Innovative Environmental Chamber Construction for Accurate Thermal Performance Evaluation of Building Envelopes in Varied Climates

The testing of multi-layer building envelopes was performed using an environmental chamber following the ASTM C1363 and ISO 8990 standards. However, performing such tests in accordance with the standards by an accredited laboratory can be extremely costly, and many laboratories have waiting lists of several months. This is a significant cost for researchers and building material testing companies in the construction industry. Therefore, the goal of this study was to design, construct, and test a portable environmental chamber for building envelopes to validate the accuracy and the efficiency of the built environmental chamber to measure the thermal performance (i.e., R-value) of wall panels at extreme climate conditions (i.e., −20 °C and 80 °C). The results indicated that the built environmental chamber is capable of maintaining the steady state temperature inside the chamber during the hot climate condition test of 65 °C (150 °F) within ±0.5 °C and during the cold climate condition test of −16 °C (3 °F) within ±1 °C, meeting the requirement of the ASTM C1363-19 standard. The results also indicated that the built environmental chamber is capable of measuring the R-value of building envelopes under hot climate conditions with an accuracy of ±0.73 ft²·°F h/BTU (±0.129 m² °C/W) and under cold climate conditions with an accuracy of ±1.02 ft² °C·h/BTU (±0.180 m² °C/W). This university-based testing program allows companies to test several building envelopes at a relatively low cost and minimum wait duration. Additionally, such an environmental chamber can be used for the accurate evaluation of innovative designs to determine promising designs and to refine wall specimen prototypes for manufactured materials.