Experimental Framework for Nondestructive Assessment of Argon Gas Content in Insulated Glass Units

Insulating glass units (IGUs) contribute significantly to energy loss among building envelopes because they are responsible for approximately 30%–50% of the energy loss due to heat exchange. To reduce these losses, low-conductivity heavy inert gases such as argon, krypton, or xenon are introduced into the cavity of the IGU (i.e., IGU’s spacer). Argon is particularly favored due to its widespread availability and cost-effectiveness compared to others. However, the aging and deterioration of IGUs cause a notable decrease in Argon gas concentration, negatively affecting their insulating properties and subsequently increasing energy demand within buildings. Therefore, it is important to regularly evaluate the argon content to maintain the insulating effectiveness of IGUs. Destructive and nondestructive methods are currently available to assess the argon content inside the IGU’s spacer; however, they possess several drawbacks. Destructive methods are impractical for on-site IGU operations as they require spacer penetration, and nondestructive methods require costly equipment and have limited accessibility. Therefore, this study presents an experimental framework to assess the argon content within IGUs utilizing nondestructive evaluation (NDE) methods. The methodology is designed in four main steps: (1) designing an experimental setup for creating accurate gas mixtures of argon and air and directing the target gas mixtures to the IGU’s spacer; (2) conducting NDE tests on IGUs with various argon contents; (3) performing a validation test of the proposed methodology to verify the accuracy and repeatability of results obtained from Step 2; and (4) establishing a relationship between the properties of the utilized NDE method and argon content within IGU. The results show that ultrasonic testing (UT) is a reliable NDE method to evaluate argon content within IGUs, with ultrasonic energy serving as the most influential UT parameter for assessing argon content within the IGU’s spacer, as evidenced by a strong correlation with an R-squared value exceeding 0.9 across all the UT measurements. This research introduces a user-friendly solution that enhances the ease of assessing argon content within IGUs’ spacers, thereby facilitating the monitoring of their operational performance. The proposed methodology for evaluating argon content holds potential benefits for IGU manufacturers, researchers, building auditors, and inspectors in the construction industry domain. Moreover, it serves as a valuable tool for improving quality control across the manufacturing, maintenance, and operational stages of IGUs.