This publication is a guide for medical gas manufacturers and/or distributors developing company-specific standard operating procedures (SOP) for qualifying suppliers who provide medical gases, medical devices, equipment, components, or services.It may be used when qualifying new suppliers or when requalifying existing suppliers of medical gases including other gases, which includes:- original manufactures of medical oxygen, nitrogen, carbon dioxide, helium, nitrous oxide, and air by compression that swap with or directly supply to other original manufacturers or their customers;- subsequent manufacturers of medical gases obtaining medical gases from an original manufacturer; and- subsequent manufacturers of medical gases obtaining medical gases from another subsequent manufacturer.