UL PRODUCT CATEGORY

Equipment for Use in and Relating to Zone Classified Hazardous Locations, AANZ


500.1502.6503.6505.1500.1502.6503.6505.1

GENERAL

Electrical equipment intended for use in and relating to Class I, Zone 0, 1 and 2 and relating to Zone 20, 21 and 22 hazardous (classified) locations has been investigated with reference to risks to life and property and for conformity to the installation and use provisions of Articles 505 and 506 of ANSI/NFPA 70, "National Electrical Code" (NEC), or United States Coast Guard (USCG) Electrical Engineering Regulations 46CFR110, "General Provisions," 46CFR111, "Electric Systems - General Requirements," 46CFR112, "Emergency Lighting and Power Systems," and 46CFR113, "Communication and Alarm Systems and Equipment." Attention is called to the limitations of the individual certifications specified in the general Guide Information for each product category, such as current, voltage, horsepower limits, markings, special descriptions and installation provisions.

Unless equipment is identified in 1) the product category title as relating to Zone classified hazardous locations or 2) the individual certifications as apparatus for use in unclassified locations, all product categories contain electrical equipment for use in Class I, Zone 0, 1 and 2 and Zone 20, 21 and 22 hazardous (classified) locations.

Regarding electrical equipment for use in and relating to Division classified locations, some general technical information is provided together with the specific technical information provided regarding Zone classified locations. For additional specific technical information regarding Division classified locations, see Equipment for Use in and Relating to Class I, II and III, Division 1 and 2 Hazardous Locations (AAIZ).

Electrical equipment for use in and relating to hazardous (classified) locations must also comply with the applicable requirements for the same type of equipment for use in unclassified locations. For additional information, see Electrical Equipment for Use in Ordinary Locations (AALZ).

HAZARDOUS (CLASSIFIED) LOCATIONS — GENERAL INFORMATION

Hazardous (classified) locations, as defined in the NEC, are locations where fire or explosion hazards may exist due to the presence of flammable gases, flammable-liquid-produced vapors, combustible-liquid-produced vapors, combustible dusts, or ignitible fibers or flyings.

There are two independent classification systems. One system is found in Articles 505 and 506 of the NEC.

Article 505 divides locations having gases and vapors into Class I, Zones and Gas Groups. A Zone 0 location is a location where ignitible concentrations are present continuously or for long periods of time under normal operating conditions. A Zone 1 location is a location where ignitible concentrations are likely to exist under normal operating conditions. A Zone 2 location is a location where ignitible concentrations are not likely to exist under normal operating conditions.
Article 506 divides locations having dusts, fibers or flyings into Zones. A Zone 20 location is a location where ignitible concentrations are present continuously or for long periods of time under normal operating conditions. A Zone 21 location is a location where ignitible concentrations are likely to exist under normal operating conditions. A Zone 22 location is a location where ignitible concentrations are not likely to exist under normal operating conditions.

The other classification system, found in Article 500 of the NEC, divides all hazardous (classified) locations into Classes, Divisions and Groups. A Division 1 location is a location where an ignitible concentration of a flammable or combustible material is present under normal operating conditions. A Division 2 location is a location where an ignitible concentration of a flammable or combustible material is not likely to exist under normal operating conditions.

Protection against explosion in hazardous (classified) locations requires that all equipment that could be exposed to the flammable or combustible atmospheres be of a type suitable for installation in such locations. The Classes, Zones and Groups for which equipment has been certified is shown in the individual certifications under the respective categories and is marked on the equipment itself.

Gas, Vapor and Dust Groups

The following paragraphs group flammable and explosive mixtures of specific gases, vapors and dusts in accordance with the NEC classifications. For a complete list of group classifications for Zone materials, see ANSI/NFPA 497, "Recommended Practice for the Classification of Flammable Liquids, Gases, or Vapors and of Hazardous (Classified) Locations for Electrical Installations in Chemical Process Areas," and ANSI/NFPA 499, "Recommended Practice for the Classification of Combustible Dusts and of Hazardous (Classified) Locations for Electrical Installations in Chemical Process Areas," together with IEC 60079-20-1, "Explosive Atmospheres - Part 20-1: Material Characteristics for Gas and Vapour Classification - Test Methods and Data," and ISO/IEC 80079-20-2, "Explosive Atmospheres - Part 20-2: Material Characteristics - Combustible Dusts Test Methods."

