From the Miele Professional Whitepaper Series

Reprocessing of laboratory glassware#Cleanlinessandefficiency

Manual cleaning versus machine reprocessingof laboratory glassware and utensils
Experiments and analyses in laboratories require a steady supply of clean laboratory glassware in sufficient quantities.
Excellent and reliable results can only be achieved if laboratory glassware and utensils are clean and residue-freefrom the outset. In other words, items should be free from any impurities and the process chemicals previously used.
Producing this level of consistent quality is rare when using manual cleaning methods, which leave laboratories open
to the risk of compromising the standards required for analytical work.
Even today, the manual cleaning of laboratory glassware is still commonplace. The reasons for this approach areusually pecuniary in nature – manual cleaning is cheaper than procuring and maintaining a laboratory glasswasher,or at least that is the general perception. Looking at the pros and cons more closely, this supposition turns out to bea fallacy.

MANUAL CLEANING AS A SOURCE OF ERRORS

FM21-1134 / 11/2021

Cleaning at the sink is not only messy and cumbersome but a great deal of time and effort is also required to achieve
the desired results. The time spent by laboratory staff can be put to much better use when reprocessing is automated.
Similarly, consistently high standards of cleaning are difficult to achieve in a manual process. Manual cleaning results
always depend on the person doing the work. Experience, the procedure and the time available all impact the outcome.

The amount of water, the temperature, process chemicals and the amount dispensed, the shape and design of thebrush used, the time spent brushing and the pressure applied determines whether laboratory glassware comes out
residue-free at the end of the process and is suitable for use in the next series of analytical experiments. All thesefactors are subject to constant change – often at the expense of reprocessing quality. In short: Wherever the humanfactor comes into the equation, the standardisation of processes becomes virtually impossible.
Manual cleaning involves a particularly high risk of damaging expensive items of laboratory glassware: Mishaps whenhandling materials, cleaning utensils and chemicals significantly reduce the service life of glassware. At the sametime, such a constellation poses a health risk to laboratory staff as employees breathe in aerosols, come into directcontact with chemicals or injure themselves on broken glass.

M A C H I N E R E P R O C E S S I N G : A N I N V E S T M E N T T H AT PAY S O F F
Given the initial outlay for a commercial laboratory glasswasher, users often question whether such a major investment
will pay off. They often, though, fail to see the long-term savings which come with machine reprocessing.
First and foremost are time savings: Staff members can devote their valuable time to other, more productive tasks,
making their work more efficient. At the same time, they are relieved of laborious and unhealthy chores, resulting in
reduced sick leave and increased levels of satisfaction and motivation among lab staff.
Furthermore, speed is a clear advantage of cleaning laboratory goods in a lab washer. While manual cleaning andrinsing takes approx. 1 minute per glass, 60 lab glassware items can be reprocessed automatically in only 24 minutes
in a machine, which corresponds to a time saving of about 59%.
Add to this the responsible use of valuable resources: The consumption of energy, water and process chemicals
is precisely geared to individual processes and achieves top-class results without wastage. Water consumption in
an automatic process is up to 63% lower compared to the consumption in a manual process. This not only helps
laboratory finances, it also considerably reduces the burden on the environment.
And, last but not least, machine reprocessing is far gentler than washing by hand. The risk of etching, scratches or
glass breakage is reduced to a minimum and the life cycle of reprocessed goods is extended.

E V E R Y T H I N G S P E A K S I N FA V O U R O F L A B O R AT O R Y G L A S S W A S H E R S
The higher investment cost of procuring and equipping a laboratory glasswasher pays off in the long run. First- classconsistent results alone are reason enough to buy a laboratory glasswasher. But lower labour costs, the reduced
consumption of electricity, water and process chemicals and the longer life expectancy of laboratory glassware will
sooner or later tip the balance. The amortisation period depends of course on individual cost structures and how
many programme cycles are run per day, but calculations based on average figures show that the investment in alaboratory glasswasher can pay off in less than 2 years.

Long-term cost comparison:
Manual vs. automated lab glassware cleaning$ 25.000$ 20.000$ 15.000$ 10.000
$

5.000

$

0Year01

2

Costs of manual cleaning

345678

Costs of automated cleaning with lab washerSample calculation: Investing in a laboratory glasswasher pays off in less than two years.

And, last but not least, a laboratory glasswasher makes reprocessing in a laboratory much safer, less prone tomistakes and hence more reliable. In all, this makes work in labs far simpler.
To make the transition from manual cleaning to machine reprocessing as smooth as possible, Miele Service andauthorised Miele service agents are close at hand throughout the life of a laboratory glasswasher. From installationand commissioning through to selecting the correct programmes and chemicals and providing assistance withissues, maintenance and repairs.