This SAE test method establishes a uniform test procedure for determining the gravimetric (mass based) efficiency and pressure drop performance levels of operator enclosure panel type filters on off-road, self-propelled work machines used in earth moving, and forestry, as defined in SAE J1116 and for agricultural equipment as defined in ANSI/ASAE S390, and equipped with an operator enclosure with a powered fresh air system. ISO/TS 11155-1 may additionally be used, which describes the use of particle sizing devices to measure the fractional (particle size) efficiency of panel type filters for automotive cabin filter applications. Automotive cabin filters are similar to filters described in this procedure, and the ISO/TS 11155-1 test method is therefore directly applicable.