Blower Door T/F

You recently carried out an intermediate blower door test which results in an negative pressure measurement n50 ACH of 0.64. Which of the following statements are correct?

This exceeds the limit required for Passive House Certification

False

This is a trick question – in fact this does comply. The blower door test is rounded down to one decimal place, so this result would be reported as 0.6, which is indeed in compliance

This is a great first result and gives you the confidence to finish out the project in the knowledge that the result will improve and the final result will be better.

False

It often happens that the blower door test result gets worse during the construction process – you can never rely on it improving.

The project has outward opening windows and can be expected to improve for the final test.

False

Outward opening windows will tend to press against their frames during a negative pressure test. Bearing in mind that the blower door test also requires a positive pressure test, we can expect the result to get worse.

As soon as you reach the blower door result of 0.6 ACH n₅₀ there is no more need to work on airtightness of the project.

False

 Even if you get a result of 0.2 (or less) you should always look for leaks in the project – because they can cause discomfort and structural damage 

You notice afterwards a leaky attic hatch and instruct the construction supervisor to have it sealed with tape for the final test.

False

Such tampering with the envelope to get a better result is not allowed

You notice a dropped ceiling in one of the rooms is not yet in place and are reassured that the result will improve once this has been allowed for in the calculation.

False

Dropped ceilings are not counted in the calculation of volumes for the blower door test and thus will have no impact on the final result

Given the size of the project (a multi-family unit of 50 apartments), this result is a great achievement.

False

The larger the project, the more easy it is generally to reach the Passive House standard. This result might be good for a detached single family dwelling, but not for a project of this scale

You thank the whole construction crew and commend them for their great work in getting such an airtight building.

False

It is always good to motivate the crew and show appreciation, but you also need to convey your concern that there remains work to be done to lower the result and that complacency can lead to reduction in airtightness ahead of the final test.

You complete a thorough leak detection assessment during the test and compile a list of leaks to be sealed ahead of the next test.

True

Leak detection is always recommended, no matter how good the result is.