Transcript Advantages of Thermal Insulation

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Fire protection
Dampness
Thermal Insulation
Acoustical construction
Anti Termite
Pen No.
Name
130450106007
Hardik
130450106008
Ishita
130450106009
Keyur
130450106010
Jay
130450106011
Tahir
130450106013
Krishna
FIRE PROTECTION
• Fire protection is the study and practice of mitigating the
unwanted effects of potentially destructive fires.
• It involves the study of the behaviour ,
compartmentalisation, suppression and investigation
of fire and its related emergencies, as well as the research
and development, production, testing and application of
mitigating systems. In structures, be they land-based,
offshore or even ships, the owners and operators are
responsible to maintain their facilities in accordance with a
design-basis that is rooted in laws, including the
local building code and fire code, which are enforced by
the Authority Having Jurisdiction.
• Buildings must be constructed in accordance with the
version of the building code that is in effect when an
application for a building permit is made.
• Building inspectors check on compliance of a building
under construction with the building code.
• Once construction is complete, a building must be
maintained in accordance with the current fire code,
which is enforced by the fire prevention officers of a local
fire department. In the event of fire
emergencies, Firefighters, fire investigators, and other fire
prevention personnel called to mitigate, investigate and
learn from the damage of a fire. Lessons learned from
fires are applied to the authoring of both building codes
and fire codes.
• Now days , engineers and code officials when referring
only to active and passive fire protection systems, and
does usually not encompass fire detection systems such
as fire alarms or smoke detection.
CAUSES OF FIRE
• Careless discarding of lighted ends of cigarettes , cigars,
matches and tobacco ,
• Smoking in unauthorised places ,
• Indifferent maintenance of machinery including overloading
and under or over lubricating of bearings ,
• General indifference to cleanliness ,
• Incorrect storage of materials ,
• Faulty workmanship and inattention to electrical
installations (this is particularly evident by the fires
which occur during the monsoon ,
• Un-approved equipment and layout ,
• Inattention of persons concerned with inspection and
patrol of the premises under their jurisdiction , and
• Inattention of fire safety regulations, etc.
FIRE FIGHTING
Firefighting is the act of extinguishing fires.
A firefighter fights fires to prevent loss of life,
and/or destruction of property and the
environment. Firefighting is a highly technical skill
that requires professionals who have spent years
training in both general firefighting techniques and
specialized areas of expertise.
CHARACTERISTICS OF FIRE
RESISTING MATERIAL
• The material should not disintegrate under the effect
of great heat.
• The expansion of the material due to heat should not
be such that it leads to instability of the structure of
which it forms a part.
• The contraction of the material due to sudden
cooling with water (during fire extinguishing process)
after it has been heated to a high temperature should
not be rapid.
In relation to fire, building materials can be
divided into two types:
a) Non-combustible materials: Non-combustible materials are those
which if decomposed by heat will do so with absorption of heat (i.e.
endothermically ) or if they do oxidise, do so with negligible
evolution of heat. These materials do not contribute to the growth or
spread of fire , but are damaged and decomposed when high
temperatures are reached. Examples of non-combustible materials
are: stones and bricks , concrete , clay products, metal, glass etc.
b) Combustible materials: Combustible materials are those which,
during fire, combine exothermically with oxygen, resulting in
evolution of lot of heat and giving rise to flame or glow. Such
materials burn and also contribute to the growth of fire. Examples of
these materials are: wood and wood products, fibreboard, straw
board etc.
FIRE PREVENTION
Fire prevention is a function of many fire
departments. The goal of fire prevention is to
educate the public to take precautions to prevent
potentially harmful fires, and be educated about
surviving them. It is a proactive method of
reducing emergencies and the damage caused by
them. Many fire departments have a Fire
Prevention Officer.
FIRE ALARMS
An automatic fire alarm system is designed to detect
the unwanted presence of fire by monitoring
environmental changes associated with combustion.
In general, a fire alarm system is classified as either
automatically actuated, manually actuated, or both.
