This part of ISO 8178, together with ISO 8178-1 and ISO 8178-11, specifies the measurement and evaluation methods for gaseous and particulate exhaust emissions from reciprocating internal combustion engines (RIC engines) under steady-state and transient conditions for field testing.

This part of ISO 8178 is applied when RIC engines used in off-road vehicles, marine installations, generating sets, diesel rail traction or similar applications need to be measured under field conditions or at site in order to determine the in-use compliance, or when it is not possible to take the measurements under test-bed conditions or to use the test-bed measurement results.

Re-checking or re-certification of engines for off-road vehicles after rebuild should preferably be tested outside the vehicle on a suitable load application and measurement device such as a dynamometer or load bank, but in-use compliance testing may be done on the vehicle.

This method can be used for determining conformity or certification of new, used or rebuilt engines at site or for in-use compliance testing of off-road vehicles. Confirmation of test-bed results with respect to ISO 8178-4 can also be performed within this part of ISO 8178. However, allowances need to be made for differences in engine operating parameters from laboratory conditions and for the accuracy of emission measurement equipment used under field conditions.

For engines used in machinery covered by additional requirements (e.g. occupational health and safety regulations, regulations for powerplants), additional test conditions and special evaluation methods may apply.