Originated as part of AS 2220—1978.Previous edition AS 2220.2—1989.Revised and redesignated as AS 1670.4—2004.Second edition AS 1670.4:2015. Originated as part of AS 2220-1978. Previous edition AS 2220.2-1989. Revised and redesignated as AS 1670.4-2004. Second edition AS 1670.4:2015.