The Insul-Stud® wall was developed by the Engineering Technology Consultants Corporation (ETC) – a small applied research company from Marysville, WA that applies advanced engineering concepts in solving advancing issues associated with the improvement of energy conversion. Some current programs of interest of ETC are power conversion, thermal efficiency, and prime movers. ETC is known for having experience in stress, vibration, fluid dynamics, structural analysis, material sciences and its application as well as computer analysis capabilities using various CAE systems.
Description of the Test Wall:
During June and December 2005, two configurations of Insul-Stud® - 6-in. thick steel-framed wall were tested in the ORNL guarded hot box using ASTM C-1363 procedure.
During hot box testing, Insul-Stud® walls were insulated with conventional unfaced R-19 fiberglass batts. In both walls perforated 6-in. steel studs were installed at 16-in. on center.
Figure 1 shows the shape of stud web perforation for the Insul-Stud® wall used for the first hot-box test. As shown on Figure 2, similar perforations were made on the top and bottom tracks. Before installation of the cavity fiberglass batt insulation, all internal air-cavities between stud and track flanges were carefully insulated with the fiberglass insulation. Conventional ½-in. thick plywood sheathing was used on both sides of these walls. After installation of the exterior and interior plywood sheathing, the wall was placed in the ORNL hot box.
Figure 1. Geometry of stud-web perforations in the first Insul-Stud® test wall.
Figure 2. Perforated track profile of the Insul-Stud® wall – stud and track cavities (between flanges and the web) were filled with thermal insulation.
For the second test, the steel studs profile was changed. To reduce thermal bridging, the stud web area was modified. Most of the steel cross-bridges going across the stud web were removed. To achieve necessary structural strength additionally, 1.5-in. thick solid-wood connectors were installed to bridge both sides of the stud web. Figure 3 shows configuration of the second wall test specimen containing solid wood local connectors.
Figure 3. Steel stud-web perforations containing 1.5-in. thick solid wood connectors in the second Insul-Stud® test wall.
Summary of Test Results:
Two configurations of 6-in. steel-framed Insul-Stud® wall insulated with unfaced R-19 fiberglass batts were tested in the ORNL guarded hot box using ASTM C-1363 procedure. During both tests the temperature difference across the hot box wall about 46°F the mean temperatures close to 75°F.
The first wall specimen contained studs with steel cross-bridges, 5.5-in. thick R-19 unfaced fiberglass batts and ½-in. thick layer of plywood on both sides of the wall. The second test wall specimen contained studs with 1.5-in. thick solid wood cross-bridges, 5.5-in. thick R-19 unfaced fiberglass batts and ½-in. thick layer of plywood on both sides of the wall.