2008 Overview of Hazardous Locations and the NEC®
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A Guide for use of Electrical Products in Hazardous Locations — © 2008
Topics for Discussion • • • •
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NEC® Article 500 Code Sections Review of Class, Division, and Groups Standards Organizations Why Articles 505 & 506 Were Added to the NEC® Review Zone System Design of Explosionproof Equipment Hazardous Location Lighting 2008 NEC® Overview Interpretation of the 2008 NEC® Changes Review EGS Product Offering
A Guide for use of Electrical Products in Hazardous Locations — © 2008
NEC® Article 500 Code Sections • • • • • • • • • • • • •
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Article 500 Hazardous (Classified) Locations Article 501 Class I Locations Article 502 Class II Locations Article 503 Class III Locations Article 504 Intrinsically Safe Systems Article 505 Class I, Zone 0, 1, and 2 Locations Article 506 Class II, Zone 20, 21, and 22 Locations Article 510 Hazardous (Classified) Locations Specific Article 511 Commercial Garages, Repair and Storage Article 513 Aircraft Hangars Article 514 Motor Fuel Dispensing Facilities Article 515 Bulk Storage Plants Article 516 Spray Application, Dipping, and Coating Processes
A Guide for use of Electrical Products in Hazardous Locations — © 2008
Class Locations
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Class I - Gases & Vapors
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Class II - Dusts
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Class III - Fibers & Flyings
A Guide for use of Electrical Products in Hazardous Locations — © 2008
Class I Locations (Gases) •
NEC® Article 500.5(B) –
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An area where FLAMMABLE GASES, FLAMMABLE LIQUID-PRODUCED VAPORS, OR COMBUSTIBLE LIQUID-PRODUCED VAPORS are or may be present in the air in sufficient quantities to produce explosive or ignitible mixtures.
A Guide for use of Electrical Products in Hazardous Locations — © 2008
Class I Locations (Gases) •
Class I Industries & Applications – – – – – – – – – – –
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Natural or liquefied gas storage facilities Chemical plants Petroleum refineries Bulk handling or storage facilities for gasoline Dip tanks Storage tanks for flammable liquids or gas Spraying areas for paints or plastics Aircraft fuel servicing areas or hangers Well drilling (oil and gas), offshore or on Pipeline pumping areas Printing machine areas
A Guide for use of Electrical Products in Hazardous Locations — © 2008
Class II Locations (Dust) •
NEC® Article 500.5(C) –
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Locations that are hazardous because of the presence of combustible dust. Shall include those specified in 500.5(C)(1) and (C)(2).
A Guide for use of Electrical Products in Hazardous Locations — © 2008
Class II Locations (Dust) •
Class II Industries and Applications – – – – –
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Grain storage, handling or processing plants Coal storage, handling or processing facilities Metal grinding or metal powder producing facilities Gunpowder or explosive (fireworks) plants Sugar, cocoa, spice or starch production or handling facilities
A Guide for use of Electrical Products in Hazardous Locations — © 2008
Class III Locations (Fibers) •
NEC® Article 500.5(D) –
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An area made hazardous because of the presence of easily ignitible 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 ignitible mixtures. Shall include those specified in 500.5(D)(1) and (D)(2).
A Guide for use of Electrical Products in Hazardous Locations — © 2008
Class III Locations (Fibers) •
Class III Industries and Applications – – –
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Cotton, textile or flax producing or handling facilities Wood cutting, pulverizing or shaping plants Clothing manufacturing facilities
A Guide for use of Electrical Products in Hazardous Locations — © 2008
Conditions
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Division 1
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Division 2
A Guide for use of Electrical Products in Hazardous Locations — © 2008
Division 1 Location •
NEC® Articles 500.5(B)(1), 500.5(C)(1) and 500.5(D)(1) – –
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An area where the hazard exists under normal operation conditions This also includes locations where the hazard is caused by frequent maintenance or repair work or frequent equipment failure
A Guide for use of Electrical Products in Hazardous Locations — © 2008
Division 2 Location •
NEC® Articles 500.5(B)(2), 500.5(C)(2), and 500.5(D)(2) –
An area where ignitible gases, vapors, dust, or fibers are handled, processed, or used, but which exist only under abnormal conditions, such as containers or closed systems from which they can only escape through accidental rupture or breakdown •
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Note: No electrically conductive dust are included in Class II, Division 2 atmospheres
A Guide for use of Electrical Products in Hazardous Locations — © 2008
Comparison of Division 1 and Division 2 for Gases
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A Guide for use of Electrical Products in Hazardous Locations — © 2008
Groups A, B, C, and D (Gases) •
NEC® Article 500.6(A) – –
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Groups indicates the degree of the hazard Groups A, B, C & D are classified by chemical families as shown in NFPA 497-2004 and 325M-1991 An important factor in classifying a gas or vapor by Group is how much pressure is created during an explosion. Group A (Acetylene) creates the most pressure, with Group B (Hydrogen) next
90.0 80.0 70.0 60.0 50.0 40.0 30.0 20.0 10.0 0.0
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A Guide for use of Electrical Products in Hazardous Locations — © 2008
Group A Acetylene Group B Hydrogen Group C Ethylene Group D Propane
Dust Groups E, F and G •
NEC® Article 500.6(B) –
