Clean ventilation – the science of compliance

Building and facilities managers are responsible for ensuring compliance with the Associated Code of Practice from the Health and Safety Commission. This states that all mechanical ventilation systems should be regularly and properly cleaned, tested and maintained to ensure that they are kept clean and free from anything which may contaminate the air. Gary Nicholls, Managing Director of Swiftclean Environmental, highlights the risks of non-compliance and what cleaning procedures and protocols need to be put in place to ensure that regulations are met.

There are a few incontrovertible facts. First, poor maintenance of mechanical ventilation systems will lead to problems with airborne particulates, bacteria, uncomfortable humidity levels (too high or too low) and inefficient energy consumption. Second, building and facilities managers whose ducts and ventilation systems fail to comply with the regulations of the Health and Safety Commission, which state that ventilations systems should be cleaned ‘as appropriate’ and subject to ‘a suitable’ system of maintenance, face a very real threat of prosecution.

Managers must comply with current workplace regulations and the Associated Code of Practice from the Health and Safety Commission, which states that all mechanical ventilation systems should be regularly and properly cleaned, tested and maintained to ensure that they are kept clean and free from anything which may contaminate the internal environment.

Dirty air ducts can affect buildings and businesses in many ways. They can cause a drop in staff productivity and morale, while also ruining interior decor. They can also result in high levels of expenditure in the form of replacing any prematurely deteriorated air conditioning systems. Things like the accumulation of deposits in bathroom and toilet extract ducting, including paper dust from toilet paper, talcum powder, human skin flakes and fibres/lint from towels and freshly washed clothing, can all combine to create an unhealthy and potentially flammable cocktail. Yet, such deposits will not build up overnight. They will have formed over a number of years causing the relatively small air passages of the extraction systems to become ever more restricted until in severe cases they will completely block.

Where to start

Building owners are often unsure where to begin, as the problems can be so complex. We always recommend starting with a survey. This can involve putting CCTV cameras down risers and through ductwork to see what is going on. In some cases we may use existing access panels to enable physical examination and to take photographic record of the condition.

Then, having established what the problem is, we present the condition report discuss and agree the remedial action plan and then set about cleaning or replacing ventilation fans/AHU’s, cleaning the ductwork, cleaning or fitting new grilles etc. We can also make sure the system is better balanced so airflow is more evenly spread throughout the building. This reduces the chance of condensation building up, particularly in washroom areas, leading to smells and toxic mould along with many of the respiratory health problems associated with poor air quality.

However, getting proper access to carry out cleaning can be a real headache. In most of the installed systems we survey there aren’t anything like enough access doors in place. It doesn’t take a genius to work out that if access for maintenance was not addressed when the system was designed; it has probably never been cleaned properly.

In most cases, the solution is for the hygiene contractor to put the access doors in himself to get at any blockages or dirty sections of ductwork.

Fire risk

There is also a secondary threat – fire. Neglected ducts, particularly in kitchens, rapidly become contaminated with a steady build-up of bacteria harbouring deposits; furthermore, inadequate cleaning especially in grease extracts means there is more risk of fire spreading throughout a building via the ventilation system. Again, this is very dangerous for both health and legislative reasons – if adequate access doors and/or cleaning regimes are not in place, insurance companies refuse to pay out in the event of a fire. In order to prevent such complications, access doors should be installed at strategic points along the system in order for regular inspection and cleaning to be carried out.

Key components of ventilation supply systems that are particularly prone to rapid build-up of harmful airborne deposits include air intake duct/plenums; air handling units/plant; heat transfer coils – particularly wet coils; humidifiers and surrounds; fan coil units; fire dampers; internal insulation; floor/ceiling plenums; induction units; and filters. Moreover, by utilising a specialist building hygiene services provider, you can ensure that regulations are met and that prosecution is avoided. By using various extraction devices, as well as specialised brushes and air jets and skilled duct hygiene staff, contaminating substances can be removed.

Maintenance regime

A regular and on-going maintenance regime should be factored into the life cycle of the system as soon as commissioning has taken place. Any lack of regular inspection and servicing will only lead to the deterioration of the system over time. It makes economic as well as technical sense to maintain standards of hygiene once a system has been newly refurbished or commissioned. The relatively new British Standard BS15780 Ventilation for buildings – Ductwork – Cleanliness of ventilation systems, published in November 2011, requires periodic inspection and monitoring of ventilation system hygiene. It also sets out pre-handover hygiene levels that a building user should expect when taking delivery of a newly installed system.

Ventilation system testing and monitoring can be tailored to meet the particular needs of individual systems, in order to establish whether or not it would be appropriate to clean a ventilation system while it is in use, as well as assist with future budgeting for ductwork cleaning plans.

Indeed, we have been heavily involved in working with the Building & Engineering Services Association (formerly HVCA) on producing a Guide to Good Practice on ductwork cleaning, called TR/19 ‘Internal Cleanliness of Ventilation Systems’. This gives comprehensive information about how ventilation systems should be cleaned and how to set up a planned hygiene maintenance programme. It should be used as the basis for any remedial and on-going maintenance programme to ensure ductwork provides an acceptable level of ventilation and removes both health and fire risks. This guide, now in its third edition, recommends three methods in which to establish an objective procedure for the measurement of accumulated deposits within the ductwork.

Best practice

TR/19 not only outlines the best practice for installing access panels into new systems and maintaining them, it also allows specifiers to deal with all aspects of the duct hygiene in one publication. TR/19 is also ideal for use by specifiers and building legislators to ensure that ventilation systems are properly maintained as adherence to the standards in TR/19 will provide detailed, recognised proof that the ventilation system in a building is safe and well maintained, which is vital for securing insurance policies. It is currently being updated to incorporate additional ventilation system hygiene monitoring guidance to keep it in line with the new British Standard mentioned earlier.

It is important that ductwork and ventilation systems are monitored and cleaned to TR/19 industry standards. Whether an individual business or part of a nationwide chain, whoever is in charge of the premises should ensure that all health and safety regulations are met and utilise a building hygiene services company accordingly. That way, fire risk a
nd health risks can be avoided, system efficiency can be optimised and your insurance company will be happy to cover clean, efficient and safe facilities.