2. WOOD
• Wood is a fire-safe building material because its behaviour in fires is well known.
• A timber frame building can withstand a fire for a long time without collapsing
because the charring of surfaces protects the structures from the fire.
Source- Bay Alarm Source- Made-in-
china.com
Source- BuildingmaterialsNationwide.com
3. • Wood doesn't flow, it simply burns from the outside in and the inner parts not exposed to the fire are just as strong as
they were before the fire.
• By contrast: steel is an excellent conductor of heat and the interior of a beam is just as hot as the outside of the beam
exposed to the fire.
• Steel buckles(melts) under conditions of high temperature but in case of wood if older wood is used for construction
, only some outer layers of wood burn and the internal layers of wood does not catch fire protecting the structure from
burning .
WOOD VS STEEL AGAINST FIRE
Fire effects on steel
Source- EDT Engineers
4. CLASSIFICATION OF WOOD
The most widely accepted flame-spread classification system appears in the
National Fire Protection Association Life Safety Code, NFPA No. 101. This
Code groups the following classes in accordance with their flame-spread and
smoke development:
Class A - Flame-spread 0-25, smoke developed 0-450.
Class B - Flame-spread 26-75, smoke developed 0-450.
Class C - Flame-spread 76-200, smoke developed 0-450.
NFPA 101 primarily applies this classification to interior wall and ceiling finish
materials.
5. POLYMERS
• IN BASIC TERMS, POLYMERS ARE VERY LONG MOLECULES TYPICALLY MADE UP
OF MANY THOUSANDS OF REPEAT UNITS. THEY INCLUDE PLASTICS, RUBBERS,
THERMOPLASTIC ELASTOMERS ETC.
TYPES OF POLYMERS
• THERE ARE 3 PRINCIPAL CLASSES OF POLYMERS – THERMOPLASTICS, THERMOSETS,
AND ELASTOMERS.
• DIFFERENTIATION BETWEEN THESE CLASSES IS BEST DEFINED BY THEIR BEHAVIOUR
UNDER APPLIED HEAT.
6. THERMOPLASTIC POLYMERS
• In thermoplastics the long chain molecules exist
in the form of linear bonding but are also bonded
to each other by secondary Van Der Waals
forces (secondary bonds).
• At a high enough heat the excitation of
the molecular chains is enough to overcome
this binding force and they are free to move over
one another thereby creating a viscous liquid.
• When the polymer is cooled the secondary
forces once again dominate and the molecular
chains revert back to a restricted state. This means
that thermoplastics can be melted and
remelted allowing them to be easily recycled.
Properties
Rigid
Brittle
High strength at elevated temperatures
Good chemical resistance
Self extinguishing
Low smoke emissions
Uses
• Thermoplastic material used in making sports equipment.
• It is also used in making toys.
• It is used in automobile parts.
• It is used in making CDs and DVDs.
• Containers like shampoo bottles, drinking bottles, and food
storage containers are made up of thermoplastic polymer.
7. THERMOSETS
• In thermosetting plastics the long chain
molecules exist in an amorphous network with
cross-linked bonding. This means that the long
molecular chains are attached to each other by
covalent bonds. The formation of these cross-
links is known as curing.
• Cross-linking sets the molecular chains in place
and therefore means that a thermosetting
plastic cannot be remelted but will instead
decompose upon being heated to a
temperature.
• Cross-linking inhibits molecular arrangement
into an ordered crystalline structure meaning
that thermosetting polymers only exist in the
amorphous state.
Uses
Producing electrical goods
Components such as panels and insulators.
Manufacturing construction equipment panels.
Since they tend to be heat resistant, Thermosets are used for
manufacturing heat shields.
Properties
Hard
Brittle
Opaque
Good electrical and heat resistance
Resistant to deformation under load
Low cost
Resistant to most acids.
8. ELASTOMERS
• In elastomers the long molecular
chains exist in the form of amorphous
linear bonding with occasional cross-
linking.
• At room temperature the level of
excitation of the chains has already
overcome the secondary Van Der
Waals bonds, however, the cross-links
that exist in the structure act to revert
the elastomer back to its original
form following deformation.
Uses
Used for rubber tires and tubes for vehicles, motorcycles,
bicycles and recreational vehicles, lawn mowers and other
yard work vehicles.
Belts
Hoses
Gloves
Matting
Toy balloons
Rubber bands
Adhesives and pencil erasers.
Properties of elastomers
•Low-temperature flexibility.
•Hardness.
•Ageing.
•Colour.
•Elongation at break.
9. REFERENCES
• •"Impact of Urbanization on Urban Lake Using High Resolution Satellite Data and GIS(A Case Study of Man Sagar
Lake of Jaipur, Rajasthan)"
• •https://web.archive.org/web/20070610135159/http://dlc.dlib.indiana.edu/archive/00001612/01/INEFWP2005.pdf
• •https://books.google.com/books?id=nWKaR6LbEGcC&pg=PA341&dq=Jalmahal&lr=#v=onepage&q=&f=false
• •https://web.archive.org/web/20100103135940/http://www.ilfsindia.com/downloads/bus_rep/jalmahal_tourism_rep.p
df
• •http://www.rediff.com/money/2007/sep/29spec1.
• htm•https://web.archive.org/web/20110721161549/http://ppp.rajasthan.gov.in/ECID/ECIDVIII.pdf
• •https://books.google.com/books?id=8aIyc7_Q8JYC&pg=PA55&dq=Jal+Mahal+place+details+Jaipur#v=onepage&
q=&f=false
• •https://web.archive.org/web/20110726201454/http://www.jaipurjda.org/page.aspx?pid=94
• •http://www.outlookindia.com/article.aspx?272097
