Plumbing Connection Spring 2016

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PLUMBING CONNECTION SPRING 2016 51
Additionally, the increased force caused by regular
movement can help prevent excessive biofilm from
accumulating in the distribution pipes.
Designers, plumbers and healthcare professionals need
to consider the risk of waterborne infection arising from the
installation of excessive numbers of outlets.
Cold water distribution pipework and storage tanks in
new healthcare premises are frequently oversized and it is
common practice to fit more tap and shower outlets than are
needed. If outlets are not used regularly the cold water within
the distribution pipes and associated cold water storage
tanks can become stagnant, and water temperatures can
rise into the temperature zone that supports the growth of
biofilm and the proliferation of Legionella bacteria.
AUSTRALIAN GUIDELINES
The Plumbing Code of Australia (NCC Volume 3 – 2015)
requires heated water be stored and delivered under
conditions which avoid the likelihood of the growth of
Legionella bacteria. The National Plumbing and Drainage
Code stipulate hot water be stored at no less than 60°C to
help prevent the growth of Legionella.
However these temperatures can cause scalding, so water
temperature is required to be controlled in accordance
with AS/NZS3500.4. This standard currently states that in
healthcare facilities the only deemed-to-satisfy solution
is through the use of thermostatic mixing valves set to a
maximum temperature of 45°C.
WHAT CAN GOWRONG
In the case of Brisbane’s Wesley Hospital, managing
the outbreak was not easy. A full scale public health unit
investigation into the hospital’s cooling and water systems,
as well as independent sampling and investigations, found
the source of contamination was the heated water system.
Contributory factors to the harbourage of Legionella
were identified in the presence of dead legs, and a lack of
awareness regarding the need for regular and on-going
maintenance of plumbing fittings.
Following the incident, Queensland Health asked almost
250 state and private hospitals to test their water systems
for Legionella. The results indicated the extent of Legionella
in water systems, with at least a quarter of all hospitals
tested returning a positive result.
LASERS . TRAFFIC
STEEL PLATES
PIPE TESTING
SHORING
PROPPING
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