English

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.

AIVC's Ventilation Information Paper #45.9 summarizes current knowledge on trends in building and ductwork airtightness in Japan.

The AIVC (Air Infiltration and Ventilation Centre), TightVent Europe (the building and ductwork airtightness platform) and venticool (the platform for resilient ventilative cooling have organised during the past 11 years 49 webinars around a wide range of topics. The main topics of the events held include:

AIVC's Ventilation Information Paper #47 gives guidance to perform a pressurization test in high-rise buildings and suggests new criteria to replace standard requirements when they cannot be met.

Many simplified models have been developed and are used around the world to estimate the infiltration rate for Energy Performance (EP) calculations, with different levels of accuracy, as described below. For example, the wind velocity can be estimated hourly, monthly or annually; based on the local climate or fixed estimated values; with or without taking into account shielding factors; etc.

AIVC's Ventilation Information Paper #46 aims to explain these simplified models and give some examples of methodologies applied in various countries.