This standard specifies the technical requirements, test methods, inspection rules, marking, packaging, transportation and storage of 1,1,1,3,5,5,5-heptamethyltrisiloxane. This standard is applicable to the preparation of 1,1,1,3,5,5,5-heptamethyltrisiloxane through acid catalytic equilibrium and fractionation using hexamethyldisiloxane and polymethylhydrogensilane as raw materials. . (hereinafter referred to as heptamethyltrisiloxane)