(a) This Standard provides technical criteria and guidelines forthe in-service inspection, care, repair or replacement, testing,and recertification of PVHO acrylic windows in Pressure Vessels forHuman Occupancy. It is intended to be used only with acrylicwindows designed, constructed, tested, and certified in accordancewith the requirements of ASME PVHO-1, Safety Standard for PressureVessels for Human Occupancy. (b) This Standard provides technicalcriteria for the user to establish the serviceability of a PVHOacrylic window under its specific environmental service conditions.Windows in protected environments as well as those in severeenvironments are addressed. Judicious use of this Standard willallow the user and/or the jurisdictional authority to determinewhen a PVHO acrylic window requires replacement.