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Breathe easy

Good air quality in the workplace is essential for the health and wellbeing of staff as well as the efficient running of the business. Steven Booth, associate director at Guardian Water Treatment, explains how it can be achieved

Last year air quality hit the headlines as the World Health Organisation labelled ambient air pollution as the “greatest environmental risk to health”, causing over three million premature deaths worldwide and a range of health problems.

Indoor air quality is a topical issue which needs to be prioritised by buildings old and new. The most common form of ventilation is simply opening a window – but in busy cities where the outdoor air is full of pollution and toxins, this could do more harm than good.

Conversely, modern technology and construction techniques have enabled buildings to be more airtight than ever before in an attempt to reduce energy wastage. But this restricts natural ventilation, potentially compromising air quality unless well maintained mechanical systems are in place. We all need to reduce our carbon emissions, but not at a cost to health.

Poor air quality causes numerous problems. It exacerbates common conditions such as asthma and contributes to sick building syndrome (SBS), causing symptoms ranging from dry or itchy skin, eyes, nose and throat to headaches, lethargy and lack of concentration. Such symptoms may be a short-term irritation for employees, but the financial effects of low staff productivity and increased time off can be significant for the business. If left unaddressed, more serious health risks may develop, including strokes and heart attacks in susceptible individuals.

A 2016 survey by the Building Engineering Services Association (BESA) reported that almost 70 per cent of office workers believe poor air quality in their workplace has a negative effect on their day-to-day output. Given that we spend an average of 212 days at work a year, it’s important to ensure well maintained air handling systems are operating effectively in all places of work – balancing energy efficiency with good quality air flow.

In most cases, improving air quality is not simply a matter of turning up the ventilation rate. For total control and peace of mind a holistic approach is required, encompassing monitoring, cleaning and ongoing maintenance.

Monitoring allows building managers to identify specific problems and address them swiftly and effectively. Important factors to check on a regular basis include temperature and humidity levels, carbon dioxide and carbon monoxide, and airborne dust, fungal spores and bacteria. Remedial action should be taken wherever necessary.

Regular air quality monitoring helps buildings to comply with the Control of Substances Hazardous to Health (COSHH) regulations. Regulation 7(1) requires employers to prevent exposure, and where this is not practicable, ensure that any exposure is adequately controlled. Monitoring helps to identify substances in the air that may pose a risk to staff.

Regular inspection and cleaning of ventilation and ductwork is also important. As the carriers and removers of air, ventilation and ductwork systems should have a minimum level of cleanliness. For example, air handling unit (AHU) grilles should be kept free from dust and grime that could restrict air flow or stop the unit from working altogether. AHUs should also undergo regular maintenance, including cleaning and sanitising of coil sections every six to 12 months, yearly removal of debris from inlet sections, and regular changing of filters.

For more dangerous environments such as commercial kitchens, ductwork cleaning is essential to mitigate fire risk as well as remove contamination from the air. Many insurers now require specialist contractors to undertake the cleaning in accordance with BESA guidelines (B&ES TR/19 – internal cleanliness of ventilation systems), which detail best practice for keeping ventilation ductwork clean.

There are specific guidelines for healthcare premises (HTM 03-01 – specialised ventilation for healthcare premises). These state that all ventilation plant should meet a minimum requirement in terms of Legionella control and safe access for inspection and maintenance. All ventilation plant should be inspected annually, the performance of critical systems (such as those servicing operating theatres) should be verified each year, and plant must be free of material or substances that could support the growth of micro-organisms.

Generally, AHU equipment and maintenance procedures need to be reviewed whenever the premises are subject to a change of use. Additional office space, significant increases in staff or other factors will impose new conditions on AHUs which could leave them struggling to service a building effectively.

Properly planned monitoring, cleaning and maintenance of air ventilation systems is not only beneficial for air quality, it contributes to HVAC efficiency, cuts the risk and cost of breakdown and reduces overheads. Providing ‘good’ air will promote the health and wellbeing of staff, boost productivity and help ensure compliance with health and safety regulations.


  • Fresh air should flow at a minimum eight litres per second, per person
  • Areas with an air flow velocity over 0.25 to 0.3 metres per second should be considered draughty
  • Areas with an air flow velocity of 0.1 metres per second are stagnant
  • For an area of normal temperature, air velocities should be between 0.1 to 0.15 metres per second (0.25 metres during the summer)
  • Rooms housing machinery should have separate extract ventilation
  • Air inlets for the ventilation system should be sited to avoid introducing pollution from outside the building – a particular issue in city centres or areas of high traffic.


Ductwork is designed to allow air to flow freely around a building. However, this also makes it an extremely efficient means of transporting hot smoke and fire from one part of a building to another. A smoke or fire damper is a barrier installed within ductwork that helps to contain the spread of smoke and fire.

This is an important health and safety issue. The Regulatory Reform (Fire Safety) Order 2005 assigns responsibility to the ‘responsible person’ in a building – usually the facilities manager or property owner. This person needs to acquaint themelves with the layout and proper functioning of the damper system.

Dampers are designed to either close via a fusible link when set temperatures are exceeded, or close upon receiving a signal linked to the smoke detection or fire alarm system. They are appropriately rated to resist the passage of smoke and fire, helping to contain the blaze without spreading its effects throughout the building.

Clearly it’s important to ensure that the system is fully functional at all times. But ventilation systems are difficult to access, which means cleaning, inspection and maintenance is easy to overlook – particularly in older buildings. Contractors tasked with the cleaning of ventilation systems are often ignorant of the complexity of the dampers within the ductwork. Yet there is a serious risk to life and property if dampers are not properly cleaned, tested and maintained.

Testing is particularly important where actuated dampers are concerned. The system as a whole must be checked, from smoke sensors to control panels, to ensure that dampers are not only capable of operating but that they’ll operate at the right time.

FMs are well advised to leave ventilation and ductwork maintenance to a FIRAS-accredited specialist who can undertake cleaning, maintenance and testing to the standards the law demands.

Bob Gate, UK business development and marketing manager at Brakel Airvent.

About Sarah OBeirne

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