FOCUS: EDUCATIONAL SERVICES
The importance of good ventilation in schools
Today more than ever good ventilation design matters in schools. Latest research highlights that the building design can improve academic performance by up to 25%. But Roy Jones, technical director at Gilberts Blackpool, says correctly designed and specified, ventilation can play a significant role in the health & wellbeing of all the people occupied within. It can also positively impact the drive towards energy reduction/ carbon Net Zero
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ust think how today’s education has evolved from that of 40 years ago. From primary schools to universities, mainstream and special schools, there are more computers along with other
technology, more vocational equipment, all generating heat and other pollutants that need to be considered. Our roads are busier, pumping more noise and pollutants into the atmosphere, which also needs to be addressed as schools generally suffer from location issues- being near main roads and transport links. Today we are also more aware of the impact that a building’s location, orientation and fabric can have on its internal environment. The core standard for our educational estate is the guidance provided by the Department for Education’s BB101, applying to both new build, currently numbering 513 confirmed schools under the Government’s latest School Rebuilding Programme, and refurbishments. Designing ventilation is complex; it is not just about the air supply to maintain the preset temperature and indoor air quality (IAQ), including C02. Add into the requirement a draught free, quiet space – especially important in special needs schools. Natural, mechanical, hybrid and mixed mode systems can provide these. Correct selection considering the use of each space must be individually reviewed: one design certainly will not fit all.
Single solution, hybrid and mixed mode solutions will be required and need to be fully reviewed at the design stage to ensure the best possible all-round answer for the occupants. We must also now factor in that our designs and systems must deliver sustainable, energy- efficient environments and achieve an internal space that people want to be in. BB101 prefers the use of natural ventilation,
providing a system with low maintenance and running costs that will achieve the required sustainability goals we strive for in our design. However, the Guidance recognises that in today’s schools, natural ventilation alone is not always able to meet today’s required stringent requirements considering the diversity of space usage within the building, including the topography and orientation of the building itself. Natural ventilation is prevalent as the method of choice for smaller schools, sports halls and atria. In the majority of current designs, the general teaching spaces may be more suited to the use of hybrid systems that make use of a mixture of mechanical and natural ventilation. In our experience, hybrid is becoming the ‘go
to’ option for these spaces, predominantly using natural ventilation and switching to mechanical supplementation (usually via an ultra-low energy fan) only as and when needed. This delivers the balance of air quality as set out in BB101 whilst reducing the energy footprint not just of each general teaching space but the building as a whole. To meet the demand for carbon/energy
reduction, hybrid ventilation has evolved to now include heat recovery, with the latest versions capable to achieving up to 75% heat recovery. You can also specify a range of ‘add-ons’ . These include LPHW coils that increase the heating capability and can obviate the need for ancillary heat emitters or heat sources such as radiators, which keep the design simple and reduce additional materials costs with all the associated reduction in embodied carbon; adding filters to the hybrid system can make a further positive contribution to the indoor air quality, meeting or exceeding the standards set out in BB101 for the variety of learning spaces by addressing
incoming pollutants from the outside air. The fact that hybrid units can be used as a single zone supply and exhaust, through a single façade, makes them simple to install and maintain, with low energy costs. These are pure hybrid solutions allowing devices to be used in single space zones to achieve all required performance goals. We are also seeing the rise of mixed mode systems where one room is being naturally ventilated whereas another eg an ICT suite is using mechanical ventilation to maintain the ambient temperature due to the demanding higher heat loads within these rooms. Hybrid units have a further “trick up their sleeves’! Heat coil options provide morning warm-up and tempering in winter, but can also offer cooling for summer overheat conditions. The same coil is utilised to achieve the relevant temperature to keep the room compliant and ensure occupants feel comfortable even in extreme conditions.
The challenge for manufacturers has been to design for all the noted criteria, so a designer can select such a product to improve room air quality from a single product, in a single zone, with the required functionality to provide the correct solution in an efficient manner. This is now a reality as today’s hybrid systems are meeting the requirements and proving to be the “go-to” solution.
Alongside ventilation designs we must also consider how certain spaces are dealt with for the specific use/purpose. As I mentioned above, whatever the preference, one design/ solution does not fit all. To that end, forward- thinking manufacturers are bringing to market new grilles and diffusers – the means by which the air supply and exhaust is achieved within the space. Latest innovations include units that have adjustability within the product design, with thermal or mechanical alteration of the inlets to provide air into the space in a correct and appropriate manner. Remember, manufacturers have the technical knowledge of how diverse methods of ventilation interact, and can support with the overall design to ensure a cohesive integration through a holistic design approach to the diversity of environments within our school buildings.
26 BUILDING SERVICES & ENVIRONMENTAL ENGINEER APRIL 2024 Read the latest at:
www.bsee.co.uk
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