Glass for a V.I.P. – Very Important Polar bear

G.James Glass supply for Polar Bear Cub Viewing Panel

Polar bears are one of the most popular bears that we endear ourselves to.  Large and cuddly, yet so fierce. It is with fascination and awe that we can look on these creatures and catch a glimpse into their lives. Here in Australia, you can only do this from a viewing platform that has a clear, wide and very secure glass barrier.

With news of the resident female polar bear, Leah’s, pregnancy, Sea World engaged the builders, Astute assist them with the construction of a new polar bear enclosure. G.James Glass & Aluminium were sought for the supply of the glass viewing panels.

A new addition to the Sea World Polar Bear family

Leah has been living with Nelson and Hudson (who are twin brothers) in a large enclosure at Sea World. The prospect of the cub came as a little surprise, as Leah was not known to be pregnant until late into her 8 month gestation period.  Cub twins were born in May 2013 to Leah and father, Nelson. Unfortunately, only one has made it to this age, but Henry is doing very well. A new enclosure was required as the mother and cub needed to be separated from the male bears. Leah needs to care for her offspring and males have been known to try and eat cubs.

Designing a New Enclosure

Work on a new enclosure was started immediately. The planning and layout for the enclosure began 10 years ago, but the final design still needed to be resolved.  It was done in cooperation with the polar bear keepers, Sea World officials and biology professionals to ensure the safety and well being of the new inhabitants.

The majority of the enclosure is concrete and timber with the glass viewing panel making up the majority of one wall – all products need to be non toxic. The layout was designed to be aesthetically reminiscent of a polar bears natural habitat and in keeping with the existing enclosure.  It includes two ice wells (ponds where ice can be left for exploration and play), a waterfall, chilled sea water pool, trees and three cooling misters. The pool has loops in the bottom of it which toys can be attached to for the polar bears to play with.

The polar bear entrance is a wide area that is partially hidden from the viewing area, and so rocks have been strategically positioned to discourage the polar bears from hiding in this corner.  This area was in its final stages of preparation when we visited, and mobile scaffolding made by QuickAlly Access Solutions was being used to support the workers completing the job.

The more serious aspects of the pen are an isolated waste catching system, security door locking mechanisms, and a safety escape niche. Polar Bears are never tamed. Keepers cannot be in an enclosure with them, as they are at risk of being attacked.   The security door prevents the polar bear door to open while keepers are in the enclosure, and in case of failure, the niche only fits a person, and has an alarm button in it to highlight help is required.

The risk factor when in close quarters with bears makes the viewing panel not only important for visitors, but it is the only area they can be easily watched by their keepers at eye level.  All photography for recording the animals behaviour and publicity purposes are taken through this panel.

The Viewing Panel

The type of glass used in the polar bear enclosure is specified. The glazing has to be thick and secure enough to ensure the safety of the polar bears, and visitors. Four layers of glass, laminated together ensure this. The glass is around 40mm thick and each of the 8 viewing panes weigh 495kg. Polar bears will scratch at the glass, and these scratches need to be polished out every couple of years. The edges of the glass, and gaps in between need to be specially designed. Polar Bears will test edges and explore gaps, so they are constructed to minimise their ability to grip and claw areas.

On completion of the enclosure, officials from the Australian Institute of Marine Science inspect the final result. Any potential hazards or dangerous surfaces are highlighted and addressed prior to the polar bears being introduced to their new surrounds.

The Cubs Entrance to Public Life

Leah has been monitored daily since the birth of her cubs. She was living in her “maternity ward” and exercising in a special enclosure for the polar bears until September. Her new home was opened to her in mid September, and it was expected she would explore it for a week or two before she and the cub were comfortable with their new surroundings.  It has since been opened to the public.

G.James Glass supply for Polar Bear Cub Viewing Panel

In Comparison to a Wild Life

In the wild, a mother will lie in a dormant state (similar to hibernation) in a den made inland of snow and ice for about the second half of the gestation period. After birth, the cubs are reared in the den for the first couple of months of their lives before being introduced to the world. The cubs have about 2 weeks to gain their strength and learn to walk over distance and run before journeying to the sea. They spend between 1 ½ and 2 ½ years with their mother before going out on their own.

Click on the images for more Polar Bear facts.

Guest Post: Comparing the energy efficiency of ‘Esky’ buildings to passively designed buildings

Breezway Louvres

This month’s guest post is by Clinton Dickens of Breezway, and discusses energy efficiency of passively designed buildings.

