Hazardous Location Rating Systems for Interlock Switches The Omron STI Hazardous Location Rated Safety Interlock Switches presented in this catalog are classified by the European standard as Ex, ExdIIc T6. A sealed contact block makes these interlock switches suitable for use in Zone 1 and Zone 2 environments, which are typical of those found in the chemical and petrochemical industries. The tables that follow explain and compare the European method with the U.S. method of classification of Explosion Proof products. The European classification of E ExdIIc T6 is explained as follows: Explanation of Marking of EX Equipment for European Market Ex = equipment corresponds to a type of protection covered by British or Baseefa Standards (e.g. BS 4683, SFA 3009) EEx = equipment corresponds to a type of protection covered by specific European Standards (e.g. EN 60079-1) E Ex indicates they meet the European safety standards of EN 60079-0 and EN 60079-1 and BS5501 parts I-V. d suffix indicates that the explosion proof enclosure of the contact block is designed to contain an internal explosion and will not ignite a surrounding flammable atmosphere. llc refers to the group of gases for which the switches are suitable. Group II gases are sub-divided into three categories by the suffix a, b, or c. Suffix c gases are the most flammable within Group II and include gases such as hydrogen. Special precautions may be required to protect the vulnerable parts Type of protection used Covered by Standard o = oil immersion EN 50015 p = pressurized apparatus EN 50016 q = powder filing EN 50017 d = flameproof enclosure EN 50018 e = increased safety EN 50019 i = intrinsic safety (ia or ib) EN 50020 m = encapsulation EN 50021 s = special protection BASEEFA SFA 3009 of the switch from corrosion, such as PVC covered cables against attack by certain corrosive elements and physical damage. The T designation represents the surface temperature classification of the switch and is divided into categories with the suffix 1 to 6. T6 is the lowest temperature and thus the safest classification with a maximum permitted surface temperature of 85 C (providing that the electric loading of the switch does not exceed its stated current rating). These switches have been tested with an ambient temperature of 60 C as opposed to the normal test limit of only 40 C, allowing them to be used in gases having a low flash point. Switches classified as E Exdllc T6 (All Omron STI Ex switches) are not suitable for use in atmospheres containing Group I gases, e.g. methane (firedamp). Please note that these switches DO NOT meet all conditions of the US classification of Class I, Div 1 due to the differences between European and US classification methods. See the table on the following page, (Figure 7.2). example EExd IIC T6 Subdivisions A, B & C are based on classification of Maximum Experimental Safe Gap (MESG) and Minimum Ignition Currents (MIC) - For more information refer to EN 50014: 1992 Annex A. Usage / gas group Group Usage place Representative gas I = Mines Methane IIA = Surface Propane IIB = Surface Ethylene, Propane IIC = Surface Hydrogen, Ethylene,Propane Fig. 7.1 Classification of maximum surface temperature T1 = 450 C T2 = 300 C The maximum surface temperature must be less than the lowest ignition T3 = 200 C temperature of the explosive atmosphere. T4 = 135 C T5 = 100 C T6 = 85 C www.omron247.c 1
hazardous location Rating Systems For Interlock Switches Classifications of Hazardous Locations Explosive Continuous Intermittent Occasional Atmosphere Presence Presence Presence (normal operating (abnormal operating conditions) conditions) IEC Zone 0 (gas) Zone 1 (gas) Zone 2 (gas) (International) Zone 20 (dust) Zone 21 (dust) Zone 22 (dust) France (19.12.88) Zone 0 (gas) Zone 1 (gas) Zone 2 (gas) and Europe Canada (CEC) CI. I Div. 1 (gas) CI. I Div. 1 (gas) CI. I Div. 2 (gas) and USA (NEC) CI. II Div. 1 (dust) CI. II Div. 1 (dust) CI. II Div. 2 (dust) CI. III Div. 1 (fibers) CI. III Div. 1 (fibers) CI. III Div. 2 (fibers) Gas Groups Place of Use Group Class & Group Representative CENELEC/IEC Canada & USA Gas Mines with firedamp l Gaseous Mines Methane Surface industries IIA I-D Propane IIB I-C Ethylene IIC I-B Hydrogen IIC I-A Acetylene Marking Temperatures Temperature Class (CENELEC/IEC) T1 T2 T3 T4 T5 T6 Group ll Maximum Surface 450 C 300 C 200 C 135 C 100 C 85 C Temperature The maximum surface temperature of equipment must always be lower than the ignition temperature of the gas present in the hazardous area. Fig. 7.2 2 www.omron247.com
