HFI Releases SMART Question and Responses for August - Q: Are Scanning Electron Microscope (SEM) Images of Before and After Cleaning Useful to Advance the Healthy Cleaning Cause?
BOISE, ID — The Healthy Facilities Institute® (HFI) Educational Center and Website has released the August 2013 Answers of the SMART - Swift Market Assessment Response Team - in response to the question: Are Scanning Electron Microscope (SEM) Images of Before and After Cleaning Useful to Advance the Healthy Cleaning Cause?
For example: Attached are two SEM Images of carpet fibers cleaned using two different methods. See SMART answers below.
Q: Are SEM Images of Before and After Cleaning Useful to Advance the Healthy Cleaning Cause?
A1: “Absolutely, I think they are. There needs to be proper context, of course, but along with the right supporting information this is very powerful” - Electrolyzed Water Supplier
A2: “Absolutely! SEM images can tell a lot about how surfaces become damaged or contaminated as well as how they respond to cleaning procedures. We are using the same technique to measure wear and contamination on hard surfaces, and are planning to begin a larger project this fall in conjunction with [a major University's] materials engineering department” - Floor Safety Expert
A3: “We routinely use SEM as well as energy dispersive X-ray (EDX) in evaluating problems, including cleaning. I see several potential issues, not in the technology itself, but in how it is employed. Since few companies have in-house SEM capability, the cost of outside analysis can become significant. First, the person conducting the study is rarely the one operating the microscope; in the case of outside labs, the researcher is rarely present. Second, there is usually considerable variability in the level of ‘clean’ across the surface of the carpet; it then becomes a question of which tuft is removed from the carpet for evaluation. This is complicated by differences in soil load resulting from differences in traffic. Third, most SEM's require that non-conductive materials such as fiber must be coated with a conductive material such as Gold. While the amount of Gold and cost is very small, the process takes a lot of time, therefore relatively few specimens are typically evaluated. The operator situation sets the stage for ‘cherry picking’ as he generally knows what the researcher is seeking and scans the samples/specimens for areas that illustrate what he believes is desired. The second dictates that a large number of samples be evaluated in order to fully characterize the ‘average’ across the sample and within the specimen, thus increasing the cost, further complicated by the third issue. Obviously, using the SEM as an effective tool is not as simple as pulling out a couple of tufts and snapping a couple of photos. Unfortunately, that is what happens in too many cases. Over the years, I have become leery of anyone who hands me a couple of photos and makes claims based on them. I was involved in a recent suit where the plaintiff's lawyer had a contract lab analyze very small amounts of a mysterious dust using SEM / EDX and came to a conclusion that was based on solid science but very flawed logic; i.e., they used the instrument to provide ‘proof’ of their theory and failed to consider any other cause. What this boils down to is that I can use the SEM (as well as any other instrument) to ‘prove’ anything I want, simply by carefully choosing the area to be photographed” - Major Carpet Mill
A4: “What would be helpful for comparison is to show the SEM of the carpet when new and then when dirty. That way the comparison will show how close the two cleaning processes were to the original condition. This four SEM images would be helpful: Initial, Dirty, Clean Process 1, Clean Process 2.”
- Major University
A5: “It's a good idea and helps populate your ability to ‘measure clean’, and that is pretty central to advancing green cleaning - sustainable cleaning - renewable cleaning - process cleaning - to clean for health, etc. I'll be happy to join in the effort.”
- Former EPA IAQ Scientist
A6: “Given the opportunities for the use and abuse of SEM; suggest these criteria be used -
• Scanning Electron Microscopy (SEM) (and/or other microscopic examination) shall be conducted of the surface when new or unsoiled, then when soiled and after cleaning to demonstrate how the cleaning process affected the original condition: Thus four SEM image types are generally-specified: Initial, Dirty, Clean Process 1, Clean Process 2.
• Scanning Electron Microscopy (SEM) (and/or other microscopic examination) shall be conducted on a sufficient number of surfaces to ensure an accurate - or average - representation of soiled and clean conditions.
• Claims relating to SEM (and/or other microscopic examination) shall include details of what was examined and how, and how conclusions were arrived at.”
- Educational Resource
SMART Task Force – Overview
The SMART - Swift Market Assessment Response Team - Task Force is a way to drive healthful ways more rapidly into the marketplace through dialog and discussion. The Task Force (TF) “meets” by email and responds to queries by the committee chair (Allen Rathey) as time permits. Rathey will query the group monthly (around the 15th of each month) asking for input on a specific topic.
The TF will consist of vendors and end-users with the early members being vendors, as this idea sprang from brainstorming a way to provide value to HFI sponsors, without endorsing any particular product or for-profit service.