WHY SHOULD SAFETY GLASS BE USED FOR DOMESTIC ROOFLIGHTS?

Most glass overhead installed in products like roof lights and skylights is termed as 'safety glass' and is known as toughened or tempered glass. Safety glass when damaged enables a toughened glass to be designed and break into tiny fragments, rather than larger fragments that are much more prone to damage, especially if the glass is mounted overhead. Security toughened glass is 4-5 times as durable as a regular annealed glass.

Safety Glass uses roof lights which in turn uses toughened safety glass of at least 4 mm in most domestic settings, though some manufacturers such as safety glass processors in India prefer to use 6 mm since it has less displacement. That reduces the roof light capacity for water ponding at safety glass construction sites.

Due to the production process, the toughened safety glass may often be vulnerable to 'spontaneous breakage' owing to impurities of Nickel Sulphide found in the glass. Manufacturing companies such as safety glass processors in India can counter this effectively by using a method called 'heat soak testing' that significantly reduces the risk of accidental breakage. For obvious safety reasons, this procedure is typically used to walk on specification glass at safety glass construction sites.

Roof lights with a panel size above 3m2 or 5mts to 13mts from floor level are vastly different and enable laminated safety glass to be used. It is intended to keep the glass intact physically to prevent it from falling, even though the safety glass itself has been broken and it should either be laminated annealed or even laminated toughened by safety glass processors in India.

HOW A TOUGHENED GLASS IS MADE?

Toughened glass is created by going through a furnace with annealed glass, heating it to above 600 ° C until it is quickly cooled. In the center of the glass, a combination of high compression load on the surface and tensile stresses increase its strength. When the safety glass cracks, the release of these stresses leads it to break into tiny bits-usually followed by a big bang as the energy is released. Toughened (tempered) glass is a preferred choice for roof lights but disadvantages could emerge and safety glass processors in India have methods to tackle it. Initially, safety glass needs to be cut to the size and shape specified before it is handled and put into use at safety glass construction sites.

Additionally, toughened glass is known to spontaneously break for no apparent reason, and the Nickel Sulphide (NiS) component inside the safety glass is now the most likely suspect.

NiS is a chemical pathogen that can exhibit itself during the toughening process; it can cause the glass to crack as it slowly changes conditions over time. This can occur at any moment, from a couple of weeks to several years or not at all. So, safety glass processors in India should examine the safety glass before they go to the safety glass construction site. To expose the safety glass to Heat Soak Testing is one of the most successful forms of overcoming this.

HEAT SOAK TESTING:

Throughout safety glass manufacturing by safety glass processors in India heat soak testing is conducted and will filter out about 95 percent of problem units. It includes heating tempered glass up to 290 degrees Celsius and maintaining it for a regulated period of time at that temperature. This cycle accelerates any reverting NiS additions to their Beta state, which may lead to glass failure.

This method of examination, though more costly, detects potential issues with toughened glass before safety glass is used in production and at safety glass construction sites. This is especially important when determining larger structural roof lights including those used for walk-on applications where heat soak testing is a Building Regulation requirement.

LAMINATED GLASS:

For certain rooflight applications, the annealed laminated glass may also be specified to comply with BS5516 Part 2 – panel sizes over 3m2, and from floor level approximately 5mts and 13mts should be laminated. Safety glass processors in India need to provide them in order to use the safety glass to its full efficiency at safety glass construction sites.

Combining two or more sheets of float glass with one or more interlayers creates laminated glass. Safety glass credibility is maintained from a 'laminated' interlayer, commonly called PolyVinylButyl (PVB), which is heated- and pressure-processed under factory conditions.

If any damage occurs, the interlayer binds together any fragments which prevent them from falling, thereby reducing the risks.

COMBINATIONS:

Toughened Laminated or HST Toughened Laminated also are specific glass requirements, especially when the glass has to execute a structural role, either in a glass floor or structural fins. Safety glass processors in India need to play an active role in distinguishing the uses of safety glass and their various combinations before applying them at the safety glass construction sites.

Contact our technical team at www.fosg.in for more information on toughened (safety) glass requirements for roof illumination.