Intumescent paints / reactive coatings
Pros: as well as being easy to apply, these are particularly popular because they leave the aesthetic appearance of the protected surface unchanged. Reduced weight, high mechanical strength and reduced bulk are further factors making this system popular. Moreover, used on metal structures they team perfectly with anti-corrosion treatments. Reactive coatings can be used outdoors but they require adequate protection.
Cons: used on steel they rarely achieve a rating above 90 minutes’ protection and beyond class R60 these reactive protective systems are considered less competitive, despite their undeniable advantages.
Lightened fire-resistant fibrous plasters
Pros: this is an economical system and one that can easily obtain very high resistance ratings, up to 240 minutes, as well as being fast to apply. In some cases it can also meet noise absorbance, sound-proofing and insulation requirements.
Cons: the aesthetic appearance undoubtedly fails to satisfy some architectural requirements and therefore it is only used when a false ceiling or protective covering is to be fitted or when the surface is not on view. In order to apply it, a plastering-screeding machine is needed, which can be hard to find and it is difficult to apply to small surfaces. These plasters remain soft and do not provide mechanical resistance to knocks and abrasions. Over time they shed their fibres and therefore are only installed in little-used environments and they may not be used outdoors where they are in contact with atmospheric agents.
Lightened fire-resistant soft plasters
Pros: this is an economical system, ideal for medium to high ratings (from 60 to 240 min) and it can be applied with a normal plastering machine.
Cons: although the aesthetic effect is better than fibrous plasters, this is still a critical issue, although this type of plaster may be left on view in machine sheds and industrial buildings or where there are no particular aesthetic requirements. It has poor mechanical strength and the fact that it is difficult to apply to small surfaces is an additional problem. As with fibrous plasters, soft plasters, particularly if gypsum-based, cannot be used outdoors, while for cement-based plasters, a protective finishing is always recommended.
Plasterboard and calcium silicate boards
Pros: this is an economical system with high resistance ratings easily obtained.
Cons: when applied to metal structures they completely change the aesthetic effect, sacrificing the building’s architectural features. Even when bonded to the surface they are never less bulky than 12mm. They offer little resistance to knocks, maintenance operations can be complicated and costly and their bulk and size makes them more difficult to move around the construction site.