English

The durability of air barrier systems is a topic that is rarely discussed during the design phase of most projects. An unfortunate amount of effort is spent on drawing details and specifying products with the sole intention of meeting energy code requirements, with much less thought being given to how those systems actually will be constructed and possibly worse – how those systems will fare over time.   

Achieving adequate airtightness of a building envelope is crucial for preventing moisture-related damages in cold and humid climate zones, such as in Norway. Leaky joints and perforations in air and vapor barriers are often critical points where damaging air leakages arise. Thus, the durability of products, such as adhesive tapes, is crucial to ensure a proper airtightness and performance of critical building details and overall constructions.

Durability of airtightness – and more generally of thermal performances – is an important question at both building and component levels. Its assessment is complicated in practice mainly due to the logistical aspects of those long duration studies and experiments. One can conduct laboratory tests with artificial ageing or deduce information from repeated in-situ tests or data analysis of existing components. In this paper, we describe two projects relevant in this context. On one hand, HAMSTER is a new bi-climatic chamber installed in 2022 in Brussels.

The DURABILITAIR project, conducted from 2016 to 2019, aimed to assess the durability of air sealing products used in building envelopes. Key findings were presented at the AIVC conferences in 2017 (Nottingham, UK) and 2019 (Ghent, Belgium). This research enhanced understanding of the in-situ characterization of air tightness evolution in homes over time and contributed to developing accelerated aging test protocols under controlled laboratory conditions. 

Adaptive comfort technology is reflecting the fact that the human body adapts to changing temperatures. As such, the temperature level where people feel comfortable is not a constant value, but changes with the seasonal variations of indoor and outdoor temperatures. 

Indoor inhalation exposure can be minimized through mechanical ventilation. On the other hand, building and mechanical ventilation design remain as the main sources of energy consumption. The present study focuses on the optimization of a displacement-ventilated room by applying computational fluid dynamics, virtual manikins and a genetic algorithm in order to minimize airborne viral density while reducing the energy consumption level. 

Smart-ventilation with airflows adapting to the need of buildings reduces energy consumptions and can improve IAQ. In some countries, smart ventilation strategies have been widely used for a long term (like Belgium, France,…). We still need to quantify IAQ and energy benefits of smart ventilation through a common internationally validated performance assessment scheme, still under development, notably in the framework of the IEA-EBC Annex 86.

The protection from chronic harm provided by exposure limit values (ELVs) is evaluated for indoor air contaminants set by regulatory bodies of member countries in the Air Infiltration and Ventilation Centre (AIVC). Significant variability was found in the regulated harm levels from ELVs for the same contaminants across different countries, highlighting inconsistencies in public health protection. The concept of a regulated harm budget (RHB) is introduced, representing the total allowed harm from regulated contaminants implicitly set by a regulatory body.

The inclusion of health-based performance indicators and metrics in ventilation system design and research is a widely discussed topic in recent years. This is due to increased awareness about the health implication of indoor air quality and due to the need for innovative ventilation system control (smart ventilation) to limit building energy use.  

Ensuring an indoor environmental quality that is acceptable to the majority of users, while also being energy efficient is a challenge. In addition, both user demands and the climate change are making it even more difficult to ensure good indoor environmental quality. One of the solutions to combat climate change is free cooling systems, such as ventilative cooling.