WATER SYSTEM SAFETY


Consequently, a temporary pathway is created for system-temperature hot water to flow down the cold pipework, into the thermostatic shower (tap or TMV) via its cold port, pass through to the outlet, and then drain away. Under these temporary conditions, the thermostatic valve reacts appropriately, with the slide valve moving to tightly close the hot port in response to expansion of the thermostatic element, while simultaneously fully opening the cold inlet port, thus passing hot water to the outlet. The cross-section schematic of the ILTDU shows the flow paths that hot and cold water follow when in Passive and then Disinfecting modes. To minimise the volume of hot water


discharged during the disinfection process, the flow rate can be throttled back at the flow control until the full shower spray pattern is just achieved (NB. the entirety of a tap/shower outlet fitting must be bathed in the hot water). Using a good quality, calibrated, digital thermometer, check the temperature of the water discharging at the outlet. Start the timer only once a minimum of 60 °C is recorded. Horne recommends a minimum thermal disinfection time of 10 minutes at 60 °C. If higher disinfection temperatures can be achieved, then the duration may be reduced slightly. Refer to the PA Thermal inactivation curve, from Spinks et al, to determine an appropriate and effective duration.


‘Golden-coloured’ water and PA reset to zero


As James had anticipated with cautious optimism, the water samples following the trial thermal disinfection yielded clear results for the first time in many months. What did take him by surprise, however, was the release of a slug of ‘golden- coloured water’ during the 10-minute hot flush. He interpreted this as the resident


‘‘


The excessive expenses associated with chemical treatments, combined with extended periods of downtime and frequent replacements of hardware (entire shower or wash-station replacements as a last resort measure), painted a grim picture of inefficiency and unsustainability


biofilm being ‘cooked’ off the internal pipe walls. Subsequent water sample results, as per the existing protocol, derived from HTM 04-01, taken at three days, two weeks, and six weeks following thermal disinfection, also returned PA negative, and allowed this ‘condemned’ shower to be restored to operational service.


Revising the HTM 04-01 Standard Operating Procedure Thoroughly persuaded by these findings, James commenced the overhaul of the Trust’s HTM 04-01 Standard Operating Procedure, recommending thermal disinfection as the primary remedial measure. Taking it a step further, however, his updated SOP also promoted increased collaboration among pertinent stakeholders in IPC, Health & Safety, Clinical teams, and hard and soft FM providers, thus fostering shared responsibility for sustaining a hygienic water system. The revised SOP, implemented across all three hospitals within the Trust, marked the dawn of a new era in proactive water hygiene management. Extrapolating the cost and time


savings achievable by implementing local thermal disinfection as standard, James calculated the following transformative improvements: outlet ‘downtime’ would plummet from more than six months to a matter of days; chemical usage could


Pseudomonas aeruginosa


100 1000


10


0.0000001 0.000001 0.00001 0.0001 0.001 0.01 0.1 1


2.2 3.3 4.4 5.5 6.6 7.7 8.8 9.9 11.0


0.0 1.1


0 200 400 600 800 Time (secs) An annotated Pseudomonas aeruginosa thermal inactivation curve. April 2024 Health Estate Journal 51 1000 1200 1400 1600 5 mins 10 mins James Donagain 55 °C 60 °C 65 °C 6 log reduction


James Donagain CMIOSH is the head of Healthcare Compliance at Skanska UK. He has acted as both AE (Water) and a consultant, to a number of prestigious NHS Trusts across the UK. He has a passion for driving collaboration, sustainability, and patient safety and risk management. He provides expertise on HTM compliance, engineering, risk management, and waterborne pathogens, and has recently provided his expertise at an inquest on an emerging waterborne pathogen.


become negligible (92% drop); FM time per outlet down 70%; hardware expenses (including POU filters) down 75%, while costs related to water sample collection and analysis could be reduced by 60% (or more if quarterly PPM thermal disinfection is also implemented). In essence, installing an ILTDU to facilitate regular thermal disinfection could result in savings of approximately £1000 per outlet. Of course, James’s perspective


transcends financial considerations. The broader advantages of thermal disinfection are numerous, including diminished environmental footprint, enhanced patient safety, simplified maintenance procedures, and strengthened cooperation among healthcare partners. James has demonstrated how


embracing sustainable innovations such as the ILTDU can allow healthcare establishments to not only better protect public health, but also advocate for environmental conservation worldwide.


Survivors (%)


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