Balustrade regulations
Glass balustrade regulations: the Part K and BS 6180 check
Pick the position, the fixing and the height, and this states the horizontal line load your barrier has to resist and what the glass itself has to carry, from BS EN 1991-1-1 and its UK National Annex, the loads BS 6180 designs to. The standard's design loads, printed with their category. Not our certification of anything.
Last reviewed against BS 6180 (barriers in and about buildings) and Approved Document K (protection from falling, collision and impact).
Why it matters
Why check before you order?
A barrier is the only glass in a building whose job is to stop a person falling. The load it has to resist is set by what the building is used for: 0.36 kN per metre on a domestic staircase, 3.0 kN per metre in a shopping mall, for what can look like the same panel. Ordering the glass before the load case is settled is how a balustrade gets built twice.
A barrier is the one piece that has to hold a person
Every other pane we cut has to survive being walked into. A barrier has to stop somebody going over the edge, which is why it is designed to a load rather than chosen from a thickness chart.
The load depends on the building, not the balcony
The same frameless panel is a 0.36 kN/m job in a house, 0.74 on that house's balcony and 3.0 in a shopping mall. Getting the row right is most of the work, and it is the part quotes get wrong.
It tells you what we cannot answer from a web page
Where the standard defers, this page says so and names the document instead of printing a number. The panel itself is specified from your load case, in writing, before anything is cut.
All areas within or serving exclusively one single-family dwelling, including stairs, landings and the edges of internal floors, but not external balconies or roof edges.
Leave that unticked for a frameless barrier where the glass itself is the guard. It is the demanding case, and it is the one most enquiries turn out to be.
Horizontal line load the barrier must resist
0.36 kN/m
0.36 kN per metre, applied horizontally at handrail height, for category A (all areas within or serving exclusively one single-family dwelling, including stairs, landings and the edges of internal floors, but not external balconies or roof edges).
- What the glass has to resist
- The glass is the barrier here, so it resists all of it: 0.5 kN per square metre spread over the panel, and 0.25 kN applied to any part of it. Those two and the line load are alternative load cases, each checked on its own, never added together.
- Height
- 1100mm clears the 900mm minimum for this position. Approved Document K Table 3.1, single-family dwellings: 900mm at stairs, landings, ramps and the edges of internal floors.
- Free-standing, no handrail
- A free-standing barrier with no handrail is the demanding case: nothing else is holding anyone back, so the glass has to keep doing its job after a pane breaks. Toughened laminated is the usual answer, and BS 6180 is explicit that a free-standing barrier without a handrail should be laminated. We specify the make-up from the load case above and the fixing below, never from a thickness someone guessed.
- The fixing
- A continuous base channel makes the panel a cantilever: the whole horizontal load arrives as a bending moment at the bottom of the glass, and the same moment goes into the channel, its fixings and whatever the channel is bolted to. On a free-standing barrier the sway at the top usually decides the thickness before the glass is anywhere near its stress limit, and BS 6180 sets the deflection limit to work to.
Send us the load case above, the fixing and the opening and we will specify the panel: make-up, interlayer and thickness, with the drawing. A barrier is structural, so this is the step we will not let anyone skip. On site and unsure of the substrate? Book a measure visit.
Send it to your builder, your engineer or your inspector. The link reopens the checker with the same barrier.
The load table
What each occupancy has to resist
A barrier in the UK is designed to BS 6180 (barriers in and about buildings), and BS 6180 takes its horizontal loads from BS EN 1991-1-1 and its UK National Annex (Table NA.8), which tabulates them by what the building is used for. Those are the figures below. The three on a row are alternative load cases, each checked on its own: the line load along the top of the barrier, the load spread over the infill, and a point load anywhere on the infill are never added together.
