What is Thermal Stress and Thermal Fracture and How to Avoid them?

windows manufactiure in western australia com-al windows

Glass is one of the most popular materials that are used today for the construction of commercial doors and windows. In combination with aluminium frames and extrusions, glass doors and windows make for robust commercial doors and windows that can stand the test of time, along with keeping the aesthetic appeal intact.

The glasses for the windows and doors are manufactured in diverse forms to fit a list of different regional preferences, weather, and climatic conditions.

For example, there is double glazed glass, laminated glass, toughened glass, sound control glass, low e glass, solar control glass, skylight glass, canopy glass, cyclonic glass, and more. All of these glasses are manufactured with their specific properties. Here, while one makes your room energy efficient, another allows sufficient light to pass through but blocks the harmful sun rays and so on. Now, if you want to have commercial glasses doors and windows installed at your own office, building, or workplace to satisfy a particular set of demands, then Com-Al Windows is the brand that you can reach out to.

Com-Al Windows is based in Perth, Western Australia, and takes pride in designing, manufacturing, and installing commercial and cyclonic glass aluminum doors, windows, and curtain walling systems.


It is due to the versatile nature, distinctive appeal, and a wide range of options for customization that the glasses are largely for today more when compared to other materials when it comes to commercial windows and doors. However, as the glasses are used both for the interiors and the exteriors of the house, which literally shields the house from external heat, cold, rain, snow, winds and cyclonic conditions, etc., they have to bear the brunt. This regular wear and tear that the glasses are exposed to often results in thermal stress and thermal fracture, which is mostly seen in cases of solar control glasses or those that absorb heat.


What is Thermal Stress?

Thermal stress can be defined as the condition when a glass experiences a difference in temperature among its parts/sections. The difference in temperature from one part to the other is caused by the uneven heating and cooling of glasses.


For example, it is the frames of the windows that are heated, thereby saving the edge of the glass, which is rather cold. Therefore, the covered edge of the glass will remain cooler when compared to the other sections, including the centre of the glass. Here, the hotter sections of the glass will expand, but at the same time, be resisted by the cooler sections, which will give rise to tensile stress. Now, if at any point, this tensile stress becomes large enough, it might also lead to breaking the glass. Such a break is known as a thermal fracture.


What is a Thermal Fracture?

Thermal fracture is the fracture of a glass window when the tensile stress becomes large enough, thereby making the hotter areas of the glass pane stretch more than usual while the other cooler areas remain unstretched.



Thermal stress and thermal fracture are sometimes noted in glasses. Glass is generally a poor conductor of heat, therefore, rapid changes in the temperature of a glass, might result in numerous stress fractures, and might eventually lead to thermal fracture.


Now, if you are wondering about the major factors that might cause thermal stress and thermal fracture in your commercial doors and windows, then the next section covers that.


Prominent Causes of Thermal Stress and Fracture in Commercial

Glass Doors and Windows and How to Avoid Them?

Here’s a look at some of the prominent factors that might cause thermal stress and thermal fracture:


Absorption of Heat and Heat Traps

As discussed earlier, it is the heat that is the primary reason for thermal stress and thermal fracture to occur. Glasses like the solar control glasses absorb the heat and are always more vulnerable to thermal stresses and fractures than regular glasses. Even the glass windows that are used in combination with blinds run the risk of the development of thermal stress. This is because the blinds result in warming up the air between the glass and the blind. The heat absorption and heat traps can be prevented to get rid of the possible causes of thermal stress and fracture.


Presence of Shadows

If shadows form, they produce a cool area that is larger/wider than even the frame. These shadows that are formed due to a permanent architectural structure are static and make the edge of the glass stay even cooler, thereby resulting in more thermal stress. Shadows are either static or mobile. It is the static shadows that are more likely to cause a thermal fracture.


Strength of the Edges

The strength of the glass edges is also responsible for the development of thermal stresses. It has been seen that if the tensile strength of the glass edge is exceeded beyond a critical point, then it may also cause a crack to develop. The magnitude of this critical point depends on the strength of the glass.


Now, if you want to get a strong glass that will evade this issue, then you need to choose a glass with a clean-cut edge or polished edge and should avoid glasses that have damaged edges.


Kind of Glass Installed

The type of glass that you select for your commercial doors and windows also plays a huge role to determine the risk of thermal stress and fracture. Glasses that have a tendency of absorbing heat and those that release less heat are more likely to be impacted by thermal stress and fracture. Solar control glass, which absorbs most of the outside hear, or those that have low emissivity coating, which restricts them to lose heat, are, therefore, not good options if you’re looking for thermal stress resistant glasses.


Textured or wired glass shall also be prevented if you want to go for a glass that won’t be much impacted by the thermal stress and fractures. This is because these glasses are weak on the edges due to the cutting process.


Kind of Frame and its Colour

The material of the frame of the glass also plays a key role when it comes to exposure to thermal stress and fracture. Here, if the frame of the glass is made up of timber or vinyl, which are insulating materials, the glass edges will remain cooler, thereby increasing the risk of thermal fracture.


Moreover, if you plan to use aluminium frames, then the choice of colour will be responsible for thermal stress and fracture. White or lighter colours reflect heat, while darker colours absorb them. Darker colours will enable the frame and the glass edges to be warmer and lessen the chances of thermal stress. Therefore, when choosing the frame, it is wiser to go for a dark-coloured non-insulating frame to protect the glass of your commercial doors and windows.


The Geographical Location

The location of the commercial building, office, or complex is another factor that contributes to thermal stress or fractures of glass doors and windows. It has been proven that the places that are close to the equator, receive the highest intensity of heat. Therefore, if your commercial space is located at a place where it receives more heat, then the glass must be adequately tested for thermal stress.


Considering all of these complex design issues, but reaching out to Com-Al Windows, will minimize your risk. Established back in 1970, Com-Al Windows brings in years of experience and expertise in the window contracting industry. It will help you get quality commercial aluminium doors and windows designed, manufactured, and installed, at your office and commercial space that would be long-lasting and make the space enjoyable to work in. Tested in Australian facilities and meeting the Australian standards, the commercial doors, and windows from Com-Al Windows would be the best fit if you are living in and around Australia.

Belmont Hub, Perth, Western Australia

Commercial Glass – Double Glazed Units – Toughened – To minimise Thermal Stress and Fracture

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