ONTARIO – On December 2, 2025 the IAPMO Standards Council published their decisions regarding two appeals submitted by Eli Howard, SMACNA and Phil Trafton, ASHRAE and April Trafton, Coffman Engineers. The Standards Council decisions (see IAPMO letter below) reverse controversial items approved earlier in the year by the UMC Technical Committee for final adoption into the 2027 UMC Code Cycle.
If the appeals were NOT granted, these proposed code changes referred to as Items #107 and #109 would have effectively banned the use of gypsum and concealed building spaces for use in return air systems in commercial, multi-family and single family construction in the 2027 UMC Code Cycle.
Eli Howard of SMACNA and Chris Walker of CAL SMACNA (see CAL SMACNA Comment Letter below) testified in support of the appeals during the November 13th Standards Council hearing at IAPMO’s World Headquarters in Ontario, CA. Their testimony focused upon the negative impacts these two items (#107 and #109) would have upon building design, costs/methods of construction, increased energy consumption and the lack of necessity to protect public safety, health and welfare. ASHRAE also testified to the merits of the appeals and negative consequences of allowing these proposals to move forward.
SMACNA, CAL SMACNA and ASHRAE are all pleased with the Standards Council decision.
IAPMO Standards Council Discussion (excerpt from 12/2 letter)
“In the decision, the Standards Council agreed with the proponents that the 2027 UMC should contain provisions to allow concealed building spaces or independent construction to be used as ducts or plenums. However, mindful of the TC’s consistent approval to the Proposal and Public Comments, the Standards Council will request that the Mechanical TC Chair establish a task group, seeking participation from industry experts and those familiar with concealed building spaces or independent constructions being used as ducts or plenums and the use of gypsum in ducts or plenums, to research specifically this topic and forward recommendations to the Mechanical TC for consideration in the 2030 code development cycle.”
Final Decision (excerpt from 12/2 letter)
“In consideration of the aforesaid, the Standards Council hereby grants the appeal. The effect of this decision is that in the 2027 edition of the Uniform Mechanical Code, 205.0, 206.0, 218.0, 601.2, 602.2 (exceptions 1 through 9)1, 603.2, 608.1, and 608.4 will contain language as shown in the 2024 Uniform Mechanical Code, as illustrated in Exhibit B.
The Council further requires the establishment of a Concealed Building Space and Independent Construction Task Group.”