With the effects of the pandemic placing greater emphasis on ventilation, the high levels of CO₂ across school building stock have become a prevalent concern. Yet, at the same time, saving energy remains a top priority in line with sustainability agendas.

With these two matters in mind, schools have historically relied on natural ventilation methods such as opening windows to maintain low energy usage. However, this approach does not guarantee good quality air. Many schools are located in suburban or heavily urbanised areas where a high count of nitrogen dioxide is in the air, along with harmful particulates such as car brake pad dust, fumes, sulphur dioxide and other pollutants.

Ventilation is one of the building services that should be high on the priority list. Proper ventilation accounts for maintaining a comfortable living environment while minimising energy usage. A well-designed and well-maintained ventilation system can help regulate indoor temperatures, reduce the need for excessive heating or cooling, and ultimately lower energy bills.

While conserving energy is important, this should not take precedence over peoples’ wellbeing – especially as younger individuals are more vulnerable. Furthermore, numerous scientific studies have highlighted that CO₂ and harmful particulates directly hinder pupil’s learning and concentration.

Coinciding with the introduction of the school rebuilding programme, now is the time for indoor air quality to be treated with greater importance through adequate ventilation.

The legislative landscape

While the Building Bulletin (BB101) is in place as a framework for ensuring effective ventilation, the recent changes to Building Regulations reflect growing concerns around management of indoor air quality. With updates to Part F, there is now a firmer guidance to adhere to. Namely that buildings must provide sufficient ventilation to keep CO₂ levels below 800ppm (parts per million).

These regulatory measures highlights the need for measuring and controlling CO₂ as part of ventilation strategy – placing further onus on schools to implement appropriate solutions.

Clearing the air

Alongside acknowledgement of regulatory guidance, there must also be an understanding of what good quality or ‘fresh’ air is. As outlined, good quality air isn’t simply air brought in from the outside. Many harmful compounds can be present that affect both health and concentration levels in pupils.

A Harvard study linked poor indoor air quality with lower cognitive function and found that particulate matter levels as little as 2.5 had significant impact on cognitive performance.

Evidenced by the rising popularity of air purifiers, another misconception is that continuous recirculation and purification constitutes fresh air. In actual fact, this air becomes stale, allowing for CO₂ and VOC (volatile organic compound) levels to increase and subsequently be inhaled. While air purifiers do have their place in a ventilation system, they should not be treated as a comprehensive solution. Such applications will remove pollutants but have no impact on CO₂ levels. As such, a good quality ventilation system is one that extracts all pollutants, brings air in from the outside and filtrates it before reaching the classroom.

Mechanical means

To ensure adequate ventilation, CO₂ should be considered as a proxy for air quality. The CO₂ level rises as a result of building occupants exhaling, while increasing the ventilation rate reduces it. On this basis, measuring CO₂ can allow for effective control of both air quality and energy usage.

Building ventilation systems often operate at constant or pre-determined ventilation rates regardless of the occupancy level of the building. Ventilation rates are normally based on maximum occupancy levels, resulting in consequent energy wastage. This is not only due to the fan operation, but also includes the energy used to condition the air for both heating and cooling modes.

Through MVHR (Mechanical Ventilation with Heat Recovery) solutions such as Elta Fans’ energy recovery units, the amount of airflow can instead be controlled to suit occupancy levels and delivered through demand-controlled ventilation (DCV). DCV is recognised as a reliable method of ensuring a building is ventilated cost effectively, while maximising indoor air quality.

Closed loop speed control for both EC and AC motor options provides major energy savings as the fan power is proportional to the speed cubed. CO₂ or temperature sensors are used to continuously measure and monitor ambient conditions in the conditioned space and provide real time feed back to the zone controller. From here, fan speed is adjusted – modulating the ventilation rate to match the specific use and occupancy of the building. Significant energy savings are made by effective DCV, which ensures that the ventilation rate continuously matches the current occupancy rate and varying ambient conditions.

Efficient Energy Conversion and Recovery

With all ventilation solutions, it’s important to consider the design properties of the ventilation system itself prior to making a decision. This is where small yet significant long term energy gains, and subsequently cost savings, can be made.

