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No hyperventilation over ventilation

Author : David Strydom

23 September 2015

How do FMs avoid the tension between designing a ventilation system and maintaining it with respect to compliance? PFM asks the experts.

Imagine you’re tasked with managing a brand new building which – unbeknown to you at the time – has in-built problems with the way the ventilation system is designed. This means that, as legislation is updated, you find yourself having to institute changes such as installing retrofit doors. Clearly, this results in tension between the way ventilation systems are designed and the way they’re maintained.

PFM spoke to several experts in order to find out how FMs and other building managers can best manage this tension.

Mike Booth, European marketing manager at Air Treatment at Fellowes UK, says to the casual observer, many new buildings in the UK can appear to be over-ventilated, a problem that arises in the design stage through a common misconception that buildings need a central air duct for ventilation. This is because many managers believe all air provided to the central air duct should be ‘fresh’.

Additionally, meeting requirements for ventilation under Part F of the building regulations means building managers and designers are focusing on the levels of fresh air that are pulled in to parts of a structure and in urban areas, they’re taking the necessary steps to meet ventilation performance criteria and minimise the ingress of external pollution into their buildings.

“As the building regulations don’t legislate for the difference in pollution levels in different areas of the country, the quality of air being pulled into commercial buildings can actually vary from city to city, even with measures to prevent external pollution,” says Booth. “However, building and FMs can significantly contribute to the quality of the air within all buildings at the design and maintenance stages by utilising revolutionary air purification technology, thus contributing to the effectiveness and functionality of the structure once complete.”

Research shows the air we share in the workplace can negatively affect our health, wellbeing and productivity, Booth points out. “Indoor pollutants such as, germs, bacteria, viruses, pollens, mould and VOCs (volatile organic compounds) can impact our health and our ability to perform at our best. With the cost of more than £14bn to UK businesses each year through sickness absence and the financial impact of presenteeism estimated to be even higher, the benefits of improved air quality become clear. A recent report from the World Green Building Council on this topic concluded that productivity gains of between 8- 11% aren’t uncommon as a result of improved better air quality.”

Products now exist in the market, which complement existing HVAC systems to remove up to 99.97% of airborne particles, says Booth. “For example, through the use of a multi-stage air purification process, AeraMax PRO greatly reduces the presence of airborne germs, allergens and odours. A HEPA filter (high efficiency particulate air), treated with an antimicrobial layer, captures 99.97% of airborne particulate down to as small as 0.3 microns.

“An activated carbon filter adsorbs unwanted odours and volatile organic compounds that can lead to poor air quality and a bipolar ioniser breaks down microorganisms and odours throughout the room, providing a cleaner, more hygienic indoor environment.”

The Environment Protection Agency recently ranked indoor air pollution among the top five environmental risks to public health, says Booth. “With employee related costs accounting for about 90% of operating costs for most businesses, it makes good business sense to invest in the quality of the environment people work in and for FMs and building managers to take a more proactive approach to ensure indoor air quality is maintained and improved in new buildings.”

Steven Hunt, MD of building services consultancy, Steven Hunt & Associates, says maintaining dated ventilation installations can present significant challenges for the FM, which is to be expected from any legacy system. “It often comes as a surprise to FMs and occupiers, however, when new ventilation systems present different - but similarly onerous - maintenance challenges.

“If the building was constructed as a speculative office development, the problem often stems from the fact that the developer’s only priority is the construction costs, so any additional budget that might reduce maintenance requirements is simply not in the cap-ex calculations.”

However, Hunt says, if the occupier signs the lease before construction begins or, even better, before the design process has been completed, there’s an opportunity for the FM to become involved in developing the ventilation system design in line with future maintenance requirements.

To do this, however, they must be aware of some common problems that can affect ease of maintenance as a result of the design or installation process.

“A common maintenance issue is the need to re-set fire dampers, which can often dropdown accidentally post installation. In theory, this should be a simple process because the ventilation system must have access doors by which the fire dampers can be reached to comply with building regulations. However, while an access door either side of the duct may be specified, constraints on time and budget at installation may result in only one door being installed.”

What’s more, Hunt adds, the door may be accessible when it’s installed but, after all the services, the ceilings and the partitions have been completed, it may no longer provide the access it was designed for. “Unfortunately, obscured access doors can also be difficult to find because they often don’t appear in the Operation & Maintenance (O&M) manual. While some building services consultants will mark access doors onto the ventilation system plans, not all do. And even if they have been marked on the plans, there is no guarantee the installation team has put them in at the designated locations!”

It’s an issue that can affect multiple ventilation system maintenance requirements, including the reset of volume control dampers if occupancy levels change, issues with condensation if the ductwork hasn’t been properly lagged and access to fan coil unit filters.

“As a result, if the FM hasn’t been involved in the design stages of the building, they may need to build cap-ex spending into the ventilation maintenance budget from the outset to allow for the provision of new access doors,” says Hunt. “In an outsourced FM scenario, this needs to be made clear to the occupier from the outset. The alternative is a ventilation system that isn't maintainable - which is simply not an option.”

Simon Medhurst, senior estimator at System Hygienics, which is part of the Hotchkiss Group, says moving into a newly handed-over building is an exciting and an incredibly busy time for any FM. “We all realise building sites can be dusty, dirty places but usually you'll find everything has been tidied up ready for handover and looks sparkling clean.”

But, Medhurst asks, what about the ventilation system? The problem with ductwork interiors is that they’re 'out-of-sight and out-of-mind' – for the builder and the FM. Duct systems are particularly vulnerable to deposits of fine builders' dusts, insulation fibres and many other impurities, he notes.