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Groups indicates the degree of the hazard, based on Electrical Resistivity from Table on right (Source: ANSI/ISA-12.10-1988) Group E (Electrically Conductive) – Atmospheres containing combustible metal dust Group F (Fuel) – Atmospheres containing Carbon Black, Charcoal, Coal, or Coke Dust Group G (Grain) – Atmospheres containing agricultural and other dusts
A Guide for use of Electrical Products in Hazardous Locations — © 2008
Summary of Class I Locations •
Class I Locations –
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Class I, Division 1 –
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There is an explosive atmosphere of gases or vapors mixed with air when an abnormal condition exists, such as failure of a containment wall or ventilation system
Class I, Groups – –
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There is or may be an explosive atmosphere of gases or vapors mixed with air present during normal operation, for any reason
Class I, Division 2 –
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Class I locations are those in which flammable gases, flammable liquid–produced vapors, or combustible liquid–produced vapors are or may be present in the air in quantities sufficient to produce explosive or ignitible mixtures
Group A. Acetylene. Group B. 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; hydrogen Group C. 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; ethylene Group D. 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; propane
A Guide for use of Electrical Products in Hazardous Locations — © 2008
Summary of Class II Locations •
Class II Locations –
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Class II, Division 1 – – –
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Combustible dust due to abnormal operations may be present in the air in quantities sufficient to produce explosive or ignitible mixtures Combustible dust accumulations are present but are normally insufficient to interfere with the normal operation of electrical equipment or other apparatus, but could as a result of infrequent malfunctioning of handling or processing equipment become suspended in the air Combustible dust accumulations on, in, or in the vicinity of the electrical equipment could be sufficient to interfere with the safe dissipation of heat from electrical equipment, or could be ignitible by abnormal operation or failure of electrical equipment
Class II, Groups –
– –
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Combustible dust is in the air under normal operating conditions in quantities sufficient to produce explosive or ignitible mixtures Mechanical failure or abnormal operation of machinery or equipment might cause such explosive or ignitible mixtures to be produced, and might also provide a source of ignition through simultaneous failure of electrical equipment, through operation of protection devices, or from other causes Group E combustible dusts may be present in quantities sufficient to be hazardous
Class II, Division 2 –
•
There is the presence of combustible dust
Group E. 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; metal dusts Group F. Atmospheres containing combustible carbonaceous dusts that have more than 8 percent total entrapped volatiles or that have been sensitized by other materials so that they present an explosion hazard; coal, carbon black, charcoal, coke dusts Group G. Atmospheres containing combustible dusts not included in Group E or F, including flour, grain, wood, plastic, and chemicals
A Guide for use of Electrical Products in Hazardous Locations — © 2008
Summary of Class III Locations • Class III Locations – Those that are hazardous because of the presence of easily ignitible fibers or materials producing combustible flyings are handled, manufactured, or used, but in which such fibers/flyings are not likely to be in suspension in the air in quantities sufficient to produce ignitible mixtures
• Class III, Division 1 – Easily ignitible fibers/flyings are handled, manufactured, or used
• Class III, Division 2 – Easily ignitible fibers/flyings are stored or handled other than in the process of manufacture
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A Guide for use of Electrical Products in Hazardous Locations — © 2008
Standards Organizations •
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AMERICAN NATIONAL STANDARDS INSTITUTE (ANSI) – Does not develop standards per se, but acts as a clearing house for information on national and international standards writing groups to prevent duplication of effort AMERICAN PETROLEUM INSTITUTE (API) – Publishes Recommended Practice for Classification of Locations for Electrical Installations in Petroleum Facilities (API RP 500) CANADIAN STANDARDS ASSOCIATION (CSA) – Established standards similar to UL for the testing of electrical products ELECTRICAL TESTING LABORATORIES (ETL) – Provides a listing, labeling and follow-up service for safety and sanitation certification of electrical and gas/oil fueled products to nationally recognized safety standards or specifically designated requirements of jurisdictional authorities FACTORY MUTUAL (FM) – Non-profit third party testing and certification organization, providing many of the same services as UL INTERNATIONAL ELECTROTECHNICAL COMMISSION (IEC) – Comprised of approximately forty member countries, including the United States. The purpose of the IEC is to establish standards for a wide variety of electrical products to encourage international trade. IEC publication 79, entitled Electrical Apparatus for Explosive Gas Atmospheres, consists of several parts covering area classification, test apparatus and several techniques used for protection of apparatus, intended for use in hazardous locations INSTITUTE OF ELECTRICAL AND ELECTRONICS ENGINEERS (IEEE) – Publishes publications which provide thorough analysis of system considerations and guidance on the design and maintenance of electrical systems and equipment INSTRUMENTATION SYSTEMS AND AUTOMATION SOCIETY (ISA) – Develops standards; certifies industry professionals; provides education and training; and publishes books and technical articles LOCAL BUILDING CODES – These codes influence and determine ultimate decisions on product suitability MANUFACTURERS DATA – Manufacturers working with recognized organizations, develop and improve products for third party certification and thus set additional product suitability standards – Standards set by such organizations identify the criteria used by manufactures in the design and company testing of its products
