Leading construction management firm JE Dunn Construction Group turned to Tremco recently to validate feasibility of a pre-fabricated stud wall design for a 100,000-square-foot hospital project in Texas.
Original plans called for the traditional sequence of installation with the air barrier installed in the field after the exterior sheathing was up. To meet their own demanding construction schedule, JE Dunn engineers proposed a unitized, pre-built panel system with Tremco’s ExoAir 230 Fluid Applied Vapor-Permeable Air Barrier applied off-site in a controlled environment where 100 percent of the panels would be finalized several months before the building was ready to receive the units.
Convinced that the proposed panelized system, which was a first for JE Dunn engineers, would provide the required weather resistance and contribute to the new structure’s energy efficiency, the firm’s quality manager wanted to further reassure the architect and property owner as well as to offer complete confidence and peace of mind.
Tremco Testing Validates Design
The solution? Tremco offered full-scale air and water leakage testing at our on-site Sustainable Building Solutions Test Facility. An 8’ x 8’ mock-up of the wall was constructed, including a deflection joint with a movable header at the top of the buck. The deflection and panel control joints were all detailed as they would be on the job site. With JE Dunn project managers and engineers in attendance, testing commenced, and results confirmed performance of the panelized system. Further, the process allowed JE Dunn to establish acceptable QA/QC procedures
for installation in the field.
Products Involved:ExoAir® 230, ExoAir® 111, ExoAir® Primer, Spectrem® 1
Conclusion & Results
Testing of the panel joints was peformed in accordance with ASTM 2357. The assembly withstood the static and cyclic wind loading conditions of the standard without damage. Air leakage for the assembly was measured at 0.007 cfm/ft² @ 1.57 psf (0.036 L/s●m2 @ 75 Pa). The industry benchmark for this test is listed by the Air Barrier Association of America, in concert with the requirements stated in the IECC and ASHRAE 90.1, not to exceed 0.04 cfm/ft2 @ 1.57 psf (0.20 L/s●m2 @ 75 Pa). This wall assembly achieved an air leakage rating more than 5 times tighter than the industry recognized requirement.
After the ASTM E2357 testing was concluded, the assembly was then put to the test for water leakage (ASTM E331), where the exterior side of the wall assembly was exposed to a continuous water spray while stepping from a minimum infiltration pressure of 137 Pa for 15 minutes (which is the minimum standard) up to 300 Pa for 2 hours.Water was never observed leaking into the assembly wall cavity. The test was concluded after the 2 hour test, far exceeding the standard test requirements at 137 Pa (2.86 psf) for 15 minutes.