ventilation

The purpose of this summary is to review Air Infiltration and Ventilation Centre activities, as reflected in its publications, related to indoor carbon dioxide over the 40 years that have transpired since its creation. These activities, like most applications of indoor CO2 to the fields of ventilation and indoor air quality, have focused on the following: control of outdoor ventilation rates, i.e., demand control ventilation; use as a tracer gas to measure outdoor air change rates; providing an indicator or metric of IAQ; and, directly impacting human health, comfort and performance.

A demonstration house was previously built and commissioned in Iqaluit, Nunavut, Canada. The purpose of the overall effort is to evaluate the performance of a high-performance building located in the Canadian Arctic, while considering the unique social, economic and logistical challenges associated with its remote location. Previous work consisted of monitoring and reporting on the energy consumption due to heating between April 2016 and April 2017.

The Arctic environment is challenging for housing ventilation and heating systems. Energy consumption and demand for space heating for northern remote community residential buildings are very high. Airtight built northern homes require energy efficient and effective ventilation systems to maintain acceptable indoor air quality and comfort, and to protect the building envelope from moisture damage.

Radon gas is a well-known building´s pollutant which can affect negatively people´s health (WHO, 2009). Radon´s source is the soil underneath buildings. Radon moves from the soil to the buildings by advection through cracks and joints, and diffusion through porous materials. Once radon enters buildings it can accumulate in lower areas due to lack of ventilation. Ventilation is one of the main ways to prevent radon from accumulating in enclosed spaces in the case of moderate radon concentrations up to 600 Bq/m3 (Collignan, 2008). 

In 2017 the Danish Building and Property Agency started a project titled “Avoiding energy waste in ventilation systems” by tracking the actual energy use in a sample of their 4 million m2 portfolio of buildings through on-line energy management tools. The project is not complete, but the key preliminary findings  described in this paper are: 

Between 2017 and 2018, the Centre for Studies and Expertise on Risks, the Environment, Mobility and Planning (Cerema) organized an airtightness measurement campaign in 117 multi-family collective and single-family French dwellings. These dwellings were built before 2005, that is, before the release in 2005 of the fifth French thermal regulation for new dwellings, that was the first to introduce specific requirements for airtightness.

Ventilation is critical in interpreting indoor air quality (IAQ), yet few IAQ assessments report ventilation rates; even when they do, the measurement method is often not fully described. Most ventilation assessments use a tracer gas test (TGT) to measure total air change rate. In a TGT, the indoor air is marked with an easily identifiable gas (tracer) so that the air change rate can be inferred by monitoring the tracer’s injection rate and concentration.

Measuring ventilation rates in occupied dwellings is challenging but represents the conditions that occupants experience. This paper explores the constraints of existing methods when measuring the ventilation rate of occupied buildings and proposes a new method addressing some of them.  

Infiltration is an uncontrolled contribution to ventilation in a building and can contribute significantly to the total ventilation rate, particularly in older, leaky, dwellings which can rely on infiltration to provide adequate indoor air quality. However, as explored in this paper, using a whole house airtightness metric to characterise ventilation rates can fail to identify low ventilation rates in specific rooms. 

The indoor thermal comfort and air quality in classrooms have become of interest worldwide, predominantly because of their influence on children’s health, learning performance and productivity. Growing concerns with building energy efficiency emphasize the significance of this topic. This paper illustrates the outcome of a field study conducted in secondary school classrooms in Sydney, Australia, during the school year in 2018/2019.