A Guide for use of Electrical Products in Hazardous Locations — © 2008
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NATIONAL FIRE PROTECTION ASSOCIATION (NFPA) – Set standards for the wiring and control of electricity. NFPA is composed of national and regional groups, plus individuals, firms and institutions interested in protecting life and property. This organization sets minimum standards to form a National Electrical Code (NEC®), which is used as a criteria for insurance, state and civic inspectors when making inspections or recommendations for electrical installations NORTH AMERICAN CERTIFICATION – The United States and Canada are both members of the IECEx Conformity Assessment Scheme. As a result for Hazardous Location Certification UL and CSA accepts each others data for purpose of providing their National Certification Marks NATIONAL ELECTRICAL MANUFACTURERS ASSOCIATION (NEMA) – Issues standards on electrical equipment on all major categories of electrical equipment. Generally where construction and performance relate to safety, reference is made to standards of others, such as Underwriters Laboratories Incorporated OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION (OSHA) – Mandates the use of electrical equipment that has been verified by third parties as being suitable for the application. Some units of a system installation are not necessarily third party certified if such certification is judged not applicable OTHER ASSOCIATIONS – Professional and technical organizations develop and/or sponsor standards as product guidelines, application recommendations, safety rules or test methods UNDERWRITERS LABORATORIES, INC. (UL) – There are over a dozen UL Published Standards that govern the design and company testing of electrical products. In addition to specific UL Standards, UL publishes three books containing the names of companies who have qualified to use the Listing or Classification Marking of Underwriters Laboratories on products which have been found to be in compliance with applicable UL requirements. These three publications can be used to obtain the names of companies who have a Listing in a specific product category, and to obtain information regarding the scope, limitations, or special conditions of a particular product category
Why Were Articles 505 & 506 Added to the NEC®? •
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To promote harmonization with international standards so that multi- national companies can globalize their standards for facilities constructed both inside and outside North America, thereby allowing a single set of standards to be utilized anywhere in the world In many instance the respective country’s National Standards contain national differences from the base IEC Standards
A Guide for use of Electrical Products in Hazardous Locations — © 2008
Article 505: Zone 0 Hazardous Locations •
Zone 0 covers areas in which an explosive gas atmosphere is present continuously or for long periods (> 1000 hrs/yr.) –
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Intrinsic Safety (Ex i) is the only method of protection permitted in Zone 0 –
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This usually applies to the inside vapor space of containers, process vessels or tanks
Used for industrial instrumentation & control
A Guide for use of Electrical Products in Hazardous Locations — © 2008
Article 505: Zone 1 Hazardous Locations •
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Zone 1 covers areas, in which an explosive gas atmosphere can be expected to be present intermittently (between 10 and 1000 hrs/yr.)
A Guide for use of Electrical Products in Hazardous Locations — © 2008
Article 505: Zone 2 Hazardous Locations •
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Zone 2 covers areas, in which an explosive gas atmosphere can only be expected under abnormal conditions (between 0.1 and 10 hrs/yr.)
A Guide for use of Electrical Products in Hazardous Locations — © 2008
Article 505: Zone 0, 1, 2 Hazardous Locations Zone 0 Zone 1 Zone 2 Non-Hazardous Zone
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A Guide for use of Electrical Products in Hazardous Locations — © 2008
Group Classification NEC® Article 505 • Group IIC. Atmospheres containing acetylene, hydrogen, or gases or vapors of equivalent hazard – This grouping is equivalent to NEC Class I, Groups A and B, as described in Sections 500.6(A)(1,2)
• Group IIB. Atmospheres containing acetaldehyde, ethylene, or gases or vapors of equivalent hazard – This grouping is equivalent to NEC Class I, Group C, as described in Section 500.6(A)(3)
• Group IIA. Atmospheres containing acetone, ammonia, ethyl alcohol, gasoline, methane, propane, or gases or vapors of equivalent hazard – This grouping is equivalent to NEC Class I, Group D, as described in Section 500.6(A)(4)
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A Guide for use of Electrical Products in Hazardous Locations — © 2008
Article 506: Zone 20 Hazardous Locations •
Zone 20 covers areas which ignitible concentrations of combustible dust or ignitible fibers/flyings are present continuously or for long periods of time –
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This usually applies to the inside of containment systems
A Guide for use of Electrical Products in Hazardous Locations — © 2008
Article 506: Zone 21 Hazardous Locations •
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Zone 21 covers areas which ignitible concentrations of combustible dust or ignitible fibers/flyings are likely to exist occasionally under normal operating conditions, frequently because of repair or maintenance operations or because of leakage Where equipment is operated or processes are carried on that could result in the release of ignitible concentrations of combustible dust or c fibers/flyings or cause simultaneous failure of electrical equipment that can become a source of ignition Can be adjacent to a Zone 20 location where effective safeguards against ventilation failure are not provided –
