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NOTE: Only one reference is generally cited for each type of product that requires NRTL approval. References may not necessarily reflect the exact current text of the cited provision. Approval by an NRTL is denoted in various ways, such as by use of the words approved, certified, listed, labeled, or even designation to a test standard.

1910.28 - Safety Requirements for Scaffolding

28(f)(2) - The scaffold shall be provided with hoisting machines that meet the requirements of a nationally recognized testing laboratory.

28(g)(3) - When hoisting machines are used on two-point suspension scaffolds, such machines shall be of a design tested and approved by a nationally recognized testing laboratory.

28(h)(2) - The hoisting machine and its supports shall be of a type tested and listed by a nationally recognized testing laboratory.

28(i)(1) - The scaffolding, including power units or manually operated winches, shall be a type tested and listed by a nationally recognized testing laboratory.

1910.36 - Design and construction requirements for exit routes

36(a)(3) - Each fire door, including its frame and hardware, must be listed or approved by a nationally recognized testing laboratory.

1910.106 - Flammable and Combustible Liquids

106(a)(29) - Safety can shall mean an approved container, of not more than 5 gallons capacity, having a spring-closing lid and spout cover and so designed that it will safely relieve internal pressure when subjected to fire exposure.

106(b)(2)(iv)(f) - Tanks and pressure vessels storing Class IB and IC liquids shall be equipped with venting devices which shall be normally closed except when venting under pressure or vacuum conditions, or with approved flame arresters.

106(b)(3)(iv)(a) - If the vent pipe is less than 10 feet in length, or greater than 2 inches in nominal inside diameter, the outlet shall be provided with a vacuum and pressure relief device or there shall be an approved flame arrester located in the vent line at the outlet or within the distance from the outlet.

106(b)(3)(v)(b) - If inside a building, each such opening shall be protected against liquid overflow and possible vapor release by means of a spring loaded check valve or other approved device.

106(b)(4)(iv)(d) - Each such opening shall be protected against liquid overflow and possible vapor release by means of a spring loaded check valve or other approved device.

106(c)(3) - Joints shall be made liquid tight. Welded or screwed joints or approved connectors shall be used.

106(d)(2)(i) - Only approved containers and portable tanks shall be used.

106(d)(4)(i) - Openings shall be provided with approved self-closing fire doors.

106(d)(4)(iii) - Electrical wiring and equipment located in inside storage rooms used for Class I liquids shall be approved under subpart S of this part for Class I, Division 2 Hazardous Locations; for Class II and Class III liquids, shall be approved for general use.

106(d)(4)(v) - Dispensing shall be by approved pump or self-closing faucet only.

106(e)(2)(iv)(d) - Flammable or combustible liquids shall be drawn from or transferred into vessels, containers, or portable tanks within a building only through a closed piping system, from safety cans, by means of a device drawing through the top, or from a container or portable tanks by gravity through an approved self-closing valve.

106(e)(5)(iv) - Where the need is indicated by special hazards of operation, flammable or combustible liquid processing equipment, major piping, and supporting steel shall be protected by approved water spray systems, deluge systems, approved fire-resistant coatings, insulation, or any combination of these.

106(g)(1)(i)(e)(5) - The dispensing nozzle is a listed automatic-closing type without a latchopen device.

106(g)(1)(i)(a) - Liquids shall be stored in approved closed containers not exceeding 60 gallons capacity, in tanks located underground, in tanks in special enclosures as described in paragraph (g)(i) of this section, or in aboveground tanks as provided for in paragraphs (g)(4)(ii), (b), (c) and (d) of this section.

106(g)(1)(iii)(a) - One container not exceeding 60 gallons capacity equipped with an approved pump is permitted.

106(g)(3)(iv)(b) 1910.106(g)(3)(iv)(b)(1) - Only listed devices may be used for dispensing Class I liquids.

106(g)(3)(iv)(b)(2) - Every dispensing device for Class I liquids installed after December 31, 1978, shall contain evidence of listing so placed that any attempt to dismantle the device will result in damage to such evidence, visible without disassembly or dismounting of the nozzle.

106(g)(3)(iv)(c) - Approved pumps taking suction through the top of the container or approved self-closing faucets shall be used.

106(g)(3)(v)(e) - An approved impact valve, incorporating a fusible link, designed to close automatically in the event of severe impact or fire exposure shall be properly installed in the dispensing supply line at the base of each individual dispensing device.

