This document discusses ablative and thermal insulation materials. It provides information on: 1) Ablative materials which protect vehicles during atmospheric reentry by absorbing, dissipating, and blocking heat. They are needed for ballistic missiles, rocket nozzles, and other high heat applications. 2) Thermal insulation materials which prevent or reduce heat transfer to maintain temperatures. They include organic materials like wool and inorganic materials like glass wool. 3) Intumescent ablators which form a foam-like char when heated, decreasing conductivity and insulating the substrate while cutting off oxygen supply. They are common as fire-retardant coatings.

1. ENGINEERING MATERIAL
ABLATIVE AND THERMAL INSULATION MATERIALS
PRESENTED TO:-
SIR TAHIR ZAHOOR
PRESENTED BY:-
 MUJAHID ALI (2K17-CHE-201)
 MUHAMMAD ABDULLAH (2K17-CHE-202)
 AHMAD BILAL (2K17-CHE-203)
 M GULFAM SAQIB (2K17-CHE-204)
 M YASIR MUSHTAQ (2K17-CHE-205)

2. ABLATIVE MATERIALS
• Introduction:
• The word ablation is derived from the suppletive past particle of
the Latin auferre , which means to remove. It was originally used in
the geologic sense to describe the combined, predominantly
thermal, processes by which a glacier waste. The present use
maintains the thermal aspects and describes the absorption,
dissipation, and blockage of heat associated with high speed entry
into the atmosphere. Thus ablative, thermal protection materials
are used to protect vehicles from damage during atmospheric
reentry.

3. Need Of Ablative Materials
1. The need of these material was first realized during the development of
operational ballistic missiles In Pennemunde, Germany, when a large
percentage of V-2s failed to reach their targets because of missile skin
disintegration by aerodynamic heating.
2. Ablative materials are also used to protect rocket nozzles and ship hulls
from propellant gas erosion, as protection from laser beam, and to
protect land based structures from high heat environment.

4. Selection of Ablative Materials:
The functional requirements of ablative heat shield must be well understood
before proper selection of material can occur. Ablative heat shield materials
not only protect a vehicle from the excessive heating, they also act as an
aerodynamic body and sometimes as a structural component. Some of the
factors which must be considered in the selection of ablative materials.
1. Intensity and duration of heating,
2. thermo-structural requirements and shape stability,
3. potential for the particle erosion,
4. weight limitations,
5. reusability

5. ABLATION MATERIALS FOR THE AEROSPACE AND
DEFENCE INDUSTRY
Some typical environments include Jet aircraft, space shuttle,
long range ballistic missile etc.
Application examples
• insulation of solid rocket engines
• deck protection of navy ships in the area of missile systems
• protection of thermal high stressed compontents in
submarine rescue systems

6. INSULATION MATERIALS
• DEFINITION OF INSULATION
Insulation materials are made to maintain the building
components and facilities as long as possible.
or
Insulations are also defined as those materials
combinations of materials which retard the flow of heat
energy .
Functions of Insulation Materials:
1. Conserve energy by reducing heat loss or gain.
2. Control surface temperatures for personnel protection
and comfort.

7. • Functions of Insulation Materials:
3) Facilitate temperature control of process.
4) Prevent vapour flow and water condensation on cold
surfaces.
5) Increase operating efficiency of
heating/ventilating/cooling, plumbing, steam, process and
power systems found in commercial and industrial
installations.
6) Prevent or reduce damage to equipment from exposure
to fire or corrosive atmospheres.
7) Reduce emissions of pollutants to the atmosphere.

8.  Those materials that prevent or reduce various modes of heat
transfer(conduction, convection and radiation) from the outside to
the inside or vice-versa, whether the environment temperature is
high or low
Advantages of Thermal Insulators
 Well chosen material can also protects the piping being insulated
from harsh environmental conditions such as UV light, salt, water,
dusts, chemicals and oil. Other characteristics may include the
ability to inhibit the growth or viruses, bacteria and fungi.
THERMAL INSULATION MATERIALS
INTRODUCTION

9. Classification of Thermal Insulators
According to the structure
1. Organic materials,
such as cotton, wool, cork, rubber and cellulose.
2. Inorganic materials:
such as glass, asbestos, rockwool, perlite, vermiculite
and calcium silicate.
3. Metallics:
such as aluminum foils and tin reflectors.