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This usually applies to the area outside of containment systems
A Guide for use of Electrical Products in Hazardous Locations — © 2008
Article 506: Zone 22 Hazardous Locations •
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Zone 22 covers areas which ignitible concentrations of combustible dust or ignitible fibers/flyings are not likely to occur in normal operation, or for a short period Where combustible dust or fibers/flyings are handled, processed, or used but normally confined within closed containers of closed systems Can be adjacent to a Zone 21 location where effective safeguards against ventilation failure are not provided –
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This usually applies locations where controllable dust layers are formed that are likely to be raised into explosive dust– air mixtures
A Guide for use of Electrical Products in Hazardous Locations — © 2008
Article 506: Zone 20, 21, 22 Hazardous Locations
Zone 20 Zone 21 Zone 22 Non-Hazardous Zone
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A Guide for use of Electrical Products in Hazardous Locations — © 2008
IEC Protection Techniques for Hazardous Areas •
Flameproof “d” –
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Flameproof Plus Increased Safety “de” –
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Location of arcing has “d” protection (flameproof) Connection terminals have “e” protection (increased safety) Typical use in switches, luminaires , controls, plugs and receptacles/sockets – Items such as power outlets, switches, some luminaires , etc., cannot be protected by “e” mode only. In this case “d” and “e” are combined
Intrinsic Safety “ia” and “ib” – –
ia Zone 0 & 1 ib Zone 1 • •
Incapable of releasing enough energy to cause an explosion Typical use in communication equipment
A Guide for use of Electrical Products in Hazardous Locations — © 2008
Zone 2 • • • • •
•
Zone 1 • •
Oil totally seals arcing and sparking devices Typical use in hazardous rated transformers and switches
Pressurization “p” – – –
px Zone 1 py Zone 1 pz Zone 2 • •
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Enclosure restricts ingress of hazardous gases nA=non sparking construction nR=restricted breathing nC=hermetically sealed, non incentive Typical use in luminaires
Oil Immersion “o” –
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Epoxy or other resin to totally seal arcing and sparking devices Typical use in luminaires controls and sealed switches
Non-Sparking “n” –
Zone 1 • • •
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High impact resistant enclosures—FRP, GRP, sheet steel/aluminum, stainless steel Enclosure will not hold static charge Maintain minimum of IP 54 ingress protection Apparatus non arcing/sparking Typical use in terminal enclosures
m Zone 1 ma Zone 0 mb Zone 1 • •
Zone 1 •
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Contain internal explosion Control external temperature of enclosure Similar to NEC® explosionproof Usually cast enclosure Typical use in luminaires and motor starters
Encapsulation “m” – – –
Increased Safety “e” –
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Zone 1
Expels ignitible vapor/gas Maintains positive enclosure pressure
Powder Filled “q” –
Zone 1 • •
Finely ground powder to totally seal arcing and sparking devices Typical use in luminaires, controls and sealed switches
IEC Protection Techniques for Areas with Combustible Dusts •
Intrinsic Safety “iD” – – –
iaD for use in Zone 20, 21, 22 iaD for use in Zone 21, 22 (Ex ibD) associated electrical apparatus - installation in the safe areas • •
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Encapsulation “mD” – –
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Incapable of releasing enough energy to cause an explosion Typical use in communication equipment
maD for use in Zone 20, 21, 22 mbD for use in Zone 21, 22 •
Epoxy or other resin to totally seal arcing and sparking devices
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Typical use in luminaires, controls and sealed switches
A Guide for use of Electrical Products in Hazardous Locations — © 2008
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Pressurization “pD” –
Zone 21, 22 • •
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Expels ignitible vapor/gas Maintains positive enclosure pressure
Protection by Enclosures “tD” – –
tD A21 Procedure A for Zone 21 tD B21 Procedure B for Zone 21 • • • • •
High impact resistant enclosures—FRP, GRP, sheet steel/aluminum, stainless steel Enclosure will not hold static charge Maintain minimum of IP 54 ingress protection Apparatus non arcing/sparking Typical use in terminal enclosures
NEMA Classified Location Enclosures • Type 7 – For indoor use in hazardous (classified) locations as Class I, Division 1, Groups A, B, C, or D
• Type 8 – For indoor or outdoor use in hazardous (classified) locations as Class I, Division 1, Groups A, B, C, or D
• Type 9 – Intended for indoor use in hazardous (classified) locations as Class II, Division 1, Groups E, F, and G
• Type 10 (MSHA) – Shall be capable of meeting the requirements of the Mine Safety and Health Administration, 30 C.F.R., Part 18 • Note: There are no provisions in NEMA types for Class III locations. However, Type 9 would be suitable
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A Guide for use of Electrical Products in Hazardous Locations — © 2008
Explosion Elements •
Fuel – – –
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Oxygen – –
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Air Other Oxidizing Atmospheres
Ignition – – –
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Flammable Gas Vapors Combustible Dusts Flyings or Fibers
Arc Spark Heat Generated by Equipment
A Guide for use of Electrical Products in Hazardous Locations — © 2008
UL Explosionproof Apparatus Definition •
Class I, Division 1 –
