ISO 21006:2006 specifies how to make a declaration of the engine weight (mass) for internal combustion engines.
For the purposes of this standard, the word weight is used as the direct equivalent of the word mass.
ISO 21006:2006 concerns reciprocating internal combustion engines (spark-ignition or compression ignition engines) but excluding free piston engines, and rotary piston engines.
NOTE These engines may be naturally aspirated or pressure-charged, either by a mechanical pressure-charger or a turbocharger.
ISO 21006:2006 applies to engines for land, rail-traction and marine use, the propulsion of automotive vehicles, propelling (or powering) non-road mobile machinery, motorcycles, the propulsion of agricultural tractors and machines, the propulsion of earth-moving machinery as defined in ISO 6165, and the propulsion of recreational or other small marine craft of full length up to 24 m .
In addition, ISO 21006:2006 may be applied to engines used to propel road-construction machines, industrial trucks and for other applications where no suitable International Standard for these engines exists.