large{\frac{lbm}{ft^3}}\)	\(\large{\frac{kg}{m^3}}\)
\(\large{ \rho_g }\) = density of gas	\(\large{\frac{lbm}{ft^3}}\)	\(\large{\frac{kg}{m^3}}\)