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Automated washing principles and common mistakes
By: Olivier Van Houtte, Product Manager, Life Sciences Washing Systems and Paul Lopolito, Manager,
Life Sciences Technical Services, S TERIS Corp
Automated washing systems are often used for critical cleaning and drying applications in research, pharmaceut-
ical and biopharmaceutical manufacturing
facilities. Typical applications include cleaning
of lab glassware and parts from equipment
used in the manufacturing of parenterals, oral
liquid and solid dosage drugs. A good under-
standing of washing’s basic principles can help
with making the best use of automated wash-
ing systems, as well as avoiding typical mis-
takes which can lead to inconsistent cleaning
performance, lower productivity and higher
operation and maintenance costs. Such know-
ledge represents an important step toward
BASIC WASHING PRINCIPLES: TACCTS
A common acronym used in the industry to
remember the cleaning parameters is TACCTS
(temperature, mechanical (action), chemistry,
coverage, time and soil). The cleaning param-
eters need to be effective at removing the
residue on the surface so understanding the
nature of the soil should be the first cleaning
parameter addressed, even though it’s the last
letter of the acronym.
The critical parameter of temperature can
apply to the pre-wash, detergent wash and
rinse phases. The temperature of the pre-wash
phase may vary based on the nature of the soil.
For fats, oils and greases, a high temperature,
around 82 C (180 F), is preferred. For minerals, a moderate temperature, around 65 C (150
F), is more adequate. For proteins and sugars,
a pre-wash temperature around ambient is
helpful. Typical temperature for a detergent
SCENARIO RESULT SOLUTION
Use hot water in pre-wash phase when cleaning
Soil is cooked on surfaces, making it more difficult to
remove during subsequent wash phase.
Select cold water for pre-wash wash.
Use cold or hot tap water in wash phase when cleaning
oily or grease/fat type soils.
Soil is not removed from surfaces, or an extremely
long cycle time is required.
Select very hot water for the pre-wash and wash
Washing with water temperature outside of the operat-
ing range of the chemicals being used
Check operation range on chemical container labels
and adjust temperature accordingly.
Performing Final rinse with cold water Very long drying time. Adjust temperature of final rinse as high as possible.
Using chemical(s) with the wrong pH Very long wash time or improper cleaning. Use alkaline chemicals for protein and organic soils,
Using acidic or alkaline detergents to clean aluminium
containers or pH-sensitive load items
Containers or load items will degrade/deteriorate. Use neutral pH chemistry for these types of materials.
Trying to clean heavily soiled and dried load items with
low detergent concentration
Wash time may need to be significantly extended. Increase detergent concentration until reasonable
result/time ratio is reached.
Using chemistries that create foam in the chamber Pump cavitation is created, resulting in lower pressure
and possible damage to pump.
Use chemicals recommended by manufacturer, or
Setting long time for rinse phases Longer total cycle time. If rinse water is recirculated, increasing time does not
improve rinsing efficiency much. It’s better to shorten
rinse time and add rinse phases if need be.
Setting high temperature for all rinse phases Longer total cycle time. Higher temperature doesn’t typically improve rinsing
efficacy. Reducing temperature shortens rinse phases
and reduces stress for equipment. Final rinse should be
heated to accelerate drying. There may be a need for
achieving some level of thermal disinfection, example:
cages in Laboratory Animal Research Industry. In this
case, heat only last rinse.
Using low-quality water for all phases Poor cleaning performance, spotting due to mineral
deposits, higher detergent usage.
Follow supplier’s recommendations for water quality.
Adjust detergent concentration based on water
Use mineral free water, at least for final rinse (reverse
osmosis, deionized, distilled, water for injection).
Using the wrong accessory for the application Inadequate coverage, poor cleaning performance Follow supplier’s recommendations for selection of
Positioning load items incorrectly
Overloading baskets and accessories Limited coverage, inconsistent cleaning results Avoid overloading