"Green Cleaning" no so many years ago was, for many professionals, an oxymoron. That is, your chemicals could be green but not clean very well, or they could clean very well but not be so green.
Green cleaning” not so many years ago was, for many
professionals, an oxymoron. That is, your chemicals could be green and not
clean very well, or they could clean very well but not be very green. Over
time, the two targets have aligned, but not completely.
At the University of Massachusetts (UMass) Toxics Use
Reduction Institute (TURI) Lab we have been involved in the performance testing
of green cleaning products for nearly 20 years, specializing in hard surface
cleaning chemicals and, most recently, cleaning equipment.
Over time, and through the IEHA’s High Performance Cleaning
Product (HPCP) program, we have seen the development of less toxic or
polluting, but very effective products, many of which we have tested and
validated in our lab.
The following explains the types of testing we do to verify
the performance of green products, plus information about some cleaning
technologies that appear to be promising (though not an endorsement of these
products). We also provide insights as to what we believe is on the horizon for
product performance evaluation.
The problem with the way most people evaluate cleaning
product effectiveness is that their comparisons tend to be subjective, not
scientific. As a testing and research lab, we believe that well-written test
protocols and repeatable science play a key role in helping professionals
choose cleaning products that work consistently well. Following are test
methods TURI scientists use to help take subjective judgments out of
Scientific Scrubbing Comparisons
An abrasion-testing device enables a real-world, variable
and repeatable rubbing or scrubbing action to compare the cleaning performance
of hard surface cleaners, such as detergents or cleansers; or to test the
durability and efficacy of scrub brushes or scouring pads.
The device uses a reciprocating linear motion at
approximately 37 cycles per minute with a constant speed over a 10 inch travel.
It utilizes a brush, sponge, cotton cloth, microfiber, or other wiper to
simulate real life situations and is used for testing either wet or dry
This process takes the guesswork out of comparing product
performance since it precisely matches pressure and rate of cleaning from
surface to surface and from product to product. It enables apples-to-apples
comparisons between cleaning methodologies to identify high performance.
Color and Gloss Comparisons
A light-detecting (spectrometer) device allows measuring the
color and gloss of surfaces before and after cleaning, permitting repeatable,
scientific visual analysis of color and gloss impacted by cleaning processes.
We make five initial measurements on the substrate or surface to get a baseline
before applying the test soil or stain. Then we take five more readings per
substrate to quantify the effect of the soiling. We then clean and measure the
test surfaces again to determine how well the cleaning agent performed.
Precise color and gloss measurements are a way to remove the
subjective “human eye” from the evaluation process, allowing more consistent
Performing gravimetric analysis verifies the cleaning
performance of environmentally preferable products, and equipment by comparing
the weight of the soil removed from the surface.
We measure before and after cleaning in triplicate
(minimally) using 2” x 4” rectangular test coupons or panels, flat sheets
matched to a particular surface’s materials of construction, for example,
stainless steel, ceramic or glass (number-etching the coupons for
Testing consists of:
- Initial weighing of pre-cleaned coupons
using an analytical balance (measuring gram weight)
- Applying the contaminant (oil, grease, soil, etc.)
to the surface of the coupons with a hand-held swab in a highly consistent
- Re-weighing the artificially-contaminated coupons
under the same conditions as (1)
- Performing the actual cleaning (involves the
primary elements of cleaning such as time, agitation, concentration and
temperature, collectively known as TACT)
- Final and third weighing of cleaned coupons under
the same conditions as (1)
Gravimetric analysis using precisely calibrated analytical
scales enables determining by weight the percentage of soil removed from
surfaces, and helps eliminate human error. These methods and devices allow us
to determine soil removal with a high level of accuracy and repeatability.
Microbial Removal or Inactivation
Since hygienic cleanliness is a vital part of a healthful
environment, TURI has recently begun working with UMass Lowell’s Department of
Clinical Laboratory and Nutritional Sciences to determine the efficacy of
products designed to remove or destroy microbes, or to eliminate the conditions
that favor microbial growth. A variety of established lab test methods are used
along with some newer field tests such as ATP and bacterial enzyme detection.
TURI has developed specific equipment-related tests to
evaluate the effectiveness of hard surface vacuuming, dust mopping, scrubbing
and other common janitorial processes.
Since lab and field testing often yield different results,
it is important where possible to integrate lab and field approaches, surfaces
tested and methods used to achieve coordinated results, synergies, better test
protocols, and greater accuracy and credibility of the testing. We are
initially piloting such a program with the IEHA and the University of WA,
Seattle. Results will be forthcoming in future articles and reports.
Within the last two years, TURI has been involved in testing
several emerging or non-standard technologies or processes with promising
results. For example:
- Steam vapor sanitation systems - applying
low-pressure, low-moisture steam to surfaces - have demonstrated rapid
microbial kill without chemicals and the need for standard dwell times. General
soil removal is also being evaluated.
- Tests show activated water - formed through water
electrolysis combined with passing a slight electrical charge through water to
the surface to be cleaned - can be as effective as some traditional glass and
general purpose cleaners. The lab is also evaluating microbial kill claims of
- Tests of vacuuming of hard floors versus dust
mopping show superior soil removal and productivity in some cases.
- Evaluations of squeegeeing moistened soils from
surfaces such as school desktops show that this process can be more effective
than wiping using microfiber or other cloths in many circumstances.
On the Horizon - Performance Scoring Systems
As part of the lab’s proposed future work, we along with our
partners are developing a scoring system to help enable cleaning professionals
to make product choices based on a single performance score. This rating will
combine factors such as Effectiveness, Ease of Use and Economy to yield a
single performance score based on an average of the points awarded for each of