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An enclosure that will withstand an internal explosion of gases or vapors and prevent those gases or vapors from igniting gases or vapors in the surrounding atmosphere outside of the enclosure
A Guide for use of Electrical Products in Hazardous Locations — © 2008
Explosionproof Enclosure Design •
An explosionproof enclosure must be able to: – – –
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U.L. explosionproof test (U.L. 1203) – –
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Withstand the internal explosion pressure Prevent propagation of flame through any joint or opening to the outside of the enclosure Maintain a low external temperature that will not ignite the surrounding flammable atmosphere
Explosion test are performed to determine the maximum pressure and propagation effect Hydrostatic pressure test at four times the highest explosion pressure
A Guide for use of Electrical Products in Hazardous Locations — © 2008
Explosionproof Equipment - Joints •
Enclosure joint designs prevent the propagation of flame, the most common types are: – – – – – –
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Ground (Flat) Joint Construction Threaded Joint Construction Labyrinth-Path Construction Precision Acme / Conical Thread Construction Close Tolerance Shaft Construction Interlocking Concentric Ring Construction
A Guide for use of Electrical Products in Hazardous Locations — © 2008
Explosionproof Equipment - Joints •
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Ground (Flat) Joint Construction
A Guide for use of Electrical Products in Hazardous Locations — © 2008
Explosionproof Equipment - Joints •
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Threaded Joint
A Guide for use of Electrical Products in Hazardous Locations — © 2008
Explosionproof Equipment - Joints •
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Labyrinth Path
A Guide for use of Electrical Products in Hazardous Locations — © 2008
Explosionproof Equipment - Joints •
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Close Tolerance Shaft
A Guide for use of Electrical Products in Hazardous Locations — © 2008
Conduit Seal Fittings •
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Required within 18 inches of an enclosure containing arcing or high temperature device. (Class I, Division 1 & 2 locations) Required in Class I, Division 1 locations where 2 inch or larger conduit enters enclosures that house terminals, splices, or taps Required at Class I boundary where conduit leaves the hazardous area U.L. requires that sealing compound/cement is certified/ approved for use with the specified sealing fitting Depth of sealing compound should be equal to trade size of conduit, having minimum thickness of 5/8 in
A Guide for use of Electrical Products in Hazardous Locations — © 2008
Conduit Seal Fittings • •
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Limit communication of gas in electrical systems Minimize pressure piling
A Guide for use of Electrical Products in Hazardous Locations — © 2008
Conduit Seal Function and Application •
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The function of a conduit seal is to prevent the passage of gases, vapors or flames from one portion of a conduit system to another They also restrict large amounts of ignitible gases or vapors from accumulating to confine explosive pressure Per the 2008 NEC, Conduit seals shall be located in accordance with article 501.15 (A)(1) through (A)(4) – – – – –
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Entering Enclosures – containing arcing, sparking or heat producing components Where a trade size 2” or larger conduit enters an enclosure containing terminals, splices or taps Two or more explosion proof enclosures Class I Division 1 Boundary Pressurized enclosures - In each conduit entry that is NOT pressurized as part of the protection system
A Guide for use of Electrical Products in Hazardous Locations — © 2008
Conduit Seal Fittings • •
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Standard conduit seal fittings are limited to 25% fill Expanded fill conduit seal fittings can be used with a conduit system allowing up to 40% conduit fill
A Guide for use of Electrical Products in Hazardous Locations — © 2008
3 Installation Methods Used Throughout the World
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A Guide for use of Electrical Products in Hazardous Locations — © 2008
Lighting Product Nameplate with UL Listing • • •
Catalog Number Third Party Certification (UL Listing Mark) Hazardous Location Suitability – – –
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Electrical Data – – – – – –
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Class I Division 2 “T” Rating Class II Group E,F,G “T” Rating Class III Lamp Information Primary voltage Operating Amperage Power Factor (90% Minimum) Hertz Rating (50 or 60) Supply Wire
A Guide for use of Electrical Products in Hazardous Locations — © 2008
Hazardous Lighting – “T” Rating •
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Every hazardous atmosphere has a temperature that, if exceeded, will cause the flammable or combustible to ignite. Accordingly, this temperature, called the “T” rating, is a critical safety benchmark. Hazardous location luminaires must run cooler than the ignition temperature of the surrounding atmosphere Per the “T” rating chart, T1 rated luminaries can only be used in locations where the atmosphere needed a temperature greater that 450° C to ignite. Conversely, T6 rated luminaires run the coolest and can be used in very volatile environments where temperatures can not exceed 85° C The “T” rating for a fixture is the temperature of the hottest spot on or in the luminaire depending on the luminaires’ Class or Zone rating. Whether the “T” rating is recorded on or in the luminaire depends on whether it is an enclosed & gasketed, explosionproof, flameproof, or restricted breathing fixture
A Guide for use of Electrical Products in Hazardous Locations — © 2008
Hazardous Lighting - “T” Rating
Degree C
ID #
351-450
T1
326-350
350
301-325
352
281-300
T2
261-280
T2A
231-260
T2B
216-230
T2C
201-215
T2D
181-200
T3
166-180
T3A
161-165
T3B
136-160
