This document covers the pressure and vacuum breather device used to ensure normal tank compartment breathing. It specifies the performance requirements and the critical dimensions of the pressure and vacuum breather device. It also specifies the tests necessary to verify compliance of the equipment with this document. The service equipment specified by this document is suitable for use with liquid petroleum products and other dangerous substances of Class 3 of ADR [1] which have a vapour pressure not exceeding 110 kPa at 50 °C and petrol, and which have no sub classification as toxic or corrosive.