Airborne infections transmitted via poorly maintained ventilation and air conditioning systems
Bacterial spores in ductwork can often be behind outbreaks of MRSA and other serious infections in hospitals
Healthcare facilities are failing to contain airborne infections transmitted via poorly maintained ventilation and air conditioning systems, according to a leading indoor air quality specialist. Dr Ghasson Shabha, senior lecturer at Birmingham School of the Built Environment, told a webinar hosted by the CIBSE ASHRAE Group that the threat posed by dirty ductwork is often overlooked by healthcare professionals, who fail to put planned maintenance strategies in place because the source of the infections is ‘out of sight, out of mind’.
He also criticised the fact that only around 5% of air conditioning systems have been inspected, despite this now being a mandatory requirement under European regulations. Bacterial spores in ductwork can often be behind outbreaks of MRSA and other serious infections in hospitals and clinics, he told his global audience, which included members of the Building & Engineering Services Association (B&ES) and the Institute of Healthcare Engineering and Estate Management (IHEEM).
‘The healthcare environment is a reservoir for potentially infective agents, which can spread unpredictably in ventilation and air conditioning systems, making the risk difficult to control and manage,’ said Shabha. ‘People seeking timely information about the patterns of cross-infection are in urgent need of better data.’
He said the ventilation hygiene industry was eager to address this potentially fatal problem, but facilities managers (FMs) did not have a system of information exchange that would highlight the risks, or the extent of the problem across the whole healthcare sector. He advocated a system – being piloted by Leicester and Rutland NHS Trusts – that uses wireless sensors embedded into mechanical ventilation, air conditioning and plumbing systems to assess the risk of airborne infection. This provides real-time data to a remote web server accessible by all healthcare FMs.
Shabha added that 3D building information modelling software could also help ventilation specialists identify ‘infection hotspots’. ‘The data can then be fed into a predictive infection criticality model (PICM) to assess the intensity, and frequency of colonisation and hotspots. This allows FMs to manage the risks more proactively.’
The diagram below shows that the recently issued British and European technical standard BSEN15780:20011 gives inspection time intervals for hospital plant engineers to check their Heating Ventilating and Air Conditioning plant. These inspections requirements cover the air filters, air handling units, terminal units, duct systems and humidification plant where fitted.
This standard clearly shows that there is a need to regularly inspect these components in HVAC systems and keep them clean to maintain high plant operating efficiency and save energy. This is certainly the case with low energy air filters where regular monitoring of operating pressure drops can ensure filters are changed at the best time to minimise energy use and maintenance costs.
There is also a firm link drawn here in the CIBSE journal article between spread of MRSA by airborne means from ventilation systems in hospitals and presumably all other similar buildings as well. The figure of only 5% of HVAC systems in hospitals being properly inspected is also a cause for concern. One would hope that vulnerable patients in hospitals would be breathing air that has been properly filtered to remove any airborne MRSA bacteria.
Another need is to prevent the build-up of deposits of airborne dust in ducts, which can provide an opportunity for MRSA to form breeding colonies. There are, of course, a number of other types of bacteria that can be transported in a similar way and also pose serious health threats to patients and staff in hospitals.
Camfil can ensure by making an inspection and recommendation that low energy air filters are supplied and fitted in the hospital HVAC systems. These filters will be effective in preventing exposure to the threat posed by airborne dust and bacteria. Clean indoor air quality is assured in the supply and recirculated air in the hospital building and risk to patient health is reduced.
Occasionally the AHU filter mountings may need re-engineering due to heavy use or corrosion to restore system integrity and stop bypass of unfiltered air. This is a service that can be offered by Camfil as a solution to restore system efficiency. Part of a package can include any coil or duct cleaning that could be required.
If you contact our office by phone or email we will send our engineer to make a no cost survey of your AHU filter systems to establish for each individual system how we can use low energy air filters along with additional measures to ensure the required level of clean air quality is delivered using minimum energy.
Additionally if you would like a training session for your hospital engineers on using low energy air filters to maximise clean indoor air quality, energy reductions and cost savings contact Anne Dempsey on +44 121 7078461.