VENTILATION & HEAT RECOVERY GUIDE
www.heatingandventilating.net
Tackling indoor air pollution for healthier living spaces
It is widely known in the industry that indoor air can contain concentrations of pollutants up to five times higher than those found outdoors – yet those operating outside the HVAC sector are less informed. So, with almost 90% of our time spent inside, Nicola Rivers, indoor climate specialist at Zehnder Group UK says it is important for the industry to help educate others on the risks and how to protect against this invisible threat
A
ir pollution, both outdoor and indoor, is the most significant environmental health risk around today. According to the World Health
Organisation it is responsible for about one in every nine deaths annually. Although air quality has gradually improved in
recent times, air pollutant concentrations “still exceed the 2005 WHO air quality guideline levels in many areas ” – meaning they are over the air quality guideline levels that are associated with important risks to public health.
The impact of indoor air quality
We know from our own research that 42 per cent of people living in the UK are still unaware that air pollution in buildings could be harming their health – and that a quarter say they have always assumed that the air inside is safe. Yet what they don’t realise is that through everyday activities such as cooking and cleaning, harmful particulate matter and volatile organic compounds (VOCs) are released into the air, and without effective ventilation, build-up to affect our health and wellbeing. For a healthy indoor climate, the indoor air needs to be refreshed to extract the pollutants that people bring into the building. It is the quality of this air that impacts on many areas of both our physical and mental health: Energy – without a constant supply of fresh
air to replenish oxygen levels, a build-up of CO2 occurs, making those inside feel sleepy and lethargic. Sleep – bedrooms should be ventilated every two hours during the night to keep CO2 levels low, resulting in a more restful sleep cycle. More sleep means a stronger immune system for those in the property. Concentration – fresh air makes it easier to think clearly. Studies have shown that they more often surroundings are ventilated, the better we perform. It is also shown to reduce stress. Mood – studies have shown that exposure to
air pollution is linked with mental health issues including psychotic, mood and neurocognitive disorders such as schizophrenia, depression and dementia. Health – particulate matter can get into the bloodstream and travel through the body, causing serious health problems such as asthma with
28 June 2024
Left: Nicola Rivers, indoor climate specialist at Zehnder Group UK
regular exposure. Chronic exposure can also lead to cardiovascular diseases, affecting the heart and blood vessels, causing inflammation and oxidative stress, which could potentially lead to heart disease, stroke, and high blood pressure.
Ventilation to protect building occupants
Within any build, hitting the minimum requirements isn’t enough and as an industry we should be pushing for higher standards to mitigate IAQ challenges. Part F of the UK Building Regulations mandates the performance of ventilation systems to achieve
the desired inflow of fresh air and outflow of pollutants within buildings. At present, however, Part F only sets minimum requirements for the rate of fresh airflow into a building - to ensure there is a sufficient supply of fresh air to push out pollutants. To create healthier, more sustainable and energy efficient environments however, consultants should be looking to replace extractor fans with a superior mechanical ventilation unit with heat recovery (MVHR). We know that mechanical ventilation provides a better and healthier indoor climate, with a lower energy load. According to the SAGE Environment and Modelling Group the minimum recommended ventilation rate suggests providing 10 litres of clean air per person per second for commercial buildings. If a ventilation system achieves a rate of six air changes per hour, it means the room’s volume is refreshed around six times in an hour. With this ventilation rate of six air changes per hour, the ventilation system can effectively remove 95% of contaminants from the air within just 30 minutes - a far more effective, and energy-efficient, means of air management than opening windows or relying solely on extractor fans. MVHR heat recovery systems also provide optimised, balanced ventilation with heat recovery up to 96%. So, unlike simple passive ventilation that allows heat to freely flow out of the building, these systems have been innovated to pass the extracted air over a heat exchange cell which recovers and retains the heat that would otherwise be lost. Not only does this improve the indoor air quality,
by filtering the incoming air of pollutants – it helps to keep the home warm – thus reducing the energy input it takes to heat up. These systems also aid cooling in the warmer
months. A modulating summer bypass activates when temperatures reach a pre-set level, turning off the heat recovery element, and then through the summer, heat and humidity is extracted from the warm, humid outdoor air before fresh air enters the building. The result is a more comfortable indoor climate with a fresh air feel all year round. The task now is to further educate on the importance of good IAQ within the refurbishment of our existing building stock as well as new build developments, so that everyone is championing for better indoor environments for all.
DOWNLOAD THE HVR APP NOW
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44
