IAPMO Publishes 2024 Editions of Uniform Plumbing Code, Uniform Mechanical Code

The International Association of Plumbing and Mechanical Officials has published the 2024 editions of the Uniform Plumbing Code and Uniform Mechanical Code in both hardcopy and electronic versions, completing a three‐year consensus development cycle accredited by the American National Standards Institute.

Significant changes to the UPC include:

• Provision for temperature-actuated, flow reduction devices for individual fittings
• New requirements for water supply and distribution manifolds
• Updated provisions for hot-water recirculating systems
• Updated minimum water quality provisions for onsite treated nonpotable water systems, nonpotable water devices and systems, for harvested rainwater systems
• New Appendix R providing minimum plumbing system requirements for tiny houses
• New Appendix S with provisions pertaining to onsite stormwater treatment systems

Significant changes to the UMC include:

• New minimum air filtration requirements for occupied spaces of mechanically ventilated buildings
• New air balancing requirements for ventilation systems
• New exceptions for materials exposed with ducts or plenums
• New refrigerant safety group classifications based on flammability and toxicity
• New requirements for refrigeration machinery rooms where A2L and B2L refrigerants are used
• New materials standards for refrigerant piping, tubing and fittings
• New design requirements for geothermal district ambient temperature loop systems
• New Appendix J addressing CO2 monitoring and clean air delivery for adequate ventilation in occupied spaces

The 2024 Uniform Codes are available electronically. The public is encouraged and invited to participate in IAPMO’s open consensus code development process. A code development timeline and other relevant information are available at IAPMO’s website: iapmo.org/code-development.