Clean Ventilation Systems – Never More Essential

December 3, 2009

The Workplace (Health, Safety and Welfare) Regulations 1992 provide an overall framework of legislation for those responsible for the management of buildings and premises to ensure that every enclosed workplace is ventilated by a sufficient quantity of fresh or purified air. Where this ventilation is provided by mechanical means the Regulations require those mechanised ventilation systems to be maintained (including under Regulation 5 cleaned “as appropriate”) in efficient working order. Failure to carry out these duties is a breach of the Regulations. Under the complementary Management of Health and Safety at Work Regulations there is a duty on every employer to conduct a risk assessment and to manage that risk appropriately.

More specific legislation in the form of The Regulatory Reform (Fire Safety) Order 2005 – now generally referred to as the Fire Safety Order – makes very clear legally enforceable demands on management to identify all possible causes for fire. In those buildings where there are catering or food production facilities, the extract ventilation system, which takes extracted air from the facility to extract to atmosphere, must be included in the building’s fire risk assessments. Action is then required to be taken to eliminate this potential fire hazard to the safety of occupants by having the system thoroughly cleaned to remove the fire hazard.

In one major area of direct Government responsibility – the NHS – there is a written commitment within its own constitution to ensure “patients are treated in an organisation that provides its services in a clean and safe environment”. The very air that patients, staff and visitors breathe must be safe and since the essential functions of ventilation systems is to circulate clean safe air it is indisputable that care should be taken to ensure that they do by being kept clean of potentially health harmful contaminants which inevitably accumulate in the ducting.

There is considerable evidence to show that uncleaned systems can assist the spread of HCAI (Healthcare Associated Infections) because temperature and humidity conditions typically found in ventilation systems provide excellent opportunities for bugs to thrive and be widely distributed. Dust on internal surfaces of ducting contains a high proportion of organic compounds including hair and skin flakes – nutrients for the growth of micro-organisms such as MRSA and C. difficile. In other words, ventilation system ducting can act both as a support for, and a disseminator of, potentially very harmful bacteria.

Most patients spend up to 90% of their time indoors. They are therefore heavily reliant on the quality of the circulated air within the hospital. At the same time, the need to conserve and optimise energy efficiency has led to a further reduction in natural ventilation from fresh air. Hospitals are becoming more air tight and warmer to comply with Building Regulations. As a result, the efficiency of the air conditioning system is paramount in ensuring maintenance of an environment conducive to patient wellbeing.

Of course, improved filtration materials play an important role in reducing the levels of contamination in general extract and supply systems and, as a consequence, a reduction in the prevalence of airborne particulates in the circulated air. This applies not only to systems in Hospitals but to properties wherever there are air filtration systems. However, even where improved filtration methods and materials have been installed in existing systems, the ductwork has rarely been cleaned as part of the upgrading programme and therefore internal duct surfaces invariably remain contaminated with dust and debris.

It is a quite regular experience for my company’s surveyors to encounter systems where the filters have been upgraded but there to has been no action taken to remove contaminants in the system which will continue to be disseminated into the working environment.

On the evidence of what is occurring in hospitals and the action being taken to improve filtration and to clean ventilation systems to eliminate, or at least reduce, this conduit for the spread of hospital infections such as MRSA, one can reasonably ask why we find so few ventilation systems being cleaned in the workplace? If ventilation systems can assist the spread of potentially fatal infections it is not unreasonable to suggest the obvious way to reduce the spread of more commonplace infections such as the common cold in general workplaces is to have the system inspected and cleaned. Unfortunately the occasions when this is carried out are very much in the minority. Maybe it is because the Regulations have no enforcement teeth, unlike The Fire Safety Order, but it is an area where buildings and facilities managers should be focussing more attention only if by cleaning ventilation systems they can reduce the amount of winter absenteeism. For a nominal fee my company will carry out a full risk assessment of these systems so that management can clearly assess the level of system contamination and to what extent it needs cleaning.

It is therefore clearly incumbent on those charged with providing safe, hygienic conditions in premises to include the cleaning of general ventilation systems as an essential part of fulfilling their responsibility to provide clean safe working conditions.

One ventilation installation which is often given less attention than its high fire risk potential warrants is the grease extract ventilation system so often linked to catering facilities.

At a recent seminar a spokesman for the London Fire Brigade drew specific attention to the fire dangers of these systems. As he stated “Uncleaned grease extract ventilation systems present probably the greatest potential fire risk in buildings with catering facilities”. He was referring to the typical grease extract system which takes grease laden air from the kitchen via the canopy to exhaust to atmosphere. Grease particles accumulate on the internal surfaces of the extract ducting requiring only a spark or flash to ignite.

There is therefore an indisputable need to have put in place a cleaning regime for grease extract systems which will ensure that potentially flammable grease deposits are fully removed.

The Fire Safety Order requires the appointment of a “responsible person” to ensure that comprehensive fire risk assessments are produced and all necessary measures taken to safeguard the lives of the building’s occupants. Unfortunately it is my experience that even where a “responsible person” has been appointed – and it is often the Facilities or Buildings Manager who takes on this role – and the grease extract system has been included in the risk assessments, a measure of dangerous complacency is often allowed to take over.

Too often having commissioned the cleaning, little effort is made to ensure the system has been thoroughly cleaned and made safe. Instead there is often reliance on a statement, sometimes not even written, from the cleaning contractor that the system has been cleaned. My experience is that all too frequently many systems have, at best, only been partially cleaned. Because to check often means some inconvenience, e.g. removing ceiling panels to reach ducting, the “responsible person” does not know how well it has been cleaned and whether or not it remains a fire risk.

This complacency brings dangers of another kind. Should a fire occur involving the ducting it will be no defence to claim “I thought it had been cleaned”. To blame the contractor might seem like a ‘get out of jail free’ card but has little validity in the context of the way Insurers, and in disputed cases the Courts, will interpret whether or not all reasonable care was taken to comply with the Legislation. It is the “responsible person’s” responsibility to ensure that he is getting what he has commissioned – the elimination of fire hazardous conditions.

Grease extract ducting cannot be cleaned unless access to the ducting has been effected to allow thorough removal of grease deposits. And don’t believe any assurance from a contractor that he will not need to install access panels as he will be using motorised or other mechanical devices to provide cleaning. These might be appropriate for cleaning air systems but grease deposits in ducting can only be fully eliminated by old fashioned elbow grease aided by cleaning chemicals, brushes, scrapers and cloths.

Finally, having checked that the system has been well cleaned demand a work completion certificate which states clearly what has been cleaned and identifies any areas which cannot be physically accessed for cleaning. You can then be confident you have complied with the Legislation and Insurance requirements.

In order to provide the Facilities Manager with a reliable standard by which to assess the effectiveness of a ventilation cleaning programme, the Heating and Ventilating Contractors’ Association have produced a “Guide to Good Practice” Internal Cleanliness of Ventilation Systems TR19 (copies can be obtained from the HVCA Tel: 020 7313 4900, Email: ). This gives guidance for the cleaning and maintenance of new build, upgraded and existing ventilation systems. It is accepted as the industry standard to which ventilation systems should be cleaned. By ensuring that only contractors are commissioned who undertake cleaning in accordance with this standard can responsible managers be confident their ventilation systems will fully perform their essential function of providing safe and hygienic conditions in the workplace.

For further information on ventilation system cleaning call Indepth Hygiene Services no 020 8661 7888 or email