Years ago I attended a week long training course in the conference centre of a large hotel right on the beachfront. The food was pretty good but the conference room felt a bit like a dungeon! There were no windows at all and one of the presenters had this cruel theory that making the air conditioning extra cold would ensure that no-one fell asleep during the after-lunch sessions.A few years later I attended another conference at a different venue that was also only 100m from the ocean. In contrast, this venue had windows looking out to the ocean and we could enjoy the fresh ocean breezes.

These two different conference venues do a pretty good job of illustrating two of the main schools of thought regarding the best way to design energy efficient buildings. The first school of thought is sometimes called the ‘Esky’ approach where buildings are tightly sealed and well insulated to improve the efficiency of the air conditioning systems (just like ice boxes seal tightly and are well insulated to keep the ice frozen). Because windows are generally small, or of a type that does not open, these buildings generally require the air conditioning systems to run whenever the building is occupied. Situations where the ‘Esky’ approach is the most sensible building design includes city centres and industrial areas where the combination of noise and air pollution make natural ventilation impractical.

The other approach is known as ‘passive design’ and includes close attention being paid to things like shading, adjusting the building’s orientation and maximising natural ventilation so that the building is naturally comfortable. Passive design can still incorporate air conditioning systems for use during extreme weather but good design can minimise the frequency of air conditioning being required. Passive design is well suited to schools, homes, resorts, suburban offices and apartments.

Breezway Louvres

The openable windows required to maximise natural ventilation in passively designed buildings generally do not seal quite as tightly as the fixed windows generally used in ‘Esky’ style buildings. Therefore the air conditioning systems in passively designed buildings will generally run less efficiently than the air conditioning systems in ‘Esky’ style buildings. The big question then is whether a system that runs efficiently, but for many hours per day uses more or less total electricity than a system which runs less efficiently, but for few hours per day.

In an attempt to answer this question, Breezway commissioned a study to compare the annual electricity required for the cooling and heating of two identical buildings, one of which had fixed windows to maximise air conditioning efficiency, and the other had Altair Louvre Windows to allow some of the cooling requirements of the building to be met using natural ventilation at the expense of reduced efficiency when the air conditioning system was used.

The modelling showed that the benefits of the great ventilation through the open Altair Louvre Windows far outweighed the reductions in air conditioning efficiency and the building with Altair Louvre Windows used almost a quarter less electricity over the course of a year to cool and heat the building.

The Breezway Technical Bulletin “The Impact of Air Infiltration And Natural Ventilation On Annual Air Conditioning Load” contains more details on the modelling study.


All texts, pictures and tables by Breezway unless stated differently.

Clinton Dickens is a Product Manager for Breezway. This article was originally published at Breezway.

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Bushfire Risk, Assessment and Glazing Solutions

Australia has a love hate relationship with bushfires. It has been so much a part of the natural history here it has become an endemic part of existence; without bushfire certain plants wont propagate, although the rest of anything living, fears it. It’s just one of the many parts of the Australian lifestyle that needs to be taken in a serious light – and be prepared for.

Assessing Bushfire Risk

There have been major developments in ways to protect in the case of bushfire – from household escape plans, to continuing technology in fire fighting strategies and more recently since dramatic fire events, building design. Australian Standards have developed AS 3959, and as part of that, a system that determines your Bushfire Attack Level or BAL. In the BAL, it gives a provision for products in the building industry to be rated according to their resistance to bushfire attack.

The BAL rating for your situation can be determined by referring to AS3959 or guides provided by your local services. NSW Rural Fire Service has a comprehensive user guide as an Application Kit to the BAL for reference. You will attain one of six rated categories. Your risk is assessed by looking at type and proximity of vegetation, and the slope of the land your property is on. Your calculated BAL rating is used to select building products. Products will be rated with the same figures, offering protection for that level of BAL rating.

BAL Rated Glazing Options

G.James Glass & Aluminium has developed a BAL manual to guide people through making the right decision when looking at glazing products. It outlines the G.James glazing suites that should be used for buildings in the following high risk categories:

  • BAL 19
  • BAL 29
  • BAL 40

The G.James BAL manual outline the glazing system, glass type, hardware, gaskets and mesh requirements for the individual systems according to your BAL rating. As an example, if you have a rating of BAL 29, and need a double hung window, we will suggest you use the following:

The 136 Series Double Hung Window with a minimum of 5mm toughened glass, standard mohair, glazing vinyls and other hardware, and external screens require a fire retardant spline with aluminium or steel mesh with an aperture of less than 2mm. This is an example only, and you need to confirm details with G.James staff that can ensure these are the products you need for your individual situation.

