Top Navigation

Technical + Downloads

 

Glass Weight Calculator

FAQ

Choosing the correct glass for your balustrade is paramount.  In any scenario safety glass will always be required.

Normally toughened glass is the standard option, this being up to 10 times stronger than the same thickness of clear annealed glass.

A second option is toughened laminate glass; this is when two panes of toughened glass are bonded together to form a single pane.  This offers the benefit that should one pane break, the other remains to safeguard any potential fall, it also reduces the potential of injury from falling glass.

Glass is toughened (tempered) by putting a cut to size piece of annealed glass through a kiln that heats the glass to molten point then rapidly cools the glass.  This causes compression on the outer surface thus increasing its strength.  Another benefit to toughened glass is that if it does break it shatters into very small pieces rather than large sharp shards.

One issue with toughened glass is a small risk of a nickel sulphide (NiS) crystal forming within the glass, this can on rare occasions create a spontaneous breakage, this can happen at any time after installation.  The risk of this happening is greatly reduced if you ask for heat soaked glass, this is an added process where the toughened glass is re-heated to a reduced temperature but then cooled slowly.

What is laminated glass?

Laminated glass consists of two sheets of glass bonded together with a special inter-layer between them.Laminate-Glass

For balustrade we normally bond two panes of toughened glass together.

There are many main types of inter-layer available, each has it’s own characteristics;

The most common inter-layers include;

 

PVB             (Poly Vinyl Butyral)      Least resistant to water

EVA             (Ethyl Vinyl Acetate)

SGP             (Sentry Glass)

CIP             (cast in place)

Please be aware that laminate inter-layers can, if not installed correctly, be affected by immersion in water and can eventually cause de-lamination of the two sheets.  Glass should never become submerged in water at any point so the correct drainage will be required to be drilled into the base channel.

The table below shows details of the Uniform Distributed Load (UDL) and required glass make up for toughened and laminate glass for use on free standing glass protective barriers (based on 1100mm top rail from finished floor level).

Design level horizontal UDL
(line load) (KN/M)
Sentry Glass (mm) PVB laminate thickness (mm) Toughened glass thickness (mm)
0.36 13.5 17.5 12
0.74 17.5 21.5 15
1.50 21.5 25.5 19
3.00 25.5 31.5 25

Within the industry there are a number of regulations and standards that determine what systems can be installed for each scenario.  We have compiled a brief summary of the regulations for your reference; please note that all of the information contained here is intended for guidance only and will vary between countries.

Below is a guide to building regulations that relate to balustrades within England and Wales. More information can be found on the BSI website (http://www.bsigroup.com/);

  • BS6180 2011 – Code of practice for barriers in and about building.
  • BS EN 12600 – Glass in building. Pendulum test. Impact test method and classification for flat glass.
  • BS6206 1982 – Code of practice for the glazing for buildings.
  • BS6399- Loading for buildings-all parts.
  • Building regulations part K; Stairs, ramps and guards.

 

Calculating the height of your Barrier:

For this example we will use a landing in a single family dwelling, in which case the barrier will need to be 900mm high.  This information can be obtained from the table titled Minimum Barrier Heights.  Please refer to this table when you are calculating the height of barriers.

Calculating the Minimum Load Capacity:

All variance of Modifications have their own unique Minimum Load Capacity.  For our example the table labelled Minimum Horizontal, advises we need a glass that meets a 0.36 kN loading for this specific assembly.

Calculating Glass Thickness:

The final table labelled Glass Thickness shows us the strength of different glass types.  Therefore using our previous example, with a toughened glass option, 12mm glass density is required.

 

Location Minimum Height of glass from finished floor level
Stairs, ramps & Landings 900mm
Balcony 1100mm
Glass Partition Any height (a manifestation may be required on the glass)
Fixed Seating up to 530mm from barrier 800mm
Any other situation 1100mm

 

In the table below examples are given of the minimum horizontal load requirements for specified locations

Minimum horizontal Load

Type of occupancy for part of the building structure Examples of specific use Horizontal uniformly distributed line load (kN/m)
Domestic and residential activities All internal areas serving single family dwellings; stairs and landings 0.36
External and internal residential situations with multiple occupance 0.74
Offices and work areas, including storage areas Light access stairs and gangways – not more than 600mm wide 0.22
Light pedestrian traffic routes in industrial and storage buildings, except designated escape routes 0.36
Areas not inline for overcrowding in office and institutional buildings 0.74
Areas where people might congregate Areas having fixed seating within 530mm of the barrier, balustrade or parapet 1.5
Areas with tables or fixed seating Restaurants and bars 1.5
Areas without obstacles for moving people and not susceptible to overcrowding Stairs, landings, corridors, ramps.  In addition external balconies and edges of roofs including areas adjacent to basement/sunken areas 0.74
Areas susceptible to overcrowding Footways to pavements less than 3m wide adjacent to basement/sunken areas 1.5
Theatres, cinemas, bars, shopping malls.  Footways to pavements greater than 3m wide adjacent to basement/sunken areas 3.0
Retail areas All retail areas including public areas of banks/building societies or betting shops 1.5
Vehicular Pedestrian areas in car parks, including stairs, landings, ramps, edges of internal floors.  Internal loads imposed by vehicles 1.5

Kilonewtons, or more commonly seen as kN, is the force that is applied to the glass balustrade. This is the test where the force is applied and a deflection measurement is taken. In the UK glass balustrade has a deflection limit of 25mm.
1.00kN equates to, rounding up, approximately 102kg

As a general overview the load requirements are as follows:
0.36kN – Internal single family domestic
– External where the drop is less than 600mm
0.74kN – External single family domestic where the drop is 600mm or greater
1.50kN – Light commercial installations such as bars and restaurants
3.00kN – Heavy commercial installations such as stadiums, airports and stations.