Class I, Zone 0, 1 and 2 Equipment

Equipment for use in Class I, Zone 0, 1 and 2 hazardous (classified) locations, as defined in Article 505 of the NEC, is investigated with respect to acceptability of operation in the presence of flammable and explosive mixtures of specific vapors and gases with air. For purposes of location classification, such mixtures have been grouped on the basis of their characteristics as follows:

Class I, Group IIC — Atmospheres containing acetylene, hydrogen, or flammable gas, flammable-liquid-produced vapor, or combustible-liquid-produced vapor mixed with air that may burn or explode, having either a maximum experimental safe gap (MESG) value less than or equal to 0.50 mm or minimum igniting current ratio (MIC ratio) less than or equal to 0.45. Group IIC is equivalent to a combination of Class I, Group A and Class I, Group B.

Class I, Group IIB — Atmospheres containing acetaldehyde, ethylene, or flammable gas, flammable-liquid-produced vapor, or combustible-liquid-produced vapor mixed with air that may burn or explode, having either maximum experimental safe gap (MESG) values greater than 0.50 mm and less than or equal to 0.90 mm or minimum igniting current ratio (MIC ratio) greater than 0.45 and less than or equal to 0.80. Group IIB is equivalent to Class I, Group C.

Class I, Group IIA — Atmospheres containing acetone, ammonia, ethyl alcohol, gasoline, methane, propane, or flammable gas, flammable-liquid-produced vapor, or combustible-liquid-produced vapor mixed with air that may burn or explode, having either a maximum experimental safe gap (MESG) value greater than 0.90 mm or minimum igniting current ratio (MIC ratio) greater than 0.80. Group IIA is equivalent to Class I, Group D.

Equipment for use in Class I, Division 1 and 2 hazardous (classified) locations, as defined in Article 500 of the NEC, is investigated with respect to acceptability of operation in the presence of flammable and explosive mixtures of specific vapors and gases with air. For purposes of location classification, such mixtures have been grouped on the basis of their characteristics as follows:

Class I, Group A — Atmospheres containing acetylene.

Class I, Group B — Atmospheres containing flammable gas, flammable-liquid-produced vapor, or combustible-liquid-produced vapor mixed with air that may burn or explode, having either a maximum experimental safe gap (MESG) value less than or equal to 0.45 mm or a minimum igniting current ratio (MIC ratio) less than or equal to 0.40. A typical Class I, Group B material is hydrogen.

Class I, Group C — Atmospheres containing flammable gas, flammable-liquid-produced vapor, or combustible-liquid-produced vapor mixed with air that may burn or explode, having either a maximum experimental safe gap (MESG) value greater than 0.45 mm and less than or equal to 0.75 mm, or a minimum igniting current ratio (MIC ratio) greater than 0.40 and less than or equal to 0.80. A typical Class I, Group C material is ethylene.

Class I, Group D — Atmospheres containing flammable gas, flammable-liquid-produced vapor, or combustible-liquid-produced vapor mixed with air that may burn or explode, having either a maximum experimental safe gap (MESG) value greater than 0.75 mm or a minimum igniting current ratio (MIC ratio) greater than 0.80. A typical Class I, Group D material is propane.

The following table compares Class I, Division 1 and 2 Gas Groups with Class I, Zone 0, 1 and 2 Gas Groups. The gases shown are representative of others in the Group.

Division 1 and 2 Zone 0, 1 and 2
A (acetylene) IIC (acetylene and hydrogen)
B (hydrogen) IIC (acetylene and hydrogen)
C (ethylene) IIB (ethylene)
D (propane) IIA (propane)

Class I, Zone 0, 1 and 2 Equipment in Zone 20, 21 and 22 Locations

Equipment certified for use in Class I, Zone 0, 1 or 2 locations is not necessarily acceptable for Zone 20, 21 or 22 locations as it may not be dust-tight or operate at a safe temperature when blanketed with dust.

Zone 20, 21 and 22 Equipment

Equipment for use in Zone 20, 21 and 22 hazardous (classified) locations, as defined in Article 506 of the NEC, is investigated with respect to acceptability of operation in the presence of combustible dusts or ignitible fibers/flyings in air. For purposes of location classification, the NEC groups combustible dust and ignitible fibers/flyings in air mixtures as follows:

Group IIIC — Atmospheres containing combustible metal dust. Group IIIC is equivalent to Class II, Group E.

Group IIIB — Atmospheres containing combustible dust other than combustible metal dust. Group IIIB is equivalent to Class II, Groups F and G.

Group IIIA — Atmospheres containing solid particles, including fibers, greater than 500 μm in nominal size, which may be suspended in air and could settle out of the atmosphere under their own weight. Group IIIA is equivalent to Class III. Examples of flyings include rayon, cotton (including cotton linters and cotton waste), sisal, jute, hemp, cocoa fiber, oakum, and baled waste kapok.

