Airbase publication

Maintaining the airtightness of building envelopes is a key factor for the energy efficiency of buildings. A fast and reliable detection of leaks plays a decisive role, especially during building renovations. For this reason, work has been done in recent years to apply an acoustic beamforming method that enables the fast, simple, and large-area detection of leaks in building envelopes. This method is based on a microphone array technology and assumes that sound primarily follows the same paths as air through the building envelope.

Airborne transmissions take place as a transport of virus or bacteria via the aerosol flow in rooms. The distribution of aerosols tends to be evenly distributed if the flow in the room is fully mixed. The aerosols distribution will be different if the room air is stratified. A vertical temperature distribution may create stratified layers with either lower or higher concentrations of exhalation from the infected person.

Measurement method for ventilation effectiveness, more specifically, for contaminant removal effectiveness with a point source corresponding to infector is analysed in this study with tracer gas measurements and infection risk calculations. Ventilation effectiveness is needed in infection risk-based ventilation design to take into account air distribution methods deviating from fully mixing. Tracer gas measurements were conducted with two source location in six non-residential spaces.

The importance of ventilation of spaces for occupants’ health has been known for many years. Ancient Egyptians used natural ventilation to remove dust and thus to reduce respiratory diseases of stone carvers working indoors (Janssen 1999). In the past ventilation has been used to reduce airborne transmission of respiratory generated infectious agents in buildings.

There are several knowledge gaps that explains a lack of knowledge on minimum ventilation rates for intercepting airborne respiratory infection. One is a lack of unifying understanding of the roles of ventilation, filtration, settling, deactivation, and most importantly temporal and spatial variation. A recent finding on the equivalence of the occupied air volume per person and dilution and a generalized Wells-Riley equation are used to define a unified dilution air flow rate. The required threshold dilution air flow rate is not a function of the setting.

Airborne exposure has been highlighted during the COVID-19 pandemic as a probable infection route. This experimental study investigates different protection methods at an office workstation, where the concentration characteristics are studied under mixing ventilation conditions. The protection methods were the room air purifier, personal air purifier, face mask, and workstation partition panels. In experiments, the breathing machine, nebulizer, and syringe pump were used to generate an aerosol distribution of paraffin oil in the room.

The ASHRAE Standard Project Committee on Ventilation and Acceptable Indoor Air Quality in Residential Buildings (62.2) has proposed an addendum to the standard that adds a harm-based Indoor Air Quality procedure as an alternative compliance method. The IAQ Procedure only considers 3 contaminants and only the sum of the harm from those three contaminants needs to be limited. This was determined by completing four stages of research.

The buildings ‘sector is facing multiple challenges due to the need to generalize a sober approach and to reduce its energy consumption, its CO2 emissions and its impact on climate change, to reduce its environmental impact and its carbon footprint, to reduce the burden of disease due to exposure to unhealthy indoor environments and to adapt and be resilient in the face of climate change and environmental changes such as the increase in pandemics, the urban heat island and outdoor pollution.

We need to improve the indoor air quality for the health of the building users, and we need to optimize and reduce energy consumption for heating, cooling, and ventilation for the sake of the global climate. In both cases the interplay between buildings, HVAC (heating, cooling, and ventilations) technologies and the users are central. Research show that technical optimization without considering the interaction and behaviour of the users may end in sub-optimal technical solutions, neither resulting in reduced energy consumption nor improved indoor air quality.

At hospitals and healthcare buildings, the ultimate objective is to save lives. According to the 2018 annual reports from the Norwegian Institute of Public Health, the incidence of postoperative wound infections (POSI) ranged from 1.6% to 13.4% depending on the surgical procedure. Surgical Site Infections (SSI) are severe complications in hospitals worldwide and Norway. SSI contributes to large societal costs through extended hospitalization, increased need for reoperation, and less participation in working life.