The REAL danger of these three types of surface damage is unpredictable spontaneous breakage. Every window if it has any age, has some scratches on it. So here I am discussing deeper scratches that quickly catch your fingernail. Here is a micrograph of a rather large bad scratch. You can see the difference between the very large scratch and the rather light much smaller scratches.
PIFs, which are point indent fractures, are chips with very small cracks or fractures. Chips don't have fractures or "legs". Each PIF might have one, two, or several cracks. These can shoot out causing very large cracks that span the window in a matter of a split second. Any kind of pressure can cause this to happen. Especially the pressure from an IGU with a case of negative deflection, ND. If the glass is annealed then the crack will span the window creating large broken pieces. But you will seldom see any kind of PIF or chip on a tempered plate. Because at the moment the PIF or chip happens, the tempered plate will completely fracture or dice out into hundreds of small pieces of glass. This is also why IGUs with ND and tempered glass, should be protected from scratches, chips and PIFs. The smallest surface damage will cause an instantaneous implosion. Loud enough to get attention.
IGUs with annealed glass that has ND and has acquired bad scratches, PIFs, and chips, should be monitored on a regular basis. Especially if the IGU(s) also have a growing problem with ND . Even more so if they are on the second or third story above a doorway or walkway. In which case a sheet of protective plastic could be applied, or the windows could be swapped out. But again since it has been conclusively proven that brand new IGUs can have a bad case of ND, the purchaser has every legal right to demand replacement. Before this can happen however, that person must know what the condition of the windows is. So an inspection must be performed!
If you have any concerns just give me a call, text, or send me an email.
Written by Henry Grover Jr.
henrygrover222@gmail.com
6034989474
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