Equipment for use in Class II, Division 1 and 2 hazardous (classified) locations, as defined in Article 500 of the NEC, is investigated with respect to acceptability of operation in the presence of combustible dusts in air. For purposes of location classification, the NEC groups combustible dust-air mixtures as follows:

Class II, Group E (Division 1 only) — Atmospheres containing combustible metal dusts, including aluminum, magnesium, and their commercial alloys, or other combustible dusts whose particle size, abrasiveness and conductivity present similar hazards in the use of electrical equipment.

Class II, Group F — Atmospheres containing combustible carbonaceous dusts that have more than 8% total entrapped volatiles (see ASTM D3175, "Standard Test Method for Volatile Matter in the Analysis Sample for Coal and Coke," for coal and coke dusts), or that have been sensitized by other materials so that they present an explosion hazard. Coal, carbon black, charcoal, and coke dusts are examples of carbonaceous dusts.

Class II, Group G — Atmospheres containing combustible dusts not included in Groups E or F, including flour, grain, wood, plastic and chemicals.

The following table compares Class II, Division 1 and 2 Dust Groups with Zone 20, 21 and 22 Dust Groups. The dust terms shown are representative of dusts in the Group.

Division 1 and 2 Zone 20, 21 and 22
E (metal dust — Division 1 only) IIIC (conductive dust)
F (carbonaceous dust) IIIB (nonconductive dust)
G (nonconductive dust) IIIB (nonconductive dust)
IIIA (ignitible fibers or flyings)

Intrinsically Safe Circuits and Apparatus, and Associated Apparatus

Intrinsically safe circuits and apparatus may be investigated for any or all of the Zones and Groups as defined in the NEC. In an intrinsically safe circuit, the energy level available in the hazardous (classified) location under normal and abnormal conditions is sufficiently low as not to cause ignition of the specified explosive atmospheres. It is important that intrinsically safe apparatus for locations containing metal dusts be constructed to exclude dust in order to maintain the energy limitations by minimizing the possibility of circuit faults. To maintain the low energy levels, it is necessary that the intrinsically safe and associated apparatus be installed and interconnected in accordance with Articles 504 and 505 of the NEC and the instructions provided with the equipment.

Associated apparatus is apparatus in which the circuits are not necessarily intrinsically safe, but which affect the energy in the intrinsically safe circuits and are relied upon to maintain intrinsic safety. Associated apparatus is not intended for use in hazardous (classified) locations unless use in hazardous (classified) locations is specifically indicated.

When interconnecting associated apparatus with equipment for use in the hazardous (classified) location, special attention should be paid to installation instructions, control drawings, or product markings which may limit the types of connections that are acceptable.

Electrical Equipment Relating to Hazardous (Classified) Locations

Electrical equipment relating to hazardous (classified) locations is commonly referred to as associated apparatus, and involves external circuit connections that are intrinsically safe or nonincendive. The equipment circuitry that supplies these external circuit connections is not necessarily intrinsically safe or nonincendive itself. This supply circuitry affects the energy in the intrinsically safe or nonincendive external circuit connections, and is relied on to maintain these circuit connections as intrinsically safe or nonincendive respectively. Such equipment is one of the following:

Electrical equipment in which the supply circuitry and external circuit connections are both explosion protected for use in their intended hazardous (classified) location.
Electrical equipment in which the supply circuitry is not explosion protected, with only the external circuit connections explosion protected for use in their intended hazardous (classified) location.

An example of associated apparatus is an intrinsic safety or nonincendive barrier, which is a network designed to limit the energy (voltage and current) available to the protected circuit in the hazardous (classified) location, under specified conditions.

Suitability of Certified Equipment

Equipment marked for Class I, Zone 0 locations is also suitable for Zone 1 and 2 locations of the same gas group and with a suitable temperature class. Equipment marked for Class I, Zone 1 locations is also suitable for Class I, Zone 2 locations of the same gas group and with a suitable temperature class. Equipment marked for Class I, Zone 2 locations is suitable only for those locations classified as Class I, Zone 2.

Equipment marked for Zone 20 locations is also suitable for Zone 21 and 22 locations with a suitable temperature class. Equipment marked for Zone 21 locations is also suitable for Zone 22 locations with a suitable temperature class. Equipment marked for Zone 22 locations is suitable only for locations classified as Zone 22.