T3C
121-135
T1
101-120
T4
86-100
T5
85
T6
Enclosed & Gasketed “T” Ratings •
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Enclosed & gasketed fixtures measure their “T” ratings on the inside. If a hazard is accidentally released into the atmosphere and reaches inside the fixture, it will not ignite assuming the fixture’s “T” rating is below that of the hazard
A Guide for use of Electrical Products in Hazardous Locations — © 2008
Explosionproof, Flameproof & Restricted Breathing “T” Ratings •
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For explosionproof and flameproof fixtures, the “T” ratings are measured on the exterior of the fixture. This is due to the explosionproof and flameproof fixture’s ability to disarm any explosion caused within the interior of the fixture. Therefore, the exterior temperature of the fixture becomes the forerunning concern Restricted breathing fixture construction is similar to enclosed & gasketed but requires a seal to give the product the “restricted breathing” rating. This allows restricted breathing fixtures to have their “T” ratings measured from the surface of the fixture
A Guide for use of Electrical Products in Hazardous Locations — © 2008
Guidelines for Luminaire Use in Zone 2 Locations Authority
Location
Method of Protection
T number measurement made at
Sealed cable and/or conduit/ optic required
NEC
Zone 2 or Division 2
UL844 Division 2
Lamp hot spot
Cable- yes Conduit- no
Externally at hot spot on surface
Optic- yes Cable- yes Conduit- yes
NEC Zone 2 IEC
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Restricted breathing (AEx nR) Restricted breathing (Ex nR)
A Guide for use of Electrical Products in Hazardous Locations — Š 2008
Comparison of NEC® and IEC Luminaire Construction •
“T” Code Measurement Points –
1984 – Class I, Div. 2 Conventional NEC fixture •
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2000 – Entry to Zone System – Class I, Zone 2 Ex nR (Restricted Breathing) • •
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Hot Spot on Globe Seal Required on Entry
2004 – Optimized Class I, Zone 2 AEx nA nR • •
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Hot Spot on LAMP
Hot Spot on Globe/Ballast Compartment Factory Sealed, no entry seals required
A Guide for use of Electrical Products in Hazardous Locations — © 2008
Comparison of NEC® and IEC Luminaire Construction • •
Restricted Breathing Advantages –
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Disadvantages – – –
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Higher wattage fixture can be utilized and still comply w/ codes Cracked or loose globe renders product unsafe Likelihood of retrofit using unapproved components Costs more than conventional fixture
A Guide for use of Electrical Products in Hazardous Locations — © 2008
2008 National Electrical Code •
The objective of Articles 500 - 516 of the NEC® is to insure that hazardous location occupancies are properly identified and evaluated, and to make sure that electrical equipment and wiring installed and used in hazardous locations does not become an ignition source for an explosive atmosphere. This is accomplished by: – – – – – – –
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Defining and classifying the forms and types of flammable materials that may be present Requiring that hazardous (classified) locations be assessed, formally classified and documented for the degree and type of hazard that they represent Recognizing different hazardous location and flammable atmosphere classification systems, and specifying how they might coexist in the same installation Defining and recognizing explosion protection techniques for electrical equipment that are matched to the particular hazardous atmosphere(s) that may be present Specifying electrical equipment marking and other certification documentation that must be provided by manufacturers of hazardous location electrical equipment to installers, users and inspectors Providing specialized installation requirements for specific hazardous location protection techniques or occupancies Providing references to standards and publications from NFPA® and other recognized organizations where users and inspectors can obtain more information Where necessary, requiring that specification and installation of electrical equipment in hazardous locations be done under the direction of specially qualified individuals
A Guide for use of Electrical Products in Hazardous Locations — © 2008
Interpretation of the 2008 NEC® • The following Article sections have been revised during the 2008 NEC® Code cycle – These changes are those that are substantive and should be noted – These changes do not include those that are editorial in nature
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A Guide for use of Electrical Products in Hazardous Locations — © 2008
Interpretation of Article 500: Hazardous (Classified) Locations, Classes I, II, and III, Divisions 1 and 2
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Section 500.1 and 500.5 –
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•
Flammable liquid-produced vapors, combustible liquid-produced vapors
Section 500.7 –
Combustible gas detection equipment
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500.1 and 500.5 adds the terms flammable liquid-produced vapors and combustible liquidproduced vapors to the list of materials that require analysis to determine of special electrical equipment or wiring is required to minimize the hazardous risks 500.7(K)(1); 500.7(K)(2); and 500.7(K)(3) now require that combustible gas detection equipment be listed for the appropriate gas group and for the detention of the specific gas or vapor to be encountered
Interpretation of Article 501: Class I Locations
•
Section 501.10 –
•
Type PVC conduit and Type RTRC conduit for Class I, Division 1 and Class I, Division 2 Areas
Section 501.30 –
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•
Flexible metal conduit and liquidtight flexible metal conduit restriction as sole ground-fault current paths
