This part of ISO 8178 specifies the measurement procedures and test cycles for the evaluation of smoke emissions from compression ignition engines under field conditions. This part of ISO 8178 is intended for use primarily as a support for in-use smoke testing programmes on engines that have been “certified” or “type approved” in accordance with the provisions of ISO 8178-9. ISO 8178-9 provides test procedures and test cycles for measurement of smoke from different applications of engines operating on the test bed. Likewise, ISO 8178-4 specifies a number of different test cycles to be used in order to characterize gaseous and particulate emissions from nonroad engines. The test cycles in ISO 8178-4 were developed in recognition of the differing operating characteristics of various categories of nonroad machines. For transient smoke test cycles, smoke testing is conducted using smokemeters that operate on the light extinction principle. The purpose of this part of ISO 8178 is to define the smoke test cycles and the methods used to measure and analyse smoke. Specifications for measurement of smoke using the light extinction principle can be found in ISO 11614. The test procedures and measurement techniques described in clauses 5 to 11 of this part of ISO 8178 are applicable to reciprocating internal combustion (RIC) engines in general. However, an engine application can only be evaluated using this part of ISO 8178 once the appropriate test cycle has been developed. Annexes A to C to this part of ISO 8178 each contains a test cycle that is relevant only for those specific applications listed in the scope of that annex. Where possible, the smoke test cycle described in the annex utilizes the engine and machine categories developed in ISO 8178-4.