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Introduction | Details of Test Section Construction
Instrumentation and Test Procedures |
Test Results | Conclusion
Details of Test Section Construction
The test assemblies used 14 gauge steel purlins nominally 8-in. high with 2-in.-wide flanges. Two assemblies were constructed outside the LSCS to suit the 8 ft by 8 ft metered area. ORNL personnel moved the tests sections into the LSCS, instrumented them, and conducted the tests for thermal performance. The first assembly tested was the Simple Saver System with R-30 fiberglass insulation and the second assembly tested was a single 6” R-19 fiberglass blanket draped across the purlins, commonly know as “over the purlin”. Post-test measurements were done of insulation thickness in the metered area and insulation thermal conductivity as a function of density. These measurements allowed the heat flow through the 8 ft x 8 ft metered area of the assemblies to be corrected to heat flow for an 8 ft x 10 ft area, yielding U-values corresponding to purlins spaced 5 ft oc in the field of a large roof.
For the fiberglass-insulated Simple Saver configuration, the fabric supported nominal R-19 unfaced blanket insulation of proper width to fit between the purlins. An additional layer of nominal R-11 unfaced blanket insulation was installed over the entire assembly, including the purlins. To form the standing-seam system, 24 gauge steel roof panels, 2-ft wide, were attached at their edges to clips and to each other. The clips were attached by screws through compressed R-11 insulation to the purlins. Standard expanded polystyrene (EPS) thermal blocks, 3/4 in. thick by 3 in. wide by 23 in. long, were laid over the purlins on top of the insulation between the clips. The R-11 insulation was also compressed between the purlins and the bottom of these thermal blocks in this assembly.
For the 6” R-19 “over the purlin” configuration, the insulation draped over the purlins was faced NAIMA 202-96 blanket insulation. The facing on nominal R-19 insulation was stretched tautly across the purlins and secured at the edges. Clips were attached by screws through the compressed R-19 insulation to the purlins. EPS thermal blocks were laid over the purlins on top of the insulation and roof panels were put in place.
Care was taken in both these assemblies to achieve the amount of sag between purlins as typically installed in the field. The amount of sag was measured by Thermal Design at seven buildings and installed in the configurations as closely as possible. Measurement of the actual sag that was achieved was not done accurately until after the tests as part of the post-test analysis.