As an example, energy recovery units have a free running, backward curved impeller and special three-dimensional blade geometry that provides reduced rotational tone, which provides greater energy savings through higher performance.

Attention should also be paid to how much thermal energy can be recuperated. With energy recovery units, the thermal energy exchange is enhanced by the large surface area of the heat exchanger resulting in as much as 92% of thermal energy being recovered.

System support

When designing and specifying a mechanical ventilation system, it’s important to always consult with the manufacturers as quite often they can offer best practice and guidance to achieve the desired performance.

For schools, there should be a particular focus on specifying high-quality filtration methods to restrict external pollutants. In line with requirements, all ventilation systems from Elta Fans come with ePM₁ Filters that offer high filtration levels and follows the ISO 16890 Standard.

When specifying mechanical ventilation systems, it must be ensured that the fan has enough power output to overcome any pressure development drop due to the filtration solution. Layout and length of the ducting, as well as any other ancillaries involved in the design will also need to be considered.

Post-installation, any solution must also be well maintained and serviced to ensure they are operating efficiently. Here, consulting with a manufacturer can ensure the right maintenance schedule is created and followed.

The future learning environment

As the school rebuilding programme comes into effect, it’s clear that ventilation and air quality must not be left behind as an afterthought. Schools must have a well-engineered system for ventilation – whether it is mechanical or hybrid – and receive the necessary support to realise such solutions. From designers to contractors, consultants to installers and beyond, the entire supply chain must consider how to deliver good indoor air quality and follow through to enable better learning environments for years to come.

The link between good indoor air quality (IAQ) and the ability to concentrate is well established, which makes ventilation a really important part of any educational building. This is very much true of universities, and Brunel University London is a prime example of that.

It prides itself on its first-class facilities, and the Hamilton Centre is the centrepiece of a bustling campus. When we were tasked with delivering a ventilation solution suited to the demands of the centre – which contains restaurants, bars, function rooms, and a student union – we knew that a low-energy but high-performance system was required.

Not so smart

One of the main problems we faced on this project was the existing ventilation system, which had been drastically over-specified. Directly responsible for ventilating a popular pizza bar, the contra-rotating roof fan that was in place was extremely energy hungry.

Of course, you want to get the best performance ventilation that you can, but this has to be balanced with energy usage. This is important from a sustainability point of view, with high CO2 emissions a side-effect of over-specification, but also in preventing running costs from spiralling out of control.

Working it out

The best way to guarantee performance without crippling energy bills is to go for a fan that incorporates an EC motor, which made Elta’s Revolution SLC EC long-cased axial fan the perfect candidate. Having an EC motor helps to reduce energy bills, plus it’s quick and easy to install, which is vital given the less-than-straightforward location we were working in.

Another strength of the Revolution SLC EC is its intuitive control system, a feature that is often-overlooked but very important in improving efficiency. The previous fan was hampered by complicated controls, meaning the guys in the pizza bar were usually too busy to operate it at all. The reduced electrical voltage of the Revolution SLC EC meant a simple dial control system could be put into the kitchen, allowing operators to easily manage the ventilation output during the day.

Final marks

University building work is always time-pressured, whether it’s during term-time or the holidays. Added to this equation is a need to minimise emissions and running costs, but still provide the level of ventilation needed for high IAQ.

There aren’t many products on the market that tick all of those boxes, but thankfully we already enjoyed a good relationship with Elta, and we knew that the Revolution SLC EC would fit the bill. The off-the-shelf low lead time made our job even easier, and has made sure the Hamilton Centre at Brunel University London can benefit from good IAQ.

What is the Green Homes Grant?

In July, Chancellor Rishi Sunak said families will receive vouchers of up to £5,000 for energy-saving changes, such as insulation or a new boiler, with the poorest getting up to £10,000. As well as improving the UK’s energy efficiency levels, it will also bring new jobs, which is of course good news.

How does it affect the ventilation sector?

Anything that helps reduce heat losses and carbon emissions from a home has to be welcomed. However, new or additional insulation and more airtight windows can reduce the natural ventilation in a property to the point where it creates an environment conducive to mould growth and increased pollutant levels.

What are the risks?

With the new scheme expected to see work start in many homes during what will be the UK’s next “condensation season”, I expect many homeowners to find that they have condensation dampness problems the following year if ventilation is not properly considered and incorporated.