106(g)(3)(vi)(a) - A listed manual or automatic-closing type hose nozzle valve shall be provided on dispensers used for the dispensing of Class I liquids.

106(g)(3)(vi)(b) - Automatic-losing type valves may be used in conjunction with an approved latch-open device.

106(g)(4)(i)(b) - Dispensing shall be by approved dispensing units with or without integral pumps and may be located on open piers, wharves, or floating docks or on shore or on piers of the solid fill type.

106(g)(9) - Each service station shall be provided with at least one fire extinguisher having a minimum approved classification of 6 B, C, located so that an extinguisher, will be within 75 feet of each pump, dispenser, underground fill pipe opening, and lubrication or service room.

106(h)(4)(ii)(b) - Approved flexible connectors may be used where vibration exists or where frequent movement is necessary. Approved hose may be used at transfer stations.

106(h)(6)(i) - Approved portable fire extinguishers of appropriate size, type, and number shall be provided.

106(h)(6)(ii)(d) - Processing plants shall be protected by an approved automatic sprinkler system or equivalent extinguishing system. If special extinguishing systems including but not limited to those employing foam, carbon dioxide, or dry chemical are provided, approved equipment shall be used and installed in an approved manner.

1910.107 - Spray Finishing Using Flammable and Combustible Materials

107(b)(5)(iv) - Space within the spray booth on the downstream and upstream sides of filters shall be protected with approved automatic sprinklers.

107(c)(6) - Electrical wiring and equipment not subject to deposits of combustible residues but located in a spraying area as herein defined shall be of explosion-proof type approved for Class I, group D locations and shall otherwise conform to the provisions of subpart S of this part, for Class I, Division 1, Hazardous Locations.

107(c)(8) - . . . . . Portable electric lamps, if used during cleaning or repairing operations, shall be of the type approved for hazardous Class I locations.

107(e)(3) - Original closed containers, approved portable tanks, approved safety cans or a properly arranged system of piping shall be used for bringing flammable or combustible liquids into spray finishing room.

107(e)(4) - Except as provided in paragraph (e)(5) of this section the withdrawal of flammable and combustible liquids from containers having a capacity of greater than 60 gallons shall be by approved pumps.

107(e)(7) - Electrically powered spray liquid heaters shall be approved and listed for the specific location in which used (see paragraph (c) of this section).

107(e)(8) - If flammable or combustible liquids are supplied to spray nozzles by positive displacement pumps, the pump discharge line shall be provided with an approved relief valve discharging to a pump suction or a safe detached location, or a device provided to stop the prime mover if the discharge pressure exceeds the safe operating pressure of the system.

107(g)(3) - Approved metal waste cans shall be provided wherever rags or waste are impregnated with finishing material and all such rags or waste deposited therein immediately after use.

107(h)(2) - Electrostatic apparatus and devices used in connection with coating operations shall be of approved types.

107(h)(12) - Where this protection is not available, other approved automatic extinguishing equipment shall be provided.

107(i)(3) - Electrostatic hand spray apparatus and devices used in connection with coating operations shall be of approved types.

107(j)(4)(iv) - Only equipment of a type approved for Class I, Division 2 hazardous locations shall be located within 18 inches of floor level.

107(l)(7)(i) - Electrostatic fluidized beds and associated equipment shall be of approved types.

107(m)(1) - All spraying operations involving the use of organic peroxides and other dual component coatings shall be conducted in approved sprinklered spray booths meeting the requirements of this section.

1910.109 - Explosives and Blasting Agents

109(d)(2)(iii)(a) - Only extinguishers listed or approved by a nationally recognized testing laboratory shall be deemed suitable for use on explosives-carrying vehicles.

109(i)(7)(i) - Sprinkler systems shall be of the approved type and installed in accordance with 1910.159.

1910.110 - Storage and Handling of Liquefied Petroleum Gases

110(b)(2)(i) - Each system utilizing DOT containers in accordance with 49 CFR Part 178 shall have its container valves, connectors, manifold valve assemblies, and regulators approved.

110(b)(2)(ii) - The system as a unit or the container assembly as a unit, and the regulator or regulators, shall be individually listed.

110(b)(2)(iii) - In systems utilizing containers of over 2,000 gallons water capacity, each regulator, container valve, excess flow valve, gaging device, and relief valve installed on or at the container, shall have its correctness as to design, construction, and performance determined by listing by a nationally recognized testing laboratory.

