Blower door preparation: agree the test boundary, conditions and safety
A rowhouse unit is approaching its planned airtightness test. Crews disagree about which openings to tape and whether installed equipment should remain operating. The superintendent needs the tester’s actual preparation instructions rather than competing site guesses.
Prepare for a blower door test with the qualified tester and the protocol that applies to this project. The test uses a controlled pressure difference to assess air leakage; opening conditions, boundary and building state therefore matter. NRCan’s guidance also identifies combustion-air and backdrafting concerns in air-leakage work. A crew should not improvise appliance arrangements or tape over an inconvenient opening simply to improve the displayed result.
Agree the preparation before the appointment
- Define the boundary and building state. Confirm whether the test concerns a unit, a group of spaces or the whole building. Identify relevant doors, openings and completion conditions with the tester. Record incomplete work and the purpose of this test. A result taken at an intermediate stage should retain that description; it is not silently converted into the final compliance result.
- Get the actual opening instructions. Ask the tester which intentional openings must be left in their specified state and which temporary arrangements are permitted by the protocol. Assign preparation and restoration responsibilities. Do not make up a universal list of taped vents or substitute a crew’s familiar routine. Keep any authorized temporary arrangement visible in the test record.
- Coordinate safe equipment and access conditions. Tell the tester about fuel-burning equipment, occupied spaces, loose material and relevant work activities. Arrange required assistance from responsible equipment personnel. Follow the actual safety instructions rather than operating gas equipment or changing its settings informally. Keep access available to the planned boundary and check that simultaneous work will not undermine a safe, meaningful test.
- Record the result and route the located follow-up. Retain the test purpose, conditions, report reference and outstanding actions. Ask the responsible team to distinguish measured leakage from suspected locations and to assign appropriate corrections. Preserve access for inspection and any required retest. An identified air leak does not authorize an unrelated membrane, firestop or structural alteration.
Common mistakes
- Taping openings without the applicable test protocol.
- Ignoring combustion equipment or occupied-space conditions.
- Reporting an intermediate result as final compliance.
- Treating a suspected leak as permission to alter another system.
Checklist
Confirm these items with the tester
- Purpose, boundary and completion state.
- Opening conditions and authorized temporary arrangements.
- Equipment safety and responsible assistance.
- Access, simultaneous work and restoration actions.
- Report reference, located follow-up and retest requirements.
Check your understanding
A crew can improve the result by taping an opening the tester has not addressed. Should it do so?
