Standard Spotlight: CAN/ULC-S742:2020

The Second Edition of CAN/ULC-S742, Standard for Air Barrier Assemblies – Specification, was published on November 9, 2020.

This Edition of the Standard was developed by the ULC Standards Task Group on Air, Vapour, and Water, and formally approved by the ULC Standard Committee on Thermal Performance and Energy Use in the Built Environment (S700).

This Second Edition National Standard of Canada includes the following changes:

• Updating the references for standards in Section 2 and Annex E;
• Removal of the classifications and the related section of the standard (causing renumbering of sections); Removal of classifications in this Standard will require reporting the air leakage rate of the air barrier assembly being tested and not just a classification code;
• Clarifications of requirements specific to walls, others specific to roofs, and those that apply to both;
• Updating the “deemed to have” air leakage rate of roof air barrier assemblies that obtained a wind uplift resistance rating as per CSA A123.21, based on the NRC research report titled “Evaluation of Air Leakage Properties of Seam-Fastened Mechanically Attached Single-ply and Polymer Modified Bitumen Roof Membrane Assemblies”;
• Correcting the statement that allows a result obtained using a given set of building height (H) and sustained wind pressure difference (P1) to be extended to other conditions of lower test conditions; and
• Correcting the order of annexes according to ULC guidelines: normative annexes appear first, then informative annexes follow (note that new Annex B is identical to former Annex D.

This Standard is referenced in the National Building Code of Canada and the National Energy Code of Canada for Buildings.

For more information, please contact the Project Manager at [email protected].

View this Standard

1. The free UL Digital View service allows registered users to read every page of any ULC or UL Standards, ULC ORDs or UL outlines of investigation online.
2. Go to https://www.shopulstandards.com/
3. Click “Browse Standards Now.”
4. Enter the ID number (digits only, no letters), keyword or keywords in the search box and click “Search”
5. In the results list, click the gray button for the standard in which you are interested, then click the “Digital View” button. You must create an account, but no payment is required, and the account stores no financial information.

Follow this Standard

If you wish to stay updated on any revisions to CAN/ULC-S742, sign up for the “Get Update Alerts”, which can be found above the “Digital View” button on the https://www.shopulstandards.com/ page, or create an account on https://csds.ul.com/canada and follow the standard.