Conservatory Glass - what are the standards?

For a conservatory to be exempt from the Building Regulations they need to meet certain requirements and the quality and standard of the glass or glazing is one of them - perhaps the most important at that. Most conservatory suppliers are very good on delivering and installing the correct glass for conservatories as many perceive this to be the biggest risk factor to health and safety.

Conservatory glass must therefore comply to the requirements of Building Regulations being Part N Glazing – safety in relation to impact, opening and cleaning.

The following short guide is necessarily worded in a general way and cannot cover every circumstance. It is intended only as a guide for manufacturers, suppliers and installers of new and replacement glass and glazing products for domestic use.

Where glass and glazing products are supplied for domestic use they must comply with the 'General Safety Requirement' of the General Product Safety Regulations 1994 (GPSR). This requires consumer products to be reasonably safe and this may be achieved by conforming with British Standard BS 6262: Part 4: 1994 with reference to the Approved Document N of the Building Regulations 1991.

The updated British Standard "BS 6262: Part 4: 1994 Code of Practice for Glazing for Buildings", introduced new requirements that glazing fitted in 'critical locations' in domestic buildings must be safe.

This may be achieved for example by fitting glass which breaks safely; small panes of ordinary glass; thicker ordinary glass; by protecting the glass with a permanent robust screen; or using plastics glazing sheet. Further details are given below.

The GPSR and the standard apply to all domestic glazing installations whether new build, replacement or refurbishment.

Certain internal and external areas are considered 'critical locations' in terms of the safety of vertical glazing, as they are at risk from accidental human impact. The critical locations defined by the standard are similar to the Approved Document N of the Building Regulations 1991.

The 'critical locations' in any internal or external domestic area are:

DOORS:- Any glazing or part of that glazing in a door, which is between the finished floor level and a height of 1500mm above the floor level, is in a 'critical location'.

DOOR SIDE PANELS:- Any glazing or part of that glazing, which is within 300mm of either side of a door edge and which is between the finished floor level and a height of 1500mm above the floor level, is in a 'critical location'

WINDOWS AND WALLS:- Any glazing or part of that glazing, which is between the finished floor level and a height of 800mm above the floor level, is in a 'critical location'.

Where only part of a glazing unit falls within a 'critical location' the whole of that unit must comply with BS 6206.

Safety glass, which complies with 'BS 6206: 1981 (1994)' may be fitted in 'critical locations'. This standard requires the glass to pass stringent tests involving impacts from a "punch bag" containing lead shot. Providing the glass does not break or breaks safely it is categorised as Class A, B, or C with A being the highest grade of safety glass.

Different types of glass can be classified as safety glass:-

Toughened Glass (also called tempered) categorised as Class A

This looks like ordinary glass but receives a special heat treatment process to toughen it. It is much stronger than ordinary glass and on impact disintegrates into small granular pieces, which are not sharp, reducing the risk of injury.

Laminated Glass available in Class A, B or C

Consists of two or more sheets of ordinary glass which are attached together by a plastic interlayer. The plastic layer provides a barrier and on impact any broken shards of glass will remain attached to the plastic reducing the risk of injury.

Wired Glass (also called Pyroshield safety clear/textured) categorised as Class C

This glass has a network/mesh of wires embedded in it. Certain types of wired glass can satisfy the impact requirements for safety glass while giving a level of fire resistance.

Plastics Glazing Sheet

Certain types of transparent plastic sheet can satisfy the impact requirements for safety glass. Please Note: Glass in doors and side panels may only be glazed in Class C materials where the smaller dimension is a maximum of 900mm. Where this dimension is greater than 900mm glazing categorised as Class A or B is required.

'British Standard 6206: 1981 (1994)' requires that each piece of safety glazing used within 'critical locations' should be marked with the all of the following:

• The British Standard number 'BS 6206'.
• Identification of the type of glass used i.e. 'L' for laminated, 'P' for plastics, 'T' for tempered (toughened), 'W' for wired or 'SFB' for safety film backed.
• The category of safety glass used i.e. 'Class A', 'Class B', or 'Class C' (based on its performance under impact tests). A suffix 'o' denotes front impact test only e.g. mirrored wardrobe doors.
• An identifiable name, trademark or other identification mark of the manufacturer. If any of the above markings are lost by cutting, then the company which carries out the cutting must replace markings a) to c) and add their own identifiable name or trade mark.