Building energy codes continue to increase in stringency, with tougher requirements for thermal performance and new calls for daylighting and views, envelope backstops, thermal bridging and more. In a June 18 Thirsty Thursday webinar from the National Glass Association, NGA Code Consultant Tom Culp, owner of Birch Point Consulting LLC, provided a rundown of recent code changes and important proposals on the horizon.
Building energy codes continue to increase in stringency, with tougher requirements for thermal performance and new calls for daylighting and views, envelope backstops, thermal bridging and more. In a June 18 Thirsty Thursday webinar from the National Glass Association, NGA Code Consultant Tom Culp, owner of Birch Point Consulting LLC, provided a rundown of recent code changes and important proposals on the horizon.
Top updates to watch
1. More stringent U-factor requirements
ASHRAE 90.1-2019 was published in October, and the updates in the standard will also be referenced in the 2021 IECC. U-factor was reduced by 5 to 17 percent. The change marks roughly a zone shift between the U-factor requirements in the 2016 version and the 2019 version, according to Culp. (For complete information on the recent updates to ASHRAE 90.1, see Glass Magazine’s Glass & Metals 501: Guide to Glazing Performance. The report includes ASHRAE’s revised climate map along with indications about roughly what glass and glazing products might meet the new requirements.)
2. Daylighting and view
Requirements for daylighting and views have come, or are coming, to the green codes—ASHRAE 189.1 and the International Green Construction Code. The ASHRAE 189.1-2017 and the 2018 IgCC expanded daylighting requirements for more spaces, including classrooms, offices, patient rooms and more. The next edition (ASHRAE 189.1-2020 and 2021 IgCC) will include a new above-core requirement for minimum views in offices, classrooms and patient rooms.
3. Envelope backstops
Envelope backstops are coming in the latest energy codes, placing limits on what can be “traded off” to meet performance requirements. Envelope backstops will require a minimum level of envelope performance no matter what else is done in the building. The implications—both positive and negative—are significant for the glass and glazing industry. Requirements for envelope backstops are complete and will appear in the 2022 version of ASHRAE 90.1, according to Culp. (Read Tom Culp’s recent column about envelope backstops and what they mean for the glass industry.)
4. Thermal bridging
Proposals for new thermal bridging requirements are up for ASHRAE 90.1-2022. Thermal bridging refers to the more thermally conductive—or thermally inefficient—sections or components of a system or wall. New proposals would require identifying and addressing of thermal bridges on a system to improve whole-system performance. Culp notes it would mostly affect colder climates.
Culp will provide additional information on energy code updates during the upcoming NGA Glass Conference.