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501.10 permits listed PVC conduit and RTRC conduit where encased in a concrete envelope a minimum of 50 mm (2 in.) thick and provided with not less than 600 mm (24 in.) of cover measured from the top of the conduit to grade 501.30 requires that liquidtight flexible metal conduit, as well as flexible metal conduit, be installed with internal or external bonding jumpers in parallel with each conduit if these conduits are “to be relied upon to complete a sole equipment grounding path.” The equipment bonding jumpers must comply with all other requirements of Section 250.102
Interpretation of Article 502: Class II Locations
•
Section 502.30(B) –
•
•
In Class II, Division 2 Areas – Fixed lighting provided with dusttight enclosures
Section 502.150(B) –
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In Class II, Division 2 Areas – Coils and windings in tight metal housings. Future requirements will be dusttight enclosures
Section 502.130(B) –
•
Liquidtight flexible metal conduit restrictions as sole ground-fault current path
Section 502.120(B) –
•
•
In Class II, Division 2 Areas – Contacts in tight-fitting enclosures. Future requirements will be dusttight enclosures
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502.30 is similar to the change in 501.30(B), this section has been rewritten to clarify that in Class III, Division 1 and 2 locations, liquidtight flexible metal conduit is not permitted to be used as equipment grounding conductor without an additional bonding jumper installed 502.120(B) states where not located in the same enclosure with switching mechanisms, control transformers, solenoids, and impedance coils shall be provided with tight metal housings without ventilating openings or shall be installed in dusttight enclosures 502.130(B) now specifically requires a rating of “dusttight” for the fixed lighting enclosure (ballast tank) 502.150(B) requires that for Class II, Division 2 locations, the enclosures must have tight fitting covers, with no openings through which sparks or burning material might escape, to minimize the entrance of dust or be dusttight. Nonincendive circuits may be contained in general purpose type enclosures. Resistors must have enclosures identified for Class II, Division 1
Interpretation of Article 503: Class III Locations
•
Section 503.30(B) –
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Liquidtight flexible metal conduit restriction as sole ground-fault current path
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Similar to the change in 501.30, this section has been rewritten to clarify that in Class III, Division 1 and 2 locations, liquidtight flexible metal conduit is not permitted to be used as equipment grounding conductor without an additional bonding jumper installed
Interpretation of Article 504: Intrinsically Safe Systems
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Section 504.2 –
•
•
Definition for Simple Apparatus
Section 504.70 –
Sealing conduits and cables to be identified for the purpose
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504.2 places any limitations on the use of simple apparatus that can be used in the hazardous location will be listed on the control drawing for the associated apparatus. In the case of using a device that will heat up, such as an RTD, care must be taken to stay below the 1.3 Watt limit to avoid creating a hot surface. Care must also be taken that the use of simple apparatus does not connect two or more intrinsically safe circuits together in the hazardous location. This can create a situation where sufficient energy could be released to cause an ignition 504.70 requirements for conduit and cable seals containing intrinsically safe wiring were clarified. Though they are not required to be explosionproof or flameproof, they shall be accessible and identified for the purpose of minimizing passage of gases, vapors or dusts under normal operating conditions. References to Articles 502, 505, 506 which cover where explosionproof or flameproof seals are not required have been included in the section
Interpretation of Article 505: Class I, Zone 0, 1, and 2 Locations
•
Section 505.7 –
•
Section 505.8
•
Section 505.8
– –
•
Combustible gas detection equipment Fiber Optic Cable Assemblies
Section 505.15(C) –
•
Addition of Encapsulation Methods “ma” and “mb”
Section 505.9(F) –
•
•
Implementation of the Zone Classification System
•
RTRC conduit and cable Schedule 80 PVC conduit for Class I, Zone 2 Areas
– –
Section 505.25(B) –
Flexible metal conduit and liquidtight flexible metal conduit restrictions as sole ground-fault current path
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•
•
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505.7 removed the rule requiring that the classification of areas and the selection of equipment and wiring methods be the sole authority of a registered professional engineer. The new language requires that the total process of implementation of the Zone Classification System be conducted by qualified persons 505.8 added additional methods of protection technique that shall be permitted for equipment in Class I, Zone 0, Zone 1, or Zone 2 locations Encapsulation “ma” Encapsulation “mb”
505.9(F) was added to address the proper wiring methods and sealing requirements for fiber optic cable assemblies installed in a Class I, Zone rated area 505.15(C) was added to permit RTRC conduit and Schedule 80 PVC conduit in Class I, Zone 2 areas of industrial establishments and where additional corrosion resistance is required 505.25(B) is similar to the change in 501.30(B), this section has been rewritten to clarify that in Class III, Division 1 and 2 locations, flexible metal conduit and liquidtight flexible metal conduit is not permitted to be used as equipment grounding conductor without an additional bonding jumper installed
Interpretation of Article 506: Zone 20, 21, and 22 Locations for Combustible Dusts or ignitible Fibers/Flyings
•
Section 506.8 –
•
Fiber optic cable assemblies
Section 506.25(B) –
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Liquidtight flexible metal conduit restriction as sole ground-fault current path
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506.8 added – – – – –
Several Protection Techniques added to the article