I would expect to see many homeowners that benefit from warmer homes and lower bills having to face some undesirable unintended consequences of thermal improvements. These would be in the form of mould and poor indoor air quality if they don’t address ventilation as part of thermal improvement works.

How can this be avoided?

The provision of a low energy mechanical ventilation system that can complement thermal improvements need not cost the earth. In the vast majority of homes with little or no existing purpose-provided ventilation measures, a modern low energy ventilation system that will ventilate the whole property, can cost as little as £700-1,000. This would include the home survey and system design, supply, installation and commissioning and also notification of the system installed to the local Building Control Body. Many will agree that is a small extra price to pay for a warm, energy efficient and healthy home.

Quality is key

It’s crucial that the people carrying out insulation improvements as a result of this funding fully understand and value indoor air quality. As such, it’s positive that the Government has stated that any tradespeople carrying out insulation improvements must register for TrustMark or Microgeneration Certification Scheme (MCS) accreditation, which will ensure they follow required standards. For example, PAS 2035:2019 is the report from the Department for Business, Energy and Industrial Strategy which provides a framework based on a ‘whole-house-approach’ to renovations.

While this is generally positive news for the UK’s housing sector, it’s crucial that  homeowners and contractors consider the provision of adequate ventilation as part of any thermal improvements works under this new government scheme.

One of the striking facts to come out of the testing is that the Mori dMEV has an annual running cost of less than £1 per year in kitchens and just £0.75 in bathroom/utility areas. Power consumption for continually running the Mori dMEV equates to just a third of the energy of an 18W low energy light bulb in use four hours a day. The unit also has exceptionally low noise levels that make it quieter than a ticking watch (typically 13 dB(A) for bathroom/utility. The product brings, to house builders, housing authorities and social landlords, unprecedented efficiency.

Each Mori dMEV also saves 1.96 kg per year of CO₂ compared to the next best unit on the market. Shortlisted for the H&V News ‘Domestic H&V Product of the Year – Sustainability and Safety’ award, the Mori dMEV constant volume unit is designed for System 3 ventilation in new build or refurbishment for social housing, and private housing applications.

Elta also contends that its latest Mori dMEV is 62% more efficient than the dMEV which won the H&V Award two years ago. During two years of intensive and stringent design and product testing, started in February 2012, the Mori dMEV has been meticulously developed by Elta. For the impeller alone, more than 35 3D models were created, 19 of which became prototypes with the most recent of these becoming the unique ‘BLADELET’ impeller.

The result is a product which has the lowest SFP (0.09 W/(L/s)) and provides the lowest running costs of any dMEV to date. Elta Residential Division, is part of the Elta Group – a family of businesses with operations in seven countries on four continents – the 2015 Ecobuild exhibition is an important opportunity to demonstrate the value of the Mori dMEV for the housing sector and, in particular in social housing.

Elta Group Building Services Head of Sales, Mathew Axford said: “Our company is committed to providing exceptional indoor air quality in the most cost effective way for the health of the nation. “Our focus at Ecobuild is to engage with social landlords and building companies to expand our message of being the ‘Home of Ventilation’ offering market leading, innovative products,” explained Matthew Axford. Other features of the Mori dMEV include: Low energy, highly efficient EC motor with onboard electronics, Operates up to 50°C, TMP safety tested of domestic fans to IEC 60335-1 AND 60335-2, Low energy, 2.5W EC motor with inbuilt constant volume control. Compliant with ISO/IEC 17025, 3 year warranty and many more. .

The fan manufacturer supplied: six SRECU heat recovery units; three aluminium long cased SmokeVent fans; five Revolution long cased fans; two backward curved, inline units; two aluminium and one GRP long cased fans and one carbon filled ATEX fan all from the company’s factory in Kingswinford near Dudley in the West Midlands. Elta’s SRECU heat recovery units are designed to create healthy air quality and comfort within buildings by providing a constant supply of warm, fresh air.

Each unit incorporates a plate heat exchanger capable of recovering up to 65% of the heat from the air being expelled through the building’s ventilation system. This cuts down on heat loss and thereby reduces the cost of heating. The outgoing air is passed over aluminium plates within the heat exchanger.

