Conversely, if there is a product leak or an installation issue, it is better to know early on, before more units from that production run (which may also include a potential systemic issue) or too many units with the same installation defect are installed. Referencing explicit language in the project specifications can ensure windows are tested at appropriate project milestones and can be incorporated into the project schedule.
Without any specific milestones listed, the contractor may set up the testing when it is most convenient for the project schedule, which is usually when the installation is complete, as to not cause a delay for the installer. However, it is in the best interest of the project and all parties to perform a test early on, before installation gets too far along, so any design, manufacturing, or installation issues can be caught before more work is performed and the cost of remediation becomes significant.
Inswing windows
If a project has elected to use inswing operable windows, there is a higher chance the window may leak under negative pressure when tested to ASTM E1105, Standard Test Method for Field Determination of Water Penetration of Installed Exterior Windows, Skylights, Doors, and Curtain Walls, by Uniform or Cyclic Static Air Pressure Difference. Leaks are often discovered at the operable sash when testing due to negative pressure, pulling the window slightly open and pulling water through any minor gaps in the operable sash gaskets. This is certainly a window type where it is important for the manufacturer and installer to witness testing and make any adjustments to the window operability, should a leak occur. If improvements to operability are made, the design team must ensure the same protocols are done to all windows on the project to reduce the risk of leakage.
Non-domestic windows
As discussed in Part 1, quality standards and testing requirements are different for domestically made windows when compared to non-domestic windows (e.g. European-made). Leaks resulting from field testing a foreign-made window to U.S. standards can cause confusion on a project due to the “passing” criteria being different.
A non-domestic window also means it is far more difficult to make repairs to the windows in the event of a systemic failure as the manufacturer is not local to the site. If the windows passed their respective European (EN) or similar window testing standards, there is not much recourse with the manufacturer to address the leaks observed during the field testing to U.S. standards.