Hazardous (Classified) Locations NEC Article 500 Class I Combustible material in the form of gas or vapor. 500-5 Division 1 (1) in which hazardous concentrations of flammable gases or vapors exist continuously, intermittently, or periodically under normal operating conditions. (2) in which ignitable concentrations of such gases or vapors may exist frequently because of repair or maintenance operations or because of leakage. (3) in which breakdown or faulty operation of flammable gases or vapors, might also cause simultaneous failure of electrical equipment. 500-5 (A) Division 2 (1) in which volatile flammable liquids or flammable gases are handled, processed, or used, but in which the hazardous liquids, vapors, or gases will normally be confined within closed containers or closed systems from which they can escape only in case of accidental rupture or breakdown of such containers or systems, or in the case of abnormal operation of equipment. (2) in which ignitable concentrations of gases or vapors are normally prevented by positive mechanical ventilation, but which might become hazardous through failure or abnormal operation of the ventilating equipment (3) that are adjacent to Class I, Division 1 locations, and to which ignitable concentrations of gases or vapors might occasionally be communicated unless such communication is prevented by adequate positive-pressure ventilation safeguards against ventilation failure are provided. 500-5(B) Group A Atmospheres containing acetylene 500-3 FPN #5 Group B Atmospheres containing hydrogen, gases or vapors of equivalent hazard, such as manufactured gas. 500-3 FPN #6 Group C Atmospheres containing ethyl ether vapors, ethylene, or cyclopropane. 500-3 FPN #7 Group D Atmospheres containing gasoline, hexane, naphtha, benzine, butane, propane, alcohol, acetone, benzol, lacquer, solvent vapors, or natural gas. 500-3 FPN #8 Group E Atmospheres containing metal dust, including aluminum, magnesium, and their commercial alloys, and other metals of similar hazardous characteristics. 500-3 FPN #17 Group F Atmospheres containing carbon black, coal, or coke dust. 500-3 FPN #14 Group G Atmospheres containing flour starch or grain dusts. 500-3 FPN #15 Fig. 7.3 www.omron247.c 3
Hazardous (Classified) Locations european STAndard Gases Combustible material in the form of gas or vapor. US Class I Zone O of flammable gases or vapors are present continuously or present for long periods of time. US Div. 1 Zone 1 of flammable gases or vapors are likely to exist under normal operating conditions, or because of leakage. US Div. 1 Zone 2 of flammable gases or vapors are not likely to occur in normal operation; but if they do, only for short periods. US Div. 2 Group IIC Atmospheres containing acetylene US Group A Group IIC Atmospheres containing hydrogen, gases or vapors of equivalent hazard, such as manufactured gas. US Group B Group IIB Atmospheres containing ethyl ether vapors, ethylene, or cyclopropane. US Group C Group IIA Atmospheres containing gasoline, hexane, naphtha, benzine, butane, propane, alcohol, acetone, benzol, lacquer, solvent vapors, or natural gas. US Group D In Prep Atmospheres containing metal dust, including aluminum, magnesium, and their commercial alloys, and other metals of similar hazardous characteristics. US Group E In Prep Atmospheres containing carbon black, coal, or coke dust. US Group F In Prep Atmospheres containing flour starch or grain dusts. US Group G Fig. 7.1 www.omron247.com 4
OMRON AUTOMATION AND SAFETY THE AMERICAS HEADQUARTERS Chicago, IL USA 847.843.7900 800.556.6766 www.omron247.com OMRON CANADA, INC. HEAD OFFICE Toronto, ON, Canada 416.286.6465 866.986.6766 www.omron247.com OMRON ELECTRONICS DE MEXICO HEAD OFFICE México DF 52.55.59.01.43.00 01-800-226-6766 mela@omron.com OMRON ELECTRONICS DE MEXICO SALES OFFICE Apodaca, N.L. 52.81.11.56.99.20 01-800-226-6766 mela@omron.com OMRON ARGENTINA SALES OFFICE Cono Sur 54.11.4783.5300 OMRON CHILE SALES OFFICE Santiago 56.9.9917.3920 OTHER OMRON LATIN AMERICA SALES 54.11.4783.5300 OMRON ELETRÔNICA DO BRASIL LTDA HEAD OFFICE São Paulo, SP, Brasil 55.11.2101.6300 www.omron.com.br OMRON EUROPE B.V. Wegalaan 67-69, NL-2132 JD, Hoofddorp, The Netherlands. +31 (0) 23 568 13 00 www.industrial.omron.eu Authorized Distributor: Automation Control Systems Machine Automation Controllers (MAC) Programmable Controllers (PLC) Operator interfaces (HMI) Distributed I/O Software Drives & Motion Controls Servo & AC Drives Motion Controllers & Encoders Temperature & Process Controllers Single and Multi-loop Controllers Sensors & Vision Proximity Sensors Photoelectric Sensors Fiber-Optic Sensors Amplified Photomicrosensors Measurement Sensors Ultrasonic Sensors Vision Sensors Industrial Components RFID/Code Readers Relays Pushbuttons & Indicators Limit and Basic Switches Timers Counters Metering Devices Power Supplies Safety Laser Scanners Safety Mats Edges and Bumpers Programmable Safety Controllers Light Curtains Safety Relays Safety Interlock Switches C332I-E-01 08/14 Note: Specifications are subject to change. 2014 Omron Electronics LLC Printed in U.S.A. Printed on recycled paper.