Your selection of glazing should not be limited. G.James have BAL glazing solutions for sliding doors, louvres, double hung windows, fixed windows, hinged doors, bifold doors, awning windows, casement windows and sliding windows. When you talk to G.James personnel, they can guide you through the options.

Requirement for Buildings

There is no requirement to alter existing building materials, but if you plan on building or renovating, you will need to implement the recommendations of the the BAL report. It is a wise idea to be aware of the rating your property would get even if you aren’t looking at building in the near future. Finding out the weak points, you can make minor adaptions to the building materials or surrounding vegetation to give yourself a better chance in case fire ever threatens your neighbourhood.

Be aware of the different ways you can keep knowledgeable about risks in your area. Know your local brigade and SES, having their contact details on hand. Check your states fire services for more information.

During recent fire incidents when the heat was on, communication became difficult due to cut lines, and websites being bombarded and going down. The NSW Rural Fire Service had a great system of reporting regular updates on their face book feed. Know where to keep up to date on the latest details and leave emergency lines free for those that require it.

Be prepared and stay safe.

Glass By Definition – Part 1

Glass Bike - Glass Definitions - G.James Glass and AluminiumThis article will assist in demystifying the types of architectural glass used in buildings. The names we use for the different glass types are generally attributed to some part of the manufacturing process. In part one of this two part series, we look at basic glass products to highly processed glazing options.

Some History on Architectural Glass

Since clear glass was being first made in about 100 CE, in Alexandria, the Romans began using it architecturally. This began the long list of manufacturing methods and specialised names attributed to the different types of processes – Broad sheet, Crown, Polished Plate, the list goes on. In 1848, a crude form of float glass was patented by inventor Henry Bessemer by pouring glass onto liquid tin, but it was very expensive. It wasn’t until 1959 that this idea for float glass was made in a practical method – a discovery by Sir Alistair Pilkington that now dominates the worldwide commercial production of architectural glass products.

Basic Float Glass Products

The differences between the basic glass types are formed in the glass making “float process”. Soda, lime and silica as well as broken glass called cullet are the major components used in the manufacture of glass. These components are mixed into a batch before being heated to approx. 1500°C in a furnace. The molten glass is then floated on a “tin bath” –  a layer of molten tin.   As the glass begins to cool it solidifies and is drawn out of the float tank in one continuous ribbon.  The glass enters the annealing or cooling lehr – it is the controlled cooling (annealing) of the glass that allows it to be cut and further processed.

Float Glass or Annealed Glass

These terms are interchangeable and refer to the respective glass manufacturing processes.  They describe glass in its basic form, before secondary manufacture.  In a general sense, Annealed Glass is used when comparing heat treated glass to non heat treated glass.

Clear Glass

Clear Glass is a piece of transparent float glass, typically uncoloured.

Tinted Glass

Tints are glass with metal oxides added to give it a specific hue. The tint or colouration is through the body of the glass and therefore darkens with an increase in thickness.  Apart from aesthetics, tinted glass is used for reducing heat gain through the glazing system. Common tints include green, blue, grey and bronze.

Super Tints

Super Tints are designed to reduce heat gain while allowing the maximum amount of light through making it a performance product. The heat absorbing qualities also make them prone to thermal stress (caused by temperature difference), and a thermal safety assessment is recommended to determine if heat treating is required (see Secondary Manufacture below). Colours include Azuria, Super Green and Super Blue.

On Line Coated Glass

Sometimes referred to as pyrolytic glass, metallic oxides are deposited onto the glass surface in the float glass tank during manufacture. These coatings can increase the performance of the glass with a range of reflective and low E products available. They are extremely hard and durable, and can be used on their own or heat treated without affecting the coating.

Low Iron Glass

The green colouration in glass is due to the iron content found in silica or sand. Low Iron Glass has less than 1/10th of the iron content of standard glass and are considered ultra clear. Low Iron Glass is ideal for use in display cases, painted glass applications like splash backs or in areas where high clarity is required.

Deli Bend or Curved Glass (Annealed)

Glass can be curved as float, by laying the glass over a mould before annealing begins. It is commonly used to make butcher or delicatessen benches (hence the name), furniture and curved architectural glass that is to be laminated.

Processed Glass

Glass requires finishing before it can be used in location, or sent for secondary manufacture. Commonly, this includes cutting to size, and edging, but there are many alternatives in both these fields.


Almost all glass will require cutting to the job size requirements, but this process also includes cuts to produce as irregular shapes, such as raked windows, shower screens with cut outs for fittings, glass walls needing spider fittings and custom profiling.

