This is the summer internship report for my 45 days summer internship at Coal Handling Plant for 2x660 MW Supercritical Thermal Power Plant Unit-5 and 6, Stage-II, Phase-III, Chhabra, Rajasthan of L & T Metallurgical and Material Handling Independent Company.

1. (From 26 May, 2016 to 08 July, 2016)
SUBMITTED BY: RAJ GUPTA
COURSE: B.Tech.
BRANCH: MECHANICAL
YEAR: 3rd
year
INSTITUTE:

2. C E R T I F I CA T E
This is to certify that this is a bonafide project work
done by Mr.______________________ a student
of National Institute of Technology, Warangal
B.Tech. Mechanical engineering 3rd
year in the
Project of COAL HANDLING PLANT FOR 2x660 MW
SUPERCRITICAL THERMAL POWER PLANT, CHHABRA ,
RAJASTHAN during 26May, 2016 to 08 July, 2016.
Date: 08-07-2016 Mr. S. Prakash
PROJECT GUIDE

3. Acknowledgement
Life of any human being is full of interaction. No one is completely self-
sufficient by himself. In our daily life we go ahead by acquiring
something from each other. This project work of mine would not have
reached its fulfillment hadn’t been the guidance shown to me by the
various people.
First of all, I am very thankful to God who is most beneficent and
merciful. I am very thankful to LARSEN & TOUBRO
CONSTRUCTIONS METALLURGICAL AND MATERIAL
HANDLING INDEPENDENT COMPANY (L&T
CONSTRUCTION, MMHIC) for having given me the opportunity to
undertake my summer internship at their Coal Handling Plant for 2x660
MW Supercritical Thermal Power Plant Unit-5 and 6, Stage-II, Phase-III,
Chhabra, Rajasthan. It was a very good learning experience for me to
have worked at this site.
I would like to give my heart-felt thanks to Mr. S.Prakash who guided
and encouraged me all through the summer internship and imparted in-
depth knowledge of the project.
I also express my thanks to all the staff members for their kind
cooperation during the internship period.
Finally, I pay my deep regards to my parent and friends whose blessings
made this project work a success.

4. ABOUT THE ORGANIZATION:
Larsen & Toubro Limited is the biggest legacy of two Danish Engineers, who built a
world-class organization that is professionally managed and a leader in India's
engineering and construction industry. It was the business of cement that brought the
young Henning Holck-Larsen and S.K. Toubro into India. They arrived on Indian
shores as representatives of the Danish engineering firm FL Smidt & Co. in
connection with the merger of cement companies that later grouped into the
Associated Cement Companies.
Together, Holck-Larsen and Toubro, founded the partnership firm of L&T in 1938,
which was converted into a limited company on February 7, 1946. Today, this has
metamorphosed into one of India's biggest success stories. The company has grown
from humble origins to a large conglomerate spanning engineering and construction.
Larsen & Toubro Construction is India’s largest construction organisation. Many of
the country's prized landmarks - its exquisite buildings, tallest structures, largest
industrial projects, longest flyover, and highest viaducts - have been built by it.
Leading-edge capabilities cover every discipline of construction: civil, mechanical,
electrical and instrumentation.
L&T Construction has the resources to execute projects of large magnitude and
technological complexity in any part of the world. The business of L&T Construction
is organized in six business sectors which will primarily be responsible for
Technology Development, Business Development, International Tendering and work
as Investment Centres. Headquarter is in Chennai, India. In India, 7 Regional Offices
and over 250 project sites. In overseas it has offices in Gulf and other overseas
locations.
L&T Construction’s cutting edge capabilities cover every discipline of construction –
civil, mechanical, electrical and instrumentation engineering and services extend to
large industrial and infrastructure projects from concept to commissioning.

