The 14^th International Buildair Symposium in Hannover (Germany) on May 16 and 17 was organised by the Energie- und Umweltzentrum am Deister (e.u.[z.], www.e-u-z.de), in close cooperation with the AIVC, TightVent and INIVE. The event brought together about 120 international experts.

On the morning of May 17, TightVent and AIVC organised a session with four presentations by Valerie Leprince (Cerema/INIVE) and Peter Wouters (AIVC Operating Agent/INIVE).

The first presentation introduced the work of TightVent and AIVC, highlighting various outputs and resources relevant to the BUILDAIR community.

The second presentation analysed trends in building and ductwork airtightness across 16 countries, focusing on regulations, metrics, testing protocols, and their role in energy performance calculations. It highlighted that building airtightness is more commonly regulated than ductwork, with many countries having building guidelines and testing protocols, while mandatory ductwork requirements remain limited. The study stresses the increasing importance of airtightness for energy efficiency and indoor air quality, recommending more testing, stricter rules, and better guidelines, particularly for ductwork systems. More information can be found in AIVC Technote 73.

The third presentation focused on regulatory developments in Belgium enhancing ventilation and indoor air quality in buildings. It detailed regional and federal measures including minimum ventilation requirements, assessment procedures, quality frameworks, and risk analysis. Notably, while Belgium has no requirements for airtightness testing or minimum airtightness levels, over 98% of all new residential buildings undergo airtightness measurements. More information can be found in AIVC VIP 45.4.

The final presentation outlined proposed revisions to ISO 9972 aiming to improve accuracy, relevance, and consistency with other standards. Key updates include revised terminology, measurement error limits, improved testing procedures, and new annexes for specific building types. Drawing on a decade of experience and research, the changes aim to promote airtightness testing and support energy-efficient building practices.