UL 913
Standard for Intrinsically Safe Apparatus and Associated Apparatus for Use in Class I, II, III, Division 1, Hazardous (Classified) Locations

DETAILS
Edition Number:5SCC Approved:--
Edition Date:1997-02-21DOD Approved: --
Price Code:CANSI Approved: 1988-05-20
Type:ulstd

  • SCOPE

    1 Scope

    1.1 This standard applies to:

    a)    Apparatus or parts of apparatus in Class I, II, or III, Division 1 locationsa;

    b)    Those parts of apparatus located outside of the Class I, II, or III, Division 1 location having a design and construction that may influence the intrinsic safety of an electrical circuit within the Class I, II, or III, Division 1 location;

    c)    Apparatus or parts of apparatus in Class I, Zone 0 or 1, Groups IIA, IIB, and IIC locations;

    d)    Those parts of apparatus located outside of the Class I, Zone 0 and 1, Groups IIA, IIB, or IIC location having a design and construction that may influence the intrinsic safety of an electrical circuit within the Class I, Zone 0 and 1, Group IIA, IIB, or IIC location.

    aSection 500-3(a) of ANSI/NFPA 70-1987 ,  National Electrical Code, states that equipment that has been approved for a Division 1 location shall be permitted in a Division 2 location of the same class and group.

    1.2 * These requirements are based on consideration of ignition in locations made hazardous by the presence of flammable or combustible material under normal atmospheric conditions.

    1.3 For the purposes of this standard, normal atmospheric conditions are considered to be:

    a)    An ambient temperature of 40°C (104°F);

    b)    An oxygen concentration not greater than 21 percent; and

    c)    A pressure of one atmosphere.

    1.4 This standard does not cover mechanisms of ignition from external sources, such as static electricity or lightning, which are not related to the electrical characteristics of the apparatus. This standard does not cover apparatus based on high voltage electrostatic principles, such as electrostatic paint spraying apparatus.

  • TABLE OF CONTENTS
    Expand All

    • Cover
    • Transmittal
    • Table of Contents
    • UL Foreword
      • Body
        • INTRODUCTION
          • 1 Scope
          • 2 Purpose
          • 3 Applicability of Other Standards
          • 4 Definitions
          • 5 Class I, Zone, and Group Equivalency
            • 5.1 Class I, zone 0 and 1, group IIA
            • 5.2 Class I, zone 0 and 1, group IIB
            • 5.3 Class I, zone 0 and 1, group IIC
          • 6 Control Drawing
          • 7 Evaluation of Intrinsic Safety
            • 7.1 Fundamental requirements
            • 7.2 Evaluation procedure
            • 7.3 * Entity evaluation
            • 7.4 * Associated apparatus evaluation
            • 7.5 * Intrinsically safe apparatus inductance and capacitance determination
            • 7.6 * Intrinsically safe and associated apparatus control drawing
            • 7.7 Intrinsically safe apparatus evaluation
        • CONSTRUCTION REQUIREMENTS
          • 8 * Creepage and Clearance Distances
          • 9 * Encapsulation
          • 10 Field Wiring Connections
          • 11 Internal Wiring Conductors
          • 12 * Protective Components
            • 12.1 General
            • 12.2 Transformers
            • 12.3 Damping windings
            • 12.4 Current-limiting resistors
            • 12.5 Blocking capacitors
            • 12.6 Shunt protective components
            • 12.7 Shunt diode barriers
            • 12.8 Optical Isolators
          • 13 Miscellaneous Components
            • 13.1 Derating of components
            • 13.2 Plug-In boards and components
            • 13.3 * Relays
          • 14 Portable Apparatus Enclosures
          • 15 Cells and Batteries
          • 16 * Maximum Temperature
        • MARKING
          • 17 General
        • COMPARISON PROCEDURE FOR DETERMINING SPARK IGNITION CAPABILITY
          • 18 * General
            • 18.1 General
            • 18.2 Resistance circuits
            • 18.3 Resistance-capacitance circuits
          • 19 Maximum voltage and current levels
        • APPARATUS FOR CLASS II AND CLASS III LOCATIONS
          • 20 Applicability of Other Requirements in this Standard
          • 21 Specific Requirements for Intrinsic Safety
          • 22 * Dust-Tight Enclosures
        • TEST PROCEDURES
          • 23 Protective Transformers Tests
            • 23.1 Routine tests
            • 23.2 Type tests
            • 23.3 Type 1(a) and type 1(b) transformers
            • 23.4 Type 2(a) transformer
            • 23.5 Type 3 transformer
          • 24 Current-Limiting Resistor
          • 25 Shunt Diode Protective Barrier Tests
          • 26 Optical Isolator Tests
          • 27 Temperature Tests
          • 28 Small Component Ignition Test
          • 29 Dielectric Tests
          • 30 Mechanical Tests
          • 31 Drop Test
          • 32 Dust-Tight Enclosure Test
          • 33 Dust Blanketing Temperature Test
          • 34 Lamp Breakage Test
          • 35 Encapsulation Tests
            • 35.1 Force test
            • 35.2 Impact test
            • 35.3 Solvent vapor exposure
          • 36 Internal Capacitance or Inductance Test
          • 37 Spark Ignition Test
            • 37.1 General Requirements
            • 37.2 * Test apparatus
            • 37.3 Gas mixtures
          • 38 Verification of Spark Test Apparatus
            • 38.1 General
            • 38.2 Test procedure
            • 38.3 Test factors
    • APPENDIXES
    • APPENDIX A Additional Information
    • APPENDIX B Referenced Publications