Automatic fire alarm systems are intended to notify
the building occupants to evacuate in the event of a
fire or other emergency, report the event to an offpremises location in order to summon emergency
services, and to prepare the structure and associated
systems to control the spread of fire and smoke.
SMOKE DETECTOR
A smoke detector is a device that detects smoke,
typically as an indicator of fire. Commercial, industrial,
and mass residential devices issue a signal to a fire alarm
system, while household detectors, known as smoke
alarms, generally issue a local audible or
visual alarm from the detector itself .
Smoke detectors are typically housed in a disk-shaped
plastic enclosure about 150 millimetres (6 in) in diameter
and 25 millimetres (1 in) thick, but the shape can vary by
manufacturer or product line. Most smoke detectors
work either by optical detection (photoelectric) or by
physical process (ionization), while others use both
detection methods to increase sensitivity to smoke.
Sensitive alarms can be used to detect, and thus deter,
smoking in areas where it is banned such as toilets and
schools.
FIRE EXTINGUISHING EQUIPMENTS
• Manual Fire Extinguishing Equipment:
These devices are useful for extinguishing fire as soon as it starts . They are not so useful when
once the fire has spread . Under this category comes the portable extinguishers of carbondioxide type or foam generation type etc. The discharge from a portable fire extinguisher lasts
only for a short duration of 20 to 120 seconds . In some cases , especially in small buildings
buckets of water , sand and asbestos blanket may be kept ready at all times to extinguish fire .
These buckets are installed at convenient locations for taking care of fire of minor size.
• Fire Hydrants:
These fire hydrants are provided on a ring main of 150 mm diameter in the ground around the
building periphery . The ring main gets water from underground tank with pressure , so that
available pressure at each hydrants is of the order of about 3.5 to 4 kg/cm.
• Wet Riser System:
The system consists of providing 100 to 150 mm dia. vertical
G.I. pipes (risers) at suitable locations in the building. A fire
pump is used to feed water from underground tank to these
pipes, to ensure a pressure of 3 kg/cm2 at uppermost outlet.
• Automatic Sprinkler System:
This arrangement is adopted for important structures like
textile mills, paper mills etc. The system consists of a
network of pipes 20 mm dia. Fixed to the ceiling of the room.
These pipes are spaced at 3 m centre to centre. Heat
actuated sprinkler heads are fixed to these pipes at regular
interval. The pipes get supply from a header.
FIRE ALARM
SMOKE DETECTOR
MANUAL FIRE ALARM
MANUAL ALARMS AND
AUTOMATIC ALARMS
FIRE HYDRANTS
WET RISER SYSTEM
GAS CYLINDER
AUTOMATIC SPRINKLER SYSTEM
Dampness in Buildings
Site preparation and resistance to
contaminates and moisture :
Protect building and people from harmful
effects caused by
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Ground moisture
Rain
Interstitial and surface condensation
Spillage of water from sanitary objects
AD Part C
What is Dampness?
Damp is generally defined as unwanted water or
moisture.
The existence of dampness in buildings is one of
the most damaging failures that can occur in
buildings.
It can cause
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Damage in brickwork by saturating it
Decay and breaking up of mortar joints
Dry and wet rot in timber structures
Corrosion of iron and steel
REASONS:
Service Performance
• Ambient temperature
• Amount of precipitation
• Relative humidity
• Position & exposure of
materials
Physical Effects
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Freeze/thaw
Timber rot
Water staining
Cyclic wetting/drying
Insulation values reduced
Electrics made unsafe
Chemical effects
Efflorescence
Cryptoflorescence
Corrosion of ferrous metals
Chemical attack (e.g. sulphate)
Cohesion loss
Effects on Health
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Ambient air conditions
Mould growth & spores
Viruses & infections
Rot & infestation
Psychological
In general we can consider moisture in the walls
of a building under four broad headings:
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Rising damp
Penetrating damp
Condensation
Entrapped moisture
Rising Damp
The majority of construction materials are porous.
This means they will soak up a considerable amount of
water.
