The rising interest in the Indoor Air Quality (IAQ) of educational buildings has been underpinned by the increase of asthma and respiratory disease amongst children. Poor air quality in learning environments not only affects the health and comfort of pupils, but can also reduce academic achievement and increase absenteeism.
Most of the exposure to environmental pollutants occurs by breathing the air indoors. These pollutants come from activities, products and materials we use every day. The air quality in our homes, schools and offices can be a staggering 2 to 5 times more polluted, and in some cases 100 times more polluted, than outdoor air.
Indoor air quality is a significant concern, because when the hours spent at school for example are added up, children on average spend the vast majority of their time indoors where they are repeatedly exposed to indoor air pollutants. Asthmatic people are particularly sensitive to poor air quality and pollutants.
The primary sources of indoor exposure to airborne chemicals are products used in interior environments, including furnishings, building materials and other household and office products, which can emit thousands of volatile organic compounds (VOCs) and particles into the air. Of all the culprits that can affect IAQ, chemical emissions are the most harmful as they can contribute to a wide range of health effects.
Moisture problems are another common source of indoor air pollution as they can lead to indoor mould growth. Mould can also emit VOCs and particulates, compromising indoor air quality and leading to negative health effects. Since it is impossible to eliminate mould spores, the best way to reduce the impact of mould on indoor air quality is to prevent or promptly repair the moisture problems that enable mould growth.
Most of the school buildings in which children spend the majority of their time are tightly sealed and insulated to ensure efficiency and comfort. Furthermore, most ventilation systems are designed to bring in very little outdoor air and instead recirculate the indoor air that has already been heated or cooled. While this strategy is effective for minimizing energy costs, it can have a negative impact on indoor air quality.
According to The Development of Regulatory Compliance Tools for Ventilation and Overheating in Schools report, put together by John Palmer – Chairman CIBSE Schools Design Group: “At any occupied time, including teaching, the occupants should be able to lower the concentration of carbon dioxide to 1000 ppm.”
“The maximum concentration of carbon dioxide should not exceed 5000 ppm during the teaching day.”
Improving the quality of indoor air is vital for human health. A recent UK study shows that pupils’ performance is increased by up to 15% in various tasks when ventilation rates in teaching spaces are increased. Common complaints in new schools are that they are stuffy, suffer from overheating, and are under ventilated.
Ventive’s passive approach to heat recovery ventilation is a great product specifically designed for schools and colleges (for both new build and retrofit) to comply with regulations. Their non-domestic (commercial) passive ventilation with heat recovery product, the Ventive C provides dependable natural ventilation with heat recovery at an average rate of 100 litres per second (wind speed of 4m/s). It can naturally remove stale air from classrooms and supplies fresh, pre-warmed air in return.
Passive Ventilation with Heat Recovery (PVHR) uses the natural buoyancy of warm air to evacuate stale air from the building and harnesses a combination of wind assistance and the balancing effect to supply fresh air in. A market-leading heat exchanger (designed, patented and manufactured by Ventive) naturally pre-warms the incoming air as the two flows pass each other, retaining heat within the building, rather than losing it to the outside during the colder months. During the summer the system works in bypass mode to purge heat from the building, reducing the risk of overheating.
The effectiveness of the system depends on the airtightness of the building and user behaviour (if you choose to open your windows for example you’ll have even better ventilation but less heat recovery) but it is free to use, with little to maintain or service – it will also last as long as the building itself.
To discuss your project requirements, contact the Ventive team today.