DON'T be fooled by Magic!

Propane Torch Fire Test – The truth behind the magic?

When it comes to magic, most people can be fooled most of the time. One manufacturer of insulated sandwich panels with combustible foam plastic cores has taken the opportunity to put their own ‘magic trick’ on the web, and have uploaded a propane torch fire test video on its web home page. As with all 'magic tricks', the intention of this video is to fool people into thinking 'seeing is believing', thus creating the impression that PIR panels don't burn, giving the illusion of non combustibility.

We have kindly provided you with the secret to this magic trick, and a video showing the REAL combustible performance of PIR and Stone wool composite panels, which is situated at the top of our web home page.


The text concerning the magical propane torch fire video reads:

“This video shows the fire performance of PIR insulation when exposed to a propane torch burning at over 1000º C. The naked PIR insulation core is exposed to the torch for over 75 minutes. The temperature on the non fire side of the PIR core reaches a maximum of 46º C despite the torch burning at over 1000º C”.


Question : What is the propane fire test?

Answer: Nothing more than a ‘magic trick’ to suggest that PIR is in some way non-combustible and comparable to truly non-combustible materials such as stone wool. The propane fire test is not in any standard nor used by any reputable fire-engineering laboratory. It is not a real test – it is a trick! And like any other magic trick it is aimed at fooling people.


Question: How does the trick work?

Answer: The propane torch has relatively low heat output but fairly high velocity. The torch is placed initially on the surface using the hot end of the flame and the PIR burns to form a thin layer of char. This acts as some protection to make the trick work. The flame is then moved closer and fixed making sure the PIR is exposed to the cold part of the flame. At the same time the high velocity gas hits the surface of the PIR and forces out most of the oxygen containing air preventing any combustion. The fact is that very little heat energy enters the PIR and the surface is relatively cool with little oxygen – hence no flames and no burning.

Question : Will the trick work on other materials?

Answer: Yes. You can use the cold part of the flame and gas velocity to get rid of air on any combustible material to make it look like it will not burn. You can repeat the trick with untreated hardwood, a paperback book and even a piece of coal. You should remember that only a small part of the propane flame is at 1000ºC with most of it considerably cooler. There is a simple experiment used in school laboratories to demonstrate the temperature variation within a flame. A match head is placed on the end of a piece of wire and this is moved about inside the flame from a Bunsen burner. This shows that only the top of the flame and its outer surface is hot enough to ignite the match head. Would this convince you that matches do not burn?

Question: What else is wrong about the test?

Answer: The company says the PIR was exposed to 1000ºC. However PIR is classed as combustible when using a real test such as BS EN ISO 1182: 2002 Reaction to fire tests for building products – Non-combustibility. BRUFMA the plastic foam insulation trade body says that PIR has a self-ignition temperature of 450ºC. So the conclusion has to be that the PIR did not get to 1000ºC.

Question: What does the low temperature recorded on the face of PIR away from the flame indicate?

Answer: Taking the claims at face value you have a sample of PIR which looks about 70mm thick with 1000ºC on one face and other reaches only 46ºC after 75 minutes. The only conclusions are:

1. The PIR is non-combustible and can resist 1000ºC for over 75 minutes suspending the basic laws of chemistry.

2. The PIR has a thermal resistance, lambda value, that is orders of scale better than that demonstrated by any other foam plastic insulation in the world.

3. The face exposed to the flame was not at 1000ºC and there was little heat entering the PIR.

We hope our blog helps you to distinguish between the real 'tricks and treats' within the our industry in 2009