This International standard specifies the requirements for the design and construction of non -electrical equipment, intended for use in explosive atmospheres, protected by the types of protection constructional safety "ch", control of ignition source "bh", liquid immersion "kh". This standard supplements and modifies the requirements in ISO 80079-36. Where a requirement of this standard conflicts with the requirement of ISO 80079-36 the requirement of this standard take precedence. Types of protection "ch", "kh" and "bh" are not applicable for Group I, EPL Ma without additional protective precautions. The types of ignition protection described in the standard can be used either on their own or in combin ation with each other to meet the requirements for equipment of Group I, Group II, and Group III depending on the ignition hazard assessment in ISO 80079-36.