How is facade cladding made and how does this relate to fire safety?

The caloric value of building materials has a major effect on their performance during fire. Compare the PCS values of the most commonly used solutions for facade cladding and find out what this means for the fire safety of your building.

Why is the calorific value of cladding materials important?

Calorific value is the amount of energy that is produced by the complete combustion of a material. This amount of energy determines how much heat a certain material contributes to a fire. More heat simply means a faster spreading of the fire. The calorific content of a panel is indicated by its PCS (abbreviation of the French term ‘Pouvoir Calorifique Supérieur’) value. The higher a PCS value is, the more calorific content a panel has. Non-combustible facade material (Euroclass A1 & A2) has a very low calorific value and thus a very low contribution to the fire. The classification of these non-combustible materials has an upper limit on the PCS values.

Comparing PCS values

In general, the lower the calorific value (pcs value) of a product, the better it is when it comes to fire safety. But what does this imply? When it comes to PCS value, two panels distinct themselves: fibre cement and stone wool (Rockpanel). They both have a very low caloric content. Stone wool, for example, is made from natural volcanic rock basalt, which can withstand extremely high temperatures by nature.

What happens to a building with ACM or ACP facade cladding in case of fire?

For ACM/ACP and HPL, the situation is much more complicated. In many cases, the core in ACM panels is made from polyethylene (PE) or polyurethane (PUR), which is highly flammable. In case of fire, the panels can delaminate and expose this core, with all its consequences. The issue with an exposed core is even becoming bigger when profiled into so-called cassettes (a common application of ACPs).  Some ACP panels do have a fire-retardant or even a non-combustible core, which leads to a lower calorific value.

Fire retardants are used to mask high calorific values

Are HPL panels firesafe?

HPL panels contain lots of organic material that will ignite when heated. This makes it combustible and explains why the manufacturers choose to use fire retardants in these products. These are needed in order to pass an SBI test. However, to be sure of a totally fire safe solution, it is strongly advised to use non-combustible panels and do not risk the somewhat dodgy performance of panels that include fire retardants to ‘mask’ their high calorific value.


Everything you need to know about fire safe facade cladding

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