IAPMO, 07/15/2016. Effective January 1, 2017. Reprints and amends the 2015 UMC. Part 4. The California Mechanical Code contains mechanical building standards of state adopting agencies. Part 4 incorporates and reprints the Uniform Mechanical Code 2015. (2016 edition published by IAPMO) Complete list of the other Title 24 codes for 2016 available HERE. Don't forget: TABS for the CMC! More about 2016 California Mechanical Code, Title 24 Part 4