In recent years the UK has seen an increase in the use of glass balustrades without the installation of handrails. BS 6180:2011 clarifies these issues, which we have listed below, if you need any clarification please contact your local building control.
If using monolithic toughened glass a handrail must also be used, in addition it must be adequately secured to act as a secondary barrier should the glass fail i.e. the handrail should remain in-situ if a panel breaks.
If toughened laminate glass is used then it is permissible to have no handrail as long as the following aspects are put into place;
The glass used must meet the design load, this will be a; line load, uniformly distributed load and a point load test (detailed within BS 6180:2011.)
Manufacturers of glass, have to provide the technical requirements on required glass thickness on meeting the required loadings.
Should a panel break and not meet the required criteria then guarding must be fitted immediately.
The glass selected must resist the appropriate design load and provide containment.

Our system is only as strong as the structure it’s installed into, therefore a suitable substructure must be in place.
The thickness of the steel and strength of the concrete vary per system used. We have tested our systems installed into either steel or concrete.
If you have any queries regarding installation, please do not hesitate to contact us. We are always happy to advise you or alternatively contact your local structural engineer.

Currently, we only manufacture and supply our products. However, we do work closely with a number of installation specialists across the UK. Therefore, if you do require this service, we would be happy to supply you with contact details of your local installers.
On the other hand if you are an installer looking to work with us to fit our products please get in contact with us; sales@pure-vista.com.

No, we do not have the facility on site to safely store glass. We know of glass suppliers we might be able to recommend. Most of your local glass suppliers or double glazing suppliers will be able to source the glass.

No, we design our systems so that no specialist tools are required and just standard trade tools can be used.

It is possible to install the frameless glass balustrade yourself. However, it is strongly recommended to use someone who is knowledgeable in the construction/glazing field. There are various things to consider such as water drainage and the substrate.
We are happy to assist with your questions on installation and advise what glass you require.

Yes the profiles can be cut and mitred for corners. You will need to use either a chop saw or mitre saw, you will need to be sure you use an aluminium blade to give a clean cut. Other metal blades can give a rough cut.

All of our main profiles are made out of aluminium.
We use stainless steel for some of our internal components and end caps.
The clamps are made out of plastic.

Our products can be anodised to a variety of colours, but as standard we produce our Balustrade systems in a stainless steel effect. This is a great option for any contemporary glass balustrade. Colour modifications are price specific and come with an increased lead time, so please contact us directly for a quote.
Another option is powder coating the aluminium. Powder coating is a type of coating that is applied as a free-flowing dry powder. The main difference between a conventional liquid paint and a powder coating is that the powder coating does not require a solvent to keep the binder and filler parts in a liquid suspension form.
A huge range of colours are available through the RAL colour chart. There may be colour variations per paint batch, so it is important for aesthetic effect that each order is treated collectively.
We do not supply pre-coated aluminium, as the risk of handling greatly increases the probability of damage to the pre-coating.

A gap must be left between the glass panels. The weakest point for glass is on the edge and with no gap the edges can touch and cause breakage, you are ‘allowed’ a 1mm-99mm gap. But glass cutting tolerances and expansion must be taken into account.
Generally most installers leave a 10mm gap between the glass panels, this is quite a safe distance to use for both glass cutting tolerances and it is easier for calculating the glass deductions when ordering.

When getting to a corner if there is no risk of wind hitting the panels we advise ‘T-ing’ the panels this is when one panel overlaps the other and reduces the gap.
If wind is likely to hit the panels there is a risk one panel can hit the other and cause damage or a breakage. To get over this the best method is to offset the panels so they cannot touch as the wind deflects them.

Wet glazing is the accepted term for a resin set balustrade system. It is when the glass is placed into, most commonly a standard U-shaped channel and a resin is poured into the system. It is then left to harden which can take many hours. The time delay can be an issue especially from the wind or any force placed against the glass could push it out of line. If the wrong resin is used there is potential there will be issues further down the line, there is a risk some ingredients will react with certain glass types, or the expansion rates vary too much and allow for cracking around the edges.
The biggest problem with a full wet glaze balustrade is if there is a reason for deglazing (such as a broken panel or glass thickness change). It is no easy feat removing glass that is fully set with resin.

Annealed glass often called float or sheet glass is what you would expect to find in most houses windows, usually 4mm thick. It is relatively weak and easy to break. It should never be used in a balustrade installation as it would fail the line load test and any glass installed up to 800mm from the floor should be toughened. When it is broken it breaks into large fragments.

Heat strengthened glass is when annealed glass is heated and cooled slowly. It is approximately twice as strong as annealed glass however it will still not pass the required regulations such as the impact test. Also when it breaks it does not form into small fragments it remains in large chunks which for balustrade overhead would have a severe risk to anyone passing below.

Toughened or Tempered glass is again annealed glass. This time it is heated to a higher temperature and then rapidly cooled. This gives the glass far stronger properties, up to five times stronger than annealed glass. It can now withstand impacts and passes the required testing. Above this, now if the glass breaks it breaks into small fragments rather than shards and is deemed safe for overhead breakage.
When installing a balustrade this is the glass that must be used.

Heat soaked glass is when toughened glass is reheated and is slowly cooled.
The reason for doing this is there is a small risk of a nickel sulphide crystal in the glass which naturally occurs in processing glass. The nickel sulphide crystal has a different expansion rate to glass so as glass heats and cools through the seasons a spontaneous breakage may occur. This can be very costly if the glass is not easy to get to after completion.
By heat soaking the glass this risk is drastically reduced and a breakage happens in the factory where another can be produced.