We often perform differential pressure testing on windows and doors for both diagnostic and quality assurance purposes. Differential pressure testing can be especially helpful early on in the construction process during an initial mock-up, in order to ensure that the final installed assembly meets performance levels and everyone's expectations.
We have found that new windows and doors do not always perform to their water penetration resistance ratings, even as new units, and may require adjustment or repair at the time of installation. For these reasons, we recommend making window and door testing a part of the normal construction process.
Once exterior cladding surfaces are in place it can be difficult and expensive to replace windows and doors. Signs of water penetration do not always occur on interior finishes until significant damage to the wall assembly has occurred. It can be problematic when performance expectations are not met and have not been verified in place.
Establishing performance criteria and testing parameters early on in the design and specification process is important in order to set expectations.