A test report is often treated as a certificate: it exists, therefore the facade is proven. That reading is too generous. A report describes what happened to one specimen, built in one way, under conditions set by a standard or a project specification. It is valuable evidence, but only if you read it properly and check that it is about something close to the facade you are buying.
Start with who tested what, and when
The first page should say which laboratory carried out the work, who requested it, the date and the standard or specification followed. Check that the laboratory is competent for the test and that the report is complete, with page numbers and signatures. Old reports on superseded methods may still be informative, but they should be read with care.
Note whether the report is for a pre-project performance test, a design-development test or a mock-up test for your project. Each answers a different question. A generic type test shows what the system can do. A project mock-up shows what the system can do with your details.
Read the specimen description first
The specimen is the most important part of the report and the one most often skimmed. Look for its overall size, the number of modules or panes, the glass build-up, the frame profiles, the anchors and the sealant and gasket types. Check that there are drawings, and that photographs show the assembled specimen before testing.
Then ask how well it matches your facade. Does it include the same type of corner, the same joint between modules, the same transom or mullion arrangement and the same opening light, if any? A curtain wall specimen without a movement joint says little about a wall that has one. Where the specimen is simpler than the project, the result applies only to the simpler conditions.
Pay attention to the mounting arrangement too. A specimen is built into a test chamber with its own frame and seals, and how it was fixed affects what it can show. If the report says nothing about how the specimen was anchored or sealed to the chamber, you cannot tell whether the result reflects the facade or the chamber. Good reports include a drawing of the mounting and the support conditions.
Know what each test measures
Reports normally contain several tests, and each measures one thing. ASTM E283 measures the rate of air leakage through a specimen under a stated pressure difference. ASTM E331 checks for water penetration under a defined water spray and static pressure difference. ASTM E330 examines the structural behaviour of the specimen under uniform static air pressure, including deflection and any permanent set.
These are not interchangeable and they do not predict each other. A specimen with good air leakage figures may still show water penetration, and one that passes a water test may deflect more than the design allows. Read each section against the requirement it is meant to meet. More detail on what a water test involves is in what ASTM E331 tests.
A report should also be clear about what is a measurement and what is a judgement. Air leakage and deflection are readings, given as numbers with units. Water penetration is an observation made by a person looking at defined locations. Both are valid, but they carry different kinds of uncertainty, and a good report says how each was recorded and by whom.
Check the pressures and the sequence
Each result is tied to a pressure or load. A report should state the pressure difference at which air leakage was measured, the pressure at which water was tested, and the loads applied in the structural test, and what the project required. The project specification sets the values, and the report should be read against them, not against a generic idea of good.
The order of tests also matters. Many programmes run air leakage, then water, then structural loading, then a repeat of air and water to see whether the specimen changed. A specimen that only passes before loading tells you less than one that passes after. Check that the sequence in the report matches the sequence in the specification.
Where a report distinguishes between serviceability and ultimate loading, read both sections. Serviceability checks look at whether the facade works normally under expected loads. A higher load shows whether the specimen remains safe beyond that. Neither says anything about how the real building will be loaded, which is set by the design and the wind load assumptions for the site.
Read observations, not only the summary
The summary table is convenient, but the observations contain the detail. Look for notes on where water appeared, how much, how long it took, how a joint moved, whether a seal opened and whether anything was repaired or adjusted during the test. A pass with several unrecorded adjustments is different from a pass with none.
Check for any modifications made during testing. If the laboratory or the manufacturer added sealant, changed a gasket or adjusted a fixing to get through a test, that change should be carried into the production design and the site work. Otherwise the tested specimen and the installed facade are not the same thing. The structural side is summarised in structural and deflection tests for facades and air leakage in air leakage in facades.
Photographs and drawings in the appendix are worth the time. Compare the photographs with the shop drawings of your project. Differences in a corner, a drainage detail or a gasket profile are exactly the sort of thing a summary will not mention. Mark them and ask the manufacturer to explain each one.
Conditions, limits and caveats
Reports often include a statement of what the result does and does not cover. Read it. A test on a specimen of one size may not extend to larger or smaller units. A result for one glass type may not apply to another. The conditions of the laboratory, such as temperature and the way the specimen was mounted, are also part of the context.
Also note what was not tested. Many reports do not include thermal performance, acoustic behaviour, impact, fire or long-term durability. If the project requires them, they need other evidence. A single report rarely covers every question the specification asks.
Be cautious about reports presented by a manufacturer as proof of a different product. A report for one profile series does not automatically cover another, even from the same company. Ask for a written statement of how the tested system relates to the one offered, and who is responsible for confirming that the relationship holds.
From report to site
A test is a snapshot of design and fabrication quality. The installed facade depends on workmanship, tolerances and sequence on site, which the laboratory cannot see. That is why many projects also include on-site checks on completed areas, agreed with the testing programme and the facade consultant.
Ask how the report's findings will be transferred into shop drawings and installation instructions. A good manufacturer can point to the detail in the report and to the same detail in the drawing. It is also worth knowing how results will be reviewed in the mock-up stage, described in facade mock-up review.
If the report is for a pre-qualification test rather than your own mock-up, ask whether any later changes to the design have been made. A revised gasket, a different glass thickness or a modified anchor can invalidate the link between the tested specimen and the product now offered. The supplier should be able to list the changes and explain why each is not significant.
Keep the report with the project record. A year or two after handover, when someone asks what the facade was designed and tested to do, the answer is in that document. Note the report number in the shop drawings and in the operation and maintenance manual, so it can be found by the people who will need it later.
A short checklist for any report
- Laboratory, date, standard and the party that requested the test.
- A full description of the specimen, with drawings and photographs.
- A comparison of the specimen with your project's size, corners, joints and glass.
- The pressures and loads applied, and the requirements they were read against.
- The test sequence, and whether results hold after loading.
- Observations and any modifications made during the test.
- Stated limits, and which performance questions the report does not answer.
General guidance for orientation, not a specification. Applicable standards, values and details are confirmed per project with the facade consultant.
