Magnetic Secondary Glazing and Fire Safety

What is magnetic secondary glazing?

Magnetic secondary glazing specifically is glazing that is fixed to your existing window frame and provides a movable solution that can be easily taken on or off the windows. Magnetic secondary glazing is therefore a great way to cut out the cold draughts, the noise coming into your property as well as reducing condensation. It is also acceptable to planning departments for use on listed buildings. However, unlike more traditional secondary panes, the magnetic glazing comes at a fraction of the cost to installed solutions and since it looks good it is a great feature for the internal parts of your home.

But are the magnetic secondary glazing panels safe? In particular how does the performance stack-up when you consider fire safety?

What is magnetic secondary glazing made from?

One important aspect that is usually not discussed much in detail is what material/s the magnetic secondary glazing is actually manufactured from and this has a big impact on fire safety of the panels. While there are a few companies out there that manufacture this solution, we advise that you therefore pay special attention to what their panels are made from.

Magnetic secondary glazing is generally made up from one of the following three materials: P.E.T. (Polyethylene terephthalate), Acrylic (Perspex) or PC (Polycarbonate). All three are equally transparent but the similarities end there! Having looked at the merits of each it is the PET that comes out on top, and here’s why!

Magnetic secondary glazing and fire test results

Fire Test: The three materials were exposed to an open flame and what happened next was recorded in a series of photographs at regular second intervals.


Top left: Acrylic, PC and PET plastics are lit. Top Right: PC burns and drips, causing the fire to spread. Bottom: The acrylic offers no fire protection whilst the PET just scars.

As you can see, the P.E.T. does not catch fire, but crystallises in a form of defence that enables it to withstand temperatures of up to 2500C.

The Acrylic, although the most commonly used product for magnetic secondary glazing, burns rapidly and provides no safety features.

The PC (used in police riot gear) burns, but also drips dangerous burning material around it further contributing to the fire.

Results: So it’s clear the P.E.T. / or Polyethylene terephthalate, is the clear winner in these fire-test scenarios.

Acrylic or PC magnetic secondary glazing panels shouldn’t really be sold to the public – they are already banned from sale to commercial premises so why should they be sold to homes?

Ecoease secondary glazing is made from PET

Ecoease are one of the few manufacturers of magnetic secondary glazing that uses PET. It provides a beautifully clear panel that doesn’t go all nasty on you when it is exposed to heat, and also drowns out the noise, keeping you nice and cosy when it is windy and cold outside.

Ecoease holds all the necessary fire safety certificates ( BS476: part 7: – class1Y), which means it could also be used in shops, retail premises and other commercial buildings.

Want to see more about Ecoease and the benefits of magnetic secondary glazing click here.

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