ENDOSCOPE DECONTAMINATION UNITS
3) The pressure relief dampers and stabilisers are set to achieve specified room differential pressures and locked. No adjustment should be carried out unless with the correct authorisation, supported by a validation procedure.
Environmental systems to manage process chemicals In addition, the hazards – which may present in both clean and dirty environments – associated with the chemicals used in decontamination facilities require attention. There will be a risk to staff associated with the use, handling, safe storage, and disposal of chemicals, detergents, and disinfectants, which will include components of peracetic acid, chlorine dioxide, hydrogen peroxide, and enzymatic detergents, some of which have occupational exposure limits.14
An EWD will always
leave some residual chemical in the bottom of the detergent and disinfectant containers when empty, which can be an exposure risk to staff when changing the containers. The COSHH aspects of the exposure risk to the chemicals and any fumes should be addressed.6 In terms of air-handling, depending upon the type of EWD, there may also need to be a dedicated machine extract to the outside from the EWD, which may dictate where this equipment is located, and the discharge type and location of the extracted air.15
Note that the entire
system may be classed as a Local Exhaust Ventilation (LEV) system under the COSHH regulations, and subject to a statutory annual inspection by a P601-certificated competent person.16 Alternatively, some EWD manufacturers have internal systems which incorporate type-tested filtration to absorb internal chemical vapours that may present a hazard. Where these systems are in place, it is essential that filtration is monitored
A balanced stabiliser positioned within a segregated facility.
and changed at the frequencies, and using methodologies, specified by the manufacturer.
Minimising the risk of operator exposure EWDs are designed to minimise the risk of operator exposure; however, they are not hermetically sealed, and the efficacy of such seals is often down to maintenance, machine handling, and operator usage. There are instances where the leakage risks are elevated, such as when the chemical bottles are changed, or if there is a spill or leak from a defective component or internal/external pipe (including supply and drain).
When changing bottles, the expected
exposure to peracetic acid is lower than during a spill scenario. Most machines use five-litre bottles of chemical, of between
Example layout – single Endoscopy Decontamination Room KEY
Differential pressure guage
EWD Endoscope
washer-disinfector Exposure indicator
Extraction boost activation button Low-level extract PA sensor
Room pressure Pressure-regulating
damper
Dirty returns and staff
Note:
1. Low-level extracts (for removal of PA) to provide a minimum of 10 ACH to comply with HTM 03-01, with capacity to provide 15 ACH boosted extract for emergency spillage situations. ACH calculations to be based on the total floor area of the department. 2. Position of low-level extracts subject to room design.
Figure 1: An example of ventilation regimes within a single Endoscopy Decontamination Room.
34 Health Estate Journal June 2022
Alternative staff and dispatch exit
Direction of air movement
“Draining board” level
PA sensor Storage
Extract boost activation button
Supply
Storage cabinet
Supply
“Draining board” level
EWD EWD
Single room endoscope decontamination facilities In a single room decontamination facility, the wash sink, EWD, and clean endoscope storage, will be in the same room. Supply air should be on the clean endoscope storage side, with extract at low level (draining board height), behind the manual cleaning sink on the opposite side of the room. The EWD should be on the wall between clean and dirty zones, and may need to incorporate a dedicated extract. The room should be maintained at a lower pressure than the surrounding areas, and the clean endoscopes stored in a positive pressure ventilated cabinet with filtered air to preserve their cleanliness.18
BS EN 16442
2-15% concentration, and the time to change is short – typically the process simply requires loosening a lid and lifting a probe/intake assembly out of the old bottle, placing it into a new one, and screwing on. Certain EWDs have insertion needles to allow ergonomic, ‘user-friendly’ handling, but there can be unforeseen leaks due to operator error in loading the containers. Peracetic acid releases vapour, but any vapour coming from the bottle neck during the short period of a bottle change is usually minimal. The exposure during a spill is likely to be much higher, due to the volume spilled, and the surface area covered – more vapour is present.
‘Engineering’ methods of control ‘Engineering’ methods of control are essential to controlling exposure (i.e., air change rates /low level extraction/ monitors/alarms etc.). Part of the Joint Advisory Group (JAG) accreditation/ certification is an audit, which includes a section that specifically mentions peracetic acid exposure and monitoring.17
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