WATER HYGIENE AND SAFETY – SPECIAL REPORT


Perversely, the major barriers to safe water in healthcare are not the microbes, but human beings. Inadequate management, lack of training, and poor communication, are all contributory factors in outbreaks of Legionnaires’ disease identified by the Health and Safety Executive.3


These outbreaks continue to occur despite the existence of national and international guidance.3,4,7 While knowledge of Legionella has stemmed from 1976, acknowledgement of the importance of the periphery of the water system has only really been established in the last two decades, for example with the neonatal outbreak and associated deaths in Belfast and other outbreaks.8–10


High profile outbreaks The growth and colonisation of waterborne pathogens continues to affect healthcare buildings. High profile outbreaks include Legionella infections within a week of the opening of the flagship Pompidou hospital in Paris in 2000, to the latest troubles with the newly opened children’s hospital in Glasgow.5,6


Since then, the increase in


highly antibiotic-resistant organisms (notably Carbapenemase Producing Enterobacteriaceae (CPE)), is highlighting the role of drains in waterborne transmission events.11,12


Engineering controls


While a gross oversimplification, it may be useful to consider control of Legionella to be mainly based around engineering controls, in contrast to most other waterborne pathogens, e.g. P. aeruginosa, which are primarily detected in the last two metres of the pipework (the periphery of the system), or CPE in the drains, demonstrating that the interaction with a wide range of staff is a key component as to whether waterborne transmission events occur.13,14


In the UK, drinking water supplied to a building must be wholesome at the time


Sources of contamination l Hot water and piping l Cold water and piping l Isolation and solenoid valves l Flexible hoses and sieves


l Thermostatic mixer valves (TMV) or thermostatic mixer taps (TMT)


l Terminal outlet fitting l Surface of the basin l Hand touch points around the HWS l Drain surfaces and course sieves l Drain traps


Cold water


Cold water tank


Water softener


Water treatment Incoming mains


Expansion vessel


Calorifier


Re-circulating hot water loop


Figure 2: Overview of the microbial risks associated with the hot and cold water system.


of supply, i.e. must be fit to use for drinking, cooking, food preparation, or washing, without any potential danger to human health.15


‘Wholesome’ also assumes


that the individual is in good health. However, as already stated, water has a resident flora, present in low numbers, but capable of causing disease in the right setting, termed by ‘opportunistic premise plumbing pathogens’.16


Contact lens


wearers know to avoid tap water due to the risk of eye infection should they contaminate their contact lens solution and lens, where the bacteria or amoeba can multiply, and cause distressing eye infections.17


contained in the Water Safety Group, which is able to harness different expertise and skillsets to overcome the issues of waterborne infections. This article aims to review some aspects of the water system in a building to: n identify common mistakes and errors that occur.


n demonstrate the hazard analysis and critical control points for microbial contamination.


However, tap manufacturers and the makers of cardiac heater cooler units considered it was safe to test components during manufacture with tap water, which introduced contamination, which, in the latter case, led to a global outbreaks.18,19


A broad risk management approach The presence of waterborne infections can only be controlled by taking a broad risk management approach to water safety. Such approaches can only be adopted and implemented by multidisciplinary teams, such as those


n address the risks to vulnerable patients. n stress the importance and value of a competent and trained Water Safety Group.


In summary, this article will give a brief overview in respect to water safety, in terms of microbes, system design, and human factors.


Mains water supply


According to the Water Act 1991, drinking water supplied to a building must be wholesome at the time of supply. ‘Wholesome’ water must be ‘fit to use for drinking, cooking, food preparation, or washing’ without any potential danger to human health by meeting the


Routes of transmission l Hand contact points


l Transmission from outlet fitting to hands on contact


l Transmission from water to hands on contact


l Splashing of droplets and aerosols from basin


l Inappropriate positioning of faucet and drain, leading to splashing


l Inappropriate use of handwash station


Figure 3: Overview of the microbial risks associated with peripheral components such as those used for a handwash station. 16 Health Estate Journal December 2020 Hot water


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