12 FACILITY MONITORING
Avoid using the unit until it has finished performing this test.
• For flat surfaces, swab a four-inch by four-inch
area, moving the swab from left to right as well
as up and down.
• For irregular surfaces such as door handles,
swab enough of an area to collect a good sample.
• Rotate the swab as it is used so that all areas of
the swab come into contact with the surface to
• After using the swab, place it in a tube, provided with most systems. Snap the top of the tube
to release a liquid that protects the sample.
• Hold the tube vertically and shake it back and
forth for about five seconds.
• Keeping the swab upright, insert it into the
monitoring device for testing.
• Wait approximately 15 seconds.
Working with the results
Let’s say we have taken an ATP reading of a cleanroom floor and the reading is 72. This reading is
too high, indicating the floor has not been cleaned
effectively, and therefore contamination is possible. Because the floor has just been cleaned in our
scenario using a mop/mop bucket, we can assume
the reason for the high ATP reading is the mopping procedure.
To eliminate mopping and attempt to reduce
the ATP reading, we have two alternatives: use an
automatic scrubber, or a less costly “autovac” floor
According to a report by the Clinical
Laboratory and Nutritional Sciences Lab at the
University of Massachusetts at Lowell, testing
results using both systems found they “had signif-
icant (98 percent) reduction in the levels of ATP
on the flooring tested.”
For the record, tests were also conducted
using the traditional floor mopping method.
According to the same testing lab, “the mop
method had a minimal reduction in ATP (44
If our high ATP reading is on a counter or sim-
ilar flat surface, it may be caused by the cleaning
cloth used to clean the surface, as mentioned earli-
er. Alternatives to using cleaning cloths to address
this problem are cleaning tools such as chemical
injection technologies that apply a cleaning solu-
tion to the surface. The flat surface area is then
wiped clean using a microfiber squeegee.
Administrators and cleaning
Whereas managers of an office building or even a
school may turn to a cleaning contractor to decide
which cleaning methods and products should be
used to clean the school, administrators of cleanrooms cannot do this. They must be very involved
in the cleaning procedure to assure quality. As we
know, improper cleaning can result in contamination, skewed research and testing results.
Work with your cleaning contractor to develop a scope of services, indicating what surfaces
(areas) must be cleaned, how often, and using
which cleaning solutions, products, and equipment. And don’t forget testing surfaces. In some
cases, ATP testing may need to be performed
throughout the week to ensure quality standards
are maintained. But look at it as a cost effective
insurance policy. ATP systems help ensure the
work done in a cleanroom is accurate, saving time,
money, and producing quality results.
Different manufacturers of ATP monitoring systems may use different scales.
Often a surface must be tested more than once
to determine an accurate ATP reading.
A cleanroom will have higher standards than,
for instance, an office building. In such cases,
an ATP reading over 35 may be fine in an office
building, but indicate “ineffective cleaning” in a
Robert Kravitz has owned three contract cleaning
companies in Northern California and has written two
books on the professional cleaning industry. Today he is
a frequent writer for the professional cleaning industry.
HUMANS IN CLEANROOMS
Here are some of the ways humans
spread contamination in cleanrooms:
• Fast motions, including horseplay
• Airborne skin flakes, oil, perspiration,
• Certain cosmetics and colognes
• Sneezing and coughing
• Work habits
• Electrical charges from people touching