CAN/CSA-E79-1-95

1. Scope 1.1 This standard specifies the constructional features and test requirements for flameproof enclosures of electrical apparatus intended to be used in explosive gas atmospheres. In addition, flameproof enclosures shall comply with the applicable requirements of IEC 79-0. This standard applies to enclosures and parts of enclosures constructed of metallic and non-metallic materials. Some additional requirements may be necessary for non-metallic materials and these are left to the discretion of the national or other appropriate authority. See Appendix A. 1.2 The ambient temperature range of -20 °C to +60 °C for the explosive gas atmosphere characteristics and -20 °C to +40 °C for the operation of electrical apparatus as given in IEC 79-0, also apply to this standard. For ambient temperatures below -20 °C, stronger enclosures may be required due to the higher explosion pressures generated at low temperatures and the possibility of brittle failure of enclosure materials. For ambient temperatures above 60 °C, it may be necessary to use smaller joint gaps because the maximum safe gap tends to decrease with an increase in ambient temperature. 1.3 This part of IEC 79 deals only with flameproof enclosures and not with other means of protection against an explosion hazard. These are covered by separate standards.