Heating and Ventilating


Clean air boosts learning

Phil Marris looks at the importance of maintaining good Indoor Air Quality within schools and what to consider in a ventilation system
It Is hard for grown adults - let alone schoolchildren - to concentrate in stuffy, humid environments. Teachers are constantly battling with the sometimes short attention spans of their students anyway, so lack of ventilation and poor Indoor Air Quality (IAQ) is another problem that they really don't need.

CO2 is the primary indicator of IAQ, and high levels are a tell-tale sign that stale air is not being replaced quickly enough in relation to the occupancy levels of the room. Studies have proven that excessive build-up of CO2 can result in poor concentration, lethargy, headaches, nausea, and has a significantly detrimental effect on attentiveness too. These ailments demonstrate that the need for good IAQ is particularly crucial in order to keep students performing to the best of their ability.

In addition, high humidity caused by poor air circulation can lead to excessive condensation, thus creating the ideal breeding ground for black mould and dust mites. As these can seriously impact our health, the need for effective ventilation is also crucial in any indoor environment frequented by the vulnerable, such as the elderly or young children, and particularly schools where children will be spending hours on end.

Furthermore, Wim Zeiler and Gert Boxem of University of Technology Eindhovenin, found that natural ventilation in classrooms without any draught prevention is an unacceptable solution to increasing IAQ, and that demand controlled ventilation conditions were required.

Unfortunately, all too often teachers think that simply opening a window is sufficient for increasing ventilation. However, this is not the case. Opening a window lets in both freezing air during the winter months and noise pollution from outside all year round - not ideal in a situation where children's concentration can be broken by the slightest distraction.

However, due to national building regulations, more and more educational facilities are moving towards energy-efficient ventilation systems to ensure premium IAQ in their learning environments.

Just some of the influential regulations include the Building Bulletin 87 (BB87) - a guide for environmental design in schools, and the Building Bulletin 93 (BB93) - a guide for acoustic design of schools.

Furthermore, the Building Bulletin 101 (BB101) - a guide for ventilation of school buildings, includes how to prevent overheating and boost Indoor Air Quality through effective use of ventilation systems.

However the need for an effective heating and ventilation solution that optimises IAQ goes beyond mere compliance. A generic, one-size-fits-all approach to ensuring good IAQ is not enough - there are too many variables in play, and ventilation should be managed on a room-by-room basis. With CO2 sensors, IAQ can be constantly monitored; and with a centralised controller, refresh units can be directed to increase or decrease the amount of fresh air being delivered.

Direct distribution of filtered air into each room via external air ducts rather than through central supply ducts, ensures a clean, healthy, and pollutant-free indoor environment.

The importance of effective ventilation in classrooms, is equalled by the need for efficient space heating, but for education authorities, buying heating and ventilation systems exclusive of each other is not cost effective.

The answer? A combination of both - specifically, a Demand Controlled Ventilation (DCV) system with balanced supply and extraction, plus an integrated low-water content heating system.

With a DCV system, the controlled supply of fresh air at low level and extraction of stale air at high level on opposite side of the classroom ensure optimal IAQ for pupils, and offers an energy efficient solution. A low-mass, low water content heat emitter will also be highly energy efficient by nature of its rapid response times and precise controllability; as well as being highly suited to low water flow temperature heat pump applications.

This two-in-one approach was recently implemented by Stockwell Primary School in South London. Funded by the Government and administered by the Lambeth Council, the educational facility underwent a £3.3million expansion to introduce nine new classrooms and a nursery - allowing for an extra class of students to be added to each year group at a time when school places are increasingly under pressure.

While the school has been expanded several times over the last few decades, the most recent extension had an added agenda. This included equipping the new learning spaces with state-of-the-art heating and ventilation systems to help the school reach a BREEAM 'Very Good' standard, and technology to improve the Indoor Air Quality (IAQ) of each classroom.

Located on the busy Stockwell High Street, opening windows was not an option due to the noise pollution and with the facades being primarily constructed from glass - which is a poor heat retainer - effective heating was essential.

The project required a system that could not only heat the space, but provide fresh, clean air into the classrooms as well. The answer was the specification of the Jaga Strada Oxygen Refresh system.

Equipped with Jaga's Low-H O technology, 12 Strada Oxygen Refresh radiators were installed throughout the six new classrooms. Jaga worked closely with the architects to come up with a novel way of introducing air into the Jaga heating and ventilating system.

Due to the external façade of the building traditional circular grilles would have looked out of place, so Jaga researched ways of achieving sufficient air volumes. The solution was to provide a 'groove' along the length of the building so the air can enter building.

The cavity wall of the building was used as a plenum area so that air can enter each of the Jaga Oxygen fans in sufficient volumes. The advanced intelligence of the system also automatically regulates the intake to manage the CO2 in each classroom.

The heating and ventilating industry now offers several types of ventilation systems to choose from. But when designing Oxygen, Jaga chose a unique displacement ventilation system. In order to prevent draughts, fresh filtered air enters the room at low velocity. Furthermore, unlike traditional ventilation systems, unique displacement ventilation enters a room at a low level where it is needed - extracting stale air from higher level.

In recent years, schools across the nation have made substantial efforts to improve their indoor air quality (IAQ). Delivering a controlled supply of filtered, fresh air by ventilation only when and where it is needed - and in the exact quantity required - throughout the nation's classroom environments, will not only improve our children's health, but ensure their learning abilities are not hindered by something as simple as the lack of fresh, clean air.

// The author is the managing director of Jaga Heating Products UK //
1 April 2014


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