8.6
Disinfection of water services
EDGE
TM
pipes intended for drinking water together with
the EDGE
TM
jointing technique without an O-ring help to
keep the hygiene level of drinking water installation. They
correspond to the requirements of AS/NZS 4020. Thus,
they are suitable for contact with drinking water. It has
been proven by KIWA that PEX pipes for water services
and heating installation do not cause any multiplication
of micro-organisms and thus do not support microbial
contamination or legionella growth.
8.6.1
Thermal disinfection in case of contamination
For drinking water installations in compliance with the
latest technical standards (no stubs, etc.), removal of dirt
can be done by thorough water rinsing as long as the dirt is
water-soluble or remains soluble in water.
If contamination is suspected, an additional thermal
disinfection as per DVGW worksheet W 551 is possible
as a sensible and urgent measure. According to the latest
technological standards, for water with temperature of
at least 70°C, it is very likely that germs and bacteria,
including legionella which is found freely
in water will be killed o. It is important that the
appropriate measures have to be taken to avoid scalding to
people.
All EDGE
TM
piping system for water services and heating
installation are suitable for multiple thermal disinfections
according to DVGW worksheet W 551 at 70°C. It must
be ensured that the allowable operating pressure is not
exceeded during thermal disinfection.
8.6.2 Chemical disinfection in the case of
contamination
Alongside with thermal disinfection, chemical disinfection
is being used more and more. Chemical and thermal
disinfection measures always strain the materials used in
water services installation. According to today’s level of
awareness, some disinfection measures are not suitable
for standard materials in installation technology. This also
applies to materials, for which it was previously assumed
that they were suiciently corrosion-resistant, e.g.
stainless steel, copper and some synthetic materials.
Before introducing these types of process measures, it
needs to be ensured that all parts of the installation system
are thermally and chemically suited for the corresponding
measure. This is regulated by DVGW worksheet 551. If
necessary, please have the suitability of the disinfectant
approved by the disinfectant’s manufacturer for all system
parts of the installation.
8.6.3 Chemical “Postrinse disinfection”
For short-term chemical disinfection (postrinse
disinfections), only special active ingredients may be used
which are specified in corresponding rules and standards.
Carrying out the disinfection measures according to the
specifications of DVGW worksheet W 291 can be done
without impairing the functionality of REHAU drinking
water installation if the active ingredients, concentrations,
application duration and maximum temperatures are
observed (as listed in Table 8-2)
It should be noted that combining thermal-chemical
disinfection at temperatures of higher than 25°C, as well as
permanent or regular disinfection cycles (e.g. monthly), are
not permitted.
In relation to the lifespan of the piping, the total number
of disinfection cycles is limited to five “postrinse
disinfections”. Otherwise, it cannot be guaranteed that the
specified lifespan will be reached.
The person carrying this out must guarantee that the water
is not used for human consumption (e.g. as drinking water)
at any time during the disinfection phase, including the
subsequent rinsing phase.
To Next Page
Loading...