  • Various regular and irregular shapes required are cut with a CNC machine.
  • V Grooved cuts in the face of glass, or brilliant cut, provides an alternate decorative finish.
  • Drilling – Holes from 5mm to 100mm can be drilled into the glass, but the hole diameter must be equal to or greater than the glass thickness. Holes can include a countersunk rim. The hole edging has a ground finish.
  • Shaping – glass can be cut at special shapes or profiles to custom requirements.

There are edge clearances that are relative to the glass thickness for the size and location of cut outs and holes drilled into a sheet of glass. Please contact your manufacturer for exact positioning limitations.


Edging provides a range of options for the perimeter of the glass to suit its application. Different edges are applied for ease of installation, to assist with further processing or to achieve a look.  One common process is arrissing – a term used to describe the method used to grind the sharp edges of glass to make them safer to handle.

  • Plain cut glass, is called Clean Cut
  • Glass to be toughened requires Rough Arris edge work – arrissed edges with a rough ground finish.
  • Smooth Arris is similar to the rough arris, but with a smoother finish to the edge.
  • Flat Grind or Flat Smooth edges are machined smooth edges suitable for silicone butt jointed applications.
  • Flat Polished is the neatest finish used for exposed edges of glass.
  • Mitred Glass has a 45 degree bevel on one side with an edge finish suitable for mitred silicone butt joints.
  • Round and Polished edge work gives the glass a curved edge for exposed perimeters.

Secondary Manufacture

Secondary Manufacture takes the various types of float glass and changes the properties in a range of production processes.

Heat Treated Glass

A general term used to describe the process of further strengthening or testing glass in a second heating and cooling process. Its is the way or speed in which the glass is cooled gives the glass stronger properties, and length of heating to test the glass.

Heat Strengthened Glass

Heat strengthening is a treatment of glass that induces a high compression layer on the surface.  This is done by cooling the reheated glass at a specific rate. This process makes glass twice as strong as annealed glass, although it is not considered safety glass.

Toughened or Tempered Glass

Toughening glass also induces a high compression layer in a similar process to heat strengthened glass. To toughen the glass, the heated glass is cooled very quickly. This makes it 4 to 5 times stronger than annealed glass of the same thickness. Certain thicknesses are considered A grade safety glass – refer to standard AS 1288.

Heat Soaked Glass

Toughened glass can spontaneously shatter due to small imperfections in glass called Nickel Sulphide inclusions. They are rare, but undetectable, and so, to ensure the glass will retain its form, heat soak testing is done. The glass is heated for a period of time which induces the Nickel Sulphide inclusions to rupture if they are present.  Glass that passes the test, has a markedly reduced possibility of failure once in location.

Curved Glass (toughened)

Curved Glass that requires toughening is bent in the toughening process.  A series of rams fold the glass to the desired shape. Tighter corners and soft curves are achievable.

Off Line Coating

High performance glass has a coating applied to its surface. Different looks can also be achieved with colour and reflectivity. Although large steps in technology over the last couple of years have increased the durability of off line coatings, some are quite delicate, and cannot be heat treated.  Others need to be used in an IGU, so the coated side of the glass is sealed from the elements and physical damage.

Laminated Glass

Laminates are made of two or more pieces of glass permanently bonded together with interlayers. Interlayers are made up of various materials to give the completed glass additional properties, for example, acoustic, colour and UV eliminating. Laminated glass is considered A grade safety glass.


IGUs consist of two panels of glass fitted together with a hermetically sealed air space in between to provide an insulative layer protecting against thermal and acoustic issues. The air in the gap is dried to prevent condensation issues.

Other common glass terms

The following terms are not processes done to manufacture glass, but are descriptions of how they are classed, rated and used.

Double Glazing

Double glazing is when two pieces of glass are used with an air gap in between. Special framing suites with glazing pockets front and back are considered double glazed, as are jockey sashes and IGUs.

Monolithic Glass

Monolithic glass is a single pane of glass as opposed to laminated, double glazed or insulated glass units.

Safety Glass

Safety glass is processed glass that is manufactured to satisfy the requirements of AS/NZS 2208 for safety glazing. Laminated and toughened glass are rated Grade A. Wired glass is rated Grade B.

Security Glass

Security Glass is designed to repel violent attack. They are usually combinations of laminated glass that incorporate toughened or polycarbonate combinations. They are not necessarily considered Safety Glass.

Part two to be released in November –

I hope you found these descriptions useful. In part two of this article, thermal glazing terms and properties will be discussed. It will include the terms used to measure and describe performance, what basis the measurements are made from and a comparison of data commonly used – glass only vs whole of window data.