| Title |
Evaluation of the Consistency and Reproducibility of In-situ Thermal Transmittance Measurements Using the Average and Dynamic Methods According to ISO 9869-1 |
| Authors |
이예지(Lee, Ye-Ji) ; 고명진(Ko, Myeong-Jin) ; 최두성(Choi, Doo-Sung) |
| DOI |
https://doi.org/10.5659/JAIK.2026.42.2.379 |
| Keywords |
Building Exterior Wall; Thermal Transmittance; Heat Flow Meter Method; Average Method; Dynamic Method; Reproducibility; Consistency |
| Abstract |
This study aims to evaluate the reliability of in-situ thermal transmittance (U-value) measurements for building exterior walls by comparing
the Average Method (AM) and the Dynamic Method (DM) specified in ISO 9869-1. Unlike previous studies that assessed accuracy relative
to the theoretical U-values calculated by ISO 6946, this research focuses on reproducibility and agreement between methods under varying
environmental conditions. Field measurements were conducted on a north-facing insulated wall specimen over seven months, and analysis
cases were classified by indoor?outdoor temperature differences of 15 °C, 20 °C, 25 °C, and 30 °C. For each case, U-values were estimated
using both methods, and accuracy, reproducibility, and consistency were quantitatively compared. The results showed that the two methods
exhibited strong correlation, with nearly identical accuracy across all temperature ranges. However, the Dynamic Method demonstrated superior
reproducibility, reducing variation by approximately 15.9 % compared to the Average Method. These findings indicate that while both
methods yield reliable U-values, the Dynamic Method is more robust under non-steady-state conditions. The study suggests that reproducibility
and consistency provide more practical indicators of measurement reliability than theoretical accuracy alone. |