| Where the barrier is | Category | Line load at handrail height (kN/m) | Load on the infill (kN/m2) | Point load on the infill (kN) |
|---|---|---|---|---|
| Domestic stairs, landings and floor edgesAll areas within or serving exclusively one single-family dwelling, including stairs, landings and the edges of internal floors, but not external balconies or roof edges | A | 0.36 | 0.5 | 0.25 |
| Domestic balcony, Juliet balcony or roof edgeExternal balconies, Juliet balconies and the edges of roofs, including those serving a single-family dwelling | A | 0.74 | 1.0 | 0.5 |
| Flats, hotels and other residentialOther residential: blocks of flats, hotels, guest houses, halls of residence and institutional buildings | A | 0.74 | 1.0 | 0.5 |
| Offices and work areasAreas not susceptible to overcrowding in office and institutional buildings, and in industrial and storage buildings except the light-traffic routes below | B | 0.74 | 1.0 | 0.5 |
| Stairs, landings and corridors in a public buildingStairs, landings, corridors and ramps in buildings other than a single-family dwelling | B, C1 to C3 | 0.74 | 1.0 | 0.5 |
| Shops and retail areasAll retail areas, including the public areas of banks, building societies and betting shops. Where overcrowding can occur, the assembly row below applies instead | D | 1.5 | 1.5 | 1.5 |
| Restaurants, cafes and barsRestaurants, cafes and bars | C1 | 1.5 | 1.5 | 1.5 |
| Areas with fixed seating close to the barrierAreas with fixed seating within 530mm of the barrier, balustrade or parapet | C2 | 1.5 | 1.5 | 1.5 |
| Assembly areas, shopping malls and crowdsAssembly areas without fixed seating, theatres, cinemas, auditoria, shopping malls and other areas susceptible to large crowds | C3, C5 | 3.0 | 1.5 | 1.5 |
| Pedestrian areas in a car parkPedestrian areas in car parks, including stairs, landings, ramps, the edges of internal floors, footways and roof edges | F, G (pedestrian areas) | 1.5 | 1.5 | 1.5 |
| Light access stairs and gangways up to 600mm wideLight access stairs and gangways not more than 600mm wide | B | 0.22 | The National Annex gives no infill figures for this row, because a barrier this narrow is normally a rail rather than a glass panel. For a glass infill here, see BS 6180 and BS EN 1991-1-1 for this category's figures. | |
| Grandstands and stadiaGrandstands, stadia and other spectator terraces | C5 | The standard does not tabulate a figure here: it refers grandstands and stadia to the requirements of the appropriate certifying authority, so see BS 6180 and BS EN 1991-1-1 for this category's figures and take the authority's own loading for the ground. | ||
| A barrier that has to stop a vehicleBarriers to car parks and vehicle ramps that have to resist the impact of a vehicle | F, G (vehicle impact) | Vehicle impact is a calculation from the vehicle's mass and speed under BS EN 1991-1-1 clause 6.3.3.2 and its National Annex, not a tabulated line load, so see BS 6180 and BS EN 1991-1-1 for this category's figures. Glass alone is not a vehicle barrier: it goes behind or above a structural one. | ||
What the three figures are
- Line load
- A horizontal load per metre run, applied along the top of the barrier at handrail height. It is the load that decides whether the barrier stays up, and it goes through the glass whenever there is no handrail to take it.
- Load on the infill
- A load spread over the face of the panel, which is what a crowd leaning on it looks like. It is the case that usually sets the thickness of an infill panel.
- Point load on the infill
- A single load applied to any part of the panel, wherever it is worst. Toughened and laminated glass answer it very differently, which is one reason the make-up is specified rather than guessed.
The sources
The loads are BS EN 1991-1-1 and its UK National Annex (Table NA.8), the values BS 6180 (barriers in and about buildings) designs to. The heights, the guarding positions and the 100mm sphere rule are Approved Document K (protection from falling, collision and impact), which is free to read on gov.uk. We reproduce the rows a glass merchant is asked about; the documents themselves carry the rest, and they decide the edge cases.
Approved Document K on gov.ukApproved Document K
Heights, gaps and where guarding is required
The loads above decide whether the barrier is strong enough. Approved Document K (protection from falling, collision and impact) decides where a barrier is needed at all, how high it has to be and what it may not let through. The checker applies the height rule to the position you pick; these are the rules behind it.
900mm
Stairs, landings, ramps and the edges of internal floors inside a single-family dwelling, and stairs and ramps in every other building. Table 3.1.
1100mm
External balconies, Juliet balconies and roof edges, and the landings and internal floor edges of buildings other than a single-family dwelling. Table 3.1.
100mm sphere
No opening in the guarding may let a 100mm sphere through, and in a building used by children under five it should not be climbable. For frameless glass that is about the gaps beside and beneath the panels, not the glass.
Anything this page does not cover, the document does, and it is free to read: Approved Document K on gov.uk. Where a row of the load table has no plain figure, the page says see BS 6180 and BS EN 1991-1-1 for this category's figures rather than printing one.