110(b)(8)(iv) - Joints on seamless copper, brass, steel, or aluminum alloy gas tubing shall be made by means of approved gas tubing fittings, or soldered or brazed with a material having a melting point exceeding 1,000 deg. F.

110(b)(9)(vii)(c) - The hose shall be approved and shall not be used where it is likely to be subjected to temperatures above 125 deg. F.

110(b)(13)(ii)(b)(7) - {i} Using an approved automatic quick-closing coupling (a type closing in both directions when coupled in the fuel line), or

110(b)(20)(i) - Except as provided in paragraph (b)(20)(ii) of this section, new commercial and industrial gas consuming appliances shall be approved.

110(b)(20)(iii) - Unattended heaters used inside buildings for the purpose of animal or poultry production or care shall be equipped with an approved automatic device designed to shut off the flow of gas to the main burners, and pilot if used, in the event of flame extinguishment.

110(c)(5)(i)(g)(1) - Hose and hose connections shall have their correctness as to design, construction and performance determined by listing by a nationally recognized testing laboratory.

110(c)(5)(i)(h) - Portable heaters, including salamanders, shall be equipped with an approved automatic device to shut off the flow of gas to the main burner, and pilot if used, in the event of flame extinguishment.

110(c)(5)(ii) - Containers having a maximum water capacity of 2 1/2 pounds (nominal 1 pound LP-Gas capacity) are permitted to be used inside of buildings as part of approved self-contained hand torch assemblies or similar appliances.

110(d)(3)(iii) - All openings in a container shall be equipped with approved automatic excess flow valves except in the following: Filling connections as provided in paragraph (d)(3)(ii) of this section; safety relief connections, liquid-level gaging devices as provided in paragraphs (b)(7)(iv), (19)(iii), and (19)(viii) of this section; pressure gage connections as provided in paragraph (b)(7)(v) of this section, as provided in paragraphs (d) (iv), (vi), and (vii) of this section.

110(d)(3)(iv)(e) - An approved pressure-reducing regulator is directly attached to the outlet of the shutoff valve and is rigidly supported, or that an approved pressure-reducing regulator is attached to the outlet of the shutoff valve by means of a suitable flexible connection, provided the regulator is adequately supported and properly protected on or at the tank.

110(d)(3)(viii) - Containers of 125 gallons water capacity or more manufactured after July 1, 1961, shall be provided with an approved device for liquid evacuation, the size of which shall be three-fourths inch National Pipe Thread minimum.

110(d)(7)(x) - Where flexible connections are used, they shall be of an approved type and shall be designed for a bursting pressure of not less than five times the vapor pressure of the product at 100 deg. F.

110(d)(7)(xi) - Container assemblies listed for interchangeable installation above ground or under ground shall conform to the requirements for aboveground installations with respect to safety relief capacity and filling density.

110(d)(14)(i) - Each bulk plant shall be provided with at least one approved portable fire extinguisher having a minimum rating of 12-B, C.

110(e)(5)(ii) - The filling connection shall be fitted with an approved double back-pressure check valve, or a positive shutoff in conjunction with an internal back-pressure check valve.

110(e)(5)(iii) - With the exceptions of paragraph (e)(5)(iv)(c) of this section, filling connections equipped with approved automatic back-pressure check valves, and safety relief valves, all connections to containers having openings for the flow of gas in excess of a No. 54 drill size shall be equipped with approved automatic excess flow valves to prevent discharge of content in case connections are broken.

110(e)(5)(iv)(e)(1) - Using an approved automatic quick-closing coupling (a type closing in both directions when uncoupled) in the fuel line, or

110(e)(6)(i) - Approved flexible connections may be used between container and regulator or between regulator and gas-air mixer within the limits of approval. In the case of removable containers an approved flexible connection shall be used between the container and the fuel line.

110(e)(9)(i) - Approved automatic pressure reducing equipment shall be installed in a secure manner between the fuel supply container and gas-air mixer for the purpose of reducing the pressure of the fuel delivered to the gas-air mixer.

110(e)(9)(ii) - An approved automatic shutoff valve shall be provided in the fuel system at some point ahead of the inlet of the gas-air mixer, designed to prevent flow of fuel to the mixer when the ignition is off and the engine is not running.

