IEC 61241-4:2001 pdf free download Electrical apparatus for use in the presence of combustible dust – Part 4: Type of protection “pD”
1Scope
This part of lEC 61241 gives requirements on the design, construction, testing and marking ofelectrical apparatus for use in combustible dust atmospheres in which a protective gas (air orinert gas), maintained at a pressure above that of the external atmosphere, is used to preventthe entry of dust which might otherwise lead to the formation of a combustible mixture withinenclosures which 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.
This standard 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,andfor the safety provisions and devices necessary to ensure that pressurization is establishedand maintained for type of protection pressurization “pD”.
Requirements for pressurized enclosures with an internal source of dust release are notincluded in this standard.
This standard does not cover the requirements for pressurized rooms with or without internalsources of dust release.
This standard does not apply to dusts of explosives which do not require atmospheric oxygenfor combustion or to pyrophoric substances.
This standard does not cover combined gas and dust hazard.Those requirements are underconsideration.
The requirements contained in this standard are supplementary to those in lEC 61241-1-1.
Normative references
The following normative documents contain provisions which, through reference in this text,constitute provisions of this part of lEC 61241.For dated references, subsequent amendmentsto, or revisions of, any of these publications do not apply. However, parties to agreements
based on this part of lEC 61241 are encouraged to investigate the possibility of applying themost recent editions of the normative documents listed below.For undated references, thelatest edition of the normative document referred to applies.Members of lEC and lSO maintainregisters of currently valid International Standards.
IEC 60034-1:1996, Rotating electrical machines – Part 1: Rating and performance 1)
IEC 61241(all parts)， Electrical apparatus for use in the presence of combustible dust
IEC 61241-1-1:1999, Electrical apparatus for use in the presence of combustible dust 一
Part 1-1: Electrical apparatus protected by enclosures and surface temperature limitation -Specification for apparatus
IEC 61241-1-2:1999,Electrical apparatus for use in the presence of combustible dust 一
Part 1-2:Electrical apparatus protected by enclosures and surface temperature limitation 一Selection, installation and maintenance
IEC 61241-3:1997,Electrical apparatus for use in the presence of combustible dust – Part 3:Classification of areas where combustible dusts are or may be present Definitions
For the purpose of this part of lEC 61241, the definitions from lEC 61241-1-1 and the followingapply.
3.1
type of protection “pD”
technique of applying a protective gas to an enclosure in order to prevent the formation of anexplosive dust atmosphere inside the enclosure by maintaining an overpressure against thesurrounding atmosphere
3.2
overpressure
pressure above ambient pressure within a pressurized enclosure
3.3
pressurization
technique of guarding against the ingress of the external dust atmosphere, which may be
explosive, into an enclosure by maintaining a protective gas therein at a pressure above that ofthe external atmosphere
3.4
protective gas
air or inert gas used for maintaining an overpressure
NOTE For the purpose of this standard inert gas means nitrogen, carbon dioxide, argon or any gas which, whenmixed with oxygen in the ratio of 4:1 as found in air, does not make the igntion and combustible properties, such ascombustible limits, more onerous.
3.5
enclosure
all the walls which surround the live parts of electrical apparatus including doors, covers, cableentries, rods,spindles and shafts and which ensure the protection of the electrical apparatus
IEC 61241-4:2001 pdf free download
