Tempered glass when it shatters, the entire pane breaks into tiny little diamond pieces. Tempered glass cannot be cut, and should not be drilled. It is very difficult to break tempered glass. YouÂll need a hammer with a sharp point. With regular glass, if you heat it up to very high temperature and pour cold water on it, you can get very interesting crack patterns. How to tell if a pane of glass is tempered 1. There are tiny dimples near the edges. 2. Tempered glass is not as flat as regular glass. Also, there is heat treated glass, and safety glass. They all have different properties. Animal glue (rabbit glue, hide glue, etc) is the strongest glue for glass. The bond is actually stronger than glass. You guys should look into making Glue-Chipping glass technique. Not difficult to learn with amazing end results. dcarch

Greenhouse Megastore is a good place to check out polycarbonate and acrylic double and triple wall coverings. The double or triple wall with 75-80% light transmission is really good material. If I were to build another greenhouse I'd probably use the double wall polycarbonate. But in a colder climate or if heating to a warmer temperature the triple wall might pay off over time. In my climate ave low 30F and heating to 40F doesn't cost much. Doubling that temp difference doubles heating cost. http://www.greenhousemegastore.com/category/polycarbonate-panels They also have heat loss and heating cost calculators so you can estimate cost and savings with various coverings.

Carolemed, You have asked some very interesting questions - I will attempt to address them all, but my answer may wander a bit because of how the various questions and answers interrelate...here goes and I hope it makes sense. And, if you don'd mind my asking, who is the window manufacturer? You are completely correct that window glass surfaces are numbered from 1 (outside of the exterior lite) to 4 (outside of the interior lite). Your description of logo locations is excellent and makes it easy to picture your IG lay-up. But, there is no inherent "surface 2" or "surface 4", it all depends on how the glass is installed in the IG unit. You cannot "turn around" the inner lite to put surface 4 to the inside of the IG and surface 3 to the outside - still very nice description. Although manufacturers will typically locate the tempered logo's on surface 2 and surface 4, there is really no requirement (other than the window company standards) that they do so so it is possible to end up with the logo on any of the four surfaces. There are a couple of possible issues in your situation, besides the scratched glass. First, and as you considered in your first post, can the panes be installed reversed on the IG? Technically, there is no "right side" or "wrong side" to tempered glass and it makes no particular difference which way they are installed on the spacer to make the IG unit - unless one of those panes has a LowE coating - then in that case it can make all the difference in the world how the lite with the coating is installed. If it's a hardcoat LowE coating then it may be a bit less critical since hardcoat coatings can be exposed, but if it's a softcoat LowE then the coating must be installed between the lites in the IG unit or it WILL scratch. Pretty much anything that touches it has the potential to scratch the exposed coating. You might take a dime and rub one corner of the glass surface. If it scratches, then I would bet dollars to donuts that you have an exposed coating. Another suggestion: when it is dark, hold an open flame (candle, lighter, etc) near the center of the window glass. You should see three reflections in the glass if it has a LowE coating - if it doesn't then you will see only two reflections. The center reflection of the three should be a different color than the two reflections flanking it. The center reflection will wshow the LowE coating if it was installed inside the IGU. Next (assuming the center reflection is the different colored one), is the center reflection closer to the inner flame or the outer flame? If it is closer to the outer flame then the coating is on surface 2. If it is closer to the inner flame reflection then it is on surface 3...did the manufacturer specify the coating location anywhere in the paperwork? The reason I am asking these questions is because I am wondering if the IG was installed in the window sash in reverse...not that the panes were installed into the IGU backwards (which would only be an issue if there was a LowE coating), but if the IG was installed backwards - and the coating is inside the IG as it should be) then you could have an issue with the coating being on the wrong surface within the IG itself. Much more often than not, the coating should be on surface 2 for maximum year-around thermal performance. If the coating is on surface 3 then you could have a fairly significant performance degradation in summer. While it shouldn't be a problem in cold weather (heating season), in summer much of the performance of the LowE coating depends on it being on the outer lite. If the IGU is installed in the window so that the coating is on surface 3.... Okay, back to the main topic. The link that Ann posted is to a site hosted by a man named Dan Fields. Mr. Fields is a window cleaner who has decided to take on the entire glass and window industry because of (in his words) defective tempered glass. Mr. Fields certainly has every right to defend his claim that it is his God-given right to use razor blade scrapers to clean windows even thought the entire glass industry may disagree with his opinion. Mr. Fields also has on one of his websites a waiver that he suggests window cleaners use to get homeowners to sign-off on the window cleaner's use of the scraper in the event that the window or door glass is scratched. Mr. Fields also brags on his site how he has quite literally damaged many windows and doors - knowing that he was doing so - but that he was not liable for that damage since he had the signed waiver in hand. Mind you that he KNOWS that he is scratching the glass, yet he continues to do so - window after window - because it is not his problem. And it makes his point - he has that God-given right to use his scraper on the glass whether it causes problems or not. He uses the terms "defective" and "low quality" throughout his sites, but with the only reference to "defective" and "low quality" relating solely to the window cleaner's use of a scraper and in no way to the actual quality of the glass itself - and there are different levels of quality in glass having nothing to do with a window cleaner's convenience. He does have a point that "fines" (the surface debris he discusses), will scratch glass when it is cleaned with a scraper. But, so will sand, and mortar, and concrete, and stucco, and anything else that has any amount of abrasive that gets trapped by the metal blade. Fines (microscopic surface glass dust and debris) are a fact of life when dealing with tempered glass. All tempered glass has fines - and while some does have more than others - he actually has a point there - fines are not a problem so long as the glass isn't scraped with a metal blade scraper. None of which helps your situation since you have scratched glass....and how it got there is now secondary to getting it resolved. Which brings up the next point or two. First, if the LowE (softcoat) is on an exposed surface - no problem because the window company made a major mistake and needs to change the IG for a new one; assuming you have a softcoat coating; which is about 85% of LowE used in the residential market. A hardcoat can be left exposed, and it can be on surface 4, but a scraper blade will scratch the hardcoat coating as well. Second, if the LowE is on the "wrong" surface - but inside the IG - then again you may have a definite mode of contention with the window company since the performance of the IGU will suffer as it was constructed and while you may (or may not) have to battle a bit for it, you can claim that they need to fix their mistake (which may mean simply that they will turn the same IG around in the sash - but you never can tell). And finally, while scratching the surface of the glass can potentially cause a weak spot, the scratches caused by using a scraper tend to be very fine (no pun intended) and are not likely to be a problem - other than aesthetic. If you end up keeping the glass but getting the scatches removed, there are a couple of systems on the market for removing scratches from glass (in fact, Mr Fields is a distributor for one brand - can you spell potential conflict-of-interest)? Anyway, some of the systems works really well at removing scratches without distorting glass. While some other systems result in unacceptable distortion to the glass surface. Avoid systems that use cerium oxide, trizac, or other abrasives since systems using those materials may be much more likely to distort glass, especially when used by someone who isn't really good at it, and you may not be happy with the results. And if you wouldn't mind keeping us posted (again, no pun intended) on your progress...good luck!

IBC and IRC enforcement is a local issue. Most jurisdictions have adopted these standards and thus, they are the law. If the building inspectors are not enforcing the code, they are also subjecting themselves and their localities to potential lawsuits and should be reported to the State Attorney General. I suspect most of these types of injuries receive an out of court settlement and therefore stay out of the newspapers. I can assure you that most people who had a child seriously injured and/or permanently scarred for life due to crashing into a window that was required to be tempered glass, would be looking for a very aggressive attorney to start filing lawsuits against any and everyone who was responsible.