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Nonresidential Reduced Infiltration

Measure Description

This proposal would expand the current prescriptive continuous air barrier requirements to additional climate zones. It would also strengthen requirements to affirm air barriers are effective at limiting air leakage by requiring verification of the air barrier 

Currently, continuous air barriers are a prescriptive requirement in newly constructed buildings in Climate Zones 10 through 16.1 This code change would expand this existing requirement to all climate zones for both new construction and alterations.  

The proposed code change would offer two options to demonstrate the air barrier is installed correctly and is working as intended: 1) whole-building air leakage testing, or 2) field verification. The primary prescriptive pathway would require a whole-building air leakage test to confirm the air barrier is effective at limiting leakage to 0.4 cubic cfm/ft2 when pressurized to 75 Pa. If the measured leakage is 0.4 cfm/ft2 or below, the building passes the test and is compliant with the code. If the measured leakage is above 0.4 cfm/ft2 the following corrective actions would be required: 

  1. Locate sources of leakage using a smoke tracer test or infrared imaging survey. 
  2. Implement corrective actions to seal leaks. 
  3. Report corrective actions taken and a justification for any leaks that were not sealed. 

If the measured leakage is above 0.6 cfm/ft2, the leakage test must be completed again after corrective actions are completed to verify leakage is below 0.6 cfm/ft2. 

The standard test procedure would be for the entire building to be tested according to ASTM E3158. However, the Statewide CASE Team is recommending that buildings with less than 10,000 ft2 of conditioned space be allowed to be tested according to RESNET/ANSI 380 – the procedure for low-rise residential buildings. Also, for larger buildings with 50,000 ft2 or more of conditioned floor area, a sectional test method approach (previously established by ASRHAE 90.1 – 2019) may be used in accordance with ASTM 3158. 

The second option to confirm the air barrier is functioning as intended is for an independent third party to complete a field verification to inspect the air barrier while it is being installed.  

The proposed code changes for testing would apply to all nonresidential buildings except in Climate Zone 7, including new construction, additions, and major alterations where at least 25 percent of the envelope is affected as defined in Section 7.2. The changes for continuous air barriers would apply to the same but include Climate Zone 7. For healthcare facilities, the proposed code changes would apply to new facilities and additions but not to alterations.  

The proposal would recommend revisions to the leakage rates used in the Standard Design and Proposed Design in the compliance software. 

Submeasures Moved to Future Code Cycles

The Statewide CASE Team is no longer pursuing the proposed changes listed below because at the time of consideration it was determined the measure would not result in sufficient savings within California climate zones.

Vestibule Requirement

This submeasure would have required vestibules be installed in the main entryways of newly constructed nonresidential buildings in order to reduce air infiltration. Vestibules are most effective in achieving energy savings when they are installed in buildings with high occupant turnover. Vestibule installation has been a part of ASHRAE 90.1 and IECC Building Code for over a decade. Exceptions to the vestibule proposal will include air curtain or revolving door installation in addition to exceptions based on the size and location of the building.

Materials that the Statewide CASE Team developed when investigating this code change for the 2022 code cycle will be moved to the Future Code Cycles section of this website. Follow this link to find materials on the vestibule requirement.

Relevant Documents

Measure proposals, supporting documents, and other outside references will be made public as they become available.

CASE Reports

Round Two Utility-Sponsored Stakeholder Meeting Materials

Round One Utility-Sponsored Stakeholder Meeting Materials

Provide Feedback

Draft CASE Report Now Available (Comments accepted until August21. 2020)

This measure description will be updated as research is developed to support the 2022 code cycle. For questions or suggestions, email info@title24stakeholders.com. Include the measure name in the subject line.

Give Us Your Feedback

The Statewide CASE Team values input from all stakeholders engaged in the Title 24, Part 6 code change process. We encourage the open exchange of code change comments and concerns.

  • Use the form above to provide feedback on this measure.