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/ Water quality regulations

EUROPEAN WATER QUALITY REGULATIONS

Regular flush Training
According to the French, German and English Understanding the problems associated with
regulations, water stagnation (in sanitary installations bacterial growth in water systems helps to limit
and mixers and taps) is a key factor in bacterial the risk of contamination.
contamination. Although French legislators have not yet focused
The European standard EN 806 5 requires that on training those responsible for the water system,
those sections of the installation that are used it is embedded and pursued in Germany
Stagnation prohibited infrequently should be flushed at regular intervals. (with three training levels, depending on the level
The recommended interval is once a week. of responsibility) and in the United Kingdom
All public and commercial buildings are affected, (with personnel competency and training
in particular schools and council buildings during programmes monitored by the Water Safety Group).
the school holidays, campsites out of season,
unoccupied hospital rooms, etc. Training those responsible helps
to control bacterial proliferation.
The German directive of September 2023, Hygiene
in Drinking Water Installations VDI 6023 Blatt 1,
requires purging to be carried out after 72 hours of
stagnation in a sanitary installation (this also includes Removable mixers and taps
WC cisterns). Note that the water in the bypass is not In addition to preventative measures, the HSE (Health
Bypass prohibited sufficiently renewed. They are therefore prohibited. and Safety Executive) recommends the use of mixers
If an installation is not used for 72 hours, rigorous and taps that can be easily removed for regular
protocols are put in place. DELABIE sees this as internal cleaning; a mechanical intervention
a step forward and proposes technical solutions that is effective for removing biofilm.
to meet this requirement (see opposite: electronic
controls). Circulating loops
A circulating loop up to the point-of-use is not
The German directive requires recommended. It doubles the length of the pipework
purging to be carried out after and therefore doubles the water volume. The biofilm
surface is increased and, as a result, the risk of
72 hours of stagnation.
bacterial development. Moreover, it makes it difficult
Measuring pressure to maintain high temperatures at all points in the
circulating loop.
Undersized pipework
The German regulation strictly prohibits oversized
pipework because it promotes bacterial growth Finally, it also makes it difficult to keep the pipe run
by reducing the water velocity. volume to less than the 3 litres recommended by
DELABIE, along the same lines, recommends slightly European directives. Indeed, if the water temperature
decreasing the diameter of the pipes to increase in a circulating loop is less than 50°C or 55°C
the water velocity to 2m/sec. (likewise the French (depending on the country), the water volume
regulation (DTU) recommends 1.5m/sec.). in the circulating loop must be included
This measure prevents the excessive development of in the 3-litre maximum calculation.
biofilm and helps to reduce the risk of contamination
without increasing noise levels.
Measuring the temperature In the UK, where there is a high risk of scalding,
thermostatic mixing valves (TMVs) must be fitted.
Oversized pipes The HSE guidance recommends keeping pipe runs
are strictly prohibited. between a thermostatic mixing valve (TMV) and the
outlet as short as possible, and the pipe run should
not exceed 2 metres. Where practicable, the TMV
should be incorporated within the tap.

A circulating loop up to the point-
of-use is not recommended.

Training relevant personnel
Building Management Systems
Contrary to popular belief, Building Management
Systems are not recommended by European
directives as they can be complicated, difficult to
handle and extremely costly and do not take away
liability if a problem occurs.

8 Hospital solutions