How your selections can impact infection control and protect patients.

The continued growth and popularity of point of use Thermostatic mixing taps/valves, (TMV) has seen this technology quickly become the preferred choice in many new healthcare facility builds and refurbishments across Australia, New Zealand and Asia. Point of Use technology has many positives including easy installation and servicing & maintenance as well as scald prevention and infection control. Most importantly, the prolonged use of these taps in Healthcare facilities has assisted in the management and control of Legionella pneumophila and other forms of water-based infections.

Exposure to Legionella pneumophila in hospitals and care facilities is due to a multitude of factors. One of the common causes is associated with complex plumbing systems cultivating bacteria to breed.

Legionnaires’ disease, or Pontiac fever, is contracted when a person inhales mist or vapour that has been contaminated with Legionella bacteria. Keeping Legionella bacteria out of buildings’ water supplies and cooling towers, as well as pools, hot spas, and fountains, is key to preventing the spread of the disease. Most people that contract Legionnaires’ disease will have symptoms of pneumonia because the Legionella bacteria grow and thrive in the lungs. It is paramount that Legionella bacteria is managed in critical healthcare environments.

Here are four key considerations when selecting the best tapware for health care environments:

Look at the internals of the tapware
(You wouldn’t buy a car without checking under the bonnet first)

“Cast Brass Bodied taps Vs Forged & Machined”

The majority of mixers used in public and commercial environments are cast in brass (Cast Brass Bodied taps). The moulds are made from sand, and although the external surfaces are plated, smooth and polished, the interiors are rough with rigid edging. These rough interiors generally display a pattern of pitting with niches that encourage bacteria to attach themselves to and breed.

Tapware with smooth interiors (Forged and Machined) have fewer niches where bacteria can attach which significantly slows down biofilm development.  Furthermore, as a preventative measure, cleaning mixers in a de-scaling solution will further reduce biofilm build-up. Consideration is needed to ensure your tapware selection is compatible with the health facilities disinfection procedures.

Spout and body dimensions
(Bigger isn’t always better)

The development of Legionella bacteria is likely to occur when water is:

  • stagnant or has a low flow
  • water temperatures between 20°C and 46°C.

The use of small bore pipework and tubing increases water velocity and reduces the instances of Bacteria settling inside tap bodies and spouts.

A study conducted in June 2010 by the BioPI laboratory, showed that taps with smooth bore bodies have, Pseudomonas aeruginosa contamination levels 14 times lower than taps with rough bodies*

Hot Water Disinfection / Sanitisation features

Water systems at risk of stagnation should be periodically flushed or disinfected to remove any contaminated water. Temperatures that provide optimal conditions of Legionella bacteria should be avoided**.

The Queensland government has recently recommended that all facilities perform an annual thermal disinfection of all pipework and outlets downstream of Thermostatic Mixing Valves (TMV’s) ***

The inclusion of “Insitu Hot Water Disinfection” on tapware means you will be able to scald the internals of the tap set with minimal interruption to patient care and service resources.

An integral component of any healthcare facilities water risk management plan is the inclusion of a Hot Water Disinfection / Hot Water Sanitisation feature. This process, along with other water treatment methods, ensure healthier plumbing systems and offer the facility lower service costings in the long-term.

Scald Prevention & Controlling Temperature Spikes

To prevent fatal outbreaks of Legionnaires' disease, particularly in hospitals and other healthcare premises, building services engineers are recommended to store and operate hot water systems at a temperature of 60°C. However, water at this temperature presents the risk of causing serious scalding. Therefore, it is advised that thermostatic mixing valves be installed in the plumbing system to ensure hot water is supplied at a safe temperature for washing and bathing. ****

When choosing mixing valves it is important to decipher which valves include additional safety features. For example, instant shut off in case there is failure to either the hot or cold water supply and/or added internal insulation to reduce the tap body becoming too hot to touch.  Other safety parameter such as temperature limiters prevent users from overriding the pre-set, safe temperature which is a necessary precaution.

*Study conducted in June 2010 by the BioPI laboratory and the Department for Biological Studies at the Jules Verne University, Amiens
****Prevention of hot tap water burns--a comparative study of three types of automatic mixing valve.  Stephen FR1Murray JP.