Section 506.9(F) –
•
•
Encapsulation “maD” Encapsulation “mbD” Protection by Enclosure “tD” Protection by Pressurization “pD” Protection by Intrinsic Safety “iD”
506.9(F) Where a fiber optic cable assembly contains conductors that are capable of carrying current, the fiber optic cable assembly shall be installed in accordance with 506.15 and 506.16, as applicable 506.25 Liquidtight flexible metal conduit shall not be used as the sole ground-fault current path. Where equipment bonding jumpers are installed, they shall comply with 250.102
Interpretation of Article 510: Hazardous (Classified) Locations – Specific
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There were no changes to Article 510 for the 2008 NEC® This is a general Article that defines the structure of the specific locations addressed in Articles 511 through 516
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Interpretation of Article 511: Commercial Garages, Repair and Storage
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Section 511.2 –
•
Section 511.3 –
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Definitions for major and minor repair garages were added Area classification general requirements
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511.2 redefined major repair garage and minor repair garage 511.3(A) and 511.3(B) have been rearranged to clarify the new definitions
Interpretation of Article 513: Aircraft Hangers
•
Section 513.2 –
•
Section 513.3 –
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Definition for aircraft painting hanger Aircraft painting hanger classification requirements
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513.2 defined the term aircraft painting hanger 513.2 was expanded to include the area classification requirements specific to the new aircraft painting hanger
Interpretation of Article 514: Motor Fuel Dispensing Facilities
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There were no significant changes made to Article 514 for the 2008 NEC®
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Interpretation of Article 515: Bulk storage plants
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Section 515.7(A) –
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Schedule 80 PVC and RTRC Conduit
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RTRC was added as a permissible wire method above Class I locations
Interpretation of Article 516: Spray Application, Dipping, and Coating Processes
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There were no significant changes made to Article 516 for the 2008 NEC®
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We provide the products…
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Conduit and Cable Fittings • • • • • •
• • • • •
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Connect Cable to an electrical enclosure Connect conduit to an electrical enclosure Couple conduit Accommodate changes in direction in conduit system Reduce or enlarge conduit Prevent abrasion of wire insulation at transition points throughout wiring system Ensure continuity of ground Attach conduit to a structure Provide a seal against water, dirt, dust, oil Relieve strain on conductors (cord grips, cable supports) Act as an extension of the mechanical protection provided by the wiring system.
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Conduit Outlet Boxes • • • •
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Some function as fittings Provide opening for splices Serve as a pulling fitting Permit access to wiring for maintenance
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Plugs and Receptacles •
Provide power to portable / fixed equipment – – – –
•
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Motors Pumps Welders Compressors
May be interlocked with switches
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Lighting Fixtures •
•
• •
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Provides illumination in areas designated as classified or explosionproof Suitable for indoor or outdoor use where hazardous, damp and corrosive conditions exist UL listings as approved for use in specific classified areas Models available for Class I, Div. 1; Class II, Div. 1; UL 844; UL 1598A; Marine Type Electric Fixtures Outside Type (Salt Water); and paint spray booths
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Cord & Cable Reels •
• •
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Continuous retractable power supply to moving machines (cranes, trains, hoists, etc) Can be sold with hand lamps Takes up slack as equipment moves
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Control Stations & Panels • • • • • •
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Push buttons Selector switches Pilot lights Meters Windows ATEX Certified
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Enclosures & Controls • •
• •
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Disconnect Switches – load disconnect Motor Starters – disconnect means, circuit protection, undervoltage protection Circuit Breaker – protection for a given device Large Junction Boxes – cast enclosure for electrical connection
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Enclosures & Controls
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•
Panelboards – protection for multiple circuits
•
Switch Racks – factory assembled control center
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EGS Brands with Hazardous Products • • • • •
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Appleton Curlee O-Z/Gedney A.T.X. Nelson
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Disclaimer • The information presented in this presentation has been assembled from various sources. Although every attempt has been made to ensure accuracy, neither EGS Electrical Group/Appleton Electric LLC nor its contributors to this publication assumes responsibility for any inaccuracies or omissions in the data presented • As a safety precaution, information to be utilized from this presentation should be verified from the National Electrical Code® and other sources
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