The Plumbing Technical Advisory Group reviewed GP2020, proposed language to provide uniform UPC guidance for installing refrigerant-based hot-water systems and to align plumbing installation text with language proposed for the International Residential Code.

Ben (TAG member) framed the issue as a coordination question between the plumbing code and mechanical provisions, asking whether the UPC language should defer room-ventilation and refrigerant-volume requirements to the mechanical code or ASHRAE standards. Ben summarized the practical concern: “If I put this heater in a closet…are you telling the industry that we need a plumbing permit, a mechanical permit in order to put this heater in?”

Members agreed that the greatest concern applies to commercial or component systems with field-installed refrigerant piping or larger refrigerant charges, not to small point-of-use unitary heat-pump water heaters sold as sealed units. Ian (TAG member) added technical context: larger systems or VRF-like arrangements can circulate refrigerant and, in a leak, displace air in occupied volumes; he referenced ASHRAE 15.2 and mechanical chapter 11 as the right references for room ventilation and refrigerant-volume calculations.

Shailesh (TAG member) and others suggested a prescriptive approach: exempt small, low-charge unitary equipment and list a refrigerant-to-room-volume threshold for when chapter 11/ASHRAE calculations apply. Staff noted chapter 11 already contains exemptions for small refrigerant charges (an example threshold discussed was about 6.6 pounds), and suggested mirroring those thresholds in the UPC language so plumbers would know when additional mechanical-ventilation requirements apply without having to consult a separate code.

TAG members further raised practical implementation questions: who would pull required permits, whether plumbers would be expected to perform refrigerant-volume calculations, and whether the language should identify “component-type” or “non-unitary” systems as the cases that trigger cross-code requirements. Eric (proponent) was consulted in advance and staff agreed to ask the proponent to draft adjusted language that would either provide a clear small-equipment exemption or explicitly reference chapter 11/ASHRAE 15.2 thresholds.

No vote was taken (no quorum). The TAG concluded by asking the proponent to refine GP2020 to explicitly define the equipment classes (unitary versus component systems), list refrigerant charge thresholds or cross-references to mechanical chapter 11/ASHRAE 15.2, and clarify expected permitting/inspection responsibilities.