The NEC also permits the following:

  • Intrinsically safe equipment for Class I, Division 1 locations to be used in a Class I, Zone 0, 1 or 2 location of the same gas group and with a suitable temperature class.
  • Equipment (other than intrinsically safe equipment) for Class I, Division 1 locations to be used in a Class I, Zone 1 or 2 location of the same gas group and with a suitable temperature class.
  • Equipment for Class I, Division 2 locations to be used in a Class I, Zone 2 location of the same gas group and with a suitable temperature class.
  • Equipment for Class I, Zone 0 locations to be used in a Class I, Division 1 or 2 location of the same gas group and with a suitable temperature class.
  • Equipment for Class I, Zone 0, 1 or 2 locations to be used in a Class I, Division 2 location of the same gas group and with a suitable temperature class.
  • Equipment for Class II, Division 1 locations to be used in a Zone 21 or 22 location with a suitable temperature class.
  • Equipment for Class II, Division 2 locations to be used in a Zone 22 location with a suitable temperature class.
  • Equipment for Zone 20 locations to be used in a Class II, Division 1 location of the same dust and with a suitable temperature class.
  • Equipment for Zone 20, 21 or 22 locations to be used in a Class II, Division 2 location of the same dust and with a suitable temperature class.
  • Equipment for Zone 20 locations with a temperature class of not greater than T120C for equipment subject to overloading or not greater than T165C for equipment not subject to overloading to be used in a Class III, Division 1 location.
  • Equipment for Zone 20, 21 or 22 locations with a temperature class of not greater than T120C for equipment subject to overloading or not greater than T165C for equipment not subject to overloading to be used in a Class III, Division 2 location.

In addition, equipment for use in hazardous (classified) locations is also suitable for use in unclassified locations.

RELATED EQUIPMENT

For additional information on electrical equipment for use in and relating to Division classified locations, see Equipment for Use in and Relating to Class I, II and III, Division 1 and 2 Hazardous Locations (AAIZ).

For additional information on electrical equipment for use in unclassified locations, see Electrical Equipment for Use in Ordinary Locations (AALZ).

TEMPERATURE CONSIDERATIONS

The marked temperature class (T-code) of the equipment is based on either the maximum external temperature or internal temperature of the equipment, depending on the protection technique used. Equipment is required to be marked with the operating temperature or temperature class (T-code) if the maximum operating temperature is more than 100°C (212°F). The marking specifies the temperature class or operating temperature based on a +40°C (+104°F) ambient temperature, or based on the higher ambient temperature if the equipment is rated and marked for an ambient temperature of greater than +40°C (+104°F). For equipment rated and marked for an upper ambient temperature of less than +40°C (+104°F), the operating temperature or temperature class is still based on +40°C (+104°F).

For other than atmospheres involving fibers and flyings, this temperature marking should not exceed the ignition temperature of the specific combustible material to be encountered. For organic dusts that may dehydrate or carbonize, the temperature marking should not exceed the lower of either the ignition temperature or 165°C.

For atmospheres involving fibers and flyings, the maximum permitted temperature is 120°C for equipment that is subject to overloading (such as motors) and 165°C for equipment that is not subject to overloading.

AMBIENT TEMPERATURES

Unless the equipment is marked otherwise, it has been investigated only for use under normal atmospheric conditions in an ambient temperature within the range of -20°C (-4°F) to +40°C (+104°F). Equipment may be investigated and marked for a lower ambient temperature that is greater than -20°C (-4°F). While equipment may be marked for an upper ambient temperature that is less than +40°C (+104°F), equipment is always investigated for an upper ambient temperature of at least +40°C (+104°F).

Use of equipment under conditions of higher than normal atmospheric pressure or oxygen partial pressure, use in artificial atmospheres, and use under conditions of excessively high ambient temperatures can increase the likelihood of ignition of flammable atmospheres. In addition, low ambient temperatures may increase explosion pressures developed within the equipment. Plastic parts of enclosures or encapsulating materials may not maintain their integrity in excessively high or low ambient, unless marked otherwise.

ENCLOSURE MODIFICATION AND MAINTENANCE

The integrity of an enclosure must be maintained. Making holes (other than conduit openings specified in the instructions) or alterations in the enclosure during installation may compromise the ability of a flameproof enclosure to contain an explosion. Most other protection techniques require a minimum IP rating and alterations in the enclosure may impair the enclosure's ability to protect against ingress of contaminants or water. See ENCLOSURE CONSIDERATIONS FOR ALL EQUIPMENT below for more information. Holding bolts and threaded parts must be screwed tight. The continued acceptability of the equipment will depend upon proper maintenance.