5. L&T Construction has played a prominent role in India’s industrial and infrastructure
development by executing several projects across length and breadth of the country and
abroad. For ease of operations and better project management, in-depth technology and
business development as well as to focus attention on domestic and international project
execution, entire operation of L&T Construction is structured into four Independent
Companies.
• Hydrocarbon IC
• Buildings & Factories IC
• Infrastructure IC
• Metallurgical & Material Handling IC
• Power Transmission & Distribution
• Heavy Engineering
• Shipbuilding
• Power
• Electrical & Automation
• Machinery & Industrial Product
METALLURGICAL AND MATERIAL HANDLING
The Metallurgical and Material Handling (MMH) business vertical is India's market leader in
Engineering, Procurement & Construction of metallurgical projects possessing the capability
and expertise to undertake engineering, procurement, manufacture, supply, construction,
erection and commissioning of projects through its dedicated business units mentioned here
under spread across length and breadth of the country with foot prints in International arena
as well.
L&T's Metals and Minerals business offer one-stop solution for the ferrous and non-ferrous
sectors. The Ferrous business unit provides Comprehensive Engineering, Procurement and
Construction (EPC) solutions for the iron and steel industry while the Non-ferrous business
unit caters to aluminium, copper, zinc, lead and mineral beneficiation plants.
EPC solutions complimented with supply of heavy bulk material handling equipment are on
offer from L&T's Bulk Material Handling (BMH) business for material handling
requirements of core sector industries through its Power and Steel, Mines, Ports & Special
Conveyors business units.
L&T's Industrial Machinery and Cast Products business unit based in Kansbahal, Odisha
undertakes design, manufacture and supply of complete range of crushing systems and
equipment, blast-free surface miner solutions, advanced Sand Manufacturing Solutions, apron

6. feeders, critical machinery and parts for steel and paper industry and castings for wind mill
and wear-resistant applications. The comprehensive product offerings are complemented with
excellent design, engineering, quality control and logistic expertise.
BULK MATERIAL HANDLING
BMH provides tailor made engineering solutions to its customers in the form of indigenously
designed & manufactured products to cater all sorts of bulk material handling needs.
L&T's equipment offerings in the material handling sector are,
 Wagon Tipplers and Side Arm Chargers
 Stacker Reclaimers
 Barrel Reclaimers
 Bucket on Bridge Reclaimers
 Mobile Transfer Conveyors
 Crushers
 Apron Feeders
 Travelling Trippers
 Spreaders
 Wagon Loaders, Ship Loaders & unloaders
 Pusher Cars & all allied equipment
 Paddle Feeders
 Flow Dividers
BMH has a successful track record of having executed more than 53 coal handling plants,
115 stockyard equipment, 12 material handling plants, 24 Raw material handling plants, 92
wagon tipplers, 8 ship unloaders, 13 wagon shifters and approx. 250 km of conveying
systems.
The Chennai and Kolkata-based engineering centres (EDRC-BMH) are ISO certified entity
(BS EN ISO 9001- 2008) and offers comprehensive engineering solutions from concept to
commissioning for a wide variety of disciplines covering Mechanical (System & Equipment),
Civil & Structural and Electrical & Instrumentation for Mining, Coal Handling for Thermal
Power Plants, Raw Material Handling in Steel Plants and Export and Import of Raw material
in Port and Harbours.
BMH provides clients with unmatched design and engineering solutions for the manufacture
and supply of critical equipment like the Stacker Reclaimers and other Stockyard Machines,
Wagon Tipplers, Marshalling Equipment, Paddle Feeders, Crushers, Grizzly Feeders and Bin
Extracting Systems including Rapid/Wagon Loading Systems.
BMH has strategic alliances with leading global technologist to avail of new concepts and
technologies and provides end-to-end solutions for critical applications:
Ashton Bulk (U.K) for Bulk handling equipment

7. UCC (U.S.A) for Ash Handling Systems
VISION & MISSION
VISION
MISSION
To achieve excellence in the field of Engineering, Procurement and Construction through
world class practice and standards in quality, safety and project management.

8. PROPOSED – PROJECT
COAL HANDLING PLANT FOR 2x660 MW SUPERCRITICAL
THERMAL POWER PLANT, CHHABRA, RAJASTHAN.

9. Project Details
Business Unit : BMH - Power BU
Cluster : Ahmedabad
Job : CHP for2X660 MW, RRVUNL, SCTPS, Stage II,Chhabra Rajasthan
Client : L&T Power
Client’s Consultant : L&T – Sargent & Lundy Ltd
Owner : Rajasthan Rajya Vidhyut Utpadan Nigam Ltd.
Owner’s Consultant : Tata Consulting Engineers
Accounting Centre : LE130258
Salient features of 2 X 660 MW Supercritical Unit # 5 & 6,
Stage-II, Phase-III
Installed Capacity : 2X660 MW Stage-II, Phase-III
Estimated project cost : 706 Crores (INR)
Land Acquired : 1475 Acres
Height of Chimney : 275 Meter (Twin Flue)
Scheduled Date of Commissioning: Unit # 5 - September 2016
Unit # 6 - December 2017
Unit # 6 was under hold for Ministry of Environment & Forest clearance up to 05.03.2015