This warms the plates which, in turn, transfer the heat to the fresh incoming air. The design of the heat exchanger keeps the incoming and outgoing air supplies separate, eliminating the possibility of any contamination of the fresh, incoming air by the expelled air. With low profile, robust casings of double skin, galvanised sheet steel and fire-resistant mineral wool infill for quiet performance, SRECU heat recovery units are directly driven by an AC external rotor motor. Efficient, easy to mount and maintain, they are designed and manufactured with procedures as defined in BS EN ISO 9001: 2008.

All the Elta units were delivered to site where they were installed by electrical contractor, N.G.Bailey, the engineering, IT and facilities services company. Main contractor for the overall project in North Hykeham was Clugston Construction Ltd. and lead civil works consultant was Arup. Run by the FCC Environment (formerly the Waste Recycling Group), the landmark EfW project came about as a result of the company securing a contract to dispose of Lincolnshire County Council’s residual waste over the next 25 years.

The facility is fed from a series of new waste transfer stations (WTS) strategically located throughout Lincolnshire in Grantham, Sleaford, Boston and Gainsborough. These stations have replaced landfill sites for disposal of local waste and are in addition to the similar station in Louth, in the Lincolnshire Wolds. Household waste is collected at these WTS, sorted and then sent to the EfW plant. There, the non-recyclable waste is stored within a large underground bunker before being used as fuel to power a hot water boiler.

The resulting steam drives a turbine capable of generating 11 megawatts of electricity. The facility was designed to treat 150,000 tonnes of residual household and commercial waste a year on behalf of Lincolnshire County Council and now exports the renewable electricity generated for sale to the National Grid. The amount of power created is sufficient to supply 10,000 to 15,000 homes. .

The SWHR180 is the latest in a new breed of fans which not only address the importance of extracting stale air, but also employs heat recovery technology which reduces the energy required to heat or cool a given space.

The nature of these environments means that ventilation is key. The challenges come from the number of people, which varies considerably depending on the time of day, and from the preparation, serving and consumption of food and drinks. This means that in a restaurant the recommendation is for 10-15 air changes per hour, in a pub 15-20 changes per hour and in popular clubs and bars 20-30 changes per hour given the additional heat generated by people dancing. Extract fans are therefore a prime means of ensuring good indoor air quality.

However, creating a pleasant environment for customers is also about providing a comfortable ambient temperature. With energy costs rising and an ever increasing emphasis on making buildings more sustainable and energy efficient, attention is being focused on how heating, ventilating and air conditioning (HVAC) systems can contribute to this.

With conventional extract fans, any air that has been previously heated or cooled is simply expelled from the building for ventilation purposes. The HVAC system must therefore compensate for the loss of energy. Fans which employ heat recovery technology enable a significant proportion of the energy that otherwise would have been wasted to be recovered. As the name implies, heat recovery units recover the energy in the extracted stale, moisture laden air and transfer it to fresh air as it enters in a counter-flow heat exchanger.

The SWHR180 from Elta offers 73% thermal efficiency through its integrated aluminium heat recovery cell. The compact unit is designed to meet the exacting demands of the pub, bar, club and restaurant environment, with an ultra low watt DC motor which ensures a smooth airflow and further reduces energy consumption.

The SWHR180 is ideal for both new-build projects and for retrofit applications. For more information please visit the dedicated heat recovery section at www.eltaselect.com or contact the sales team on +44 (0) 1384 272800

Elta is part of the £85 million Elta Group, a family of businesses with operations in six countries on four continents which, together with a network of international distributors, provides quality fans and related air movement equipment to customers worldwide.

The Linwood Toyota dealership, located on the Phoenix Retail Park in Linwood, is part of the Arnold Clark Group, Europe’s largest independently-owned, family-run car company. The Sales Manager at the branch is Jim McGregor who recognised that the heating within the showroom was resulting in hot and cold spots, a not uncommon occurrence, particularly in buildings characterised by large open spaces. He approached Kevan McKenna at Keets, based in a Glasgow, who recommended the new ZOO range recently launched by manufacturer Elta.

