Is Polyester Flammable? Is it Fire Resistant?

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Polyester is one of the most popular synthetic fabrics to be used in clothing. It’s hard wearing and, when used in the right proportion, it often looks great too. One reason that clothing manufacturers love polyester is that it’s, comparative to natural fibers, very cheap and easy to work with and that keeps their costs down. But is the polyester in your clothing a fire hazard? 

Polyester is not considered to be flammable. It will melt around 220 degrees Celsius and ignite at roughly 440 degrees Celsius. It is considered to be safe for use in a wide-variety of clothing. 

Let’s take a look at what polyester is, how it behaves when heated and any fire concerns. Take a look.

Also read: What Makes Something Flammable?

What Is Polyester? 

is polyester flammable

Polyester is a generic, catch-all term for any kind of fabric that is made from polyester yarn (or sometimes, from polyester fibers). 

The full name of polyester is polyethylene terephthalate (that’s PET). You can make it by mixing together terephthalic acid and ethylene glycol (also known as “antifreeze” to most of us). 

The finished product is 100% synthetic and is a form of polymer (plastic). 

It was invented back in 1941 by a pair of British chemists, but it didn’t really catch on in the garment industry until the 1970s. 

The memorable polyester shiny suits of the 70s were due to the fact that polyester was advertised as being able to be worn for months without needing to be ironed.

In addition to clothes, you can often find polyester in furnishings and other textile products that’s because it’s very durable and is resistant to chemical reactions.

Polyester is also easy to dye, shape retaining, strong, lightweight and easy to care for. 

In short, if you’re in the textile industry – polyester is a very useful fabric, indeed. 

Also read: At What Temperature Does Cotton Burn? Is it Flammable?

Can It Catch Fire?

Yes, polyester can catch fire because given enough time and heat, as most things do. But, in general, polyester requires more heat to burn than most fabrics (particularly cotton or linen but also other synthetic fibers) and when it does finally burn, it usually melts.

You do not want to be wearing a polyester garment that melts. This is not a positive quality of polyester. Molten polyester can cause far more severe burns to the skin than a fabric that burns away. 

This video does a side by side comparison lighting different t-shirt materials on fire:

T-shirt Flammability Test

Also read: Is Resin Flammable? [Epoxy, Polyester]

What About 100% Polyester?

No, while 100% polyester will burn, mainly because everything will burn if you get it hot enough and apply enough heat over time, 100% polyester is not flammable.

In fact, while polyester may be considered combustible, it definitely won’t burn easily. 

However, it is worth noting that polyester is often blended with other fabrics and it isn’t possible to say, with any degree of certainty, how these blends will perform when subjected to flame.

For example, in theory, a cotton-polyester blend should be less flammable than regular cotton (which burns very easily), but more flammable than polyester though without testing that particular blend – it’s not possible to say how much more or less flammable the mix is. 

It is worth noting that if polyester does burn, the fumes that it releases are likely to be toxic and you should evacuate the area. When researchers tested burning polymers in 100 meters cubed rooms with rats – it took very little polymer being burned to kill a rat. 

The good news is that human beings are bigger than rats and can take rather more punishment, but it does suggest that you should stay well out of the way of fumes if you can help it. 

Also read: Are Spider Webs Flammable? Sorta…

Is It Fire-Resistant?

Polyester, according to the Washington Post, and most of the textile industry is fire-resistant. That is it doesn’t catch fire very easily when exposed to a naked flame. 

That doesn’t mean that polyester can’t catch fire, just that it requires more effort to ignite it in the first place when compared to other materials.

This means that it has been rated as safe for the use in garments and fabrics that end up on our bedding and bed clothes (and for children’s bedwear too). 

It is worth noting, however, for the sake of completeness that many people have concerns about the use of phthalates in clothing and bedding. 

There is no evidence that these compounds are harmful in any specific manner, as yet, but concerns exist that they may cause cancers and interfere with human hormone production. 

If that bothers you, you might want to steer clear of polyester when buying bedding, pajamas, etc. and particularly for your children. 

Fire is, after all, not the only concern in most people’s purchasing decisions. 

Also read: Is Nylon Flammable? Kinda…

At What Temperature Does It Melt?

The good news is that polyester requires a temperature of around 428 degrees Fahrenheit (220 degrees Celsius) before it will melt.

You are not likely to encounter temperatures like these very often in everyday life. That is, after all, twice as hot as boiling water. 

However, you should always take care of your clothes when working near open flames, fires, etc. while polyester is fire resistant, it is not fireproof. 

Also read: Is Styrofoam Flammable? [Polystyrene]

At What Temperature Does It Burn?

Polyester has an ignition temperature of around 432 to 488 degrees Celsius, that’s 809 to 910 degrees Fahrenheit. 

That’s very hot, indeed, and is why polyester is considered to be flame-resistant, there are very few situations in real life where you encounter this much heat. 

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