Some of the commonly used terms and abbreviations in Air Barrier code and practice:
| 50 and 75 Pa | Pascals, a measure of air pressure on a surface that imitates a strong wind. |
| ACH | Air Changes per Hour |
| NL | Normalized Leakage (expressed as NLR - Normalized Leakage Rate, or NLA - Normalized Leakage Area). A measurement of the airtightness of a building relative to its size and number of stories. Defined in ASHRAE Standard 119. |
| 0.02 L/(s∙m2) | 0.02 Litres per second per metre squared. Measurement of the acceptable amount of air that can get through a material being used as a barrier. This test is done with air pressure (75 Pa) in a lab. |
| Conditioned Space | The inside of the building that you're ventilating, heating or cooling. |
| Infiltration/ Exfiltration | Air Leakage into and out of a building, respectively |
| Assemblies | All the parts of construction for a specific area of a building - for example a typical wall assembly is drywall, vapour barrier, studs, insulation, sheeting, house wrap, strapping and siding. |
| NEBC | National Energy Building Code |
| NBC | National Building Code |