Rising Damp
Causes
Other potential causes of rising damp include:
1. By-passing of the DPC caused by bridging
internally by a porous floor screed
2. By-passing of the DPC externally by raised
paths, planting borders etc
3. By-passing of the DPC with external render
coating
Riley, Cotgrave (2005)
Rising Damp
Effect
• Stained decoration
• Rusting to skirting nails
• Decay to timber skirting
• Breakdown of plasterwork
Rising Damp
Remedial DPCs
The purpose of remedial DPCs is to attempt to arrest
the oassage of moisture frim the ground through
the walls by inhibiting the natural process of
capillary action.
One can categorise the most common forms of
remedial DPCs into
• Chemical DPCs
• Physical DPCs
Riley, Cotgrave (2005)
Division of Sustainable Development
Rising Damp
Chemical DPCs
This technique uses liquid which is either
introduced into the wall by simple gravity
or under pressure.
This liquid will either fill the pores of a
material with water resistant material
(pore fillers) or line them with a nonwettable surface to reduce capillary
attraction (pore liners).
Thus a damp proof course will be created.
Riley, Cotgrave (2005)
Remedial actions
Physical DPCs
Are layers of impervious
material which is
inserted into a carefully
cut gap.
Pieces have to overlap to
make sure they are
tight.
Penetrating Damp
Ingress of rainfall
Erosion of the façade surface
material
Propulsion of the water
through openings
Penetrating Damp
Hydrostatic Pressure
Pressure exerted by liquids at rest
•Below ground
• Retaining walls, basements
•Above ground
• Water accumulation
Impervious membranes for below ground structures, high
quality concrete and modifications of the site conditions
(drainage) can help to protect against the risk of
penetration damp through hydrostatic pressure
Entrapped Moisture
The construction process has traditionally relied on the
use of 'wet trades' such as plastering and concreting,
which introduce high levels of water into the building
during construction.
In the period following construction there will be a
natural drying process.
Some of this water will evaporate before the building is
occupied.
Riley, Cotgrave (2005)
Remedial actions
There are several ways of diagnosing
rising damp.
• Damp meter profiling (more often used
for timber structures)
• Quantitative measurement, on site and
laboratory testing
Riley, Cotgrave (2005)
THERMAL INSULATION
General :
It is established by the laws of heat transfer that when there is
Difference in temperature between the inside and outside or different
parts of the building exists, heat transfer take place from areas of
higher temperature to those of lower temperature. This heat transfer
may take place by or more the three methods namely, conduction,
convection and radiation.
In very hot regions, when the buildings are internally cooled and
the outside atmosphere is unbearably warm, it is necessary to check the
entry of heat from outside into the building. Similarly, in very colder
region, when the buildings are internally warm where outside
atmosphere is very cool, it is essential to check this heat loss from the
building.
The term thermal insulation is used to indicate the construction
or provisions by way of which transmission of heat from or the room is
retarded.
the objective of thermal insulation is to minimise the transfer of
heat between outside and inside of the building.
Advantages of Thermal Insulation:
The advantages derived from thermal insulation are:
1. Comfort:
Due to thermal insulation, the room remains cool in summer and
warm in winter than outside. This results in comfortable living.
2. Fuel saving:
Due to thermal insulation, the demand of heating in winter and
refrigeration in summer is considerably reduced. This results in lot of
fuel saving and maintenance cost.
3. Preventation of condensation:
Use of thermal insulating materials inside a room results in
preventation of condesation on the interior walls and ceiling etc.
4. Water system:
The use thermal insulation materials prevents the freezing of water
taps in extreme winter, and heat loss in case of hot water system.
Basic Definitions:
1. Conduction :
Conduction is the direct transmission of heat through a material.
The amount of heat transfer by conduction depends upon:
Z temperature difference
Z thickness of solid medium
Z area of exposed surface
Z time for which heat flow takes place
Z conductivity of the medium
Z density of the medium
2. Convection:
Heat is transmitted by convection in fluids and gases, as a result of
convection. Air movement causes the heat insulator. It is preferable
to ensure that excessive air change is avoided.
