If you want to learn more about fire safety, then you should know what materials are flammable and which aren’t. That’s where our guides come in handy. We are here to tell you which materials and substances are prone to catching fire, and which ones are flammable or combustible.
One of the most common questions we get asked is: is glass flammable? You’ve all heard the stories about some kid who uses glass to make fires, so what about the glass itself? Is it a fire hazard?
That’s what we are here to find out! But first, let’s take a look at what glass actually is, to find out whether it will burn in a fire.
What Exactly Is Glass?
Glass is used for a range of purposes. We use glass in the windows in our homes, we use it for eyeglasses, and we use it for cups, lightbulbs, windscreens, phone screens, you name it! Glass is all around us. But, have you ever stopped to think about what glass actually is?
Glass is made by melting sand, soda ash or limestone. These materials are melted at such a high temperature and cooled so quickly that it forms a completely new material: glass.
When melted, this substance will be in a liquid form, but when cooled rapidly, it will turn into glass that can be shaped or altered, depending on what it will be used for.
It may surprise you to find that glass can even be formed naturally. In the case of volcanoes, the temperatures are incredibly hot inside, and they can erupt, which creates natural glass when it reacts with sand or limestone.
Due to its natural creation, it is said that humans have been using glass for centuries, and has even been dated back to about 3,600 B.C.
Glass is also one of mankind’s greatest inventions. Its transparent appearance makes it perfect for utilizing it for a range of purposes, from eyeglasses to coffee mugs, tea light holders to jars. It can even be used for insulation or for fiber optic communications!
Nowadays, glass is commonly made from Silicon Dioxide, which is either sand or quartz, and can include other ingredients to give it extra uses or qualities. As it is made from Silicon Dioxide, this means that glass is an oxide of silicon, and cannot burn easily. So, is glass actually flammable?
Is Regular Glass Flammable?
The short answer to this question is no, glass is not flammable as it does not easily catch fire. This is because it is made from fully oxidized silicon, which means that the only way it can burn is if you create temperatures so extremely high that the silicon and oxygen bonds are broken apart.
If this was to happen, the silicon produced would burn. However, it is highly unlikely that you would be able to produce such high heats and temperatures that the glass would ever burn.
For instance, there would be little chance of glass burning in your home, even if the whole house was ablaze, as the temperatures produced in a house fire are significantly lower than those needed to burn and break down the glass.
In most cases, you are unable to set fire to glass or ignite it, as it really is not very flammable.
Will Glass Burn In A Fire?
No, glass will not burn in a fire. This is largely because it is not flammable or combustible, meaning that you cannot burn it because it cannot be oxidized.
However, you may have noticed that glass can mark in a fire, or it can be streaked with dark, black marks when stuck in a fire.
Whilst it may look like the glass is burning, it actually is not. The dark marks can be wiped off, or scrubbed away, and you will see that the glass underneath is not harmed, burned or altered in any way.
Glass will not be able to burn in a fire, but it will be able to melt at very high temperatures. Glass only melts at a temperature of about 1,400 degrees to 1,600 degrees celsius, which is roughly 2,500 degrees to 2,900 degrees fahrenheit!
It can also crack when exposed to extreme temperatures, but this depends on the glass itself as some types are designed to be very resistant to high temperatures, such as glass cups or kettles.
What Is Fire Glass?
You can also get what is called fire glass. This type of glass is made up of lots of small glass pebbles that are formed from ordinary recycled glass.
Although it is regular glass broken up into small pieces and pebbles for fires, it does have a lower flammability level than a large, unbroken piece of glass.
However, it does not really burn any more than normal glass does, and is not considered flammable. Fire glass is only named fire glass because it adds a nicer look to fires, and creates dancing and enthralling flames.
Will Tempered Glass Catch Fire?
On the other hand, we have tempered glass. Now, this type of glass is made to withstand thermal shock, and so it can withstand very high temperatures, and very fast temperature changes.
For instance, you can have it in hot flames, and then place it in cold water and it will not crack or break. Therefore, tempered glass is also fireproof and fire resistant.
Will Tempered Glass Crack Under Heat?
No, tempered glass will not crack under heat as it is designed specifically to withstand thermal shock and extreme temperatures.
However, it still has the same melting point as normal glass, so it will break eventually, but this would be under extreme conditions.
Can You Ignite Glass With A Lighter?
No, it is not possible to ignite glass with a lighter, though you will leave smoky marks on the glass where you attempted to burn it. Whilst this may look like it has been burnt, it is just the residue of the smoke, and will wipe off.
To summarize, glass is not typically flammable. Whilst most substances will melt and burn when it reaches a certain temperature, glass is designed to withstand very high temperatures, and will only begin to melt at around 2,500 degrees fahrenheit!