According to the Chartered Institute of Environmental Health, young children can spend up to 90% of their time indoors as well as an estimated 1,300 hours in school buildings alone, in just one academic year. As such, addressing indoor air quality (IAQ) within educational facilities is absolutely crucial. Here, Robert Dennis, Product Marketing Executive at Airflow Developments looks at the important role Mechanical Ventilation & Heat Recovery (MVHR) can play in achieving a comfortable and healthy interior environment.
The importance of IAQ
After a study published in the European Respiratory Journal showed that concentrations of some air pollutants could be up to five times higher indoors than outdoors, the need to review IAQ has become essential.
When inside of a school building, children must be provided with a healthy and productive environment. If the IAQ is poor it can lead to an array of medical ailments including asthma and cardiovascular difficulty, as well as a lack of concentration, which has the potential to affect their academic performance. Indeed, a UK study by the University of Reading’s School of Construction Management and Engineering proved the correlation between inadequate ventilation in schools and academic achievement. The study found that pupil performance significantly increased by up to 15%, in various tasks, once ventilation in teaching spaces was improved.
How To Comply
Architects looking for legislative information should refer to the latest guidelines on ventilation, thermal comfort and indoor air quality from the Department for Education (DfE). Helping to form the basis of these, are the guidelines provided by the World Health Organisation (WHO) as they offer more current and comprehensive information than that which is set out in the Government’s own Building Regulations 2010; Approved Document F.
Embracing Technical Innovation
The good news is that when it comes to selecting appropriate ventilation technology leading manufacturers such as Airflow can provide a wide portfolio of products that can help to provide the ideal working environment for pupils and at the same time, ensure an energy efficient system is in place.
For new school buildings, using Mechanical Ventilation with Heat Recovery (MVHR) is a logical option. MVHR systems will remove stale air from inside the building whilst heat energy is extracted from it via a heat exchanger. This energy is then used to pre-warm clean healthy air that is continually being brought in from outside, and then consequently filtered and circulated around the building.
A good example is the Duplexvent Commercial Heat Recovery range from Airflow; having been specifically designed to improve indoor air quality and create a healthier internal environment by guaranteeing the constant supply of fresh air. The units have an inbuilt filtration system to clean out airborne allergens such as dust, pollen and mould spores that can exacerbate hayfever and asthma, conditions children are particularly susceptible to.
Architects also have a duty of care to take into account, another key challenge facing educational buildings. The most recent DfE guidelines highlight that overheating in classrooms and over-glazed larger spaces such as libraries and learning resource centres is becoming a common issue.
To negate overheating in the summer months it is absolutely critical architects choose units with a 100% effective summer bypass function to prevent excess retention of heat. By utilising a motorised damper connected to a temperature sensor to automatically seal off the heat exchanger, a 100% bypass facility will ensure the MVHR reduces solar gain by guaranteeing that the supply air is not heated by the extract air passing through the heat exchanger.
Since January 2016, the ErP Directive has made it mandatory for MVHR units to include a summer bypass function. However, be aware that not all compliant systems are equally effective and when specifying MVHR it is best practice to ensure the system includes a 100% bypass function.
Finding An Efficient Solution
Ventilation currently accounts for around 30% of heat loss in commercial buildings. For school premises, there is clearly a need to try and reduce ongoing costs. Therefore a product solution needs to be found that can provide effective ventilation as well as reduce energy wastage.
For market leading capability, architects should look to MVHR systems that have been designed with high performance polypropylene exchangers. These will transfer recovered heat from warm to cold air, achieving up to 95% thermal efficiency. This can translate into a 40% saving on heating costs for the school’s building managers, due to less energy being required to heat incoming air. In some cases it can also reduce the average payback period (dependant upon demand) of an MVHR unit from 7.5 years to 3 years, compared to traditional units with only 50% thermal efficiency.
Where a customised heat recovery solution is required, the Multi and Multi-N Line Duplexvent range from Airflow can be tailored to suit individual specifications and delivered in four to six weeks to meet tight renovation project deadlines. Available in 72 different mounting versions with indoor/outdoor installation options, key benefits of the system include low energy/noise EC fans, automatic frost protection, 100% bypass facility and the option of zonal ventilation control, making it easier to maintain internal comfort levels throughout the year in the UK’s changeable climate.
Advice for Architects
Those responsible for planning ventilation in any educational building should always seek advice from reputable manufacturers to help specify the most effective solution to suit the individual requirements. Specialists such as Airflow will be able to examine the size and type of building, and look at where an architect is planning to have ventilation installed, to suggest how best to optimise air quality, enhance energy efficiency and achieve the desired results.
For more information on Airflow Developments visit: www.airflow.com