BS 6180 is the document everyone names and almost nobody reads. If you have been handed a drawing marked "barrier to BS 6180" and you are trying to work out what that actually commits you to, this page sets it out: what the standard is, where the numbers really come from, and what the figures mean when you are buying a balustrade rather than designing one.
We make barriers to these rules every week, under UKCA certification to BS EN 1090-2, so this is written from the manufacturing side rather than the textbook side.
What BS 6180 actually is
BS 6180:2011 is called Barriers in and about buildings. Code of practice. Two things follow from that title.
It is a code of practice, not law. Nothing obliges you to follow it. What makes it matter is that Approved Document K points at it, and building control bodies treat it as the normal way of showing a barrier has been properly designed. Depart from it and you can still comply, but you then have to justify how.
And it covers barriers, which is broader than balustrades. Guarding to a floor edge, a Juliet balcony, a stair flight, a roof edge, a sunken area, a car park. Glass, steel, timber, masonry. The same design thinking applies to all of them.
Where the loadings really come from
This is the part most pages on this subject get wrong, including some written by people who should know better.
Approved Document K, paragraph 3.2(c), says guarding should resist, as a minimum, the loads given in BS EN 1991-1-1 with its UK National Annex and PD 6688-1-1. It is only after that, at the end of the same paragraph, that it says: for further guidance on the design of barriers and infill panels, refer to BS 6180.
So the loads are Eurocode loads. BS 6180 is where you go for how to turn those loads into a barrier that works. The reason everybody calls them "BS 6180 loadings" is that BS 6180 tabulates the same figures in its Table 2, which is far easier to find than the National Annex.
In practice it makes no difference to the numbers. It makes a difference when a building control officer or an engineer asks you which document you designed to, and it is worth knowing which answer is the correct one.
The three load cases
A barrier is not checked against one force. It is checked against three, and a barrier can pass one and fail another.
- Horizontal line load, in kN per metre run. Applied at 1100mm above finished floor level, or above the pitch line on a stair, regardless of how tall the barrier actually is. This is the crowd-leaning case.
- Uniformly distributed load on the infill, in kN per square metre, applied over any one square metre of the infill below handrail level. This is the many-people-pressed-against-it case.
- Concentrated load on the infill, in kN, applied over a small area at the most vulnerable point on the panel. This is the one-person-with-a-sharp-elbow case, and on glass it is usually the one that sizes the panel.
The line load being applied at a fixed 1100mm catches people out. A 900mm high internal balustrade is still checked for a load applied at 1100mm. You are not designing for where the rail is, you are designing for where a person pushes.
The loading figures by building use
These are the categories Dio-Met works with most. The full table runs to fifteen rows and covers grandstands, vehicle loading and other cases outside our range, so check the standard itself if your building is not listed here.
| Where the barrier is | Line load (kN/m) | Infill UDL (kN/m²) | Point load (kN) |
|---|---|---|---|
| Inside a single family dwelling: stairs, landings, internal floor edges | 0.36 | 0.5 | 0.25 |
| External and Juliet balconies on a single family dwelling, and roof edges | 0.74 | 1.0 | 0.5 |
| Other residential, institutional, educational and office areas not susceptible to overcrowding, including stairs, landings, corridors and ramps | 0.74 | 1.0 | 0.5 |
| Light access stairs and gangways not more than 600mm wide | 0.22 | n/a | n/a |
| Restaurants and bars, retail, fixed seating within 530mm, pedestrian areas in car parks | 1.5 | 1.5 | 1.5 |
| Assembly areas, theatres, cinemas, shopping malls | 3.0 | 1.5 | 1.5 |
Two figures do most of the work in domestic jobs. 0.36 kN/m inside the house. 0.74 kN/m the moment you step outside onto a balcony or a roof edge. That doubling is why an internal landing balustrade and an external balcony balustrade that look identical are not the same product.
And note what sits in the 0.74 row: a Juliet balcony on an ordinary house is designed to the same line load as a full walk-out balcony. It is a barrier across an opening at height, and the standard treats it accordingly.
