Fire resistance
In fire, concrete performs well – both as an
engineered structure, and as a material in its own right.
Because of concrete’s inherent material
properties, it can be used to minimise fire risk for the lowest
initial cost while requiring the least in terms of ongoing
maintenance. In most cases, concrete does not require any
additional fire-protection because of its built-in resistance to
fire. It is a non-combustible material (i.e. it does not burn), and
has a slow rate of heat transfer. Concrete ensures that structural
integrity remains, fire compartmentation is not compromised and
shielding from heat can be relied upon.
Benefits
Concrete as a material
Concrete does not burn – it cannot be set on
fire unlike other materials in a building and it does not emit any
toxic fumes when affected by fire.
Concrete is proven to have a high degree of
fire resistance and, in the majority of applications, can be
described as virtually fireproof. This excellent performance is due
in the main to concrete’s constituent materials (cement and
aggregates) which, when chemically combined within concrete, form a
material that is essentially inert and, importantly for fire safety
design, has relatively poor thermal conductivity. It is this slow
rate of conductivity (heat transfer) that enables concrete to act
as an effective fire shield not only between adjacent spaces, but
also to protect itself from fire damage.
Concrete structures
Concrete structures perform well in fire. This
is because of the combination of the inherent properties of the
concrete itself, along with the appropriate design of the
structural elements to give the required fire performance and the
design of the overall structure to ensure robustness.
Fire performance is the ability of a
particular structural element (as opposed to any particular
building material) to fulfil its designed function for a period of
time in the event of a fire. These criteria appear in UK and
European fire safety codes.
Concrete proof
The impact of a major fire at Tytherington County High School,
Cheshire, was limited due to the fire resistance of the concrete
structure. Rather than taking a year to be demolished and replaced,
as was the case with an adjacent lightweight structure, the
concrete classrooms were repaired ready for the following term.
For detailed guidance on concrete and fire, visit
the publications library to purchase the publication
Performance of Concrete Structures in Fire.