Page 13 - Water_Controls_for_Healthcare

HOSPITAL
DELABIE’s solutions for infection control / SOLUTIONS

THE END OF NON RETURN VALVES

The use of water in healthcare facilities creates
significant sanitary challenges. Excerpts from a legal expert’s verdict in the investigation into
Bacterial contamination in water systems represents the deaths, caused by Legionella, of 6 residents of a French
an extremely high risk to the health of those patients retirement home between 2006 and 2008 conclude that: SECURITHERM SECURITOUCH
with weakened immune systems, mainly linked to the "the drop-off of the zinc and copper hydroxide found on
proliferation of Legionella spp. and Pseudomonas the non-return valves located upstream of the thermostatic
aeruginosa. mixer are responsible for the CW being heated up by
the HW. It’s the triggering factor for bacterial proliferation ...".
Cross flow between the hot and cold water
inevitably creates conditions favourable to bacterial
development in water controls. It is, therefore, fundamental that mixers’ closing
To reduce this risk, all conventional thermostatic mechanisms are located upstream of the mixing
mixers have non-return valves. Conventionally used chamber to prevent any cross flow between DHW
to prevent the hot water from entering the cold and DCW. As a result, the non-return valves, whose
water supply (or vice-versa, according to the higher reliability cannot be guaranteed, become redundant.
pressure), these valves are now considered to be SECURITHERM
principal causes of bacterial development. DELABIE has developed a unique, patented
However, non-return valves are not reliable because mechanism for its thermostatic mixers which does
sooner or later impurities prevent them from being not need non-return valves. The risk of cross flow
watertight, meaning they cannot function correctly. In is therefore completely eliminated.
the event of failure, they are responsible for DHW/ For more information see page 110.
DCW cross flow, causing irrecoverable conditions
favourable to bacterial development inside mixers.

A French standard, NF Medical which came into effect
at the end of 2016, demands that a mixer shuts off
prior to the mixing chamber, removing the need
for non-return valves on water inlets. BIOSAFE

Hospital solutions 11