MAINTENANCE JANUARY 2020
UNDER
PRESSURE
High-pressure washdowns are often used in manufacturing sites
due to their increased e ciency and reduced costs. However,
they may be causing lasting damage to your machinery
BY PAUL TAYLOR, HEAD OF INDUSTRIAL PRODUCTS (UK), TÜV SÜD
The high-pressure washdown cleaning
technique has wide applications,
particularly in the food, beverage and
pharmaceutical sectors. While highpressure
washdowns off er enhanced
cleaning effi ciency, they also reduce
water and detergent usage, reducing costs and
minimising the environmental impact.
However, sourcing equipment that reacts
well to a regular high-pressure washdown has
its challenges, as even the smallest sealing fl aws
will result in water ingress into machinery.
Fortunately, help with addressing this problem
is provided by the ingress protection (IP) rating
system defi ned in IEC 60529, with category IP69K
specifi cally relating to high-pressure washdown.
Although the IP69K rating was originally
developed for equipment used on road vehicles
and is only defi ned in the German DIN 40 050
version of the standard, it has now been adopted
other machinery intended for
use in washdown areas.
When using the IP69K rating
the equipment is tested with
a spray nozzle that is fed with
water at 80°C at a pressure of
80 to 100 bar and a fl ow rate
of 14 to 16 l/min. The nozzle
is positioned 50 to 100 mm
from the equipment under test
at angles of 0, 40, 60 and 90
degrees for 30 seconds each.
The equipment under test is
mounted on a turntable that
rotates at 5rpm. At the end of
the test, there must have been
no ingress of water.
Beyond IP69K
A common mistake made by
purchasers of machinery is to
simply specify a IP69K-rated
machine. However, this does not
cover the fi tting of any postmanufacture
additions such
as push buttons and indicator
lights. Neither does it allow for
any necessary drilling into the
enclosure that is required for
the addition of power cables
once the machine is on site. All
of this can impact the machine’s
integrity, creating potential
leakage points.
To ensure problem-free
operation in washdown areas,
it is therefore important to
maintain the ingress protection
rating during assembly and
installation. As an example, this
can be achieved by sealing pushbuttons
and indicator lamps, as
well as using IP69K glands for
cable entries.
Other factors
Although water ingress
protection is a key factor
to consider when selecting
equipment for use in washdown
areas, there are other aspects
that also need to be taken into
account. This includes the
material used in the fabrication
of the equipment. For example,
it is not unusual for food
manufacturing companies to
carry out washdown procedures
as often as a dozen times
every day, regularly exposing
machinery not only to the
water jets themselves, but also
to the detergent used in the
cleaning process.
While many materials
cannot withstand this regular
exposure, stainless steel
can. For this reason, grade
316 stainless steel is usually
specifi ed for equipment
by many suppliers of enclosures,
sensors and
A number of
factors can a ect
the e ectiveness
of a washdown,
says Paul Taylor
of TÜV SÜD
(below)
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