According to ISO 9972:2015, what is the recommended reference pressure for reporting air leakage rates?

The recommended reference pressure for reporting air leakage rates according to ISO 9972:2015 is 50 Pa. This standard specifies that measurements of airtightness should be conducted and reported at this pressure level because it reflects a balance between building uses and external pressure variations that occur due to wind or temperature differences.

Using 50 Pa as the reference pressure allows for a consistent and standardized comparison of air permeability across different buildings and conditions. This level is significant, as it is representative of typical service conditions that can be encountered in real-world applications. By adopting 50 Pa as a common reference, stakeholders, including architects, engineers, and builders, can better assess and manage the energy performance of buildings, contributing to improved indoor air quality and energy efficiency.

In contrast, other pressures such as 25 Pa, 75 Pa, or 100 Pa may not provide the same level of relevance to typical living conditions or could lead to variations in the reported leakage rates, making it harder to draw meaningful comparisons or deductions in performance across different structures.