5/17/2023 0 Comments Mock weather wallFirst, the AAMA nozzle testing of the primary seal without the secondary seal installed (Figure 7) was performed, and then the AAMA nozzle test was repeated with the secondary seal installed. Testing was then performed in two phases. The project team modified the backer rod sizes to better accommodate the required spacing needed to adequately install the sealant while allowing drainage. The visual mockup did not have either the primary or secondary seals installed previously, which allowed for further review of the sealant detailing around the cassettes and chairs as these seals were installed. Given the laboratory mockup was offsite at a testing facility, the project team elected to use the onsite visual mockup (Figure 6) as an opportunity to correct the observed defects in the sealant installation. You May Also Like Assessing aluminum's LCA It was determined the leakage was a result of tooling marks during the application of the secondary weather seal around the cassettes and glazing chairs (Figure 5). Portions of the primary seals were then removed to discover primary and secondary seals had bonded together at certain locations, thus preventing drainage (Figure 4). However, water was not draining from the weeps. Within minutes, water leakage was observed on the interior side of the curtain wall mullions. The AAMA nozzle test was conducted at a modified water pressure water was applied to the openings made in the primary weather seal to confirm adequate drainage from the weeps within the system.ĭuring nozzle testing, holes were cut in the secondary weather seal at the head of the mockup (Figure 2) and the nozzle was used at a low pressure 34 kPa (5 psi) and volume to test the drainage plane between the sealant joints (Figure 3). Additionally, the project team incorporated a modified AAMA nozzle test to evaluate the effectiveness of the drainage plane between the primary and secondary seals. The authors also incorporated AAMA 501.2, Quality Assurance and Diagnostic Water Leakage Field Check of Installed Storefronts, Curtain Walls and Sloped Glazing Systems, which involves a calibrated spray nozzle, for testing the primary and secondary weather seals after both are installed for water infiltration resistance. The laboratory performance testing included the standard testing protocol outlined in AAMA 501. Given the complexity and nonstandard use of the curtain wall system, the authors determined a full-scale laboratory mockup would be required in addition to a visual field mockup. The system included field-applied primary and secondary weather seals. The curtain wall system consisted of structural steel mullions, which supported aluminum carrier and cassette framing onto which the insulated glass unit (IGU) was structurally glazed. The following two cases studies illustrate the benefits of mockup testing and lessons learned.The first case study includes laboratory, field, and in-situ mockups for an elaborate custom faceted curtain wall system, and illustrates a mockup’s usefulness in resolving performance issues before they become manifest within the construction. Figure 3: Modified American Architectural Manufacturers Association (AAMA) nozzle test at curtain wall mockup.
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