University campus – optimal indoor air quality and the student
Barry Richards, Senior Projects Manager, Artic Building Services Ltd delves into how air quality in lecture theatres can be achieved.
The global pandemic has changed everyone's perception of optimal study conditions and has also illuminated the importance of good air quality when it comes to study environments within universities and schools. Concerns around air quality will continue in the post-Covid world as people remain acutely aware of the risk of infection.
As a result, educational institutes will need to be more flexible than ever to allow for students to learn alongside each other safely and optimise the use of study space. Universities and schools in particular are faced with increased pressure as the students return to campus following the successful transition from remote working and learning, along with the additional funds provided by the government to support students through the pandemic.
Temperature
A recent university study was undertaken which included testing students in different climate-controlled rooms. In this study, it was concluded that the optimum temperature for a learning environment is between 21-25° Celsius.
But it goes a lot further than optimal temperature alone and it is very apparent that all aspects of the climate we learn in play an extremely significant role.
Ventilation
Ventilation is widely considered the best-known method of improving Indoor Air Quality (IAQ). As COVID-19 becomes a virus that we learn to live with, it is clear that ventilation in workplaces and learning spaces will play an important role in the control and reduction of the transmission of viruses. Chartered Institute Building Service Engineers (CIBSE) advise that 10 l/s/person is a minimum recommended supply of air volume for any working space. However, the more fresh air delivered to any space along with minimised or eliminated recirculation the better. The need for increased ventilation to deal with viruses moving forward will continue to challenge existing ventilation design in all spaces.
Humidity
Humidity plays a major factor in air quality and occupant’s health and comfort as well as being known to support the spread of viruses and infection when levels are not optimal. It is suggested that a humidity level of between 40-60 percent is best for cognitive function. However, increasing the humidity levels has a positive impact on work performance.
Volume & distribution
Measuring the air flow rate relative to the size of a room is useful to understand how quickly the ventilation removes contaminants from the air. To mitigate the risk of spreading viruses, a ventilation rate of 6 air changes per hour would be a general rule of thumb, although different applications require different design.
In principle, 6 air changes per hour means that 6 times the air volume of the room is provided every hour by the ventilation system. However, as the new fresh air mixes with the air that is already in the room it will dilute, so it doesn’t necessarily mean that all the air is changed 6 times within the hour. At 6 air changes per hour, approximately 95% of the contaminants in the air would be removed in 30 minutes.
It is too early to know if or how ventilation systems will change in the future to accommodate the risk of infection, however consultants are already considering the impact of retrofit solutions to tie in with occupant comfort as we move into a more sustainable future.
Updating study areas to meet demands
Leading universities and educational institutions, along with the private sector will have assessed their teaching and workspaces to determine the works that would be needed to not only make it safe for the return of their students but to provide an optimal study & work environment for the future.
Given the diverse age of some these estates, which include Grade I and II listed buildings, some of the spaces are served with ventilation equipment that is over 25-30 years old. For these areas to be brought up to recommended levels, Building Managers need to recognise the issues of the existing ventilation which can lead to problems with the build-up of stale air.
New advice around Indoor Air Quality (IAQ), and the BESA guidance in place helps Building Managers set up IAQ. Using mechanical ventilation systems and targeted filtration is recognised as the most effective way to reduce the risk of disease transmission. No specific government funding has been allocated to help address this issue, but the Building Managers have acknowledged the importance to refit the spaces with the very latest ventilation & air quality equipment. One thing we are also aware of, is that the constant flow of fresh air is essential where large numbers of students gather for long periods of time to avoid the reduction of alertness and concentration and to reduce the risk of virus transmission.
A project recently carried out to a lecture theatre included options to either retrofit the existing ventilation equipment or completely upgrade the system. The controls for the existing ventilation equipment were dated and used a pneumatic air system to control pressure dampers and switches. To overhaul or repair existing ventilation equipment would not be cost effective on the scale of the project, nor would it provide the energy efficiency needed to meet the principles of their sustainability strategy.
The installation of new Mitsubishi Lossnay heat recovery systems was selected which allows for the continuous influx of fresh air and the exhaust of stale indoor air to ensure that the indoor oxygen levels are maintained for the optimum balance of comfort and safety whilst meeting the required air changes. This heat recovery unit also tempers the supply air using heat transfer from the extracted air without recirculating.
The air is heated and cooled using in-line DX Coils piped back to the condensers, this system not only controls the lecture space temperature, but it also helps maintain humidity levels within the recommended parameters. It will extract up to 80% of the heat energy from the outgoing air, transferring it via heat exchanger to heat up the incoming air flow. This will significantly reduce the amount of energy needed to bring the temperature of the lecture theatre up to an optimal level of around 21° and maintain it at this temperature all year round.
The energy efficiency and utilisation of heat recovery technology means the DX coils used to temper the supply air are kept down at just 3.12kW meaning they are the perfect choice for providing a clean and temperate atmosphere for the students within the lecture theatre.
With additional units, the capability to give the amount of air changes required for each of the lecture theatre upgrades to meet CIBSE’s guidelines could be achieved. The newly installed units will provide ample fresh air into the lecture space whilst ensuring the correct temperature control for optimum learning. The installation of the equipment will now safely allow socially distanced students in the short term but up to 70 people into the lecture theatre at one time for longer term planning.
Summary
The importance of Indoor Air Quality isn’t one to shy away from, and studies reveal that the value of having optimal study conditions for students has a significant part to play in the future of educational institutes. In making these adaptations and utilising such energy efficient systems, it allows for extended budgets to be injected directly back into the university’s students’ education while focusing on their safety.
