Question:

 If you get a moment, please address a question for me, since I am a bit confused about what the IICRC S100 Standard and Reference Guide for Professional On-Location Carpet Cleaning says about dry compound and dry foam cleaning.  Are the terms “absorbent” and “adsorbent” interchangeable or is it due to the polymer and cellulosic-based product for the reason?  Are these cleaning methods really dry?

 Answer from Jeff Bishop, SCRT Technical Director: 

The term used in the industry is “absorbent compound” method and it’s been use in the S100 for 20 years now.  Of course, we know that there are two types of sorbents: ab and ad-sorbents.  So the term that should have been used in the S100 is simply “sorbent” compound cleaning or perhaps even dry compound cleaning.  Unfortunately, it takes a technical editor to do this, a person who doesn’t exist in the IICRC process today.   It’s a bit confusing and unnecessarily verbose to have to say “absorbent/adsorbent compound cleaning” as has been proposed by some as an alternative name, each time one refers to the method, when simply saying sorbent (a word that some in the industry have not discovered) compound would do the trick. 

 Briefly stated, absorbents draw in and adsorbents adhere, and to that extent the terms are not technically interchangeable; but rather, they refer to physical material properties that are different, but which achieve essentially the same result.  Still, “sorbent” is the proper term to use and industry instructors can explain the technical details. 

 Neither of the sorbent cleaning methods are actually “dry.”  All have some amount of moisture added; therefore, the correct classification would be “minimum moisture cleaning method.”  In fact, some products produced for commercial used today have moisture added to the extent that it can literally be squeezed out of the sorbent material.  This added moisture and detergent enhances cleaning and even improves visual appearance, especially when coupled with efficient post-application vacuuming.   

 However, sorbent compound cleaning has yet to be tested for physical soil removal using laboratory X-ray fluorescence (XRF) testing. 

 To assume that sorbent compounds are completely safe from association with physical hazards is a mistake.  Walking across a carpet  before the sorbent compound cleaner dries completely can result in slip/fall potential in areas where carpet transitions to hard surfaces.  Also airborne dusts created by applying some “dry” compounds can create respiratory irritation.  And I know of no studies that address the long-term health effects from breathing some sorbent components. 

 Certainly, drying time is increased with some of the “wetter” and more effective materials produced today, although under “normal” conditions of temperature and humidity in air condition (either heated or cooled) buildings should enable the carpet to dry in 30 minutes to an hour; perhaps a bit longer in humid coastal areas. 

 As for dry foam and shampoo cleaning, the detergent chemistry is very similar.  A product I used to compound and sell as a “shampoo” had raw ingredients that were sold by the detergent formulator as a DFS, or “dry foam shampoo.”  However, the application equipment was different (cylindrical versus rotary brush action) so those were separated in S100 as “different” methods. 

I hope this helps calrify the issue.