Page 11 - 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 BIOSAFE
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 SHW
to prevent the hot water from entering the cold and SCW. 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. is therefore completely eliminated.
In the event of failure, they are responsible for SHW/ For more information see pages 112 and 116.
SCW cross flow, causing irrecoverable conditions
favourable to bacterial development inside mixers.

A new 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

DELABIE THERMOSTATIC TECHNOLOGY CONVENTIONAL THERMOSTATIC TECHNOLOGY
SHW SCW SHW SCW
2 2
4 1 4 1
1 Temperature control 1 Temperature control
2 No non-return valves 2 Non-return valves
3 Mixed water 3 Mixed water
4 Mixer opening control 3 4 Mixer opening control 3
5 Mixing chamber 5 Mixing chamber
5 SMW SMW 5
By closing the control 4, the SHW is closed. Sooner or later, the non-return valves are obstructed by impurities
The thermostatic cell therefore closes the SCW. causing cross flow between the SHW and the SCW,
There is no risk of cross flow between SHW and SCW. responsible for bacterial development.

Hospital solutions 9