Maximum experimental safe gap

Maximum experimental safe gap (MESG) is a standardized measurement of how easily a gas flame will pass through a narrow gap bordered by heat-absorbing metal. MESG is used to classify flammable gases for the design and/or selection of electrical equipment in hazardous areas, and flame arrestor devices.[1] The National Electric Code classifies Class I hazardous locations into different groups depending on the respective MESG's of gases in the area.[2]

Examples

NEC Class I Group and Gas MESG[2]
NEC Class I Group	Gas MESG	Example Gas
Group A	0.25 mm	Acetylene
Group B	≤0.45 mm (Except acetylene)	Hydrogen
Group C	0.45 mm < x ≤ 0.75 mm	Ethylene
Group D	> 0.75 mm	Propane

References

Enardo Flame Arrestor Technology. "Flame Arrestor Technology" (PDF).
Class I: Flammable gases, vapors or liquids

http://site.ul.com/global/documents/offerings/services/hazardouslocations/CI_groups.pdf%5B%5D

This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.

[1] Enardo Flame Arrestor Technology. "Flame Arrestor Technology" (PDF).

[UL-2] Class I: Flammable gases, vapors or liquids