This part of ISO 10263 specifies a uniform test method for measuring the contribution to operator environmental temperature provided by a heating, ventilating and air conditioning system operating in a specific ambient environment. The method might not determine the complete climatic environment of the operator since this is also affected by heat load from sources other than those on the machine, for example solar heating. ISO 10263-6 is to be used in conjunction with this part of ISO 10263 to determine more accurately the complete heat loading on the operator enclosure. Minimum performance levels for the machine’s operator enclosure heating, ventilating and air conditioning systems are established in this part of ISO 10263. NOTE The HVAC is also referred to as the climate control system.