Safety glass Rules and Regs:
1972 saw the introduction in the glazing industry of a new 'code of practice' number CP152 which more or less said that in doors use 6mm glass instead of 4mm glass on the basis that is is thicker and therefore harder to break. In fully glazed doors such as patio doors toughened(tempered) glass was recommended, but all too often not used because of the extra cost to the seller, and because firms selling on price had to keep their costs down, people were stillhaving some very nasty accidents.
Location of Safety glass in the home:
1972 saw the introduction in the glazing
'Safety' glass is now mandatory in the home since 1992 when Building Regulations part N, covering glazing materials and their locations for all building work was very first introduced. I believe this was also updated in 1995 and the regulations apply to not only new, but alsoreplacement glass. Briefly then, all glass changed since 1992 should have been done so withthe use of safety glass in areas most at risk (called critical locations).
This means most doors and all glazing in windows where the glass is within 2ft 7in - or 800mm, of the floor or ground, where particularly toddlers and the elderly are most at risk.
The 'law' about safety glass:
No 'law' as such, although the industry has to comply with British Standards, and we wouldin effect be breaking the law by not complying with the relevant standards. This is becauseThe Consumer Protection Act 1987 states that "it is an offence to supply goods which fail tocomply with the general safety requirement". In effect this means that BS6262 Part 4 shouldbe regarded, for all practical purposes, as a legal requirement for any glass either sold, or supplied and fitted, directly to the public knowingly for use in critical locations.
There are two main types of safety glass used in the home:
Laminated glass is a combination of two or more glass sheets with one or more interlayer of plastic (PVB) or resin. In case of breakage, the interlayer holds the fragments together and continues to provide resistance to the passage of persons or objects. This glass is particularly suitable where it is important to ensure the resistance of the whole sheet after breakage such as: shop-fronts, balconies, stair-railings, roof glazing. Production
There are two types of laminated glass: PVB and resin laminated glass:
- PVB laminated glass is two or more sheets of glass which are bonded together with one or more layers (PVB) under heat and pressure to form a single piece.
- Resins laminated glass is manufactured by pouring liquid resin into the cavity between two sheets of glass which are held together until the resin cures.
Toughened (tempered) glass
Four to five times harder to break than ordinary annealed glass, and if it breaks it does so safely by disintegrating into thousands of very small pieces with dulled edges (like car windscreens used to). In a normal thickness of 4mm (unless you get a 'cheap and nasty' door which might have 3mm thickness), this is what is commonly used in most sliding patio doors and front and back doors in the replacement industry today.
The other type of safety glass is Laminated, which looks much like ordinary glass but has an almost indiscernible tint, which some customers think makes them look as if their net curtains are dirty! The slight tint is the result of the sandwich structure of laminated glass where two layers of 3mm glass are used with a tough plastic interlayer called polyvinyl butyrain (pvb). The combination of the extra thickness , now 6.4mm overall, and the plastic interlayer is what gives it the slight tint. Although laminated glass uses ordinary non toughened annealed glass, when hit hard enough the outer layer of glass may crack, but the broken pieces will adhere firmly to the interlayer, and so stop splinters of glass flying off.
All glass in the blue shaded area should be safety.
Most Conservatories should be fitted with safety glass everywhere, except in the fanlightswhere it is not really necessary. Buying on price could mean sacrificing safety- is penny pinching worth it!