110(e)(12)(iv) - An approved automatic shutoff valve shall be provided in the fuel system ahead of the engine, designed to prevent flow of fuel to the engine when the ignition is off or if the engine should stop.

110(f)(5)(iv) - Each opening from such storage rooms to other parts of the building shall be protected by a 1 1/2 hour (B) fire door listed by a nationally recognized testing laboratory.

110(f)(7) - Storage locations other than supply depots separated and located apart from dealer, reseller, or user establishments shall be provided with at least one approved portable fire extinguisher having a minimum rating of 8-B, C.

110(h)(3)(iii) - All openings in the container except those listed below shall be equipped with approved excess flow check valves:

110(h)(6)(i)(g) - Where flexible connections are used, they shall be of an approved type and shall be designed for a bursting pressure of not less than five times the vapor pressure of the product at 100 deg F.

110(h)(14) - Each service station shall be provided with at least one approved portable fire extinguisher having at least an 8-B, C, rating.

1910.111 - Storage and Handling of Anhydrous Ammonia

111(b)(1) - "Approval of equipment and systems." Each appurtenance shall be approved in accordance with paragraph (b)(1)(ii) of this section.

111(b)(1)(ii) - It is accepted, or certified, or listed, or labeled, or otherwise determined to be safe by a nationally recognized testing laboratory; or

111(b)(8)(iv) - Such hose shall be equipped with approved shutoff valves at the discharge end.

111(b)(14)(i) - Each container except those filled by weight shall be equipped with an approved liquid-level gaging device.

111(f)(3)(iv) - All containers shall be equipped for spray loading (filling in the vapor space) or with an approved vapor return valve of adequate capacity.

111(g)(4)(iv) - All containers with a capacity exceeding 250 gallons shall be equipped for spray loading or with an approved vapor return valve.

111(g)(4)(v) - All vapor and liquid connections except safety-relief valves and those specifically exempted by paragraph (b)(6)(v) of this section shall be equipped with approved excess-flow valves or may be fitted with quick-closing internal valves which, except during operating periods, shall remain closed.

1910.157 - Portable Fire Extinguishers

157(c)(2) - Only approved portable fire extinguishers shall be used to meet the requirements of this section.

1910.159 - Automatic Sprinkler Systems

159(c)(1)(ii) - The employer shall assure that only approved equipment and devices are used in the design and installation of automatic sprinkler systems used to comply with this standard.

159(c)(8)(i) - The employer shall assure that only approved sprinklers are used on systems.

1910.160 - Fixed Extinguishing Systems, General

160(b)(1) - Fixed extinguishing system components and agents shall be designed and approved for use on the specific fire hazards they are expected to control or extinguish.

160(b)(13) - Automatic detection equipment shall be approved, installed and maintained in accordance with 1910.164.

160(c)(4) - The employer shall provide automatic actuation of total flooding systems by means of an approved fire detection device installed and interconnected with a pre-discharge employee alarm system to give employees time to safely exit from the discharge area prior to system discharge.

1910.162 - Fixed Extinguishing Systems, Gaseous Agent

162(b)(1) - Agents used for initial supply and replenishment shall be of the type approved for the system's application.

1910.164 - Fire Detection Systems

164(b)(1) - The employer shall assure that all devices and equipment constructed and installed to comply with this standard are approved for the purpose for which they are intended.

1910.165 - Employee Alarm Systems

165(c)(1) - The employer shall assure that all devices, components, combinations of devices or systems constructed and installed to comply with this standard are approved.

1910.178 - Powered Industrial Trucks

178(a)(3) - Approved trucks shall bear a label or some other identifying mark indicating approval by the testing laboratory.

178(c)(2)(ii)(a) - . . . . except approved power-operated industrial trucks designated as EX may be used in such atmospheres.

178(c)(2)(ii)(b) - In atmospheres where dust of magnesium, aluminum or aluminum bronze may be present, fuses, switches, motor controllers, and circuit breakers of trucks shall have enclosures specifically approved for such locations.

178(c)(2)(iii) - Only approved power-operated industrial trucks designated as EX may be used in atmospheres containing acetone, acrylonitrile, alcohol, ammonia, benzine, benzol, butane, ethylene dichloride, gasoline, hexane, lacquer solvent vapors, naphtha, natural gas, propane, propylene, styrene, vinyl acetate, vinyl chloride, or xylenes in quantities sufficient to produce explosive or ignitable mixtures and where such concentrations of these gases or vapors exist continuously, intermittently or periodically under normal operating conditions or may exist frequently because of repair, maintenance operations, leakage, breakdown or faulty operation of equipment.