Guarding heights under Approved Document K
Heights are not in BS 6180. They are in Approved Document K, Diagram 3.1, and this is the table that settles the 900 versus 1100 argument.
| Building and location | Minimum height |
|---|---|
| Single family dwellings: stairs, landings, ramps, edges of internal floors | 900mm for all elements |
| Single family dwellings: external balconies, including Juliette balconies, and edges of roof | 1100mm |
| Factories and warehouses (light traffic): stairs and ramps | 900mm |
| Factories and warehouses (light traffic): landings and edges of floors | 1100mm |
| Residential, institutional, educational, office and public buildings: all locations | 900mm for flights, otherwise 1100mm |
| Assembly: within 530mm in front of fixed seating | 800mm |
| Assembly: all other locations | 900mm for flights, elsewhere 1100mm |
| Retail: all locations | 900mm for flights, otherwise 1100mm |
The single most common mistake we see on domestic work is 1100mm being specified for an internal landing. Inside a house it is 900mm, for stairs, landings and internal floor edges alike. 1100mm applies when you go outside, or when the building is not a single family dwelling and the barrier is not on a flight.
A small point of trivia with a practical edge: Approved Document K spells it "Juliette balconies". Most of the trade spells it Juliet. Both turn up on drawings and neither is wrong.
When you need guarding at all
Requirement K2 sets two different trigger heights, and they are further apart than people expect.
- In dwellings: guarding where someone could be injured falling from a height of more than 600mm.
- In buildings other than dwellings: guarding where someone could fall more than the height of two risers, or 380mm if the drop is not part of a stair.
So a raised terrace 500mm above the garden needs no guarding at a house. The same step in a school or an office does.
The 100mm sphere, and the rule about horizontal rails
Approved Document K paragraph 3.3 applies where a building may be used by children under five years old during normal use. Two requirements, and the second is routinely misquoted.
- A 100mm sphere must not be able to pass through any opening in the guarding.
- Avoid horizontal rails.
Most of the industry paraphrases the second as "non-climbable", which is the intent but not the wording. The document asks you to avoid horizontal rails, because a horizontal rail is a ladder rung to a toddler. Vertical bars, mesh and glass infill all satisfy it comfortably. A classic ranch-style rail does not.
On our own open riser staircases the 100mm rule is handled by the tread rather than by extra bars. The pressed steel tread tray is folded down behind each tread, which closes the riser gap so a 100mm sphere cannot pass, and no separate riser infill is needed.
Glass barriers
Glass has to carry the same three loads as any other barrier, and then satisfy a set of rules of its own. The industry guidance here is Glass and Glazing Federation Data Sheet 7.2, which works alongside BS 6180.
Impact classification
Glass in a barrier has to give containment, which is tested to BS EN 12600 and expressed as a three part class such as 1(B)1. The minimum class depends on the free path, meaning how far a person could run or fall at the glass before hitting it.
- Free path up to 1500mm: toughened to class 3(C)3, or laminated to class 3(B)3.
- Free path over 1500mm: toughened to class 1(C)1, or laminated to class 1(B)1.
Meeting the impact class is not the same as carrying the loads. A thin pane can pass the impact test and still be nowhere near strong enough for the line load. Both have to be satisfied.
Deflection
BS 6180 limits how far a barrier may flex, on the basis that a barrier which feels unsafe is a problem even if it is structurally fine. The working limit for glass is L/65 or 25mm, whichever is smaller, where L depends on how the panel is held: the longest dimension of the glass if it is framed, or the distance from the clamping to the top edge if it is free-standing.
This is why frameless glass gets thicker as it gets taller even though the loads have not changed. On a tall free-standing panel it is almost always deflection that decides the thickness, not strength.
Toughened or laminated
Both are permitted. The question is what happens the day a panel breaks.
A single toughened pane gives containment right up until it breaks, and then gives none at all. It collapses into fragments and leaves an open hole. Laminated glass holds together on the interlayer, so a broken panel still contains the opening while it is replaced.
Our position, and it is the one we would want for our own house: where the glass is the only thing between a person and a drop, use laminated. A free-standing frameless panel with nothing above it is exactly that situation. Where there is a steel top rail or a handrail that would still contain the opening with the glass gone, toughened is a reasonable choice and most of our framed systems use it.
This is a specification decision taken before the glass is cut, not something that can be changed later, so raise it at enquiry stage.
