What a factory mock-up test proves.

A catalog test report proves that one window, at one size, passed in a laboratory. A factory mock-up test proves that your configuration passes: your sizes, your mullions, your glass. It happens before the order is built, while a change is still a line on a drawing and not a crew on a lift.

Four kinds of evidence.

A window package can be backed by four different things. They answer different questions, and one does not replace another.

The report sets the rating.

Every rating starts in the lab. Vistaza's highest certified classes are AW-PG100 for the Vi6 casement, AW-PG70 for the Vi5 fixed window and CW-PG50 for the sliding door. Each belongs to the type and the size that was tested.

Projects rarely use only the tested size. For other sizes the industry uses a comparative analysis under AAMA 2502. It is an engineering evaluation, not a test. It looks at three things:

• How the load spreads across the frame members, and how large it is.
• The section properties and the strength of those members.
• The connections between them, and how far they deflect.

The result is an analysis report that shows the design pressure each size can carry. It is normally signed and sealed by a registered professional engineer.

What the mock-up adds.

Calculations cover structure. They do not show how a coupled assembly deals with water. A project-specific unit often combines parts that were never tested together. A fixed light over a casement. A door with a sidelight. A PTAC louver glazed into the same frame as the window. A heavier acoustic glass in a large sash.

A mock-up builds that assembly and tests it for three things:

• Air. A chamber is sealed over the unit. A pressure difference is applied and the air passing through is measured. Technicians may use fog to see the path a leak takes.
• Water. Water is sprayed on the outside while the pressure difference is held. This imitates heavy, wind-driven rain. Any water that reaches the inside is recorded.
• Structure. The unit is loaded to the design wind pressure. Deflection is measured, and any damage is noted.

We do both. We test at the factory, and an independent agency tests on the job.

When a project calls for a mock-up, an identical twin of the mock-up unit is built alongside it: the same specification, the same materials, the same production line, at the same time. One goes to the site. The twin stays at the factory and is tested there, in the factory's own test bay, to the same procedure the jobsite test will use and at a higher load. Whatever the twin shows is fixed and tested again until it passes, and the same fix is made to the unit going to the site.

The mock-up on the site is then tested by an independent testing agency. We do not run that test. The aim is that it confirms what the factory test already showed. The project team can attend the factory test too.

Find the leak while it is still a line on a drawing.

What it tends to find.

Three causes of failure come up again and again.

• Parts that do not suit each other. A gasket, a glazing bead or a mullion joint that works alone and leaks in combination.
• Sequence. Seals and joints put together in the wrong order. A mock-up built in the correct sequence becomes the reference for production.
• Fabrication defects. A weld, a drainage slot or a seal that needs correcting before it is repeated on every unit.

A failure at this stage costs a revision. The same failure found on the building costs replacements, rework and schedule.

What it does not prove.

A factory mock-up does not test the installation. Most leaks on a building are not through the window. They are around it: the flashing, the sealant joint, the order in which the opening was prepared. That is what the field test is for.

Field tests of newly installed windows follow AAMA 502. Air is measured to ASTM E783, and water is tested to ASTM E1105, with a spray rack outside and a chamber inside. For storefront and curtain wall the matching specification is AAMA 503. AAMA 501.2 is a hose test for storefront, curtain wall and sloped glazing. It checks joints that are meant to stay closed for good, and it is not the method for operable windows and doors. Unless the specification says otherwise, AAMA 502 runs the field water test at two-thirds of the tested and rated laboratory pressure.

An independent testing agency runs the field test. Vistaza does not install windows and is not the test lab. Its technician attends the field water test, so that the person who knows the product is present if a question comes up.

What to write into the specification.

1. Which configurations get a mock-up. Pick the largest, the most complex, and the most repeated.
2. The test pressures for air, water and structure, taken from the project's design pressures.
3. Who attends, and who signs the result.
4. The order of events: the mock-up is approved before production is released.
5. The field test method, the number of specimens and the test pressure, so that nobody is negotiating them on the day.

The tested classes and report numbers for every Vistaza type are on the strength page. For the support around testing and site work, see the page for professionals.