10. Classification of Thermal Insulators
-According to the Shape
1. Rolls:-
vary in the degree of flexibility and the ability to bend or
pressure. They could be fastened by nails like glass wool,
rock wool, polyethylene and foil-ceramic rolls.
2. Sheets:
There are specific dimensions and thicknesses such as
polyethylene layers, polystyrene, cork and cellulose.
3. Liquid or gaseous fluids:
poured or sprayed on to form the desired dielectric layer,
such as polyurethane foam and epoxy.
4. Grains:
a powder or granules are usually placed in the spaces
between the walls and it can also be mixed with some other
materials. Examples of such materials granulated cork and
polymers.

11. Graph To Understand Thermal Insulation Concept

12.  Low thermal conductivity.
 Chemical Stability
 Non-combustible.
 Rigidity
 Low Cost
 Light Weight
 Fire Proof
 Water Repellent
 Pipe insulation materials can be manufactured from rubber,
wool, glass fibers or cork. The polyurethane or P.U. is a
synthetic material that is commonly used these days due to its
low thermal conductivity and other good properties.
PROPERTIES OF THERMAL INSULATORS

13. Factors influencing performance on
Thermal Insulators
• Insulation performance is influenced by many factors, the
most prominent of which include:
• Thermal conductivity ("k" or "λ" value)
• Surface emissivity ("ε" value)
• Insulation thickness
• Density
• Specific heat capacity
• Thermal bridging
• It is important to note that the factors influencing
performance may vary over time as material ages or
environmental conditions change.

14. INSULATING
MATERIALS
 Fiberglass
 Mineral Wool
 Cellulose
 Polyurethane Foam
 Polystyrene

15. THERMAL INSULATING MATERIALS

16. THERMAL INSULATING MATERIAL PROPERTIES
AND INSTALLATION

17. Table: Thermal Insulating Materials and their available forms

18. CHARACTERISTICS OF
INTUMESCENT ABLATORS
• Intumescence is a heat insulating mechanism where the insulator
forms a foam-like material through enlargement, swelling, or
bubbling of the virgin material under the action of heat.
• This type of ablative material is best suited to low heat fluxes and
mild thermal environments. Intumescent ablative materials offer
two advantages to the insulation designer.
• First, as the intumescent material expands, the thermal
conductivity value decreases, providing excellent insulation for
the substrate. materials.

19. • Second, the ablative material forms a dense
char which cuts off the oxygen supply to the
substrate. The most common use of
intumeseent ablative materials is as a fire-
retardant paint protection for metals,
plastics, wood, and other
• The physical aspects of the
intumescent reaction is illustrated in
Figure
• Initially, the material acts as a heat
sink absorbing all of the incident heat.
As in charring materials, the low
value for thermal diffusivity causes
the heat to be entrained close to the
surface of the material resulting in a
rapid rise in the temperature of the
surface region. When the intumescent
reaction temperature is reached, a
pyrolysis generation zone forms. The
hot pyrolysis gases produced by the
decomposition reactions perculate
toward the surface of the ablator.
Physical model of an intumescent ablator.

20. • As the gases come in contact with the virgin material, an
expanded region of lower density foamy material is formed.
This region of foamy material is called the intumesced region.
• Difference Between Intumescent Ablators and
Charring Ablators
major difference between intumescent and charring
ablators is the response of the thermal conductivity
and specific heat values for the ablative materials
to increasing temperature.

21. • As shown in Figure, the result of the intumescent reaction is a decrease in
the value of thermal conductivity as the material temperature increases.
Effects of temperature on the thermal
conductivity value of an intumescent ablator.

22. • the result of the intumescent reaction is an increase in the
value for specific heat as the material temperature increases.
Effects of temperature on the specific heat value of
an intumescent ablator.

23. THERMAL PROPERTIES OF INTUMESCENT
ABLATORS.

24. MECHANICAL PROPERTIES OF INTUMESCENT
MATERIALS
• Intumescent ablative materials possess good mechanical
strength properties.
• The ablative coating is capable of adding structural strength
to a structure and surviving the blast from a missile rocket.
• Most commercial applications of intumescent materials are as
a paint or trowelable coating for fire-retardant purposes.