What this means when you are buying rather than designing
If you are not the engineer, four things decide which barrier you need, and they are the four we will ask you for.
- What the building is. House, flat, school, office, bar. That picks the line load, and it is the difference between 0.36 and 3.0.
- Inside or outside. That picks the height and, on a dwelling, doubles the load.
- How far the drop is. That decides whether guarding is required at all, and feeds the glass impact class.
- Whether children under five will use the building. That brings in the sphere and the horizontal rail rules.
What we certify is what we make. Our fabricated steelwork is UKCA marked to BS EN 1090-2 under factory production control, with coded welders and documented QC, and we supply the declaration of performance with the job. What we cannot certify is the structure we are fixing to. Whether your wall, slab, joist or parapet will take the fixings is a question for your engineer, and it is not something anyone can answer from a photograph.
Glass is bought in rather than made here, so it carries its own manufacturer's certification and sits outside our ten year warranty on fabrication.
Frequently asked questions
Is BS 6180 a legal requirement?
No. It is a code of practice. The legal requirement is Part K of the Building Regulations. BS 6180 is the recognised route to showing you have met it, which is why building control expect to see it named.
What is the minimum height for a balustrade in a house?
900mm for stairs, landings and internal floor edges. 1100mm for external balconies, Juliet balconies and roof edges.
What line load does a domestic balcony balustrade need to take?
0.74 kN per metre, applied horizontally at 1100mm above floor level, plus 1.0 kN/m² on the infill and a 0.5 kN point load.
Why is my internal balustrade designed for a load at 1100mm when it is only 900mm tall?
Because the standard applies the line load at a fixed 1100mm above the floor whatever the barrier height. It represents where a person pushes, not where the rail is.
Does a glass balustrade have to be laminated?
Not in every case. Where the glass is the sole containment, with no handrail or top rail above it, laminated is the right answer because a broken toughened panel leaves an open gap. Where a rail would still contain the opening, toughened is acceptable.
Does BS 6180 cover the fixings and the structure behind them?
It covers the barrier and how it is designed. What the barrier is fixed into is a matter for the structural design of the building, and remains the responsibility of your engineer.
Can you supply what building control will want to see?
Yes. We supply the UKCA declaration of performance for the fabricated steelwork, glass certification from the processor, and the general arrangement drawing. Tell us at order stage if building control have asked for anything specific.
Related
- Glass Balustrade Building Regulations UK: the same rules applied specifically to glass balustrades
- Balcony and Juliet Balcony Building Regulations: heights, loads and openings for balconies
- Handrail Building Regulations UK: handrail heights, grip sizes and continuity
- Staircase Building Regulations UK: rise, going, headroom and stair guarding
- Glass Balustrade Fixing Guide: methods and substrates
- Metal and Glass Balustrades: our full range, priced online
Talk to us about your barrier
If you have a drawing marked up to BS 6180 and you want to know what it will cost to build, send it over. We have been making barriers to these rules in our Sheffield workshop for 35+ years and we deal with building control queries every week. Call 0114 243 9009, email sales@diomet.co.uk, or price a balustrade online.
About this guidance
This page is general information, written by a manufacturer to help you understand what the standards ask for. It is not a structural design, it is not a specification for your project, and it is not a substitute for advice from a structural engineer or from your building control body.
Any figures given apply to the specific arrangement described. They do not carry across automatically to a different height, span, glass make-up, fixing arrangement or substrate. Suitability for your own project remains the responsibility of you, your designer, your structural engineer or your building control body.
Standards are revised and guidance changes. The heights and triggers on this page are taken from Approved Document K (2013 edition, England). The loading figures are those given in BS EN 1991-1-1 with its UK National Annex and PD 6688-1-1, as tabulated in BS 6180:2011. The glass guidance follows Glass and Glazing Federation Data Sheet 7.2. Check the current version of any standard named here before relying on it, and satisfy yourself that it applies to your situation and to your part of the UK, because Scotland and Northern Ireland have their own technical standards.
Nothing on this page forms part of a contract. What we supply is covered by the specification and the terms in force at the time of order. If you want a definitive answer for your own job, send us the details and we will give you one in writing.