This study utilized a CONTAM simulation to assess the effects of airtightness improvements in TNPI rooms. Sobol sensitivity analysis was used to evaluate the impact of building envelope elements on pressure differentials and contaminant dispersion. Results showed that inter-room penetrations, ward doors, and ward ceilings significantly influenced differential pressure, while exterior walls and inter-room penetrations predominantly affected contaminant dispersion.

Although the physics concerning air pressures in buildings don’t differ between countries, often different reference values of the pressure difference over the envelope are used to determine air tightness and ventilation characteristics. The air transfer devices for natural ventilation, integrated in the façades or the internal building structure, are characterized at a pressure difference between 1 and 20 Pa depending on the country. For example, Belgium uses 2 or 10 Pa as a reference, the Netherlands adopts 1 Pa, whereas France applies 10 or 20 Pa.

Ensuring the airtightness of building envelopes is crucial for enhancing the energy efficiency of buildings. The prompt detection of leaks is essential, particularly when undertaking building renovations. Consequently, efforts have been made in recent years to implement new measurement techniques that facilitate the rapid, straightforward, and wide-scale identification of leaks in building envelopes. Two notable methods are the use of acoustic and thermographic technologies.

Improving the energy efficiency of buildings and the quality of indoor air requires accurate assessments of airtightness. The conventional regression method, Ordinary Least Squares (OLS) regression—as shown in ISO 9972—encounters challenges in the occurrence of fluctuating wind conditions, affecting the reliability of air permeability measurements.

The WTA-Leaflets (International Association for Science and Technology of Building Maintenance and Monuments Preservation", (WTA)) provide recommendations on how a defined quality of building airtightness can be achieved when renovating existing buildings. These recommendations are guidelines that support planners, builder and quality inspectors involved in construction in their implementation. 
The leaflet series consists of 3 parts: 

All new dwellings in England and Wales are required to undergo a model-based overheating risk assessment prior to construction. An important model input is the building infiltration rate, which is usually estimated using a conversion factor on the dwelling airtightness. There is a paucity of evidence regarding the reliability of these methods in summertime. This aim of this paper is to provide new evidence on the relationship between airtightness and infiltration during summertime.

Building ventilation and retrofitting strategies for homes can bring multiple benefits in the context of achieving Sustainable Development Goals (SDGs) by reducing carbon emissions in the building sector. However, current SDG approaches are fragmented, narrowly focusing on specific areas related to each goal, which now requires an integrated approach.

A significant challenge lies in decarbonising existing residential stock to meet higher energy performance standards, necessitating increased energy retrofit activity. Despite the importance of energy retrofits, challenges arise in maintaining indoor environmental quality. While positive air quality and health benefits have been reported through targeted energy-retrofit activities, there are also numerous cases where indoor pollutant concentrations increase post-retrofit.

Air and airborne contaminant mixing in building spaces is important to ventilation system design and performance, tracer gas measurements of ventilation rates, and occupant exposure to indoor pollutants. The physics of air and contaminant mixing have been studied for decades and are fairly well understood. Nevertheless, many discussions of building ventilation, air movement and indoor air quality use the term “perfect mixing” without a clear discussion of what it means or how it applies to the situation being considered.

This keynote presented the new government guidance on the health risks of damp and mould for the housing sector in England. This guidance highlights the serious risks that damp and mould can pose to tenants’ health, the legal responsibilities of social and private rented housing providers, the imperative to respond quickly, and the practical steps that should be taken both to address damp and mould and prevent them. Research led by UKHSA found that there was a considerable burden of respiratory illness in England from residential damp and mould.