623-Hygiene / 748
H
ygiene
BOS-PRD-0304.900902
4
.
7
.
3 C
o
l
d
w
a
te
r
inst
a
ll
a
tion
The risk assessment in the cold water system
should
focus on areas where the water could be warmed up
by external sources (i.e. engine room environmental temperature) in combination with proliferation and
forming of a biological layer and/or sediment.
The temperature in the coldwater system
should
preferably be not more than 20ºC and not exceed 25ºC. In
case the temperature exceeds 25ºC, measures
should
be taken by either to improve the system (i.e.
insulation of pipes) or to implement controlling measures. The controlling measures
should
comply with the
legislation.
Proliferation (stagnated or still water) is caused by (amongst others) stagnation of several weeks or still water
in dead end lines. Stagnant water
should
be flushed every week. Dead end lines
should
be removed or
properly separated from the system.
Where the assessment demonstrates that there is no reasonably foreseeable risk or that risks are
insignificant and unlikely to increase, no further assessment or measures are necessary. However,
should
the situation change, the assessment
shall
be reviewed and any necessary changes implemented.
4
.
7
.
4
I
m
p
r
oving
t
h
e
system
Where according to the assessment a Legionella risk may exist, the water system
should
be improved.
In case the system could not be improved the risk
should
be controlled.
The system
should
be improved i.e. remove dead ends.
Whenever (hot) taps are no longer required for use they
should
be removed and cut back to the recirculation
loop.
The traditional approach to Legionella control is temperature control.
It is recommended that:
x
Hot water
should
be stored at least 60°C and distributed so that it reaches this minimum temperature
at the outlets;
x
The release of water spray
should
be controlled;
x
Water temperatures and conditions that favour the proliferation of Legionella bacteria and other
micro-organism
should
be avoided;
x
Water stagnation
should
be avoided;
x
The use of materials that harbour bacteria and other micro-organism
should
be avoided, or provide
nutrients for microbial growth;
x
Maintain the cleanliness of the system and the water in it;
x
Water treatment techniques
should
be used and ensure the correct and safe operation and
maintenance of the water system.
Points for improvement
should
be recorded in respective form and to be dealt with according to the planning.
Version 04. Original date: 25/05/2012. Version date: 31/12/2014. Valid version only on QMS site. Uncontrolled document when printed.
Procedure prepared by: BOS QHSE Coordinator. Approved by: BOS QHSES Manager. Validated by: BOS Quality Representative
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