“One thousand square metres of office floor could easily have 500m of ductwork running in it, representing perhaps 200 square metres of ductwork surface. Since the ductwork is typically the only means of carrying all the air to the user, this sort of contamination can be significant. The last thing the FM wants is the aggravation of dealing with complaints of smells, dry and itchy eyes, and irritation of upper and lower respiratory tract, caused by dirt in the new ductwork.”

Since 2011 British Standard EN15780 'Ventilation for Buildings – Ductwork – Cleanliness of Ventilation Systems' has been in place to lay down measurable levels of cleanliness for various classes of building type, whereby a high quality office needs to meet a higher standard than a warehouse, for example, says Medhurst.

“If the construction team supplier and buyer cannot agree on whether a duct system is sufficiently clean, there are highly accurate, laboratory-based measurements that can be carried out to assure whether the correct standards have been met. This is similar to cleanliness handover documentation that you might expect to see for water systems.”

If documentation on system cleanliness is missing from the handover documents, then the FM may well need to inspect for themselves. “Over the past 10-15 years the industry has got much better at providing access panels that are sufficient to allow at least inspection of the duct interiors,” he explains. “The usual advice is that ‘if you drag you finger across the duct surface and it leaves a mark, then it probably needs cleaning’. That should be sufficient to flag up initial concerns and to establish whether specific testing should be carried out by a specialist surveyor who knows their way around HVAC systems and their hygiene.”

You may be pleased as an FM to walk into a brand new building, but that doesn’t always mean everything is working as it should, says John Sands, principal consultant of BSRIA, the Building Services Research and Information Association. So how do you ensure the design of the services systems translate into installations which can be operated successfully?

“In construction projects, no one sets out to build a poorly preforming building. However, what is delivered by the supply chain at Practical Completion may be problematic to operate in practice,” says Sands. “This outcome may be owing to various reasons, ranging from obvious issues such as poor site installation quality to less tangible matters such as unclear or misunderstood scoping or briefing – in simple terms both parties had a different idea of what was required.”

One thing which is clear is that the chances of achieving a successful project outcome are greatly increased by considering the operational aspects as early as possible, Sands explains. “After all, the construction project will result in an asset for use by the business commissioning it, and how that asset will be used by the business should form a key part of the briefing process.”

As well as including information in the design brief on how the building or facility will be used, the organisation’s asset operations strategy should also be detailed. “This will include how the facility will be managed and maintained – by an in-house resource or through a service provider, for example, or a need to use particular system approaches or suppliers to complement the existing asset portfolio.

“These aspects will then be considered as part of the overall design philosophy and approach adopted by the delivery team. Similarly, important operational elements such as naming strategies for assets, spaces and doors would also be useful to know at the briefing stage and then adopted throughout the process, avoiding the need to rename these later.

“A methodology such as soft landings, originally devised by Mark Way and developed further by the Usable Buildings Trust (UBT) and BSRIA, provides a framework in which to set clear objectives and to monitor them initially throughout the procurement and construction phases,” says Sands.

“Then, rather than ending involvement after construction, the supply chain are kept engaged throughout the initial operating period of up to three years post Practical Completion, with the same key objectives being compared to actual performance via post occupancy evaluation studies, also as part of the Soft Landings approach.”

As part of its BIM Level 2 strategy, government has developed its own version of soft landings – called GSL, or government soft landings – which aims to set clear metrics by which to judge the performance of the project. “Any such metrics should focus on the traditional measures for construction projects such as capital cost and programme but also at the operational outcomes. Does the asset deliver what was required? Without this result the whole project could have been an expensive mistake.”

Make no mistake, the FM has a key part to play in delivering successful buildings, Sands points out.  “The operability and maintainability of a building or asset are just as important as their heating or ventilation systems, and so should be considered as central factors, taken into account at design stage and revisited throughout the project to ensure they’re still being met.”   

Peter Dyment, Camfil’s air quality and building energy consultant, says, generally, ventilation systems in buildings used to be much less complicated in terms of what was expected. The basic purpose of the system was to ensure the air in the serviced parts of the building was changed with sufficient frequency to stop build-up of unhealthy levels of carbon dioxide and indoor sourced pollutants and odours.

However, today the demands from building occupants are higher. The supply air must be cleaned and the air delivered at the correct temperature and humidity. This has to be achieved as well as the low energy requirements of the Specific Fan Power SFG.

“There should be no tension between compliance to design a system to meet the latest demands, but the designer must specify correctly to ensure the system isn't vulnerable to cost engineering at the installation stage of a project,” says Dyment. “If this happens, then frequently the FM can be left with an HVAC system that can be difficult to maintain and control and expensive to operate.”

As an example, says Dyment, in large city centre buildings the HVAC system needs to clean the supply air which is often polluted by traffic emissions. “These emissions are toxic - fine combustion particles PM2.5 and nitrogen dioxide gas. Both are hazardous to health and Group 1 carcinogens as labelled by the World Health Organisation. To deliver clean indoor air quality the European standard EN13779:2007 advises minimum F7 class filters be used and recommended F9 for the best clean indoor air.

“These filter classes are given by the European standard EN779:2012. In highly polluted areas EN13779:2007 also advises use of gas phase filtration to remove nitrogen dioxide. Eurovent, the manufacturers association, recently published a revised energy rating system for air filters that enables selection of A+ rated filters have extremely low operating pressure drops which result in low energy use in the fan motor of the air handling unit. “

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