178(c)(2)(v) - In locations used for the storage of hazardous liquids in sealed containers or liquified or compressed gases in containers, approved power-operated industrial trucks designated as DS, ES, GS, or LPS may be used.

178(c)(2)(vi)(a) - Only approved power operated industrial trucks designated as EX shall be used in atmospheres in which combustible dust is or may be in suspension continuously, intermittently, or periodically under normal operating conditions, in quantities sufficient to produce explosive or ignitable mixtures, or where mechanical failure or abnormal operation of machinery or equipment might cause such mixtures to be produced.

178(c)(2)(vii) - Only approved power-operated industrial trucks designated as DY, EE, or EX shall be used in atmospheres in which combustible dust will not normally be in suspension in the air or will not be likely to be thrown into suspension by the normal operation of equipment or apparatus in quantities sufficient to produce explosive or ignitable mixtures but where deposits or accumulations of such dust may be ignited by arcs or sparks originating in the truck.

178(c)(2)(viii) - Only approved power-operated industrial trucks designated as DY, EE, or EX shall be used in locations which are hazardous because of the presence of easily ignitable fibers or flyings but in which such fibers or flyings are not likely to be in suspension in the air in quantities sufficient to produce ignitable mixtures.

178(c)(2)(ix) - Only approved power-operated industrial trucks designated as DS, DY, ES, EE, EX, GS, or LPS shall be used in locations where easily ignitable fibers are stored or handled, including outside storage, but are not being processed or manufactured. Industrial trucks designated as E, which have been previously used in these locations may be continued in use.

178(c)(2)(x) - On piers and wharves handling general cargo, any approved power-operated industrial truck designated as Type D, E, G, or LP may be used, or trucks which conform to the requirements for these types may be used.

178(c)(2)(xi) - If storage warehouses and outside storage locations are hazardous only the approved power-operated industrial truck specified for such locations in this paragraph (c) (2) shall be used. If not classified as hazardous, any approved power-operated industrial truck designated as Type D, E, G, or LP may be used, or trucks which conform to the requirements for these types may be used.

178(c)(2)(xii) - If general industrial or commercial properties are hazardous, only approved power-operated industrial trucks specified for such locations in this paragraph (c) (2) shall be used. If not classified as hazardous, any approved power-operated industrial truck designated as Type D, E, G, or LP may be used, or trucks which conform to the requirements of these types may be used.

178(d) - Power-operated industrial trucks that have been originally approved for the use of gasoline for fuel, when converted to the use of liquefied petroleum gas fuel in accordance with paragraph (q) of this section, may be used in those locations where G, GS or LP, and LPS designated trucks have been specified in the preceding paragraphs.

178(m)(11) - Only approved industrial trucks shall be used in hazardous locations.

178(q)(12) - Industrial trucks originally approved for the use of gasoline for fuel may be converted to liquefied petroleum gas fuel provided the complete conversion results in a truck which embodies the features specified for LP or LPS designated trucks. Such conversion equipment shall be approved.

1910.180 - Crawler Locomotive and Truck Cranes

180(h)(2)(ii) - The load shall be attached to the hook by means of slings or other approved devices.

180(i)(4)(i) - Refueling with small portable containers shall be done with an approved safety type can equipped with an automatic closing cap and flame arrester.

1910.181 - Derricks

181(j)(4)(i) - Refueling with portable containers shall be done with approved safety type containers equipped with automatic closing cap and flame arrester.

1910.253 - Oxygen-Fuel Gas Welding and Cutting

253(a)(1) - No device or attachment facilitating or permitting mixtures of air or oxygen with flammable gases prior to consumption, except at the burner or in a standard torch, shall be allowed unless approved for the purpose.

253(a)(2) - Under no condition shall acetylene be generated, piped (except in approved cylinder manifolds) or utilized at a pressure in excess of 15 psig (103 kPa gauge pressure) or 30 psia (206 kPa absolute).

253(a)(3) - Only approved apparatus such as torches, regulators or pressure-reducing valves, acetylene generators, and manifolds shall be used.

253(c)(1)(i) - Manifolds shall be approved either separately for each component part or as an assembled unit.

