Mould in Air Conditioning Systems
While the toxic “black mold” (Stachybotrys chartarum or Stachybotrys atra) does not appear to be as prevalent in the UK as it is in parts of the US, many air conditioning systems are breeding grounds other very commonly occurring moulds which are also cause for concern. Due to recently publicised out breaks over the past few years, Legionella has been the focus of much attention but other forms of microbial contamination are now attracting the attention of building owners and managers.Mould is present in any warm, moist environment (i.e. heated enclosed rooms, rain forests, garden beds etc). However, under normal circumstances, a healthy human body can easily deal with these exposures and they have no harmful affects. It is only when these contaminants are concentrated and a person is continually exposed (i.e. a building HVAC system) that health problems start to occur and are exacerbated by pre-existing conditions or disorders.
As public concern for better indoor air quality, improved indoor environment quality and improved ventilation hygiene have grown over the past decade, the cleaning of HVAC systems has now become a widely adopted practice. Australian standards and accepted industry maintenance practice outline requirements for HVAC system and component inspection and cleaning, very little criteria for evaluating and assessing different types and levels of contamination are provided. In response to this, the Australian Institute of Refrigeration, Airconditioning and Heating (AIRAH) has released the “AIRAH HVAC Hygiene Best Practice Guidelines”.
The new Guidelines cover:
- The criteria for evaluating the internal cleanliness of the HVAC system components
- How to determine when cleaning is required, according to building use
- Which components should be evaluated, the types of contamination and post fire and flood damage assessments
- Minimum inspection and maintenance frequencies
- Test methods to determinate if a system has achieved required levels of hygiene
- Recommendations for new access openings to facilitate inspection and cleaning.
; "The Contractors Health and Safety Assessment Scheme")
