# Specific Gravity of Gas

on . Posted in Classical Mechanics

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 $$\large{\frac{lbm}{ft^3}}$$ $$\large{\frac{kg}{m^3}}$$