UL 921
Commercial Dishwashers

DETAILS
Edition Number:7SCC Approved:--
Edition Date:2016-03-23DOD Approved: 1992-06-18
Price Code:DANSI Approved: 2017-09-20
Type:ulcsa

  • SCOPE

    1 Scope

    1.1 This Standard covers commercial, freestanding, under-counter, and counter-insert dishwashers, utensil-washers, and glass washers using water as the principal cleaning medium, hereafter referred to as dishwashers. These dishwashers utilize steam, gas, or electric heaters for heating the water. Heated water is provided to a dishwasher by means of steam, gas, or electric heating systems integral to the appliance, or by means not integral to the dishwasher that is provided at the installation site.

    1.2 This Standard covers:

    a)    electric dishwashers rated 600 V or less, installed in accordance with the Canadian Electrical Code (CEC), Part 1, CSA C22.1, and the National Electrical Code (NEC), NFPA 70; and

    b)    the gas-handling, gas-burning, and gas-control features of gas-fired dishwashers having inputs of 400,000 Btu (420 MJ) per hour or less, limited to 0.5 psig (3.45 kPa) inlet pressure, installed in accordance with the National Fuel Gas Code, ANSI Z223.1/NFPA 54, the International Fuel Gas Code, ICC IFGC, or the Natural Gas and Propane Installation Code, CSA B149.1 for use with:

    1)    natural gas;

    2)    manufactured gas;

    3)    mixed gas;

    4)    propane gas;

    5)    liquefied petroleum gases; or

    6)    LP gas-air mixtures.

    1.3 These requirements cover dishwashers intended for use in commercial establishments, such as kitchens of restaurants and hospitals, where they are not intended to be accessible to the public.

  • TABLE OF CONTENTS
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    • Cover
    • Transmittal
    • UL Harmonized Standard Title Page
    • Table of Contents
      • Commercial Dishwashers
        • 1 Scope
        • 2 General
          • 2.1 Components
          • 2.2 Units of measurement
          • 2.3 Reference publications
          • 2.4 General requirements
        • 3 Definitions
        • 4 Construction Requirements Applicable To All Dishwashers
          • 4.1 General
          • 4.2 Field-attached accessories
          • 4.3 Doors and covers
          • 4.4 Accessibility of current-carrying parts
          • 4.5 Corrosion protection
          • 4.6 Mechanical assembly
          • 4.7 Power-supply connections
          • 4.8 Current-carrying parts
          • 4.9 Internal wiring
          • 4.10 Separation of circuits
          • 4.11 Insulating materials
          • 4.12 Thermal insulation
          • 4.13 Equipment grounding
          • 4.14 Lampholders
          • 4.15 Receptacles
          • 4.16 Capacitors
          • 4.17 Overcurrent- or overload-protective devices
          • 4.18 Overcurrent and overload protection for motors
          • 4.19 Overcurrent protection for transformers
          • 4.20 Overcurrent protection for conductors
          • 4.21 Switches
          • 4.22 Controls
          • 4.23 Spacings
          • 4.23A Alternative spacings-clearances and creepage distances
          • 4.24 Seals and gaskets
          • 4.25 Moisture condensation
        • 5 Construction Requirements Unique To Gas-Fired Dishwashers
          • 5.1 General
          • 5.2 Manually-operated gas valves
          • 5.3 Automatic valves and safety shutoff valves
          • 5.4 Gas pressure regulators
          • 5.5 Ignition systems
          • 5.6 Pilot-gas filters
          • 5.7 Gas supply line
          • 5.8 Semi-rigid tubing
        • 6 Reduction Of Risk Of Injury To Persons – Requirements Applicable To All Dishwashers
          • 6.1 Enclosure and guards
          • 6.2 Automatic restarting of motor
          • 6.3 Parts subject to air or steam pressure
          • 6.4 Pressure-relief devices
        • 7 Performance Requirements Applicable To All Dishwashers
          • 7.1 General
          • 7.2 Electrical input test
          • 7.3 Starting current test
          • 7.4 Normal temperature test
          • 7.5 Temperature measuring equipment and enclosure setup
          • 7.6 Dielectric voltage-withstand test
          • 7.7 Flexing test
          • 7.8 Insulation resistance following humidity conditioning test
          • 7.9 Water exposure tests
          • 7.10 Flooding of current-carrying parts test
          • 7.11 Hydrostatic pressure test
          • 7.12 Reservoir overflow test
          • 7.13 Liquid containers, seals, and diaphragms tests
          • 7.14 Limited short-circuit test (motor protection)
          • 7.15 Abnormal operation test
          • 7.16 Blocked plunger test
          • 7.17 Overvoltage for electrolytic capacitors test
          • 7.18 Overload on switches test
          • 7.19 Transformer overcurrent protection test
          • 7.20 Transformer burnout test
          • 7.21 Door interlock endurance test
          • 7.22 Loading door/drawer moment load test
          • 7.23 Strain relief test
          • 7.24 Push-back relief test
        • 8 Performance Requirements Unique To Electrically-Heated Dishwashers
          • 8.1 Automatic temperature control tests
        • 9 Performance Requirements Unique To Gas-Fired Dishwashers
          • 9.1 General
          • 9.2 Test gases
          • 9.3 Test pressures and burner adjustments test
          • 9.4 Normal operation – combustion test
          • 9.5 Undervoltage combustion test
          • 9.6 Combustion air failure test
          • 9.7 Burner operating characteristics test
          • 9.8 Pilot ignition systems test
          • 9.9 Direct ignition systems tests
          • 9.10 Flue gas temperature for draft hood appliances test
        • 10 Manufacturing And Production Tests Unique To Electrically-Heated Dishwashers
          • 10.1 Production line dielectric voltage-withstand test
          • 10.2 Production line grounding continuity test
        • 11 Manufacturing And Production Tests Unique To Gas-Fired Dishwashers
        • 12 Rating Requirements Applicable To All Dishwashers
        • 13 Marking Requirements Applicable To All Dishwashers
        • 14 Marking Requirements Unique To Electrically-Heated Dishwashers
        • 15 Marking Requirements Unique To Gas-Fired Dishwashers
        • 16 Installation Instructions Applicable to All Dishwashers
        • 17 Installation Instruction Requirements Unique to Electrically-Heated Dishwashers
        • 18 Installation Instruction Requirements Unique To Gas-Fired Dishwashers
    • EVALUATION OF ELECTRONIC CIRCUITS(Normative)
    • APPENDIX A
    • APPENDIX B