ENVIRONMENTAL CONSIDERATIONS

Unless the equipment is marked otherwise, it is intended to be used indoors where severe corrosive conditions are not likely to be present. Equipment investigated for severe environmental conditions is marked with an enclosure type designation or other designation indicating the suitability of the equipment in different environments. See ENCLOSURE CONSIDERATIONS FOR ALL EQUIPMENT below for more information.

ENCLOSURE CONSIDERATIONS FOR ALL EQUIPMENT

Section 110.11 of the NEC directs that equipment shall not be used in damp or wet locations; locations where exposed to gases, fumes, vapors, liquids or other agents having a deteriorating effect on the equipment; or locations where exposed to excessive temperatures unless the equipment is identified for use in such environments. Section 300.6 of the NEC provides guidance regarding protection against corrosion. To assist Authorities Having Jurisdiction, electrical equipment certified for use in and relating to hazardous (classified) locations may be investigated for use in certain operating environments and marked with an enclosure type number(s). The following table summarizes the intended uses of the various enclosure types.

Provides a Degree of Protection
Against the Following Environmental Conditions:
Type of Enclosure
1 2 3 3R 3S 3X 3RX 3SX 4 4X 5 6 6P 12 12K 13
Incidental contact with the enclosed equipment X X X X X X X X X X X X X X X X
Falling dirt X X X X X X X X X X X X X X X X
Dripping and light splashing of noncorrosive liquids X X X X X X X X X X X X X X X
Rain, snow and sleet X X X X X X X X X X
Rain, snow and sleet (external mechanism shall be operable when ice covered) X X
Circulating dust, lint, fibers and flyings X X X X X X X X X X X
Settling airborne dust, lint, fibers and flyings X X X X X X X X X X X X
Windblown dust X X X X X X X X
Hosedown and splashing water X X X X
Oil and coolant seepage X X X
Oil or coolant spraying and splashing X
Corrosive agents X X X X X
Occasional temporary submersion X X
Occasional prolonged submersion X

Enclosures for indoor locations include Types 1, 2, 5, 7, 9, 12, 12K and 13; enclosures for indoor or outdoor locations include Types 3, 3R, 3S, 4, 4X, 6 and 6P.

In some cases, individual appliances and equipment may be marked "Raintight" or "Rainproof," indicating that they have been subjected to a test designed to simulate exposure to beating rain. For equipment designated as "Raintight" such exposure will not result in entrance of water. For equipment designated as "Rainproof" such exposure will not interfere with the operation of the apparatus or result in wetting of live parts and wiring within the enclosure.

Additionally or alternatively, IEC 60529, "Degrees of Protection Provided by Enclosures (IP Code)," describes a system for classifying the degrees of ingress protection (or IP Code) provided by the enclosures of electrical equipment as follows:

First Characteristic Numeral • Degrees of Protection Against Ingress of Solid Foreign Objects
• Degrees of Protection Against Access to Hazardous Parts
Second Characteristic Numeral Degrees of Protection Against Ingress of Water Harmful Effects
IP0X • Nonprotected
• Nonprotected
IPX0 Nonprotected
IP1X • 50 mm diameter and greater
• Back of hand
IPX1 Vertically dripping
IP2X • 12.5 mm diameter and greater
• Finger
IPX2 Dripping (15 degrees tilted)
IP3X • 2.5 mm diameter and greater
• Tool
IPX3 Spraying
IP4X • 1.0 mm diameter and greater
• Wire
IPX4 Splashing
IP5X • Dust-protected
• Wire
IPX5 Jetting
IP6X • Dust-tight
• Wire
IPX6 Powerful jetting
    IPX7 Temporary immersion
    IPX8 Continuous immersion

FITTINGS AT SUPPLY ENTRIES

Consideration should be given to the Type or IP rating of fittings used at supply entries. When the manufacturer supplies a fitting with the enclosure, enclosures are intended to be connected to the wiring system using the fitting provided. If no fitting is provided by the manufacturer, the fitting employed must meet or exceed the Type or IP rating of the enclosure, so that the assembly maintains its protection against contaminants.

CABLE AND CONDUIT SEALS

Equipment with a factory-installed conduit seal is marked "Leads factory sealed," or equivalent wording. The absence of this marking indicates that the need for a field-installed seal in accordance with Section 505.16 of the NEC should be determined.

PROCESS SEALS

Process-connected electrical equipment provided with seals to prevent the migration of process fluids into the electrical system are either the single-seal or dual-seal types. The construction, testing and marking requirements for process seals are found in ANSI/UL 122701, "Requirements for Process Sealing Between Electrical Systems and Flammable or Combustible Process Fluids."