3. Radiation:
Heat is transmitted by radiation through space in the form of
radiant energy. When the radiation strike an object, some of the
energy is absorbed and transformed into heat. One of the ways of
reducing heat absorption from radiation is to introduce a suitable
reflecting surface.
4. Thermal conductivity(K) :
The thermal conductivity of a material is the amount of heat that
will flow through an unit area of material, of unite thickness in one
hour, when the difference of two temperatures is maintained 1 ˚ C.
It is expressed as
k cal.cm
m 2 h. deg C
5. Thermal resistivity :
This is the reciprocal of thermal conductivity and is denoted by
1
K
.
6. Thermal condutance (c):
It is thermal transmission of a single layer structure per unit area
divided by temperature difference between the hot and cold faces.
It is expressed by k cal
m 2 h. deg C
7. Thermal resistance (R):
It is the reciprocal of thermal conductance. For a structure having
plane parallel faces, thermal resistance is equal (L) divided by
thermal conductivity.
R
L
K
It is expressed as m2 .h. deg C
k.cal
8. Surface coefficient(f):
It is the thermal transmission by convection, conduction or radiation
from unit area of the surface, for unit temperature difference
between the surface and the surrounding area.
It is expressed as
k
cal
m 2 h. deg C
9. Surface resistance:
It is reciprocal of surface coefficient.
2
It is expressed as m .h. deg C
k .cal
10. Total Thermal resistance:
Total thermal resistance is the sum of the surface resistance and the
thermal resistance of the building unit itself.
1
1
 RT  [
 ]  R1  R 2  R3  ........
fo fi
Where,
f  outside surface conductance
o
f  inside surface conductance
i
1
f
 for walls and roofs may be taken as 0.0515.
o
1
f
for walls may be taken as 0.125.
i
1
f

for roof may be taken as 0.171.
i
2
It is expressed as m .h. deg C
k .cal
11. Thermal transmittance (u):
Overall thermal transmittance is thermal transmission through
unite area of the given building divided by the temperature
difference between the air or other fluid either side of building unit
in ‘steady state’ condition.
It is reciprocal of total thermal resistance.
cal
It is expressed as k
m 2 h. deg C
12. Thermal damping (D) :
It is given by D  (T o  T i) 100
To
Where, T o = outside temperature range
T i = inside temperature range
It depends on the thermal resistance of the materials used in the
structure .
13. Thermal time constant (T):
It is the ratio of heat stored to thermal transmittance of the
structure.
Q
T
u
Where , Q = quantity of heat stored.
Thermal insulating materials
Various form of thermal insulating materials are:
1. Slab of block insulation
2. Blanket insulation
3. Loose fill insulation
4. Bat insulating materials
5. Insulating boards
6. Refective sheet materials
7. Light weight materials
1. Slab or block insulation:
they are made up cork boards, cellular glass blocks, mineral wood
blocks , or wood fibres bound together with cement.
These slabs or blocks are fabricated in size up to 60*120 cm the
walls and roofs for lining purposes.
2 Blanket insulation:
they are mad up of flexible fibrous materials and available in rolls.
These fibrous materials are made from mineral wood, wood fibre,
cotton, animal hair etc. The blanket insulation are prepared in
thickness of 1 to 8 cm in rolls are directly spread on surface of walls
and ceilings.
3. Loose fill insulations:
They consist of fibrous materials , like rock wool, slag wool, cellulose
or fibre wool etc. They are loosely poured into the studding space
and other similar spaces, for heat insulation purposes.
4. Bat insulation materials :
They are soft materials similar to blanket insulation, but are smaller
in size and greater in thickness usually 5 to 9 cm. They are also
spread on the surface of walls and ceilings.
5. Insulating boards:
they are structural insulating board prepared wood cane and other
materials by binding the fibers with adhesives in thicknesses and
sizes, these board are used for interior lining of walls and roof and for
partition.
6. Refective sheet materials:
Refective sheet materials have high reflectivity and low emissibility,
thus offering high heat resistance. These reflective insulation consists
of sheet or gypsum boards, steel sheet reflective materials, etc . They
are generally used along with air spaces air space such into two or
more vertical layers.
