ISO 5674:2004 specifies laboratory tests for determining the strength and wear resistance of guards for PTO drive shafts on tractors and machinery used in agriculture and forestry, and their acceptance criteria. It is intended to be used in combination with ISO 5673. ISO 5674:2004 is applicable to the testing of such PTO drive shaft guards and their restraining means. It is not applicable to the testing of guards designed and constructed to be used as steps. Neither is it applicable to guard types whose use is limited by national regulations.