This can pose obvious safety risks. Annealed glass which has not been heat tempered, if broken will not break into the “safety” chunks or dices, but will in fact break into jagged shards. For most types of glass, the temperature required for annealing is within the range of 850–900° F (454 – 482° C). Annealed glass tends to be cheaper, because the processes are not as lengthy.This type of glass tends to break into longer and sharp shards when broken. Standard strength: average breaking point of 6,000 psi; Sharp shards: breaks into large, sharp pieces that can be very dangerous; Flexibility in design: annealed glass can be cut, fabricated or otherwise altered throughout its lifetime. The breakage pattern more closely resembles annealed glass, which can be an advantage in situations where you want the glass to stay in the opening rather than fall out.
Heat strengthened glass is a semi tempered glass which retains the normal properties of ordinary float glass. Annealing of glass is a process in which hot glass objects are gradually cooled to relieve any internal stresses. Annealing glass is one such technique utilized by glass fabricators and manufacturers. Cutting after strengthening (with traditional methods) may weaken the glass. When glass is not annealed correctly, the thermal stress can significantly decrease the overall strength of the glass. The range depends on the composition of the glass but is usually about 450°C. Annealed glass is used when an economical solution is desired. Annealed glass tends to break into longer, jagged shards which can cause significant injury. The annealing process is critical to the durability of glass. (Picture of my beads in the kiln just after the annealing process) ANNEAL: Definition: The process of slowly cooling a completed glass object in a kiln or annealing oven. Toughened glass is also stronger and more resistant to heat than normal glass, which is why it is commonly used in products like car windows, oven doors, shower screens, glass cookware and furniture. This type of failure is often a design issue. ... (>10,000 psi) that is 4 to 5 times stronger to resist breakage, has less chance of thermal stress break, and when damaged, creates small fragments rather than dangerous shards. They both look similar and can be shaped into different sizes, colors, and thicknesses. 36 X 60.
Clear float glass comes in the following types: Standard clear, low-iron glass, standard tints. As a result, tempered glass is less likely to experience a thermal break. When tempered glass is broken (as shown above), it shatters into thousands of tiny pebbles, practically eliminating the danger of human injury caused by sharp edges and flying shards of glass. The cooling pattern causes the outer surfaces to contract faster than the center thus giving the tempered glass its strength. 36 X 60 48 X 60 48 X 84 … This is the process that makes the glass four to five times stronger and safer than annealed or untreated glass. 1/8” DOUBLE STRENGTH CLEAR. Consequently, when tempered glass is broken, it shatters into thousands of tiny pebbles—this practically eliminates the danger of human injury caused by sharp edges and flying shards. Annealed Glass. Although it doesn’t shatter like tempered glass, it can fracture into dangerous shards. The term, "anneal," is mainly used to describe the glass-cooling process that is performed at a fabricator's float plant. If the glass is cooled slowly through that range, so that the temperature near the surface is never very different from that of the interior, then the strain in the resulting object is much reduced. Among the variety of issues for improperly annealed glass is the probability of the glass to crack or shatter from just a slight temperature change. Annealed glass is heated to approximately 650-700 º C, but the cooling process is slower than that for tempered glass. In rare instances, if toughened glass is damaged - for example by chips and scratches - it can lead to the glass breaking, seemingly of its own accord.