UL 795
Standard for Commercial-Industrial Gas Heating Equipment

DETAILS
Edition Number:8SCC Approved:--
Edition Date:2016-12-02DOD Approved: 1992-01-27
Price Code:CANSI Approved: --
Type:ulstd

  • SCOPE

    1 Scope

    1.1 These requirements apply to factory-built gas appliances having inputs of more than 400,000 Btu per hour, per individual combustion chamber which require flame failure and other precautions and which are intended primarily for commercial and industrial installation. The appliances covered by these requirements are comfort heating furnaces, heaters and gas-fired boiler assemblies except watertube boilers having outputs of 10,000 pounds of steam per hour or more.

    1.2 These requirements also apply to all high pressure steam and high temperature water gas-fired boiler assemblies regardless of Btu per hour input.

    1.3 Gas-heating equipment covered by these requirements may be operated without a competent attendant being constantly on duty at the burners while the appliances are in operation.

    1.4 Additional installation and operation requirements are available for central-heating gas appliances, floor furnaces, room heaters, unit heaters, and water heaters as defined by the National Fuel Gas Code, NFPA 54, and by the Liquefied Petroleum Gas Code, NFPA 58, as applicable.

  • TABLE OF CONTENTS
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    • Cover
    • Transmittal
    • Table of Contents
      • Body
        • INTRODUCTION
          • 1 Scope
          • 2 Glossary
          • 3 Units of Measurement
          • 4 Undated References
          • 5 Components
        • CONSTRUCTION – MECHANICAL
          • 6 General
          • 7 Corrosion Protection
          • 8 General Components and Devices
        • CONSTRUCTION – ELECTRICAL
          • 9 General
          • 10 Servicing and Adjustment
          • 11 Electrical Enclosures
          • 12 Field Wiring Connections
          • 13 Internal Wiring
          • 14 Separation of Circuits
          • 15 Mounting of Components
          • 16 Motors and Motor Overcurrent or Overload Protection
          • 17 Overcurrent Protection of High-Voltage Control-Circuit Conductors
            • 17.1 General
            • 17.2 Tapped high-voltage control circuits
            • 17.3 Overcurrent-protective devices
          • 18 Overcurrent Protection of Transformers
            • 18.1 High-voltage transformers
            • 18.2 Thermal protection
            • 18.3 Low-voltage transformers
            • 18.4 Overcurrent protective devices
          • 19 Switches and Controllers
          • 20 Capacitors
          • 21 Electrical Insulating Material
          • 22 Spacings – High-Voltage Circuits
          • 23 Spacings – Low-Voltage Circuits
          • 24 Accessibility of Uninsulated Live Parts
          • 25 Bonding For Grounding
        • CONSTRUCTION – BURNER ASSEMBLIES
          • 26 General
          • 27 Combination Gas-Oil Burner Assemblies
        • CONSTRUCTION – BOILERS, FURNACES AND HEATERS
          • 28 General
          • 29 Accessibility
          • 30 Baffles
          • 31 Limit Controls
            • 31.1 General
            • 31.2 Liquid level limit controls – boilers
            • 31.3 Pressure limit controls – boilers
            • 31.4 Temperature limit controls – boilers
            • 31.5 Temperature limit controls – warm air furnaces and heaters
          • 32 Installation of External Controls and Fittings on Boilers
          • 33 Flue Dampers, Draft Regulators, and Draft Hoods
          • 34 Bleeds and Vents
          • 35 Bases
          • 36 Heating Surfaces and Combustion Chambers
          • 37 Radiation Shields
          • 38 Materials in Air Handling Compartments
          • 39 Casings
          • 40 Fuel Lines and Components
          • 41 Flue Collars
          • 42 Air Filters
        • PERFORMANCE
          • 43 General
          • 44 Test Installations
            • 44.1 Floor-mounted devices
            • 44.2 Suspended furnaces
            • 44.3 Unit heaters
            • 44.4 Test ducts for furnaces
          • 45 Test Methods
            • 45.1 Firing conditions
            • 45.2 Temperature measurements
          • 46 Burner Assembly Tests
            • 46.1 Combustion test
            • 46.2 Combustion air failure test
            • 46.3 Undervoltage test
            • 46.4 Power interruption test
            • 46.5 Pilot supervision test
            • 46.6 Ignition, gas-electric high tension test
            • 46.7 Ignition, gas-electric hot-wire – Undervoltage test
            • 46.8 Ignition, gas-electric hot-wire – Igniter endurance test
            • 46.9 Ignition, gas-electric hot-wire – Temperature test
            • 46.10 Ignition, multiple burner test
            • 46.11 Delayed ignition test
          • 47 Operation Tests
            • 47.1 Device limit control cutout test
            • 47.2 Continuity of operation for furnaces and heaters test
            • 47.3 Air flow of horizontal furnaces test
          • 48 Temperature Tests
            • 48.1 General
            • 48.2 Continuous operation test
            • 48.3 Blocked inlet of furnaces and heaters test
            • 48.4 Fan failure of furnaces and heaters test
            • 48.5 Blocked outlet of furnaces and duct-connected heaters test
          • 49 Low Water Cutoff of Boilers Test
          • 50 Short-Circuit Test
          • 51 Overload Test, High-Voltage Transformers
          • 52 Burnout Test, High-Voltage Transformers
          • 53 Dielectric Voltage-Withstand Test
          • 54 Draft Hood Equipped Devices
            • 54.1 Blocked outlet test
            • 54.2 Downdrafts and updrafts test
            • 54.3 Spillage test
            • 54.4 Draft hood strength test
            • 54.5 Condensing-type devices
          • 55 Blocked Outlet of Forced or Induced Draft Equipped Condensing Appliances Test
          • 56 Direct Vent Tests
            • 56.1 Direct vent system leakage test
            • 56.2 Direct vent wind tests
            • 56.3 Direct vent rain test
            • 56.4 Direct vent load test
            • 56.5 Direct vent impact test
          • 57 Flame Test
          • 58 Strain Relief Test
        • OUTDOOR-USE EQUIPMENT
          • 59 General
          • 60 Enclosures
          • 61 Field Wiring Connections
          • 62 Wiring
          • 63 Outdoor-Use Equipment Tests
            • 63.1 General
            • 63.2 Rain test
            • 63.3 Wind test
          • 64 Gaskets
          • 65 Chromic Acid Dropping Test
        • MANUFACTURING AND PRODUCTION TESTS
          • 66 General
        • MARKINGS
          • 67 General
        • INSTRUCTIONS
          • 68 General