No place for dirty ducting

Published: 30-Sep-2010

Effective ventilation is key for controlled, contamination-free environments. Richard Norman, md of Indepth Hygiene Services, talks about the importance of cleaning HVAC systems

Effective ventilation is key for controlled, contamination-free environments. Richard Norman, md of Indepth Hygiene Services, a specialist in ventilation systems cleaning, talks about the importance of cleaning HVAC systems

There has never been a time when those responsible for maintaining ventilation systems had more reason to ensure they are kept in a clean and safe condition. On a fundamental level the UK’s National Health Service (NHS) is charged with the responsibility in its own constitution to ensure “patients are treated by 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 unpolluted. Since the essential function of a ventilation (air conditioning) system is to circulate clean, safe air it is indisputable that those with a particular responsibility for maintaining ventilation systems should take all possible steps to do just that.

The most recent changes to Building Regulations covering healthcare premises, particularly hospitals, require buildings to be “better sealed and more airtight.” This often results in warmer, stuffier conditions, and air conditioning is the only solution to redress the situation by providing clean, filtered air.

Unfortunately, in Indepth Hygiene Services’ experience air conditioning systems – with a few exceptions – are not being given the priority attention they warrant by those responsible for maintaining comfortable, safe conditions. The company frequently encounters systems where the ducting retains measurable deposits of dust and debris. Invariably these systems show further evidence that they have not been cleaned: no access panels have been fitted in the ductwork, indicating that probably no duct cleaning has been carried out.

In commom with other contractors, Indepth Hygiene Services carries out ductwork cleaning using mechanical brush units, but for a thorough deep clean panels should be installed, particularly near any bends, to ensure all surfaces are effectively cleaned throughout the system.

Dr Ghasson Shabha, Course Leader at the School of Property Constructions and Planning at Birmingham City University, has published extensively his findings on the link between uncleaned air conditioning systems and the spread of HCAIs. These studies are ongoing, but he maintains that temperature and humidity conditions typically found in ventilation ducting provide excellent opportunities for these bugs to thrive.

As he stated in Facilities Management World: “MRSA is a frequent component of hospital dust which can easily circulate through the air supply and return via ventilation systems, which poses a major risk of cross infection. The situation has been exacerbated due to the need to conserve and optimise energy efficiency, leading to a significant reduction of natural ventilation from fresh air”.

It is known that environmental conditions can affect the survival and presence of micro-organisms. Humidity levels are also known to encourage microbial survival and growth of mould, mildew and bacteria on the internal surfaces of ductwork. This leads to an enhanced production of allergens. The components of dust and debris within air conditioning systems will include human hair and skin debris.

Temperature and humidity levels typically found in air conditioning systems and the presence of materials conducive to the development of micro-organisms underline the importance of having ductwork systems professionally cleaned. Without cleaning there will be a steady build-up of dust and organic compounds to provide ideal conditions for micro-organisms such as MRSA and C difficile to thrive.

Of course, it is not only ductwork cleaning that can play an important role in the fight against HCAIs. Selection and maintenance of air filters is also an important factor. Dust and particulates can pass through poor quality filters. Installation of high efficiency (HEPA) filters plays an essential role in combating the spread of infection.

The need for action was further underlined this year. Following a National Resistance Alert in January concerning the number of NHS patients returning from medical treatment in India carrying NDM-1, further concern has been expressed in The Lancet and the national press about the sharp increase in the incidence of infection from this source.

Leading microbiologist Dr Richard Hastings has also stated: “There is no doubt in my mind that more drastic action has to be taken to combat hospital bugs and this is even more paramount now NDM-1 has entered UK hospitals.”

It is believed that UK healthcare will be increasingly challenged because these organisms are resistant to all but a very few antibiotics. At the same time it has strengthened the importance of ensuring that all potential transmission routes are identified and appropriate action taken. As already explained above, there is plenty of evidence to show that micro-organisms can be transmitted and spread through ventilation ductwork systems.

It is a pity that so little of the extra monies recently made available to the UK NHS for a “deep cleaning” drive were devoted to the cleaning of air conditioning systems. There was certainly evidence of more cleaning of ledges, rails and bedframes, for example, and greater exhortations for more regular handwashing, but there is no obvious evidence of some of this money going to the cleaning of air conditioning systems.

It is my experience that little acknowledgement has been given to the growing evidence of the link between the failure to carry out ventilation ductwork cleaning and the incidence of HCAIs.

There has, however, been an increase in the awareness among estates management of the importance of ensuring system filtration is fully effective. It is indisputable that improved filtration can play an important role in reducing levels of contamination in system ducting and, as a result, a reduction in the prevalence of airborne particulates in the circulated air.

But even where better filters have been introduced to improve the indoor air quality the condition of the ducting system beyond the filters has frequently been ignored, which Dr Shabha has shown can provide breeding conditions for micro-organisms.

Perhaps it is the concern that to access the ducting to carry out a cleaning programme would involve disruption and inconvenience that deters managers from implementing a comprehensive system improvement programme. While I readily acknowledge that special arrangements have to be made for access to ducting that often runs above ward space, it is my experience that disruption can be kept to a minimum by careful planning of the deep cleaning programme, which fully acknowledges the need to put continuing patient care as an absolute priority.

The Department of Health’s guidelines embodied in Health Technical Memorandum HTM 03-01 provide clear advice and guidance on the legal aspects of the need to maintain ventilation systems so that they do not present a potential threat to the health and wellbeing of all hospital occupants – staff, patients and visitors. These guidelines point out the dangers of increased health risks should there be a failure to maintain ventilation systems which, it recommends, should be inspected at least annually. Where ventilation systems are serving facilities requiring the highest standards of air cleanliness it is recommended that they are visually inspected quarterly and subjected to performance analysis.

There is a further reason why ventilation systems should be viewed in their entirety: the government’s commitment to reduce energy use throughout the UK embodied in the CRC (Carbon Reduction Commitment) Energy Efficiency Scheme. It has been well documented that HVAC can account for 70% of an organisation’s energy costs.

A claim made by the Carbon Trust, which was set up to provide specialist support to business and the public sector to help cut carbon emissions and save energy, is that inefficient and dirty ventilation systems can increase energy consumption by up to 60%. It is the condition of the ducting, coils and filters that puts the main resistance on the fan, and the fan is a major user of energy. So the need to cut energy costs lends further weight to why these systems should be reviewed in their entirety rather than just piecemeal.

More than ever before it is clearly incumbent on those charged with providing safe, hygienic conditions in hospitals to include ventilation ductwork cleaning not only as an essential part of their attack on the incidence of HCAIs but also as a contribution to the requirement to save energy costs.

Indepth Hygiene Services can provide a free comprehensive review of ventilation systems that includes a written and photographic report giving a clear appraisal of the presence of any healthcare risk.

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