7. Light weight materials:
the cement or concrete products have lower insulation value. But,
with the use of light weight materials, such as blast furnace clay ,
aggregate, porous aggregater or concrete , its resistance against heat
can be improved.
Thermal insulation roofs:
IS: 3792-1966 recommends that no roof should have an overall
transmittance of more than 2.0 cal/m ² h deg C. It is also
recommended that the roof should not have thermal damping
less than 75 percent.
-> heat gain through roofs may be reduced by adopting the
following methods:
1. Heat insulating materials may be applied externally or
internally to the roofs.
In case of external application, heat insulating materials
may be installed over the roof but below a waterproof course.
IN case of internal application, heat insulating materials
may be fixed by adhesive or otherwise, on the underside of
roofs from within the rooms.
2. The false ceiling of insulating materials as shown in fig may be
provided below the roofs with air gaps in between.
3. For flat roofs external insulation may also be done by arranging
asbestos cement sheet or corrugated G.I. sheet on brick with air gap
as shown in fig.
4. Shining and reflective insulation materials may be installed or laid on
the top of the roof.
5. Flat roofs may be kept cool by flooded water either by storing or
spraying regularly.
6. Roofs may be white washed before on-set of each summer.
7. Top exposed surface of roof may be covered by 2.5 cm thick layer of
coconut pitch cement concrete. Such a concrete is prepared by
mixing coconut pitch with cement and water. After, laying , it is
covered with an impermeable layer and then allowed to dry fpr 20
to 30 days.
Thermal insulation of Exposed walls:
IS:3192-1966 recommends that no exposed wall should have an overall
thermal transmittance for more than 2.2 k cal/m²h deg C. It is also
recommended that the wall should not have a thermal daming
less be increased.
Heat insulation of exposed walls may be achieved by the
following methods:
1. The thickness of the walls may be increased.
2. Cavity wall construction may be adopted for external walls.
3. The walls may be constructed out of suitable heat insulating
materials.
4. The heat insulating materials of different type can be installed
or fixed on the inside and outside of the exposed wall in order
to reduce the thermal transmittance to the desired limits.
5. For partition walls, and air space may be created by fixing the
sheathing of hard boards or battens on either side of the wall.
6. Light coloured white wash or distemper may be applied on the
exposed surface of the wall to increase thermal insulation value.
Thermal Insulation Exposed Doors and
Windows:
All doors, windows, ventilator, etc. which are exposed, transmit heat
to a considerable extent. The following methods can be suitably used
to achive heat insulation of exposed doors, windows, etc.
1. Reduction of incidence solar heat:
-> The incidence of solar heat on the exposed doors and windows can
be reduced by the following means:
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By use external shading, such as louvered shutters, sun-breakers and
chajjas or weather sheds.
By adopting internal shading , such as curtains in heavy folds,
venetian blind, etc.
2. Reduction of heat transmission :
Where glazed windows and doors are provided the reduction of heat
transmission may be achieved by insulating glass or double glass
with air space in between or by any other suitable means.
Acoustical Construction
• Acoustics is the science of sound , which deals
with origin , propagation and auditory
sensation of sound. It also deals with design
and construction of different building units to
set optimum conitions for producing and
listening speech , music ect.
The Knowledge of acoustics is
necessary for the proper functional
design of
Theatres:-
• Cinema halls:-
Conference hall:-
Hospitals:-
Sound
• Sound is genrated in the air when a surface is
vibrated. The vibrating surface setsup waves
of compression and refraction in the air and
these set the ear drum vibrating. The
movements of the ear drum are translated by
the brain into sound sensation.
• When the sound waves are periodic regular
and long continued, they produce a pleasing
effect
Such a sound is known as musical
sound
When the sound wave is non-periodic irregular
and of very short duration, it produces
displeasing effect. Such a sound is known as
noise.
Characteristics of audible sound:•
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There are three characteristics of sound:1. Intensity and loudness.
