In this section
What is building ventilation?
Ventilation is the movement of air throughout a building by either natural or mechanical means. For mechanical ventilation, an exhaust and supply ductwork is installed to exchange stale air for fresh air and mechanical equipment is attached to the ductwork to provide air filtration and comfortable levels of temperature. For natural ventilation systems, a combination of sustainable strategies are used to provide a comfortable temperature for the occupants. At UBC Vancouver and UBC Okanagan, there are buildings with occupied spaces that may be ventilated naturally or mechanically.
How are UBC HVAC systems managed at UBC?
HVAC systems are engineered to follow WorkSafeBC Occupational Health & Safety Regulations (OHSR) and the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) standards and guidelines. The regulations and standard stipulate the requirements around the design, operation, and maintenance of HVAC systems. Compliance with WorkSafeBC and ASHRAE are a primary focus of the technical and trade specialists within UBC Facilities.
The design of a HVAC system is dependent on the usage of the space. For example, all air from science laboratory spaces are directly exhausted outside. In highly specialized labs, HVAC is equipped to capture high risk substances as per regulatory requirements. In common areas or office spaces, air can be recirculated. The number of air exchanges per hour is also dependent on the classification of the space and it is specified in the ASHRAE Standards.
Given the mild climate in Vancouver, the HVAC system at UBC is able to take advantage of bringing in outdoor air, and systems are monitored and adjusted based on the temperature outside. The majority of buildings on campus use 100% outdoor air (free cooling) during late spring, summer, and early fall, with the exception of buildings or spaces with mechanical cooling, such as air conditioning. In the winter months, very little outdoor air is used when temperatures drop to zero or below.
Who monitors and replaces HVAC filters to buildings on campus?
A comprehensive filter monitoring and replacement program is performed by Facilities. We have a dedicated team of National Air Filter Association (NAFA) Certified Technicians that are certified NAFA Certified Technician Level 1 (NCT) trained professionals conducting routine inspections and filter change out as per NAFA Installation and Operation of Air Filtration Systems in compliance with American Society of Heating and Ventilation Engineers (ASHRAE) recommendations. We conduct filter change outs based on operating context, inspection results, diagnostic readings and time based replacements.
Should I use a Carbon Dioxide (CO2) monitor to measure ventilation?
Carbon dioxide (CO2) may be used as an indirect measure of ventilation, but should not be used as an indicator of COVID-19 transmission risk. In order for the CO2 measurements to be interpreted accurately, the following considerations should be accounted for:
- CO2 sensors should be annually calibrated and maintained as per manufacturer’s instructions. The validity and averaging times of the sensors should also be considered
- All information and data obtained from monitoring with CO2 sensors must be evaluated correctly by a qualified individual which includes comparing the results to the appropriate WorkSafeBC regulations
- Individuals must have formal education and training on developing appropriate sampling strategies for indoor air quality monitoring which includes:
- Equipment placement where the area is well mixed. The CO2 sensors may need to be relocated several times in the space to obtain an accurate representation of the room’s dynamics.
- Monitoring for an appropriate length of time to account for temporal variations in CO2 levels.
- The occupancy levels in the room should be reflective of how many individuals will typically use the space.
- The impact of air flow from surrounding rooms and/or doors and windows being open vs closed should be considered.
- Changes in ventilation rates due to variations in the building mechanical system should be considered.
It is important to note that carbon dioxide measurements taken in spaces for indoor air quality purposes are not meant to be read as an inhalation hazard.
With the UBC Campus Rules in place and the additional measures that have been implemented for buildings, such as improved air filtration and increased ventilation, UBC spaces are a safe work environment.
Do building ventilation requirements need to change due to COVID-19?
An HVAC working group has been established to determine and recommend any further technical measures that should be taken with building ventilation systems to ensure a high standard of safety and reduce the risk of COVID-19 transmission. The HVAC working group consists of trained subject matter experts from UBC Facilities and Safety & Risk Services.
To ensure the building ventilation systems are maintained in good operating condition, the Facilities team will continue to inspect and service the HVAC systems throughout the campus both remotely for performance of the entire mechanical system, and locally onsite to inspect the condition of various components of the central air handling unit. This includes assessment of filter media and replacement to industry standards and recommendations when required.
A comprehensive filter monitoring and replacement program is performed by Facilities, a dedicated Building Operations crew of National Air Filter Association (NAFA) Certified Technicians. Interval based filter changes augmented with filter alarms sent to the Buildings Operations Centre ensures the filters are maintained properly to provide good air quality to the buildings.
In response to COVID-19, the American Society of Heating and Ventilation Engineers (ASHRAE) recommended upgrading to MERV 13 filters for central air handling units in buildings. Facilities had adopted MERV-13 filters as the standard in all buildings that could accept the size of the filter several years ago, so no changes to the filter program were required.
For more information on COVID-19 transmission, please visit British Columbia Center for Disease Control (BCCDC) and WorkSafeBC.