So going around at the moment is that FD a term we have all accepted over the past 20 years, isn’t actually a thing and glass fines do not fuse to the glass during the tempering process…
I was a member of that world email group for a while now its been more or less silent until yesterday when there was over 20 posts about IWCA removing and denying that FD are real.
here is a copy and paste of the explanation:
"_Group, I like everyone’s analogies on this issue that has confused windows cleaners for years. _
Before I offer some insight on glass research, I would like to first state one thing. Earlier today I laid out the nine major items that the IWCA has accomplished thru the Glass Committee for window cleaners. Not once did I mention “fabricating debris” in that email because the IWCA Glass Committee has always striven to do much more than have a single minded focus. If you have missed that, please go back and read the nine points… Yes - window cleaners are in a better position today than ten years ago.
_With that said, I see much confusion in the many comments on the subject of fabricating debris. The fact is, when this theory developed almost 20 years ago it did something - it gave window cleaners a simple explanation for what we saw in the field on a daily basis - that heat treated glass was different and it scratched randomly for no apparent reason. It was a simple explanation, carved out with much field observation and out of the box thinking along with an elementary collection of microscopes… _
However, 20 years later things have changed… The microscopes these days that look at the very same blurry images that appear to be what we would have called “fab debris” comet scratched years ago can now show with clarity what is actually on the surface. And it’s not pieces of fused debris from unwashed glass that went thru a tempering oven. Science showed us that.
Move forward, and despite sending sample after sample to glass scientists around the world no one could locate the elusive fused particle of glass dust. Not a single scientist anywhere on the planet attributes scratched glass to fused glass particles from unwashed glass.
Move forward a few years, science proved that glass particles in a tempering oven do not melt and fuse like we had imagined they did - no they actually brush off the surface during multiple experiments.
Move forward again glass science studies explained to us the chemistry reaction of water/humidity with the soda lime silica glass surface and the reaction going on there, having multiple effects on glass surface chemistry and thus the wear patterns.
Move forward again and we learned that yes, heat treated glass surfaces (both heat strengthened and fully tempered) are very different than annealed glass. As flat glass goes thru stages of heat treatment, although it becomes more impact resistant (thus meeting safety requirements) it also becomes easier to indent with a particle, “softer” if you will. Yes - it is easier to initiate a scratch on heat treated glass than annealed glass in the lab.
_Future studies will be concentrating on the variations of flat glass tin surface verses air surface, using both wear pattern tests and indentation tests. Some scratched glass recovered from job sites exhibit similar patterns with regard the tin surface. Other observations are brand new, even to some glass scientists. _
_Areas that need attention and further studies are varying amounts of tin in the surface based on where in the ribbon the Glass came from (basically tin gets absorbed a varying rates on the ribbon from middle to outer edges and depending upon thickness and other factors); the mixtures of various tints into the raw glass and how that effects the glass surface; and a few additional surprises. _
We need to look beyond assigning a simple explanation such as “fab debris”, and look to the extensive research being done around the globe. Yes, heat treated glass surfaces are different. Yes, many times heat treated glass scratches easier than annealed glass. We all seem to agree on these same observations in the field and now science is backing up our observations.
So why argue about the 20 year old fab debris theory and instead look with an open mind to what research and science is teaching us. This is not a conspiracy, it’s just old fashioned research in a modern world.
_In summary, it would be easy to say “all glass is the same and when we see changes in surface behavior than its defective.” But listen, that’s not true. The glass surface is much more complex than that. _
Which brings me back to my nine major points that the IWCA Glass Committee did to help window cleaners, none of which focused on fab debris but all of which focused on real world issues in the field.
_As far as the science goes, it is fascinating - and it is showing us things in the lab that we have seen symptoms of for years in the field - but it is a journey. You all have a choice to either embrace a 20 year old theory that may have been well meaning and served a simplistic purpose at the time, or open your minds and learn more about the product you clean every day. _
The choice is yours and I respect your individual right to choose. As always I am open for discussion publicly or privately."
So for all those that don’t receive these emails here is some news you might want to be aware of.