Bury St Edmunds, Suffolk United Kingdom (PressExposure) March 05, 2011 -- Aside from the usual domestic water services, ACOP L8 (Approved Code of Practice for Legionnaire's Disease) also deals with 'other risk systems'. These are effectively any water system or processes using water that meet the 'chain of events'. Therefore with reference to a dental practice, L8 applies not only to the usual taps, toilets etc but also to Dental Unit Water Lines (DUWL) about which there is a raft of information.
In light of this, a risk assessment should be undertaken for the entire practice water system, this is usually completed by an external from an LCA (Legionella Control Association) registered company. Specific to the DUWL, it is likely that the following recommendations will be made;
1. Make up supply should ideally be distilled or RO water. If self-contained bottled water is used, this should be separated from the mains by a Type-A air gap.
2. Lines should be flushed for 20-30 seconds between patients, 2 minutes at the beginning and end of each day and following any significant period of infrequent use.
3. If not in use, the system should be totally drained and re-commissioned prior to use
4. Periodic disinfection using sodium hypochlorite, or similar chemical, should be undertaken (frequency is usually as determined by risk assessment and will take into account quality and source of water). It is important to ensure that the system is thoroughly flushed post disinfection prior to clinical use.
5. In general it is recommended that the production of a fine mist or aerosol is minimized as much as possible
It has been suggested that Legionella bacteria in DUWLs may contribute to respiratory illness amongst dental teams and patients, though much of this date is derived from a hospital setting. It is likely that the majority of incidences are linked to larger, more complex water systems where other conditions, such as lack of thermal control or cross contamination are a problem.
In all cases, a risk assessment is the first port of call to establish risk levels and ongoing management requirements.
For more information visit http://www.nemco-utilities.co.uk or call the office on 01284 724503.
More information is available in the following publications:
HTM 01-05 - 'Decontamination in primary care dental practices'
HTM 04-01 - 'The Control of Legionella, hygiene, "safe" hot water, cold water and drinking water'