Straight about it
What we specify, and what we will not guess
The panel comes from the load case
We specify a barrier panel from the horizontal load for the occupancy, the height, the span between fixings and the fixing itself. Not from a thickness chart, and not from what the last job used. You get the make-up in writing with the drawing before anything is cut.
Free-standing is the demanding case
A barrier with no handrail carries the line load through the glass and has nothing else holding anyone back if a pane breaks. It asks the most of the panel, of the base channel and of whatever that channel is bolted into, and it is the case most enquiries turn out to be.
Toughened laminated is the usual answer
For a free-standing barrier it is what BS 6180 points at and what we fit: a laminated panel that breaks stays on its interlayer and keeps the opening closed until it is replaced. Monolithic toughened has its place as an infill under a handrail that would still be standing.
So there is one honest next step from this page. Ask us for a specification with the load case above, the opening and how you want it held, and we will specify the panel, the interlayer and the fixing, and price it. If the substrate is the unknown, book a measure visit and we will look at it on site. The cut-to-size configurator is the right route for a plain rectangular infill panel between posts, under a handrail that carries the load, once the make-up is agreed. It is the wrong route for a free-standing barrier, so we do not send you there with one.
Working out whether the glass has to be safety glass at all? The Part K safety glass checker answers that for every position in the building, and the thickness by use guide gives the trade-standard starting point for everything that is not a barrier.
Straight answers
Balustrade questions
What are the regulations for a glass balustrade in the UK?
Two documents decide it. Approved Document K (protection from falling, collision and impact) sets where guarding is required, how high it has to be and that a 100mm sphere must not pass through it. BS 6180 is the standard the barrier itself is designed to, and it takes its horizontal loads from BS EN 1991-1-1 and the UK National Annex, which tabulates them by what the building is used for. The glass on top of that has to be safety glass classified under BS EN 12600.
What horizontal load does a barrier have to resist?
It depends entirely on the occupancy. A barrier serving one single-family dwelling takes 0.36 kN per metre; the same house's external balcony or roof edge takes 0.74 kN per metre; offices, flats, hotels and public stairs take 0.74; shops, restaurants, bars and pedestrian areas in car parks take 1.5; assembly areas, shopping malls and anywhere susceptible to large crowds take 3.0. The full table is on this page, with the infill loads beside each row.
How thick does glass have to be for a balustrade?
There is no single answer, and any page that gives you one without asking about the load case is guessing. The thickness comes from the horizontal load for that occupancy, the height of the barrier, the span between fixings, how it is held and what has to happen if a pane breaks. Tell us those and we will specify it, with the drawing. The thickness by use guide gives the trade-standard starting point for a barrier, and says the same thing: barrier loading needs a site-specific check.
How high does a glass balustrade have to be?
Approved Document K Table 3.1: 900mm at stairs, landings, ramps and the edges of internal floors inside a single-family dwelling, and 1100mm at external balconies, Juliet balconies and roof edges. In other buildings it is 900mm on stairs and ramps and 1100mm at landings and the edges of internal floors. A barrier in front of an openable window is measured to the bottom of the opening. The checker compares the height you enter against the row for your position.
Does a glass balustrade need a handrail?
Not always, but the answer changes the glass. Where a handrail on its own supports takes the horizontal line load, the glass is an infill and only has to resist the distributed and point loads on its face. Where there is no handrail the barrier is free-standing: the glass carries the line load itself, and nothing else is holding anyone back if a pane breaks. BS 6180 is explicit that a free-standing barrier with no handrail should be laminated glass.
Toughened or laminated for a balustrade?
Toughened laminated is the usual specification for a free-standing barrier, because a laminated panel that breaks stays in one piece on its interlayer and keeps the opening closed while it is replaced. Monolithic toughened is used for infill panels where a handrail, carried independently, would still be standing after a pane broke. Which of the two applies to your barrier is part of the specification, not a preference.
Is this checker a structural certification?
No. It reproduces the standard's design loads for the case you describe and checks your height against Approved Document K. It does not size a panel, design a fixing or certify a barrier, and nothing on this page is a substitute for an engineer where the structure is in question. Ask us for a specification and we will do the work properly.
Every tool the workshop publishes is listed on the free glass tools page, and each one states its own sources and its own limits.