253(c)(1)(v) - High-pressure fuel-gas manifolds to be provided with approved pressure-regulating devices.

253(c)(2)(i) - Manifolds shall be approved either separately for each component part or as an assembled unit.

253(c)(2)(vi) - High-pressure oxygen manifolds shall be provided with approved pressure-regulating devices.

253(c)(4)(v) - Portable outlet headers for fuel-gas service shall be provided with an approved hydraulic back-pressure valve installed at the inlet and preceding the service outlets, unless an approved pressure-reducing regulator, an approved back-flow check valve, or an approved hydraulic back-pressure valve is installed at each outlet.

253(c)(5)(ii) - All manifolds and parts used in methods of manifolding to be used only for the gas or gases for which they are approved.

253(c)(5)(iii) - When acetylene cylinders are coupled, approved flash arresters shall be installed between each cylinder and the coupler block.

253(d)(2)(iii) - Joints in seamless copper, brass, or stainless steel tubing shall be approved gas tubing fittings or the joints shall be brazed.

253(e)(3)(ii) - Approved protective equipment (designated P(F) in Figs. Q-1, Q-2, and Q-3) shall be installed in fuel-gas piping to prevent:

253(e)(3)(ii)(C)(2) - Backflow protection shall be provided by an approved device that will prevent oxygen from flowing into the fuel-gas system or fuel from flowing into the oxygen system (see S(F), Figs. Q-1 and Q-2)

253(e)(3)(ii)(C)(3) - Flash-back protection shall be provided by an approved device that will prevent flame from passing into the fuel-gas system.

253(e)(3)(ii)(C)(4) - Back-pressure protection shall be provided by an approved pressure-relief device set at a pressure not greater than the pressure rating of the backflow or the flashback protection device, whichever is lower.

253(f)(1)(i) - Generators shall be of approved construction and shall be plainly marked with the maximum rate of acetylene in cubic feet per hour for which they are designed; the weight and size of carbide necessary for a single charge; the manufacturer's name and address; and the name or number of the type of generator.

253(f)(4)(iv)(A) - The compressor or booster system to be of an approved type.

253(f)(4)(iv)(E) - Compressor or booster pump discharge outlets shall be provided with approved protective equipment.

253(f)(5)(i)(A) - All portable generators shall be of a type approved for portable use.

253(f)(6)(i)(I) - Windows in partitions shall be wired glass and approved metal frames with fixed sash.

1910.265 - Sawmills

265(d)(2)(iv)(b) - Powered pond boats or rafts shall be provided with at least one approved fire extinguisher, and one lifering with line attached.

265(d)(2)(iv)(c) - Boat fuel shall be transported and stored in approved safety containers.

1910.268 - Telecommunications

268(g)(2)(i)(A) - Production samples of lineman's safety straps, body belts and lanyards shall be approved by a nationally recognized testing laboratory, as having been tested in accordance with and as meeting the requirements of this paragraph.

1910.303 - General Requirements

303(a) - The conductors and equipment required or permitted by this subpart shall be acceptable only if approved, as defined in Sec. 1910.399.

303(g)(2)(i) - Except as required or permitted elsewhere in this subpart, live parts of electric equipment operating at 50 volts or more shall be guarded against accidental contact by approved cabinets or other forms of approved enclosures, or by any of the following means:

1910.307 - Hazardous (classified) locations

307(b) - Equipment, wiring methods, and installations of equipment in hazardous (classified) locations shall be intrinsically safe, approved for the hazardous (classified) location, or safe or for the hazardous (classified) location.

307(b)(1) - Equipment and associated wiring approved as intrinsically safe shall be permitted in any hazardous (classified) location for which it is approved.

307(b)(2)(i) - Equipment shall be approved not only for the class of location but also for the ignitable or combustible properties of the specific gas, vapor, dust, or fiber that will be present.

307(b)(2)(ii) - Equipment shall be marked to show the class, group, and operating temperature or temperature range, based on operation in a 40 degrees C ambient, for which it is approved.

307(d) - Equipment that has been approved for a Division 1 location may be installed in a Division 2 location of the same class and group.

Note: With respect to 1910.303 and 1910.307, the definition of “Acceptable” under 29 CFR 1910.399 specifies, with few exceptions, that conductors and equipment must be approved only by “nationally recognized testing laboratories.” Similar definitions apply to the other sections that require approval.