WATER SYSTEM SAFETY
James sat down to examine the Midland Trust’s data. His fresh eyes revealed a troubling frequency of Pseudomonas aeruginosa contamination incidents, alongside significant financial and operational strains linked to the organisation’s conventional mitigation methods. The heart of the problem was an unsustainable dependence on ineffective consumable chemicals and point-of-use water filters, which not only burdened NHS resources, but also posed considerable environmental concerns. 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.
Opportunity for a full assessment James’s prior involvement at King’s College Hospital now enabled him to acquaint the WSG with the idea of local thermal disinfection of water outlets utilising the readily available hot water supply. While the ILTDU presented a promising solution to effectively address the ongoing Pseudomonas aeruginosa contamination issue, now he also had the opportunity to fully assess the alternative operational expenses, environmental impact, and other tangible advantages. To demonstrate the solution provided
by the ILTDU, this time he was able to conduct a different trial format to his previous evaluation at King’s College Hospital. A single Pseudomonas aeruginosa problematic outlet was selected for this trial – it was a worst-case scenario, a shower slated for complete hardware replacement, but also one that epitomised such outlets across the hospital estate, and highlighted the ineffective ‘remedies’ already employed. This shower fitting had been ‘positive’ for over eight months, despite continued
HWS CWS
An ILDTU in disinfection mode with the temporary hot water flow path shown by red arrows.
remedial action; in addition to a required weekly duty flush, it had also undergone six unsuccessful treatments with Sodium Hypochlorite (NAClO), and consumed many hours of FM time, while the costs for point-of-use (POU) water filters, chemicals, water sample collection, and analysis, racked up.
As part of the trial selection process, the
hot water feed to the candidate shower was also temperature tested to ensure that it was compliant with HTM 04-01 and could achieve temperatures above 60 °C – the minimum thermal disinfection temperature recommended by Horne. The trial in this case therefore swapped
complete hardware replacement with ILTDU installation. That installation would follow the same protocol as previous new hardware installations, i.e. replacement hardware (ILTDU and any pipework), plus all the tools required to complete the task
HWS CWS
are pre-sanitised. The ILTDU was then installed across both the hot and cold water supply drops, orientated to match flow arrows with the supply flow direction, and ensuring good access to the ILTDU operation keyhole.
Mounting costs By the time of this ILTDU installation, chemically treating this single outlet unsuccessfully had already cost upwards of £750 (labour, POU filters, and sampling/ analysis costs), plus an entire day of FM time, and six batches of chemicals. Standard ‘last resort’ mitigation would be to entirely replace the shower fitting (or tap, TMV, pipework, wash-hand basin, and trap) estimated at a further £900, plus pre- installation sanitation chemicals and three hours’ labour. The costs to install the alternative ILTDU
equate to less than a third of that figure (£280), with generally comparable volumes of pre-installation chemicals and time. James oversaw the first thermal
1/2 turn
1/4 turn
disinfection of the shower: with the shower hose and handset directed safely away to avoid harm, the dedicated key, with its large ‘Very Hot Water’ warning sign, was inserted into the keyhole and rotated clockwise through 180 degrees, to shift the mechanism from Passive to Disinfecting mode. The ILTDU operates via a simple four-
HOT COLD To thermostatic mixing valve HOT COLD To thermostatic mixing valve
Schematic diagrams of the hot and cold water flow paths when the ILTDU device is in Passive and Disinfection modes.
50 Health Estate Journal April 2024
way link mechanism that rotates two 3-way ball valves. The left-hand (hot side) ball valve undergoes a 180-degree rotation, allowing for a flow path to open through the bridging piece. Meanwhile, the right-hand (cold side) ball valve rotates 90 degrees, closing the cold water supply upstream, and opening a flow path from the bridging piece to the downstream cold pipework.
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