How the test works
Several calibrated fans are set up at exterior doors or openings and run together until the building, or the section under test, reaches the target pressure difference, usually 75 Pa. The airflow through the fans equals the air leaking through the enclosure. Results are reported as:
- Air leakage rate in L/s per m² of enclosure area at 75 Pa, the measure Toronto uses
- Equivalent leakage area in cm² at 10 Pa
Tests follow ASTM E3158-18, the standard method for large and multizone buildings. Toronto Green Standard projects also follow the City's Whole Building Air Leakage Testing Protocol.
Whole-building or guarded testing
Whole-building
The whole enclosure tested at once. Preferred by the City, and simplest to report, for low-rise and mid-rise buildings.
Guarded
For towers, sections are tested with neighbouring floors pressurized to match. Toronto requires the podium, the base and top of the tower, unique floors, and two floors for every ten: at least five tests for an 18-storey tower with a podium.
Targets and typical results
| L/s per m² at 75 Pa | |
|---|---|
| Toronto Green Standard Tier 2 target | 2.0 or less |
| Canadian buildings studied for the NRC (median of 87) | About 2.0 |
| Canadian buildings studied for the NRC (average) | About 2.9 |
In other words, roughly half of the Canadian buildings in that study measured above Toronto's target. Testing while it's still reachable is how projects pass.
The Enbridge incentive
For new commercial, institutional and multi-residential buildings of 25,000 sq ft or more in Enbridge Gas territory, Enbridge pays up to 80% of testing (to $30,000, or $0.50 per sq ft) and up to 50% of sealing the leaks found (to $15,000). Testing must be to ASTM E3158-18 and happen before the envelope is fully constructed. See the cost guide for a worked example.
What we deliver
- Test plan at the 50 to 75% construction documents stage: fan calculations, locations and power, procedure and team
- Air barrier review of the drawings, and an optional mid-construction leak walk with smoke or thermography
- Test day to ASTM E3158-18 and the Toronto protocol
- Report for the City, the Tier 2 verifier and Enbridge, with practical sealing steps and a retest if the target is missed
Preparing for test day? Use the large building airtightness checklist. Building houses or townhomes instead? See blower door testing for houses.
Sources: City of Toronto: Whole Building Air Leakage Testing Protocol · Toronto Green Standard v4 · Enbridge Gas: Commercial Airtightness Testing Program · RDH Building Science for the National Research Council: Study of Part 3 Building Airtightness. Program details change; we confirm current rules before you commit.