Premature failure can be caused owing to any field alternation like edge grinding, sand blasting or acid etching. Tempered glass does not permit any cutting or drilling; after it has been tempered else it can lead to premature failure. During certain lightning conditions, a particular visible pattern shows up. This is not a defect but a part of the tempering process. The phenomenon of ‘iridescence’ is a common characteristic in tempered glass. Spontaneity in breaking, which is a result of impact damage, weld splatter, windblown debris and internal inclusion, make tempered glass more vulnerable. This vulnerability calls for having an alternative in the form of heat strengthened glass. Breakage is spontaneous. Bow, wrap and/or process roll distortion may evidently be present.