BS EN 61241-4:2006 PDF

BS EN 61241-4 specifies the requirements for the design, construction, testing and marking of electrical apparatus for use in combustible dust atmospheres. These are atmospheres in which a protective gas (air or inert gas), maintained at a pressure above that of the external atmosphere, is used to prevent the entry of dust which might otherwise lead to the formation of a combustible mixture within enclosures that do not contain a source of combustible dust. This standard contains the specific requirements for construction and testing, including protective requirements that apply to electrical apparatus with type of protection pressurization "pD" intended for use in potentially combustible dust atmospheres. Part 4 of BS EN 61241 includes the requirements for the construction of the enclosure and its associated components, including, if any, the inlet and outlet ducts for the protective gas, and for the safety provisions and devices necessary to ensure that pressurization is established and maintained for type of protection pressurization "pD". This standard does not cover the requirements for pressurized rooms with or without internal sources of dust release, nor does it apply to dusts of explosives which do not require atmospheric oxygen for combustion or to pyrophoric substances. Requirements for pressurized enclosures with an internal source of dust release are not included in this standard. This standard does not cover combined gas and dust hazard. Those requirements are under consideration. The requirements contained in this standard are supplementary to those in . Contents include Scope Normative references Definitions Pressurization principle Protective gas Automatic disconnection Cleaning Discharge of protective gas General constructional requirements Electrical performance of apparatus ...