UL 913:2019 pdf download.Intrinsically Safe Apparatus and Associated Apparatus for Use in Classl, ll, and lll, Division 1, Hazardous (Classified) Locations.
6.2 Zone 20, Group lIA
6.2.1 Intrinsically safe and associated apparatus intended to be marked in accordance with 11.1 shallcomply with all the applicable requirements for Class ll hazardous (classified) locations as applicable,
6.3 zone 20, Group mB
6.3.1 Intrinsically sale and associated apparatus intended to be marked in accordance with 11.2 shallcomply with all the applicable requirements for Class ll,Group F, Group G or both Groups F and Ghazardous (classified) locations as applicable.
6.4 zone 20, Group llc
6.4.1 Intrinsically safe and associated apparatus intended to be marked in accordance with 11.3 shallcomply with all the applicable requirements for Class ll,Group E hazardous (classified) locations asapplicable.
7 Apparatus For Class ll And Class lll Locations7.1General
7.1.1 Intrinsically safe apparatus and associated wiring for Class ll and Class ll locations shall complywith the requirements in Sections 1 - 5 in this standard,as applicable and shall also comply with therequirements of 7.1.2 and either 7.1.3 or7.1.4.
7.1.2*The temperature of exposed surfaces of apparatus shall be determined when tested according tothe procedures described in 9.1 -9.3.For this requirement, "exposed”means exposed to the flammableor combustible atmosphere or material. Parts within a dust-tight enclosure are not considered exposed;the outside surfaces of the enclasure are exposed.
Exception:Temperatures of small components under fault conditions shall be permitted to exceed theselimits if it is shown by test that such higher termperatures will not result in ignition or charring.
