Strong winds can seriously damage a building’s exterior features. The risk increases when glass doors, windows, and curtain walls aren’t robust enough to withstand the intense pressure caused by wind velocity. Z6 can help prevent a glass-all-over-the-lobby scenario by applying our ASTM 330 testing standard, a method designed to assess the health of your building’s most vulnerable components.
The ASTM330 Testing Standard
This method tests the structural performance of exterior features like windows, skylights, and doors. It’s also suitable to test different curtain wall assemblies that consist of glass, metal, stone components, and masonry.
In short, the ASTM 330 testing standard determines how such components perform under uniform static air pressure differences. The test is also limited to the features mentioned above and isn’t designed to assess the structural integrity of any construction adjacent to the door or window being tested.
How Z6 Applies the ASTM330 Testing Standard
In general, this test method consists of sealing the test specimen against one side of a test chamber, and then, depending on the specific type of test loading program, air is either added or exhausted. The air is pumped at a rate that consistently maintains the test pressure difference across the window or door. The outdoor panel of the specimen always faces the higher-pressure side for positive loads, while the indoor does the same except for negative loads.
There are two variations of the ASTM 330 testing standard. Procedure A is used when no load-deflection curve is required, and Procedure B is performed when a load-deflection curve is needed.
When the Specimen Shatters
When a window or curtain wall is strong enough to resist local wind speeds, it’s unlikely to break during an ASTM 330 test. But sometimes, breakage does occur, and in most cases, this failure is caused by the duration of the load on the glass (which we keep to a minimum during testing).
When a specimen breaks, the test is stopped, and the item is carefully examined to identify the cause. If the breakage was triggered by the failure of supporting structures (like the frame or fasteners), we’ll record our findings and discontinue the test. The glass will be replaced if a structural problem was not the cause. The test will restart with the original fasteners at the load point where the breakage occurred.
Tests Are Backed by Detailed Reports
We record and measure the item’s deflection, deformations, and observable distress or failures. The final report also covers the important basics, like when the test was performed and a description of the item tested (including detailed dimensional drawings).
Depending on the procedure (A or B), the report will also include a tabulation of pressure differences exerted on the specimen, test load increments, duration of the pressure differences, and any resulting deflections and deformations and their locations.
The following will also be added to the report:
- The particulars of all report authors, experts, and companies involved
- A statement that confirms all the tests were completed following this test method or a complete description of any deviations or adaptations of the test method
- If the conformity of a particular specification has been tested, the specification will be clearly identified and described.
- The ambient conditions before and during the tests
- A record of all visual observations made during the test
- A record of any tape or film that was used to seal the specimen against air leakage and whether these materials influenced the outcome of the tests
- Any other data that is useful to the understanding of the test report.
Each ASTM 330 Test is Unique
For the best results, we ensure that every ASTM 330 test is tailor-made to a specific building. To achieve this, we use the site’s geographic location and data from wind velocity maps that are provided in ASCE/SEI 7. This helps our experts to determine the correct design wind loads and uniform static air pressure differences to be used in the method.
We also anchor each specimen inside the test chamber as authentically as possible; in other words, we secure the piece with the same type and number of supports used during the installation of the unit in the building. Together with our in-depth report, both factors provide the best prediction of how the exterior glass features on your property will hold up against windy conditions.
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With over half a century of experience in construction, we are a versatile company that combines cutting-edge technology and expertise to enhance the understanding of buildings. Our team of tech-savvy professionals posses a deep knowledge of building design and regulations, allowing us to provide insightful recommendations for improving building structures. Get in touch with us for all your building envelope commissioning needs.