The standard is updated every three years, and addenda directly affect design.
Almost as soon as ASHRAE standards are published, subject matter experts, industry professionals and other interested parties begin to propose addenda. In the case of flagship standards, such as ASHRAE Standard 90.1: Energy Standard for Buildings Except Low-Rise Residential Buildings, there can be dozens of addenda, which are usually incorporated into the next edition. As of this writing there are 33 published addenda to Standard 90.1, which can be found on ASHRAE’s website. Of these, Addenda a, f, j, l, n and au all either clarify or improve upon one of the performance-based compliance paths, further encouraging their use.
Addendum f allows engineers to take credit for energy efficiency measures that are required by Section 11 in the prescriptive path when using the energy cost budget or performance rating method, making these two performance-based paths even more attractive.
Addendum l adds an entirely new informative appendix, Appendix M, which provides jurisdictions with a path to net zero operational energy emissions over the course of multiple code cycles. While compliance with informative appendices is not required, it is worth noting that the performance rating method also started out as an informative appendix. Even if Appendix M is not eventually elevated to a normative appendix, the fact that it is written as code enforceable language ready for use by authorities having jurisdiction means that for more climate focused local governments, compliance with ASHRAE Standard 90.1 could mean compliance with this appendix.
With ASHRAE’s recent establishment of the Center of Excellence for Building Decarbonization and the stated goal of ASHRAE Standard 90.1 becoming a net zero carbon code by the 2031 edition, new and experienced engineers alike should keep abreast of the latest addenda to stay ahead of the game.
