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Building Products July 2017

EDUCATION BUILDINGS planners to consider the size of the room and occupancy rates. A suitable control strategy is also important with a variety of potential users operating the system, from building and facility managers through to teachers and students themselves. The Facility Output Specification is the document which forms the basis for the design of new and renovated schools. To meet the required ventilation levels, whenever spaces are occupied, purpose provided ventilation should provide external air supply to all teaching and learning spaces of a minimum of 3 litres/sec. per person, and a minimum daily average of 5 litres/sec. per person at any occupied time. There are three main approaches to ventilation in education in the UK currently. These include natural ventilation which is suitable for many types of buildings located in mild or moderate climates. This would typically mean an “open window” environment. The BB101 guide for schools outlines a significant need for natural ventilation and where appropriate, simple, responsive mechanical ventilation to maintain air quality. Thermal comfort and control is more important than temperature. Thermal controls should be easy to use and quick to adapt to changing uses of space. Lastly, but of equal importance, good acoustics are essential. These aid effective learning, pupil engagement, and wellbeing. Mechanical ventilation can ensure that the quality of air is controlled, exhaust moisture and 18 BUILDING PRODUCTS | JULY 2017 odours out of rooms. There is potentially less ductwork compared to balanced ventilation with the possibility of individual controls per room. This can be a good solution in areas of high pollution. Analysis of the severity of health problems caused, and the number of people affected by air pollution was carried out for the Department for Communities and Local Government in 2008. One of the most serious indoor air quality risks identified is one over which building designers and occupants have limited control. Particles - predominantly products of combustion - increase the risk, and the severity, of heart disease and respiratory illnesses. The main source of particulate pollution is traffic, especially in UK cities. London, along with 11 other UK cities, has frequently seen spikes in air pollution already in 2017. One way to counteract outdoor air-pollution in schools is to use a fully ducted ventilation system with extra fine filters fitted. A hybrid ventilation system allows the controlled introduction of outdoor air ventilation into a building by both mechanical and passive means. It has built-in controls to allow the mechanical and passive systems to work in conjunction with one another. This should avoid additional ventilation loads compared to using mechanical ventilation alone. Controls play an important role in hybrid ventilation, allowing the system to switch between mechanical and passive ventilation seasonally, diurnally or based on a measured parameter. Hybrid ventilation can support the current trend to build schools and classrooms with a modular or standardised approach as seen with the Priority Schools Building Programme (PSBP). Hybrid Ventilation is an innovative and energyefficient way to provide outdoor air ventilation to buildings, and in some conditions, to cool them, thus reducing energy otherwise required from conventional sources. It can lead to a lower building life-cycle cost and create a healthier environment for building occupants. There can be a greater sense of occupant satisfaction due to the increased ability to exercise control over the ventilation provided. The lifecycle of the product can be extended and there is a strong ROI as there is less use of the mechanical elements and therefore lower maintenance required. Using the latest controls available, the building manager can ensure that the system is operating as it should and end-users can be given guidance as to the correct action to take for optimum performance. There are many benefits from using a more natural approach to ventilating a school building, from both the perspective of improving learning outcomes, health and concentration and also the opportunity to reduce energy costs for schools and local authorities through using less mechanical approaches. Nick Hopper is Technical Director of Monodraught <<< Continued from page 17


Building Products July 2017
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