PROTECTION OF EQUIPMENT AND TRANSMISSION SYSTEMS USING OPTICAL RADIATION

Equipment and transmission systems that use optical radiation and are intended for use in hazardous (classified) locations may pose a risk of ignition. This includes equipment and systems, which themselves are located outside the hazardous (classified) locations, but their emitted optical radiation enters such locations.

For Class I, Zone 2 or Zone 22 equipment and systems incorporating a laser light source or other optical radiation source, the construction, testing and marking requirements that may be applied for such equipment and systems are found in ANSI/UL 60079-28, "Explosive Atmospheres - Part 28: Protection of Equipment and Transmission Systems Using Optical Radiation."

For Class I , Zone 1 or Zone 21 equipment and systems:

  • when incorporating a laser light source, the laser light source complies with Class 1 limits in accordance with IEC 60825-1, "Safety of Laser Products - Part 1: Equipment Classification and Requirements," (a single-fault investigation). Alternatively, the laser light source may comply with ANSI/UL 60079-28; and
  • when incorporating other optical radiation sources, the construction, testing and marking requirements that may be applied for such equipment and systems are found in ANSI/UL 60079-28.

For Class I, Zone 0 or Zone 20 equipment and systems:

  • when incorporating a laser light source, the laser light source complies with ANSI/UL 60079-28; and
  • when incorporating other optical radiation sources, the construction, testing and marking requirements that may be applied for such equipment and systems are found in ANSI/UL 60079-28.

The protection technique identification for equipment and systems that comply with ANSI/UL 60079-28 and that may be marked on the equipment include "op is," "op pr" or "op sh," with the identified Class and Zone dependent upon the design of the equipment, as applicable.

WIRING METHODS

Wiring methods permitted by the NEC for hazardous (classified) locations are, in general, more restrictive than those permitted for unclassified locations. Extra-hard-usage flexible cord is only permitted for connection of portable luminaires and other types of portable utilization equipment and the fixed portion of their supply circuit, or in other situations where flexibility is necessary for the installation as determined by the Authority Having Jurisdiction.

REQUIREMENTS

The basic hazardous (classified) locations standards used to investigate these products with respect to risk of explosion for Class I, Zone 0, 1 and 2 are referenced below for the location classifications and protection techniques shown. Note that for all equipment, ANSI/UL 60079-0, "Explosive Atmospheres - Part 0: Equipment - General Requirements," is also used.

Note: The standard edition and any revision date, if applicable, of the basic hazardous (classified) locations standards used to investigate products in this category is recorded in the Report and not in the Guide Information or individual certifications.


Location
Classification


Standard
Protection
Technique
Identification
Zone 0 ANSI/UL 60079-1,  "Explosive Atmospheres - Part 1: Equipment Protection by Flameproof Enclosures "d""  da
ANSI/UL 60079-11,  "Explosive Atmospheres - Part 11: Equipment Protection by Intrinsic Safety "i""  ia
ANSI/UL 60079-18,  "Explosive Atmospheres - Part 18: Equipment Protection by Encapsulation "m""  ma
ANSI/UL 60079-28,  "Explosive Atmospheres - Part 28: Protection of Equipment and Transmission Systems Using Optical Radiation"  op is, op sh
Zone 1 ANSI/UL 60079-1,  "Explosive Atmospheres - Part 1: Equipment Protection by Flameproof Enclosures "d""  db
ANSI/UL 60079-2,  "Explosive Atmospheres - Part 2: Equipment Protection by Pressurized Enclosures "p""  pxb, pyb
ANSI/UL 60079-5,  "Explosive Atmospheres - Part 5: Equipment Protection by Powder Filling "q""  q
ANSI/UL 60079-6,  "Explosive Atmospheres - Part 6: Equipment Protection by Oil Immersion "o""  ob
ANSI/UL 60079-7,  "Explosive Atmospheres - Part 7: Equipment Protection by Increased Safety "e""  eb
ANSI/UL 60079-11,  "Explosive Atmospheres - Part 11: Equipment Protection by Intrinsic Safety "i""  ib
ANSI/UL 60079-18,  "Explosive Atmospheres - Part 18: Equipment Protection by Encapsulation "m""  mb
ANSI/UL 60079-28,  "Explosive Atmospheres - Part 28: Protection of Equipment and Transmission Systems Using Optical Radiation"  op is, op pr, op sh
Zone 2 ANSI/UL 60079-1,  "Explosive Atmospheres - Part 1: Equipment Protection by Flameproof Enclosures "d""  dc
ANSI/UL 60079-2,  "Explosive Atmospheres - Part 2: Equipment Protection by Pressurized Enclosures "p""  pzc
ANSI/UL 60079-6,  "Explosive Atmospheres - Part 6: Equipment Protection by Oil Immersion "o""  oc
ANSI/UL 60079-7,  "Explosive Atmospheres - Part 7: Equipment Protection by Increased Safety "e""  ec
ANSI/UL 60079-11,  "Explosive Atmospheres - Part 11: Equipment Protection by Intrinsic Safety "i""  ic
ANSI/UL 60079-15,  "Explosive Atmospheres - Part 15: Equipment Protection by Type of Protection "n""  nA, nC, nR
ANSI/UL 60079-18,  "Explosive Atmospheres - Part 18: Equipment Protection by Encapsulation "m""  mc
ANSI/UL 60079-28,  "Explosive Atmospheres - Part 28: Protection of Equipment and Transmission Systems Using Optical Radiation"  op is, op pr, op sh
Unclassified ANSI/UL 60079-11,  "Explosive Atmospheres - Part 11: Equipment Protection by Intrinsic Safety "i""  [ia], [ib], [ic]

