Permit · MVQ2600061Washington DC Open DataHVAC
822 6th St SW, Washington, Dc 20024
Washington · DC
Issued
Thursday, April 9, 2026
Filed value
Not listed
Contractor
Melissa DiazCounty
District of Columbia
Status
issued
Washington · DC
22 feet width units B2601217, B2601512, B2601514, B2601513 The District of Columbia Mechanical Code is currently in the 2017 cycle, which does not have the A2L refrigerant requirements that later ICC codes have. Therefore, the DC Department of Buildings has elected to allow for the installation of A2L refrigerant piping, as is allowed by the 2024 International Mechanical Code. Section 1109.2.5 of the 2024 IMC requires that refrigerant piping penetrating two or more floor/ceiling assemblies be enclosed in a fire-resistance-rated shaft enclosure. It also lists exceptions. Exception 2 states: Piping in a direct refrigeration system using Group A1 refrigerant where the refrigerant quantity does not exceed the limits of Table 1103.1 for the smallest occupied space through which the piping passes. The 2024 IMC borrows language from ASHRAE 15-2022, but changes the language in this exception. This code modification request is to modify the code to utilize language directly from ASHRAE 15-2022. The difference we would like the DOB to consider is the second exception. Instead of specifying A1 refrigerants, the exception states: Piping in a high-probability system where the refrigerant concentration does not exceed the amounts shown in ASHRAE Standard 34, Table 4-1 or 4-2, for the smallest occupied space through which the piping passes.