This standard is issued under the fixed designation C ; the number immediately 1 This test method is under the jurisdiction of ASTM Committee C- 16 on. ASTM C () Standard Test Method for Thermal Performance of Building Materials and Envelope Assemblies by Means of a Hot Box Apparatus. Annual. Our calibrated hot box is one of the largest in the country accepting test assemblies up to 9’x16′. Its design allows any orientation from fully vertical to fully .
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A Hot Box is a specially-calibrated instrument in the Home Innovation building product testing lab designed to measure heat flow for large building specimens. The hot box has two sides as illustrated in the diagram below: A 1c363 circulates air on each side as shown by the arrows in the schematic. The building system wall, ceiling, roof, etc.
Large-Scale Hot Box
The energy input to the hot side is precisely measured for both the power to the heater and the power to the circulating fan.
Direct current DC power is used to power both the heater and the fans as DC current provides a more accurate measurement of the power input.
Approximately thermocouples measure air and surface temperatures on both sides of the Hot Box. As we know from the Second Law of Thermodynamics, energy moves from hot towards cold.
So once we know the temperature difference across the test specimen and the heat flow, we can calculate the R-value or U-value. The key to an accurate result is correctly measuring the heat input to the hot side and ensuring that all the heat goes from the hot side to the cold side and that none either leaks out of the Hot Box or bypasses the test specimen.
To adjust for any energy that goes through the Hot Box walls or tries to bypass through the specimen frame, we calibrate the box. The box has a heat flow meter consisting of two awtm built into its walls.
The heat flow meter reading is proportional to the amount of energy not going through the test specimen. By running multiple conditions, we develop a calibration curve and use it to provide accurate results.
It accommodates test specimens up to x1363 feet by 16 feet. In this type of testing, bigger is definitely better.
Code officials and designers want R-value data they can count on, but without testing, the R-value of the assembled component is unknown. Hot Box testing is a reliable way to capture shareable, marketable data that is a superior to data gathered via modeling.
Consider the typical residential wall, which consists of a wood frame with fiberglass insulation between the studs, sheathing, a weather resistive barrier, drywall on the interior walls, and exterior siding. Many high performance wall systems now also have a layer of rigid foam. In this somewhat typical scenario, three factors complicate the R-value calculation. Second, each building material has different thermal conductivity and some materials, especially the wood framing members, are not uniformly distributed through the assembled wall system.
Finally, heat flow in this scenario is a three-dimensional phenomenon. It’s easy to model one-dimensional conductive heat flow, but modeling three-dimensional heat transfer is much more difficult and less reliable. Further, some of the modeling parameters, such as contact resistance between the various layers, are difficult to establish accurately for modeling.
Home Innovation ASTM C Hot Box | Home Innovation Research Labs
The Hot Box removes any concerns that modeling parameters and assumptions are incorrect because the test is conducted on actual wall or ceiling specimens, allowing our building science experts to determine the answer with a high degree of confidence.
A wide variety of materials and systems have been tested in our Hot Box ranging from a typical wood-framed wall, to a reflective system, to metal building roofs, to floor systems, and masonry systems.
We’d be happy to work with you to conduct custom thermal testing for your residential wstm system. To learn more about how Hot Box testing can help your success in the market, contact us. Trends Leading the way with innovative, fresh ideas for builders and manufacturers.
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