Guidance revised August 2026
Stairs, Balustrading & Barriers
Guidance notes for glass protecting a change in level - Approved Document K and BS 6180.
Glass used in stairs, balustrading and barriers most often falls under Building Regulations Approved Document K (Protection from falling, collision and impact). Barrier loadings are given in BS 6180:2011, Barriers in and about buildings - Code of practice.
The two design approaches
Whether you need a handrail changes the glass specification entirely. Decide this first.
| Infill panel | Free-standing barrier | |
|---|---|---|
| Handrail | Yes - fitted independently of the glass, not on it | None |
| Typical glass | Single toughened, minimum 10mm | Toughened laminated, minimum 17.5mm |
| What carries the load if the glass fails | The handrail | The remaining laminated leaf |
Infill panels - with an independent handrail
A single toughened glass, normally a minimum of 10mm, can be used only if there is a handrail above that is fitted independently of the glass - not fixed to it. The handrail must itself be capable of withstanding the loadings required to satisfy the regulations.
The reason for the independent handrail is that if the glass breaks and falls away, the handrail remains intact and prevents anyone falling.
Recommended maximum spans
| Glass | Recommended maximum width |
|---|---|
| 10mm toughened | 2100mm |
| 12mm toughened | 2400mm |
Larger spans are always possible, but loadings must be considered and additional fixings used to reduce load deflection on the glass. If in doubt, we can provide basic calculations on whether an item will pass the loadings applied in an infill or free-standing installation.
Where larger glass panels are planned, drilling for security pins in suitably robust clamps should be considered. Generally two pins per panel - one each side - is adequate to prevent the glass slipping or dropping.
Free-standing barriers - no handrail
Where no handrail is fitted, the material must meet the loadings set out in Approved Document K. As a minimum this will generally be 17.5mm toughened laminated, though industry practice is now moving towards 21.5mm.
| Specification | Status |
|---|---|
| 17.5mm toughened laminated - 2 x 8mm toughened, 1.5mm interlayer | Generally the minimum |
| 21.5mm toughened laminated | Industry norm is moving to this. Greater load resistance and less deflection in both normal and broken states. |
What a toughened laminated barrier does
- In its normal installed state it provides the load resistance required to meet Approved Document K.
- If one leaf breaks, the remaining leaf retains a barrier, but with reduced structural integrity.
- On breakage, the lamination prevents shattered glass from falling or spreading, causing less damage to people and property.
Fixings
| Fixing type | Suitability |
|---|---|
| Free-standing U-channel | Preferred. By design, offers greater load dissipation into the glass and the fixing substrate. There is greater evidence to support this type meeting Approved Document K without further calculations. |
| Round stand-off point fixings | Use with care. Must be of a size and specification suitable for the application, placed no more than 500mm apart, and offer adequate surface contact to dissipate bending forces. By the nature of their design they offer reduced contact area and high load dissipation into the glass and substrate. |
| Edge point-fixing clamps | Generally not acceptable for free-standing barriers - they do not offer the surface contact area required to dissipate loadings. |
Consideration must also be given to the fixing substrate, and whether it is capable of withstanding the bending forces transmitted through the glass and fixings.
Fixing holes in toughened laminates
Hole diameter should generally equal the thickness of the glass, with a tolerance allowance of 3-4mm on the tight size of the bush, to allow clearance for any excess EVA in the holes and any minor misalignment.
Holes in barriers, other than those required for perimeter fixings, are generally not acceptable - they greatly reduce the load the barrier can withstand.
How we make them
We CNC match-pair our toughened laminates wherever possible. This gives accurate alignment between the panels for a flush edge finish, and the CNC machined edges produce stronger glass panels than traditional edging machines.
Related standards
| Standard | Covers |
|---|---|
| Approved Document K (2013 edition) | Protection from falling, collision and impact. Applies in England. |
| BS 6180:2011 | Barriers in and about buildings - Code of practice. Includes minimum horizontal imposed loads for parapets, barriers and balustrades. |
| BS 6262-4 | Glazing for buildings - safety related to human impact. Referenced by BS 6180 for glass in full-height barriers. |
| BS EN 12600 | Impact classification for flat glass. |
Sources: Approved Document K, 2013 edition, HM Government (Open Government Licence); BS 6180:2011; Park Glass Ltd manufacturing guidance. Standards current as at August 2026.
