scope:

This standard provides requirements for the testing, design, installation, and maintenance of electrical resistance heat tracing in general industries as applied to pipelines, vessels, pretraced and thermally insulated instrument tubing and piping, and mechanical equipment. The electrical resistance heat tracing is in the form of series heating cables, parallel heating cables, and surface heating devices. In this standard, the terms hazardous (classified) locations and potentially flammable atmospheres refer to the same conditions. The requirements also include test criteria to determine the suitability of these heating devices utilized in industrial applications as applied in unclassified (ordinary) and hazardous (classified) locations as follows:

Class I ¹

Division 1

Division 2

Zone 1

Zone 2

Class II

Division 1

Division 2

Class III

Division 1

Division 2

Unclassified (ordinary)

¹ Class I is a term used with zone locations in the USA and Canada.