The basic hazardous (classified) locations standards used to investigate these products with respect to the risk of explosion for Zone 20, 21 and 22 are referenced below for the location classifications and protection techniques shown. Note that for all equipment ANSI/UL 60079-0, "Explosive Atmospheres - Part 0: Equipment - General Requirements," is also used.

Note: The standard edition and any revision date, if applicable, of the basic hazardous (classified) locations standards used to investigate products in this category is recorded in the Report and not in the Guide Information or individual certifications.


Location
Classification


Standard
Protection
Technique
Identification
Zone 20 ANSI/UL 60079-11,  "Explosive Atmospheres - Part 11: Equipment Protection by Intrinsic Safety 'i'"  ia
ANSI/UL 60079-18,  "Explosive Atmospheres - Part 18: Equipment Protection by Encapsulation 'm'"  ma
ANSI/UL 60079-28,  "Explosive Atmospheres - Part 28: Protection of Equipment and Transmission Systems Using Optical Radiation"  op is, op sh
ANSI/UL 60079-31,  "Explosive Atmospheres - Part 31: Equipment Dust Ignition Protection by Enclosure 't'"  ta
Zone 21 ANSI/UL 60079-2,  "Explosive Atmospheres - Part 2: Equipment Protection by Pressurized Enclosures "p""  pxb, pyb
ANSI/UL 60079-11,  "Explosive Atmospheres - Part 11: Equipment Protection by Intrinsic Safety 'i'"  ib
ANSI/UL 60079-18,  "Explosive Atmospheres - Part 18: Equipment Protection by Encapsulation 'm'"  mb
ANSI/UL 60079-28,  "Explosive Atmospheres - Part 28: Protection of Equipment and Transmission Systems Using Optical Radiation"  op is, op pr, op sh
ANSI/UL 60079-31,  "Explosive Atmospheres - Part 31: Equipment Dust Ignition Protection by Enclosure 't'"  tb
Zone 22 ANSI/UL 60079-2,  "Explosive Atmospheres - Part 2: Equipment Protection by Pressurized Enclosures "p""  pzc
ANSI/UL 60079-11,  "Explosive Atmospheres - Part 11: Equipment Protection by Intrinsic Safety 'i'"  ic
ANSI/UL 60079-18,  "Explosive Atmospheres - Part 18: Equipment Protection by Encapsulation 'm'"  mc
ANSI/UL 60079-28,  "Explosive Atmospheres - Part 28: Protection of Equipment and Transmission Systems Using Optical Radiation"  op is, op pr, op sh
ANSI/UL 60079-31,  "Explosive Atmospheres - Part 31: Equipment Dust Ignition Protection by Enclosure 't'"  tc
Unclassified ANSI/UL 60079-11,  "Explosive Atmospheres - Part 11: Equipment Protection by Intrinsic Safety 'i'"  [ia], [ib], [ic]

Unless otherwise specified in the general Guide Information for each product category, the basic unclassified locations standard used to investigate these products with respect to risk of fire, electric shock and injury to persons is from the following list, with the applicable standard for low-voltage applications, based on the determination made by the manufacturer:

For low-voltage applications:

Part I of ANSI/UL 508, "Industrial Control Equipment"
ANSI/UL 60065, "Audio, Video and Similar Electronic Apparatus - Safety Requirements"
ANSI/UL 60950-1, "Information Technology Equipment - Safety - Part 1: General Requirements"
ANSI/UL 61010-1, "Safety Requirements for Electrical Equipment for Measurement, Control, and Laboratory Use - Part 1: General Requirements"

For medium-voltage applications:

ANSI/UL 347, "Medium-Voltage AC Contactors, Controllers, and Control Centers"

INSTRUCTIONS AND PRODUCT MARKINGS

These products are intended to be installed in accordance with the installation instructions provided with the product. It is critical that the cautionary statements and installation and operating instructions on the product and in accompanying literature be followed. The protection technique identification letter(s) is marked on the product. Products employing multiple protection techniques are marked with all applicable identifications. For example, a control station containing a flameproof switch and an encapsulated pilot light, mounted in an increased safety enclosure, is marked with all three protection techniques: "edm."