The ZOO or ‘Zone of Occupancy‘ destratification fans have been developed to address the problem of heat rising which can result in the upper area of a given space being warmer than the lower area where it is actually needed. With the ever increasing focus on energy costs, the wasted energy from overheating a space to achieve the desired temperature in the occupied area is becoming more of an issue. By installing two fans in the roof space of the Toyota showroom, columns of air gently force the warmer air down to floor level, ensuring a much more even distribution of the heat and therefore significantly improving the environment for the Arnold Clark customers.

The ZOO approach is designed to prevent the need to overheat an entire space to achieve comfortable temperatures at floor level. The fact that heat rises results in thermal stratification, meaning that the upper areas of a space are typically warmer than the lower areas where it is actually needed i.e. the ‘Zone of Occupancy‘.

Overheating results in significant increases in energy consumption, particularly in buildings with high ceilings where the temperature differential between floor and ceiling is greater. This is also true in the months when cooling of the building is required. Again, thermal stratification causes variations in temperature which can often result in the over-cooling of an area to achieve the required temperature at floor level.

Elta’s new ZOO fans are designed to distribute the heating or cooling evenly throughout the occupied zone, generating columns of air which gently force the stratified air down to the Zone of Occupancy, therefore removing the need for physical ductwork. In cooling situations, the fans can be used in closer proximity to operate as spot coolers, taking advantage of the evaporative cooling sensation.

The fans feature the latest in impeller technology: the FE2owlet sickle bladed aerofoil profile axial impeller powered by the fully speed-controllable Ziehl-Abegg external rotor motor. To reduce noise, the blade has been designed with serrations on the trailing edge of the wing, like the owl, hence the name. These serrations serve to muffle sound, with further noise reduction achieved by the incorporation of winglets, as seen on jet aircraft, on each blade. On an aircraft, the winglets are designed to smooth the airflow across the wing near the tip and reduce the lift-induced drag caused by wingtip vortices. The reduced vortices at the tip of the impeller blade lessen the turbulence and noise generated, as well as easing the path of the following blade, thereby improving efficiency and performance.

With the focus in HVAC increasingly on energy efficiency, the ZOO fan is specifically designed to address this. Not only can it significantly reduce a building’s energy consumption, but the fan itself is energy efficient and quiet in operation. It is fully speed-controllable, allowing the fan speed to be reduced to the minimum necessary to maintain the required temperature differential. De-stratifying an air mass consumes more energy than simply maintaining equilibrium. Once the air is de-stratified, the fan speed can be turned down typically by 30 to 60 percent, providing a major reduction in fan absorbed power.

Alan Macklin, Group Technical Manager at the Elta Group, comments: “The projected energy savings for space heating range from 10 to as much as 40 percent by reducing the energy required to condition the air in an occupied space. Of the estimated 40 percent of the world’s energy that is consumed by buildings, some 85 percent is used for room heating and cooling. It is therefore readily apparent that this is an area where any contribution to improving energy management can have a significant impact. Destratification of occupied areas using ZOO fans will result in energy efficient ventilation and lower the operational costs of the building while maintaining good indoor air quality.”

Elta is part of the £85 million Elta Group, a family of businesses with operations in six countries on four continents which, together with a network of international distributors, provides quality fans and related air movement equipment to customers worldwide.

The new alliance between Elta and Ziehl-Abegg was a significant move made to ensure that Elta new products comply with the requirements of the new European legislation regarding energy efficiency. The first tier of the Energy related Products (ErP) Directive will implement mandatory fan efficiency legislation from 1st January 2013 with more onerous requirements to follow in January 2015, but Elta has taken a preemptive stance which will ensure their product range is in advance of the legislative deadlines.

The launch of the first Elta products to be powered by Ziehl technology includes the Raptor range. Available as a plate fan, cased axial fan, or plate mounted ATEX fan, the Raptor is the only fan currently available on the HVAC market to feature the Ziehl FE2owlet impeller. The research department at KÌÄå_nzelsau based Ziehl-Abegg drew from nature in developing the all new Owlet, recognising the owl as a bird renowned for its silence in flight.

By borrowing scientific insights into the owl’s flight characteristics and combining it with the company’s extensive aero-acoustics knowledge, Ziehl have produced a completely new blade geometry which excels in terms of low noise emission, reliability and high efficiency. To reduce noise, the blade has been designed with serrations on the trailing edge of the wing, like the owl, which serves to muffle the sound of the owl’s wing beats. Improved efficiency and performance is achieved through winglets on each blade, used on aircraft to smooth airflow near the wing tip to reduce the lift-induced drag caused by wing tip vortices.

