This document discusses various fire-resistant building materials, their properties, and applications. It describes materials like stone, brick, steel, concrete, glass, asbestos cement, plaster/mortar, gypsum, terra-cotta and stucco. These materials have high melting points and conduct heat slowly, allowing them to maintain structural integrity when exposed to fire for extended periods. Proper material selection and construction techniques are important to achieve adequate fire resistance for buildings.
2. INTRODUCTION
The fire hazards associated with materials, products, and assemblies used in buildings
and other structures have long been a subject of concern and regulation. The hazards of
flammable gases and flammable and combustible liquids are widely recognized and
regulated with respect to their production, transportation, and utilization. Historically,
combustible materials used as part of a building’s construction have been regulated
more so than the furnishings and contents brought into buildings, but in recent years
the fire hazards and risks associated with furnishings and contents have come under
increased scrutiny as the contribution of these products to fires becomes more widely
recognized.
Evaluation of the fire hazards of materials is complicated, because so many variables
can influence the process. These variables include material properties and
configurations, environmental conditions, and enclosure effects. Consequently, the fire
hazards associated with different materials depend not only on their chemical and
physical properties, but also on their applications.
-Uncontrolled fires present hazards to life and property due to release of smoke, toxic
and corrosive compounds, and release of heat in all fire stages (pre-ignition, ignition,
fire growth and flame spread, steady state, and decay). The non-thermal and thermal
hazards are created primarily due to the use of products made of combustible materials
(both natural and synthetic). These products are used in a variety of ways in residential,
private, government, industrial, transportation, and manufacturing applications.
Consequently, numerous fire scenarios need to be considered for testing of products
MATERIALS CHARACTERISTICS
Various products are constructed from natural and synthetic materials containing
carbon, hydrogen, oxygen, nitrogen, sulphur, and halogen atoms that are attached to
each other by a variety of chemical bonds in the structure.
The fire resistance of the materials and products is identified in terms of the ease or
difficulty with which materials or products undergo a transformation through the
following processes when exposed to heat: • softening and melting • decomposition,
vaporization, and charring • ignition • flame spread and fire growth • release of heat •
release of smoke, toxic, and corrosive compounds
3. Fire-Resistant Building Materials
According to ‘National Building Code of India’ (Part 4 Fire and Life Safety-2005) fire
resistance is a property of either an element or material of building construction and is
the measure of its ability to satisfy for a stated period of some or all of the following
criteria:
(a) Resistance to collapse(b) Resistance to penetration of flame and hot gases
(c) Resistance to temperature rise on the unexposed face up to a maximum of 180
degree Celsius and/or average temperature of 150 degree Celsius.
Building materials used in constructing a house can be of two types:
01. Non-combustible Materials
02. Combustible Materials
Non-Combustible Materials
These materials do not contribute to the growth of fire but may get damaged when the
temperature is reached to a very high level where decomposition of fusion occurs,
resulting in the loss of strength of the building. If such materials are used in the
structure, it may maintain the integrity of structure for longer duration but may
eventually collapse. Examples of such materials are metal, stone, glass, concrete, clay
products, gypsum products and asbestos products.
Combustible Materials
Combustible materials will combine exothermically with oxygen, give rise to flame
and spread the fire. Such materials whether form part of the structure or contents of the
building, burn themselves and increase the intensity and growth of fire i.e. it acts as a
fuel for the fire. Examples of such materials are wood and all wooden products,
manufactured products such as fibre board, straw board, etc.
It can be said that non-combustible materials are safe up to certain level to use in
building / house for the simple facts it cannot become the fuel for fire.
Nowadays there is a fast-growing awareness amongst the architects and engineers to
plan, design and construct the buildings, keeping the safety of the occupants as the
focus in the event of outbreak of fire. Once the fire starts, it has a tendency to ignite all
the combustible materials of the surrounding area and if not checked in time, it may
spread to other parts of the buildings and ultimately lead to the collapse of the building.
Most of the countries have described fire resistance in terms of duration of resistance to
fire i.e. 1 hour, 2 hours of fire resistance etc. There are also norms and regulations that
should be kept in mind by architects & engineers to design buildings.
4. Fire-Resistant Materials
01. Stones
Stones are used in a hilly area where stones are available easily. Depending upon their
characteristics, different types of stones are used at different places. Polished granites
are used as table tops, cladding for walls and columns. Stones are also used in backyard
garden for planters, in entrance hallway in home and to build compound wall. Granite,
sandstone and limestone are used to build walls. Slate stones are used in roofs and
floors.
Stone has a higher capacity to withstand fire up to 13000C – 15000C, beyond which it
starts melting/breaking. The use of stone in a fire-resisting construction should be
restricted to a minimum as this fire-resistant material cannot resist sudden cooling and
breaks into pieces.
02. Bricks
Bricks are the most common and favoured
construction material throughout the world.