TECHNOLOGY THAT PROVIDES LOCATION INFORMATION

The performance or reliability of any technology that provides location information functionality of equipment covered under this category has not been investigated. Examples of such technology include global positioning systems (GPS), enhanced 911 (E911) hardware, digital pinging, cellular triangulation, and passive radar reflection. This technology has only been investigated for the explosion, fire, shock and casualty hazards required by the applicable safety standards. UL certification does not cover the performance or reliability of any technology that provides location information functionality. UL makes no claims, representations or warranties whatsoever regarding the performance or reliability of any technology that provides location information functionality of equipment covered under this category.

OPEN-TYPE EQUIPMENT

Unless indicated otherwise in the Guide Information for the applicable hazardous (classified) locations product category, and where permitted for comparable unclassified locations products, open-type hazardous (classified) locations equipment is permitted when it is intended for installation within a suitable enclosure. Examples of installation issues to consider when determining the suitability of the equipment enclosure include, but are not limited to, the following as applicable: 1) the involved area classification, 2) protection against any specific environmental conditions, 3) thread engagement, and 4) whether a tool is required for opening of the enclosure. Installation requirements relating to the suitability of the enclosure are specified in the instructions or markings for the open-type equipment.

MARINE EQUIPMENT

Certain equipment has been specifically investigated and certified for use aboard marine vessels. Such equipment has been investigated in accordance with the applicable requirements of UL, the United States Coast Guard (USCG), the American Boat and Yacht Council, Inc. (ABYC), and the National Fire Protection Association (NFPA). For additional information, see the general Guide Information for the specific product category. Equipment bearing UL's Marine Mark is suitable for use only with stranded copper wire.

FIELD-MODIFIED OR REBUILT EQUIPMENT

An authorized use of the UL Mark is the manufacturer's declaration that a product was manufactured in accordance with the applicable certification requirements, and was in compliance with those requirements when it was shipped from the factory. When a product bearing a UL Mark is modified or rebuilt (including being refurbished, remanufactured, reconditioned or renovated) after it leaves the factory where the UL Mark was applied, UL does not know if the product continues to meet the applicable requirements unless the modification or rebuilding has been specifically investigated by UL. The only exceptions to this are when a UL-certified product has specific markings for field-installed equipment or the replacement of components, or when the individual product is addressed through one of the specific programs noted below.

Evidence that UL has specifically investigated the modification or rebuilding can only be demonstrated by a product that bears the UL Mark or label of one of UL's programs for modified or rebuilt equipment, which include:

UL Rebuilt Product Certifications — UL's rebuilt product certifications cover a wide range of product types. The general Guide Information for each product category with a rebuilt certification program identifies the applicable requirements and the specific marking for products rebuilt under the program. Only rebuilt products that bear the UL Mark together with the word "Rebuilt," "Refurbished," "Remanufactured," "Reconditioned" or "Renovated" have been investigated by UL to the applicable certification requirements.
UL Retrofit Certifications — UL's retrofit certifications include an investigation of all required component parts, including instructions, for retrofitting specific types of certified products in the field. Products investigated under this program bear a UL Mark together with the product identity including the word "Retrofit."
UL Field Evaluated Products — For products identified by the Authority Having Jurisdiction, owner, or other regulatory body as being acceptable to evaluate after installation or otherwise outside of the manufacturer's location, UL's Field Evaluation program addresses investigation to applicable product requirements based on the specific application and use location for the particular equipment. The specific equipment investigated under this program bears the UL Field Evaluation label.

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UL, in performing its functions in accordance with its objectives, does not assume or undertake to discharge any responsibility of the manufacturer or any other party. UL shall not incur any obligation or liability for any loss, expense or damages, including incidental or consequential damages, arising out of or in connection with the use, interpretation of, or reliance upon this Guide Information.

Last Updated on 2018-10-03
AANZ.GuideInfo AANZ Active 20181003 20181003

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