Conference Agenda

Estimating airtightness is challenging due to variability in influencing factors. Existing models face limitations such as lack of standardization, sensitivity to construction quality, insufficient representative data, and complexity that reduce their practical utility for designers. This work explores the application of a predictive approach from measured data using Generalized Linear Models (GLIM) that is applicable across diverse construction scenarios. The model incorporates 14 main variables and 6 interaction terms, which explains over 50% of the variability in airtightness (n50). A typical case study has been chosen in order to show the model’s application, making it user-friendly. This example explores the criteria followed for each variable and building characteristics so that the model can be easily extrapolated to other contexts and applied to other cases.

This study addresses two key challenges related to uncertainty assessment in fan pressurization measurements: (1) estimating the typical precision error (general approach), and (2) providing a rigorous framework for uncertainty calculation in individual tests (specific approach). The general approach is investigated through the analysis of multiple repeatability and reproducibility studies, including two new datasets reported by the authors. The specific approach is assessed by applying and comparing different uncertainty propagation frameworks on two controlled datasets.

For the general approach, results indicate a precision error of 1-2% for the measurement method itself, 2-3% when different experienced operators conduct the test without preparing the building, 4% when operators also prepare the building but with external verification, and up to 20% when no verification is performed, or with unexperienced operators. However, the limited availability of reproducibility data restricts the generalizability of these findings.

For the specific approach, results show that all tested procedures perform similarly at 50 Pa (0.2 in.) in terms of both observed and estimated uncertainty. At 4 Pa (0.016 in.), all weighted procedures reduce the precision error compared to the unweighted ISO method. Based on these results, the authors recommend the WLOC procedure with newly proposed weights, as it is fully based on the GUM framework, supported by dedicated studies, and applicable even when equipment specifications are unknown or when only single-point measurements are available at each pressure station.

Airtightness plays a vital role in the quantification of energy performance and indoor environmental quality. In large buildings, quantifying whole building airtightness has historically been a challenge to achieve due to various factors (i.e., implications of stack effect, inhomogeneity of building pressures). As a result, practitioners often attempt to extrapolate the whole building airtightness from data obtained through guarded or unguarded (compartmentalization) testing. This paper discusses the lessons learned from conducting whole building, unguarded, and guarded airtightness tests on three (3) buildings. Through the lessons learned in the field, this study aims to address the challenges associated with guarded airtightness testing, including airflow pathways, pressure balancing, and compartmental boundaries. The findings challenge the validity of the theoretical assumption that combining guarded test results equate to a reliable whole-building test. Additionally, this study highlights the importance of test planning, setup, and consistency throughout several tests as critical to derive consistent test results. This study will contribute to future airtightness field testing standards, research, and enable practitioners to refine methods for large building assessments.