Transitioning to New HVAC Safety Standards

Ensuring Compliance with UL 60335-2-40

05 June 2018

Published in 2012 and revised in the fall of 2017, UL 60335-2-40 will replace other standards such as UL 474, UL 484 and UL 1995. Products certified to previous standards will not be grandfathered to UL 60335-2-40, meaning both new and existing products will need to undergo significant testing for the new standard, which goes into effect on November 30, 2022.

The most recent version, UL 60335-2-40 2nd Edition is based upon IEC 60335-2-40 Edition 5.0 and applies to:

  • Packaged air conditioners and heat pumps
  • Partial units (unmatched condensing unit, evaporating unit, condenser unit, or evaporator unit)
  • Liquid chillers and hydronic fan coil units
  • Hot water heat pumps
  • Dehumidifiers
  • Supplemental heaters (designed as part of an appliance package)
  • Equipment with flammable refrigerants

The standard outlines multiple requirements for spacing, components, and flammable refrigerants in both direct and indirect systems. Additionally, the standard includes more stringent testing requirements for multiple factors, including:

  • Loss of charge test, in appliances where the compressor is enclosed in a way that may be inadequately ventilated
  • Non-metallic material flammability in proximity to electrical connections, which specifies:
    • Flammability characteristics
    • Nichrome wire test requirements
  • Power input and current test
  • Heating test
  • Abnormal temperature tests
  • Electric heating tests
  • Ball pressure test
  • Glow wire test

It is anticipated that the standard will continue to evolve, expanding its scope and broadening the requirements. With additional changes on the horizon and a standard that must be met in both new and existing products within 5 years, it is important than manufacturers begin the transition as soon as possible to maintain operations and product development. Stay well-informed on the requirements of the standard and begin implementing the changes to meet them. For more details on the scope and requirements of UL 60335-2-40, download our complimentary webinar recording.

Tim Halsor is the engineering team leader for electrical HVAC safety at Intertek's Plano, Texas facility. He is a member of several standard technical panels, including those for UL 60335-2-40, ASHRAE 15.2 and IEC System of Conformity Assessment Schemes for Electrotechnical Equipment and Components (IECEE) for Household and Similar Equipment.