When designing and building a passive house, air tighness is a major issue. So develop a froma air barrier strategy at the very beginning. Appoint or nominate a quality assurance and airthigness champion. The airtighness testing organization must be acceptable to the certifying body. Pressurization and depressurisation testing must be carried out and the results averaged. For a passive house or EnerPHit acceptance test, the building must be finished, no temporary sealing, other than to exclude the ventilaiton system, is permitted.
Example: The passive house air tighness target is < 0,6 ACH-1 @ 50 Pa for newbuild projects and < 0,1 ACH-1 @ 50 Pa for EnerPHit refurbishment projects. The quoted targets are the final acceptance value; it is sensible to leave a margin to allow for the leakage often found around services that are installed after the first air tightness test. This should be at least 25%, which means aiming for preliminary test results of:
- < 0,45 ACH-1 @ 50 Pa for newbuild projects and
- < 0,75 ACH-1 @ 50 Pa for refurbishment projects.
Excerpt from “How to build a Passivhaus: Rules of thumb”, Passivhaus Trust, April 2015