This part of ISO 8528 specifies the principal charac- teristics of a reciprocating internal combustion (RIC) engine when used for alternating current {a.c.) gen- erating set applications. It applies to RIC engines for a.c. generating sets for land and marine use, excluding generating sets used on aircraft or to propel land vehicles and loco- motives. For some specific applications (for example, essen- tial hospital supplies, high rise buildings, etc), sup- plementary requirements may be necessary. The provisions of this part of ISO 8528 should be re- garded as a basis. The terms vvhich define the speed governing and the speed characteristics of RIC engines are listed and explained where they apply specifically to the use of the engine for driving generators. For other reciprocating-type prime movers (e.g. sevvage gas engines, steam engines), the provisions of this part of ISO 8528 should be used as a basis.