Balcony Systems Solutions Ltd Information Page:
Railing/Balustrade types, usages and legal requirements
There is much confusion and many rumors in the market place regarding the legal requirements for railings or balustrades.
This breaks downs to a few subjects
What materials are allowed?
What height is required?
What loadings are these balustrades meant to withstand and how are these applied, tested or calculated?
What categories are there for different railing or balustrade usages or areas?
The
information below is an attempt to simplify and translate into layman's
terms what is basically stated in BS6180:1999 "Barriers in and about
buildings - Code of practice". The information on the loadings is taken
from BS6399-1:1996 "Loadings for buildings - Part1: Code of practice
for dead and imposed loads"
What materials are allowed?
There is no limitation per se which material can be used as the balustrade structure, obviously the material chosen must be
- Rigid and strong, be able to resist and not bend under pressure.
- Durable and suitable to the area they are to be applied to.
Plastics
are not usually used for balustrade structures, but rather metallic
elements such as steel, stainless steel or aluminium. Wood is and has
been a popular material but maintenance becomes an element to take into
consideration.
Sometimes the balustrade structure includes and
is the barrier, such as in the case of bars or perforated metal panels.
And in many cases in the modern build use is made of glass as infill
panels.
When using glass you are obliged to use what is designated as safety glass, this can be either toughened
(Heat treated to close to 700' Celsius and cooled quickly creating a
strong layer on both faces of the glass while locking inside the glass
a lot of tension making it approximately four times stronger to impact
than regular float glass, toughened glass in meant to "break safely"
and shatter into thousands of small, and therefore, not dangerous
little bits) or laminated (Two glass panels
with a plastic or resin based interlayer that is allowed to break under
impact but must not allow the impacting body to penetrate the panel)
In
the United Kingdom toughened glass is the most used glass in
balustrades. Whereas in Europe single pane toughened glass is not
allowed. Only laminated glass is allowed.
Thickness and type
of glass depends on the area it must protect and impact class required
and size of each single pane used, more on this in the section relating
to loadings.
What height is required?
For internal railings or balustrades that are inside a single family dwelling the height required is 0.9m from "datum" (the height you can stand on) to the top of the handrail. This is the same for stairs in these area as well.
For external balcony or terrace areas the required height is 1.1m from datum to top of handrail.
What loadings are these railings/balustrades meant to withstand and how are these applied, tested or calculated?
The
loads are expressed in kN/m (kilo Newton meter) in simple terms this is
a quantity very similar to 100Kg (220lb) of pressure per meter length.
If for example it is stated that there is 1.0kN/m it will be appx the
equivalent of one person weighing 100kg putting their full weight on
one meter length.
There are two basic loads that are required
to be met; (a) Loading on the handrail and (b) loading on the infill.
The loading on the handrail is called a "uniformly distributed line
load" (basically meaning that the load needs to be calculated in a
fashion that allows for even distribution of the pressure along the
complete length of the element, as opposed to the sum of the load
applied to one point). The load on the infill, be it glass, metal or
other, is tested and calculated in two separate ways; a distributed
load and a "point load". This means the infill of the railing,
balustrade or barrier must be able to stand an evenly distributed
pressure as well as a concentrated pressure on a small point.
The loads are tested or calculated whereby the maximum deflection under pressure must not exceed 25mm.
You can divide regulations into these basic areas;
A)
Domestic & residential (single family home) internal
stairs/landings etc in which case the handrail pressure must be able to
take 0.36kN/m For external balconies & also in light office areas
non susceptible to overcrowding this is doubled to 0.74 kN/m (this can
be compared to having one averagely weighing person 75kg applying the
full force of their body on every meter of the balcony)
B)
Public areas such as retail areas, bars & restaurants the handrail
pressure must be able to take 1.5 kN/m. This is doubled to a dramatic
3.0 kN/m in areas such as malls, discotheques and areas susceptible to
overcrowding.
As the point load is the more severe, the loadings on the infill panels are as follows:
A)
Domestic & residential (single family home) internal
stairs/landings etc Point load: 0.25kN/m For external balconies &
also in light office areas non susceptible to overcrowding 0.5kN/m.
B)
On all public areas such as retail areas, malls, discotheques, areas
susceptible to overcrowding, bars & restaurants the point load must
be able to take 1.5kN/m.
When dealing with
glass barrier one more element must be taken into account and that is
impact resistance of the glass. A minimum of 10mm glass should be
employed in balcony areas that are wider than 1.5m.
