Internal Gas Rod Load is the force imposed on the rod, caused by pressure inside the cylinder against the head end and crank end piston areas. Ariel's gas rod load equations apply internal cylinder pressure, accounting for pressure losses through valves and cylinder passages.

Ariel uses internal gas rod loads for a compressor frame rating. Combined gas and inertia loads are not part of the frame rating, but are used for determining the crosshead pin load reversal.

For Internal Gas Rod Load equations, please refer to the Ariel Calculation Method topic.