2. Fequency and pitch.
3. Quality or tone.
Reflection of sound :• When a free sound wave travellng through air
strikes a uniform, solid, large, plane, surface, it
is reflected in the same manner as that of a
light ray.
• The angle which the incident wave makes with
the palne surface is equal to the angle which
the reflected wave makes with the palne
surface.
Common Acoustical Defects:•
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1. Reverberation
2. Echoes
3. Sound Foci
4. Dead spots
5. Insufficient loudness
6. Exterior noise
General principles and factors in
Acoustical design:•
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1. site selection and planning
2. volume i.e. Size and height
3. shape
4. seats and seating arrangement
5. reverbration
6. sound absorption
7. treatment of interior surface
Anti Termite Treatment:• The termites are popularly known as white
ants and they are found in abundance in
tropical and sub-tropical countries.
• They are very fast in eating wood and other
cellulosic materials as food.
• The term used to indicate the treatment in
which is given to a building so as to prevent
the growth of termite in a building.
How do u recognize it..?
• Wood that sounds hollow when tapped.
• A temporary swarm of winged insects in your home or from
the soil around your home.
• Any cracked or bubbling paint or frass (termite droppings).
• Mud tubes on exterior walls, wooden beams, or in crawl
spaces.
• Discarded wings from swarmers.
• Termite infestation is difficult
to detect as they work from
the inside to the outside.
• Termites actually live hundreds
of feet below the ground.
Termite infestation is not in
numbers of tens or hundreds.
There would be huge colonies
in thousands that you have to
deal with.
• They spread their wings in no
time eating into every corner
of your home. If neglected you
might just not have anything
left in a few months time.
•
• Anti termite treatment may be divided into
two categories:
A. Pre – construction treatment
B. Post – construction treatment
Pre – construction treatment
• This treatment is started right at the initial
stage of construction building. This is divided
into 3 parts :
Site preparation
Soil treatment
Structural barriers
Site Preparation
• This operation consists of removal of stumps,
roots, logs, waste wood etc. from the soil at the
construction site.
• If termite mounds are detected , these should be
destructed by use of insecticide solution ,
consisting of any one of the following chemicals :
Chemical
Concentration by weight
DDT
5%
BHC
0.05%
Aldrin
0.25%
• 4 liter of these emulsion in water is required
per cubic meter of volume of mound.
• Holes are made in the mound at several places
by use of crow bar and the insecticides
emulsion is poured in these holes.
Soil treatment
• Chemical treatment to the soil at the time of
construction of the building is the best and only
reliable method to protect the building against
terminates.
Chemical
Concentration by weight
Heptachlor
0.5%
Chlordane
1%
Aldrin
0.5%
• An insecticide solution of any of DDT, BHC, Aldrin,
Heptachlor in water emulsion should be applied evenly
either with a water cane or sprayer at following stages.
1.
2.
3.
In foundation pits , to treat
the bottom sides up to 30 cm
height.
The refill earth on both the
sides of all built up walls, for
width 30 cm and depth 45
cm.
Before lying the floor the
entire levelled surface is to
be treated at the rate of 5
liters of emulsion per square
meter.
Structural barriers
• To prevent the entry of
termites through walls barriers
may be provided continuously
at plinth level.
• Such structural barrier may be
in the form of a cement
concrete layer or metal layer
at plinth level.
• Cement concrete layer may be
5 to 7.5 cm thick and metal
barrier may consist of no
corrodible sheets of copper or
G.I. of 0.8 mm thick.
Post – Construction Treatment:• It is a maintenance treatment for those buildings
which are already under attack of termites.
• First of all detect the points of entry of termites in
the building.
• Wherever these shelter tubes are detected, these
should be destroyed after injecting anti – termite
emulsion through these.
• If there exists a concrete cover or masonry apron
around the walls of your building, holes are
drilled as close as possible to the plinth wall
about 300mm (1ft) apart from each other.
• Insecticide is then poured, so that it reaches
the soil to eliminate the termites present
there and to stop them from re-infesting.
• If your building is on pillars, the holes are
drilled around the pillars and insecticide
poured into the soil.