General Ventilation System Cleaning

General Ventilation System Cleaning

Why Clean Air Ventilation System?

Effective Air Ventilation Cleaning

Everyone working in offices, shops, factories, hospitals, laboratories etc. requires a minimum standard of fresh air to produce a healthy working environment. One way that this can be provided is by effective general ventilation.Employers must understand the benefits of effective general ventilation in the workplace.

Dust and debris found in unclean ductwork, together with temperature and humidity levels, have been linked to the growth and spread of MRSA and other micro-organisms in hospitals. It is similar to how flu and other common cold infections spread through poorly maintained and unclean workplace systems.

General ventilation or ‘dilution’ ventilation is a term used to define the flow of air into and

out of a working area, for example an office space, so that any contaminants are diluted by adding some fresh air. This can be provided by:

  • Natural ventilation which relies on wind pressure and temperature differences to move fresh air through a building and is usually not fully controllable
  • ‘Forced’ or mechanical ventilation which uses mechanical supply and/or extraction to provide fresh air and is controllable
  • To ensure a well-ventilated workplace you should provide general ventilation that removes

stale, contaminated, or hot and humid air so that your employees do not suffer any ill-health effects. These systems must be kept clean and maintained on a regular basis.


In order to ensure that conditions for building occupants are comfortable and safe there is a ‘duty of care’ requirement for owners and managers to ensure that ventilation systems are kept clean. Buildings normally require a clean every 2-3 years depending on usage and location although some may require more frequent cleaning such as:-

  • Heavily used buildings
  • Buildings which generate greater quantities of dust (e.g. factories, clothing stores)
  • Buildings which are exposed to greater quantities of pollution from outside (e.g. in city centres, next to motorways or next to industrial sites)
  • Buildings which need cleaner than average air or where risk to occupants is higher (e.g. computer data centres, hospitals, nursing homes)

The ACOP to regulation 6 of the WHSW Regulations 1992 requires that any mechanical

ventilation systems, including air conditioning systems, which you use to provide fresh air

should be regularly and properly cleaned, tested and maintained to make sure that they

are kept clean and free from anything which may contaminate the air and cause health problems. As a general rule, if you run your finger along the opening of a duct and it collects dust then it probably needs cleaning. Organisations such as the Heating and Ventilating Contractors Association (HVCA) now Known as the B&ES and the Chartered Institution of Building Services Engineers (CIBSE) provide information on testing for likely contaminants in ductwork and on cleaning.


The guiding principle of this document is that a defined, measurable level of cleanliness should be achieved. In cases of doubt regarding procedures, facilities and methods to achieve cleanliness then this principle defines success or failure.

When specifying or agreeing cleanliness criteria on newly installed or existing ducting it is important that all interested parties clearly agree on the cleanliness quality class of each ventilation system as defined by BS EN 15780 (see section 5.14 of this Guide) as each of these classes has a different acceptable levels of dust accumulation.

The Workplace (Health, Safety and Welfare) Regulation 1992 requires that effective provision should be made 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 required those mechanical ventilation systems to be maintained (including cleaned as appropriate) in efficient working order. Failure to carry out these duties is a breach of the Regulations. (Please see Appendix B for further reference.)

The Corporate Manslaughter and Corporate Homicide Act 2007 places a much greater corporate responsibility and business risk on organisations in terms of the consequences of health and safety compliance failure, particularly where inadequately cleaned systems heighten the risk of fire and fire spread.

1.7 General ventilation systems (not affected by kitchen grease) as defined, and referred to in this Guide include, but are not limited to, the following:

  • Ductwork
  • Air handling units
  • Fan coil and induction units
  • Constant air volume units
  • Variable air volume units
  • Control dampers
  • Attenuators
  • Air terminals
  • Ancillary components associated with the air distribution system

24-7 Elite Clean will provide expert guidance and information to ensure you can fill your compliance obligations and cater for your system cleanliness thus catering for the well being of your staff and visitors.