- THE MAGAZINE
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.
Performance TestsThe 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 effectiveness evaluations.
Scientific Scrubbing ComparisonsAn 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 cleaning.
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 ComparisonsA 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 results.
Gravimetric ComparisonsPerforming 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 identification).
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 manner
- 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 InactivationSince 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.
Equipment TestingTURI has developed specific equipment-related tests to evaluate the effectiveness of hard surface vacuuming, dust mopping, scrubbing and other common janitorial processes.
Field TestingSince 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.
Promising TechnologiesWithin 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 these products.
- 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.