This specification covers chemically resistant, low expansion borosilicate glasses (Type I, Class A) used to manufacture beaded and end flanged-glass pipes and fittings for pressure and vacuum applications. Both the inside and outside surfaces of the glass shall be reasonably free of surface defects, such as open blisters or airlines and scratches, and shall be completely free of chips and checks. Pipe and fittings may be suitably heat treated (tempered) or annealed as specified by the manufacturer. Products should adhere to chemical, physical, and dimensional requirements, as well as minimum and maximum operating temperature, thermal shock resistance, and pressure ratings.