LISTEN...

The NECB talks about air leakage and air barrier systems in Division B, Part 3 - Building Envelope.

In Section 3.2.4., the general requirements for controlling air leakage are described like so:

• (3.2.4.2.) The air barrier system must have a normalized leakage rate no more than 1.5 litres per second per metre squared. This implies that you have to test the air barrier system, using specific instructions from ASTM E3158 "Standard Test Method for Measuring the Air Leakage Rate of a Large or Multizone Building".

OR...

• (3.2.4.3.) The air barrier assemblies must have an air leakage rate no more than 0.2 litres per second per metre square when air pressure tested at 75 pascals. This requires testing using specific instructions from CAN/ULC 742 "Standard for Air Barrier Assemblies".
  • This part also describes how the air barrier assembly will be required to act as the primary layer for resistance to air leakage, and that there must be at least one material in the assembly that is providing that principle resistance.
  • The properties of the individual barrier material must match with specifics from CAN/ULC 741 "Standard for Air Barrier Materials".

Additionally, air leakage and how to address it in large buildings is discussed in Part 8 of the NECB - Building Energy Performance Compliance Path. In this section, acceptable conditions are outlined as designers and builders compare the project building (proposed) to the virtual energy model building (reference).