The GGF is a trade association for all those who make, supply or fit flat glass, such as windows, film or plastics. Here is their advice on ‘critical areas’ of glazing.

Critical safety areas

Areas of internal and external walls which are considered critical in terms of safety are:

• Between the finished floor level and 1500mm above that level in doors, and in side panels which are within 300mm of either edge of the door.
• Between the finished floor level and 800mm above that level in the case of walls, partitions and windows.
• Mirrored doors and panels.

It is important to note that any part of a glass area affected must meet the requirements in its entirety and not just in the relevant section.

Requirements of BS 6262 Part 4

There are four recommended solutions to the problem of glazing ‘critical locations’ to meet the new requirements:

Safe Breakage
For doors and door side panels, the glazing used should not break, or should break safely in accordance with Class C of the standard impact test BS 6206 (1981) if 900mm wide or less, or Class B if wider than 900mm. For other low level glazing the pane should comply with at least BS 6206 Class C. Use laminated or toughened glass, or plastics glazing sheet, or wired glass, that meet BS 6206, or glass with plastic film applied so the pane of glass with film meets BS 6206. For unbacked mirror glazing accessible to impact from one side only, the pane should comply with BS 6206 Class CO if equal to or less than 900mm wide or Class BO if wider than 900mm. Unbacked glazing either has no backing behind its entire area, or has a backing which does not retain its integrity or is cracked or broken when tested as described in BS 7449 (1991): Appendix A. If the mirror glazing is fully backed by a solid material, like a wall or timber wardrobe door and it is securely fixed so that there is space of no more than 25mm between the mirror and the backing material, then a glass which does not comply with BS 6206 may be used.

Small Panes
Ordinary annealed glass may be used in small panes up to a maximum width of 250mm and an area not exceeding 0.5m². Such glass must not be less than 6mm in thickness, except in the case of traditional leaded lights and copper lights, where 4mm can be used.

Robustness
Robustness refers to the strength of the glazing forming fronts to non-domestic buildings such as shops, showrooms, offices, factories and public buildings. Some glazing, such as polycarbonate, is inherently strong. Annealed glass that does not normally comply with BS 6206, can gain robustness with increased thickness. Annealed glass may only be used in critical locations, therefore, when the nominal thickness and dimensions are as listed in CRITICAL SAFETY AREAS (Pic 1)

Permanent Screen Protection
If the glazing is installed behind a permanent robust screen, it need not itself comply with any other safety requirements provided that the protecting screen: (a) would prevent a sphere of 75mm diameter from coming into contact with the glazing, (b) is sufficiently robust to sustain at least a centrally applied force of 1100 Newtons. If the protective system is multi-railed, each rail must satisfy this recommendation.

Safety glazing material
Doors and side panels over 900mm wide, not less then BS6206 Class B. Doors and side panels up to 900mm wide, not less than BS 6206 Class C. Low level glazing mostly BS 6206 Class C.

Not less than 6mm annealed glass
Note: areas of annealed glass less than 0.5m² and not greater than 250mm in width must not be less than 6mm in thickness, except in the case of traditional leaded lights and copper lights.

Areas of increased risk

In places where the planned activity generates a special risk, for instance gymnasia or other places for energetic activity, the glazing should comply with at least Class C of BS 6206. In such situations, a designer should consider if a higher class is required or if additional safeguards, such as protective rails or screens, or manifestation, are necessary. For bathing areas including those for baths, showers and swimming pools, or wherever there is a risk of slipping on wet surfaces, safety glazing should comply with Class C of BS 6206. Where there is a difference of more than 0.5m between the levels on either side of the glazing, in addition refer to the separate Code of Practice for Protective Barriers, BS 6180. The use of BS 6180 is not limited to bathing areas.

Manifestation in non-domestic buildings

There are circumstances in non-domestic buildings where large uninterrupted areas of transparent glazing form, or are part of, the internal or external walls and doors of shops, showrooms, offices, factories and public buildings. In these circumstances, to prevent collision, it is necessary for the glazing to incorporate features which make it apparent. This can be achieved by:

• The presence of mullions, transoms, substantial door frames, stall risers or large push and pull door handles.
• Permanent and substantial manifestation by indicators such as broken or solid lines, patterns or company logos, positioned between 600mm and 1500mm above floor level at appropriate horizontal intervals.