The Raptor fan range features an all metal casing, treated to ensure full corrosion protection, with all parts including the guard finished in a powder coated polyester epoxy paint to ensure long lasting and robust performance. The Ziehl-Abegg motors are highly efficient, lightweight external rotor motors with sealed for life, maintenance free ball bearings, allowing the fans to be installed at any angle.

Incorporated into Elta’s products, the Centrifugal Fans include the Vpro backward curved impeller with threedimensional profiled blade and optimised blade geometry providing high efficiency and low noise levels.

A number of re-engineered Elta’s products are to be launched, including the Hideaway, Quietflow, Singleflow, Twinflow, Skyflow and QUBe fans, all of which are powered by Ziehl-Abegg motors and impellers.

Elta is part of the £85 million Elta Group, a family of businesses with operations in six countries on four continents which, together with a network of international distributors, provides quality fans and related air movement equipment to customers worldwide.

The company produce chocolate-coated biscuits and confectionery for worldwide distribution. Its well-known and well-loved speciality biscuit range includes Tunnocks’ Caramel Wafers, Snowballs, Caramel Logs and Teacakes. The distinctive foil wrappings – cartoonish, art nouveau design with a rosy-cheeked boy on the front – are still the same as when they were originated back in 1952.

A total of 28 Elta Skyflow SSFV roof unit fans were supplied during the refurbishment of Tunnocks’ roof directly above the ovens and caramel department in the busy biscuit plant. The Skyflow units were delivered quickly from stock on the Pensnett Trading Estate, Kingswinford, West Midlands, through Elta distributor Fans & Spares in Glasgow (shortly to be opening a new branch in Edinburgh), to replace the old, down-discharge units which were noisy and depositing debris directly onto the roof which was then causing problems as it collected in the guttering.

The Elta SSFV range comprises vertical discharge axial flow roof extract units, which are designed to discharge the air at higher velocities away from roof levels, balancing the need to satisfy architects’ aesthetic demands against a vertical format.

Tunnocks’ bakery in Uddingston is situated in a very exposed location in South Lanarkshire, on the north side of the River Clyde, approximately seven miles to the south-east of Glasgow, so it was important that the roof-fitted fans are durable and robust.

The Skyflow vertical top cowl and fan support housing is manufactured from UV-stabilised, GRP for a hardwearing product, finished in goose wing grey. The fans are of a long-lasting and robust construction from mild steel – suitably treated to ensure corrosion protection – the inlet guards are bright, zinc-plated and the fan plate and motor are powder-coated, epoxy paint finish. Air operated shutters are fitted as standard to stop any discharged (dirty) air from re-entering the building, as well as offering protection against the weather.

Just as importantly, the Elta Skyflow SSFV roof unit fans also have good performance and noise characteristics. Staff at Tunnocks’ bakery are extremely pleased with the quiet running of the fans and say that their installation has made for a more pleasant working environment.

Thomas Tunnock Limited was started in 1890 by Thomas Tunnock whose father had been a cabinet and coffin maker. Thomas wanted to try his hand at running a bakery and bought out an existing baker on Bellshill Road in Uddingston and the company has been family-run ever since. In 1947, the business erected the current factory on 34 Old Mill Road and underwent a big expansion in the 1950s when its caramel wafers were introduced. More than three million teacakes, which were first created in 1960, are now being produced at the bakery each week. In 2009, Scottish author Craig McGill wrote a poem dedicated to Tunnock’s Snowballs: “Wee, mallow, rounded, choccy biccy,O, what a panic’s in my tummy! One needs tae eat ye hasty Wi bickering brattle! I wad be laith to rin oot of thee, An hae to eat a tattie.”

For more information on our products or services please contact Elta Building Services on +44 (0)1384 275800 or Elta Applied Technology on +44 (0)1489 566500. Alternatively please visit our website eltauk.com

Elta is part of the £85 million Elta Group, a family of businesses with operations in six countries on four continents which, together with a network of international distributors, provides quality fans and related air movement equipment to customers worldwide.