Is Steel Non-Combustible?

Non-Combustible Construction Materials

A decision published by the European Commission in October 1996 established what construction materials should be given a Class A fire rating, without testing, due to their low level of combustibility and steel was one of them. The Class A rating is also valid without testing even when the material is coated with an inorganic layer (such as coatings used on metal).

The full list awarded Class A fire rating covers a broad spectrum of materials used in construction, including:

• Minerals
• expanded clay, perlite and vermiculite
• mineral wool
• mineral aggregates
• cement, fibre cement and lime
• concrete, including ready-mixed, precast reinforced, prestressed and aggregate concrete
• blast furnace slag and pulverised fly ash
• gypsum and gypsum based plasters
• mortar with inorganic binding agents
• clay products, including bricks, tiles, paving and fireclay products
• natural stone and slate
• glass and glass ceramics
• Metals (although not in finely divided form)
• iron, steel and stainless steel
• copper and copper alloys
• zinc and zinc alloys
• aluminium and aluminium alloys
• lead

In the light of subsequent events – most notably the tragic Grenfell Tower fire disaster – products that may have at one time been specified for cost savings, convenience, aesthetic appeal and even environmental sustainability have been condemned by the Building (Amendment) Regulations 2018 as unsafe and replaced with Class A alternatives, often at great expense to property owners.

Definition of Non-Combustible

A material that is non-combustible will not burn or ignite when subjected to expected levels of fire or heat. It therefore cannot act as an agent to spread fire to other parts of a building, in contrast with combustible materials such as wood and some plastics.

A non-combustible material may still distort or lose structural integrity if exposed to extreme temperatures, but by the time a fire has reached that stage, it is expected that there will have been sufficient opportunity to evacuate the building safely.

Fire Safety on Roof Terraces

While a roof terrace on a residential or commercial development may not be the most heavily or constantly populated area of the building, fire safety is equally as important as inside.

• As heat rises, fire can quickly spread to the upper parts of a building
• Fire cannot be as easily suppressed outdoors compared with inside a building where fire doors and walls act as barriers to flames, heat and smoke
• Rooftop areas can be utilised for evacuation via helicopter

Raaft roof terrace systems and associated products – planters, decking and tiles – offer full Class A certified solutions for rooftop landscaping. An extruded aluminium support structure stands on fire-rated adjustable pedestals; planters are manufactured from galvanised or CorTen weathering steel, or given a powder-coated finish that doesn’t have the flammability of ‘wet’ paint coatings; decking and tiles are made from porcelain, which has excellent fireproof properties.

A roof terrace should be an area where residents or employees can escape the bustle of the streets or the hustle of the office and enjoy fresh air, relaxation and nature at its best. With a Raaft terrace system guaranteeing fire safety, everyone engaged in a construction project, from the architect to the installer, the developer to the contractor, can enjoy peace of mind.

If you are proposing, designing or specifying a roof terrace for your property and would like to know more about Class A compliance, give Raaft a call on +44 (0)20 3146 7879 or email [email protected] to be put in touch with our friendly, helpful team.