This SAE Standard applies to off-road, self-propelled work machines used in construction, general-purpose industrial, agricultural, forestry, and specialized mining machinery as defined in SAE J1116 JUN86, and establishes the following minimum performance levels in the operator's environment for the seated position: Minimum operator enclosure pressurization and ventilation levels in the operator's environment for the seated position. Maximum temperature differential under air conditioning operation. Minimum temperature differential under heater operation.