Bricks are used for the construction of wall, lintel
and arch, retaining wall, cavity wall and damp roof
courses etc.First class bricks are practically fireproof as they can withstand the
exposure of fire for a considerable length of time.
Being poor conductors of heat, the bricks can withstand high temperatures up to
13000C without causing serious effects. Fire bricks are best for use in fire-resisting
construction. Fire bricks have melting point about 28000C.
03. Steel
Steel is used to build high rise building, residential
buildings. Steel is used in beam, column, lintel purlin,
roof, ceiling, walls etc. It is also used in building as
heating and cooling equipment and interior ducting.
At about 6000C, its yield strength is reduced to only
one-third of its value at normal temperatures.
Steel melts at 14000C. The term fireproof does not
necessarily mean that an item cannot ever burn: It
relates to measured performance under specific
conditions of testing and evaluation.
Fireproofing does not allow treated items to be
entirely unaffected by any fire, as conventional
materials are not immune to the effects of fire at
a sufficient intensity and/or duration.
5. Fire-Resistant Materials
04. Wrought-Iron and Cast-Iron
Wrought iron is used as a decorative purpose in outdoor stairs, railing, gates and
fences. Cast-iron is rarely used for fire-resisting point of view in construction as on
sudden cooling, it gets contracted and breaks into pieces or fragments. They melt at
around 11000C to 15000C. For using cast iron in fire-resistive construction, it should
also be protected by a suitable covering of bricks, concrete etc
05. Aluminium
Aluminium is used for window frames, for roofing, and curtain walling, as well as for
cast door handles, catches for windows and staircases.
In some advanced countries, the aluminium is being used for reinforcement purposes in
multi-storied structures because of its light weight and anti-corrosion properties.
Melting point of aluminium is about 6600C.
06. Concrete
In general, it is a bad conductor of heat and
is a good fire-resistant material. Concrete
does not have melting point but there is loss
of strength after certain degree of temperature.
There is no loss of strength in concrete up to
2500C. The actual degree of fire-resistance of concrete depends upon the nature of
aggregates used and its density. In case of RCC and pre-stressed construction, it
depends upon the position of steel in concrete. RCC structure can resist fire up to
10000C for one hour. Coarse aggregates, like foamed slag, blast furnace slag, crushed
brick, crushed limestone, cinder etc. are best suited for concrete for fire resistance.
Aggregates like flint, gravel, granite etc. possess poor fire-resisting characteristics.
07. Glass
Because of its low thermal conductivity, glass is a very
good fire-resistant material. Glass melts at approximately
around 14000C to 16000C. Sudden and extreme changes
in temperature, however, result in fracture or cracks.
But when glass is reinforced with steel wire netting,
e.g., in wired glass, its fire resistance is considerably
increased, and its tendency to fracture with sudden
changes in temperature, gets minimized.
Reinforced glass has a higher melting point and hence commonly used for making fire-
resisting doors, skylight, windows etc. in construction work. Glass Ceramic can handle
very high temperature and are suitable for fire-proof doors.
6. Fire-Resistant Materials
08. Asbestos Cement
This fire-resistant material, which is formed by combining fibrous mineral with
Portland cement, has a great fire-resistive value. Its melting point is about 8710C.
Asbestos cement products are widely used for the construction of fire-resistive
partitions and roofs among others. Being poor conductor of heat and incombustible
material, the structural members blended with asbestos cement offer great resistance
to cracking, swelling, or disintegration when subjected to fire.
09. Plaster or Mortar
It is an incombustible fire-resistant material and
hence used for protecting the walls and ceilings of
building from fire-risks. Cement plaster is better
than lime plaster as the latter is likely to be
calcined. The fire resistance of the plaster to fire
hazards can be increased by using it in thicker
layer or reinforcing the plaster with metal lathes.
10. Gypsum
Gypsum is another commonly used fire-resistant material used in
construction world. Gypsum has melting point about
1000C–1500C. Many structural materials are attached underneath
with gypsum sheeting to prevent any fire hazards and to achieve
good fire-resistant ratings.
11. Terra-Cotta
It is also a clay product like brick but possesses better fire-resisting qualities than
bricks. Being costlier, its use is restricted to fire-resisting floors only.
12. Stucco
Stucco is a plaster that has been used for centuries for both structural purposes and
artistic. Modern stucco is made of Portland cement, sand and lime, and it serves as an
excellent and durable fire-resistant material for buildings. Stucco is often suggested as
one of the best materials for boxing in hazardous eaves. Because of versitality in
finishing techniques, stucco can come in various textures and colours.
Gypsum plaster is also applied on steel columns and other steel members to increase
their fire-resistive qualities. The use of fire-resistant materials like cement mortar with
surkhi or pozzolana is preferred from the viewpoint of fire-resistance. Nowadays
vermiculite plaster is also used as fire-resistant material. Vermiculite is used in building
boards because of its low density and good insulation properties.