api5000’Obsolete’, ’discontinued’ or ’withdrawn’ API flanges have not been included in the above slide rule. Important note:- the above slide rule assumes ambient temperatures. Additionally, asAPI 6A TYPE 6B 5000 PSI Blind pipe flanges are used to seal the end of a piping system or pressure vessel openings to prevent flow.API 6A TYPE 6B 5000 PSI Blind flanges are mainly