10. Original Contract Value : 704.80 Crs + Taxes
(Firm Price, Service Tax Extra)
Revised Contract Value : 712.93 Crs +Taxes
Contractual Start Date : 10th June – 2013
Actual Start Date : 26th March - 2014
Contractual Finish : 15th Mar 2016 for Unit # 5
15th June 2016 for Unit # 6
Expected finish : 15th Sep 2016 for Unit # 5
15th Dec 2017 for Unit # 6
Unit # 6 was under hold up to 05.03.2015
Conveyors : 18 Km (Approx.)
Wagon Tippler : 4 No's
Apron Feeder : 4 No's
Stacker Reclaimer : 2 No's
Reclaimer : 2 No's
Primary Crusher House : 2 No's
Secondary Crusher House : 2 No's
Emergency Reclaim Hopper: 4 No's
Substation Buildings : 5 No's
Cables : 1238 Km
(HT / LT / Control / Instrumentation)

11. Technical Details of Project
Description Capacity Quantity
Conveyors Rated- 2000 TPH & 1000 TPH 18 Km
(Approx.)
Design – 2500 TPH & 1250 TPH 50 Nos.
Conveyor Belt 1600 MM & 1400 MM wide 36 Km.
Wagon Tippler 25 Tips/HR ROTA Side With
Modifications
4 No.
Apron Feeder Rated -2000 TPH Design- 2500 TPH 4 No.
Stacker Reclaimer
Stacking- 2000 TPH (Rated) / 2500
TPH(Design)
2 No.
Reclaiming – 1000 TPH (PEAK) & 765
(AVG)
Reclaimer PEAK- 1000 TPH & AVG- 765 TPH 2 NOS.
Crushers Rated- 1000 TPH DESIGN- 1500
TPH
8 NOS.
Vibrating Grizzly
Feeder
Rated- 1000 TPH DESIGN- 1500
TPH
8 NOS.
Fixed Grizzly Rated- 2000 TPH DESIGN- 3000
TPH
2 NOS.
Rotary Breaker Rated- 2000 TPH DESIGN- 3000
TPH
2 NOS.

12. Layout of CHP- Chhabra

13. INTRODUCTION TO COAL HANDLING PLANT
 The purpose of the Coal handling plant in a thermal power plant is to Process raw coal
& insure against the irregular supply of coal which is dependent on many players in
the Supply chain.
 The function of a CHP is to receive process, store, and feed the Coal bunkers
consistently over the entire life of the Power plant.
 Coal is received from mines in the form of lumps, the sizes varying from 100mm to
400mm, in two types of wagons through Rail; BOBR meaning Bogie Open Bottom
Rapid discharge & BOXN meaning Bogie Open High Sided Side discharge Wagon.
BOBR wagons are unloaded in Track Hoppers & BOXN Wagons are unloaded by
Wagon tipplers.
 Coal is then supplied to the crusher house through vibrating feeders to sieve the coal
before feeding to the crusher; 20% of the coal that is received is already <20mm size
so this is separated & only larger lumps are fed to the Crusher. The crusher breaks the
lumps to sizes<20mm which is the input size to the coal pulverizers.
 The crushed coal is fed to the conveyors in the crusher house through belt feeders;
coal is either directly fed to the coal bunkers or to the Stacker/Reclaimers for stocking
when the bunkers are full.
 The stacking is done to insulate the plant against the erratic supply of coal.
 CERC allows stocking of 1 ½ months stock of coal for Pit head plants.
 In case of non-receipt of wagons the coal from the stock pile is reclaimed through the
Stacker/ Reclaimers & fed to the coal bunkers.
 To increase redundancy, certain plants also have Emergency reclaim Hoppers near the
crushed coal Stock pile where the dozers are used to feed coal to the bunkers when the
reclaimers breakdown.
 Coal is conveyed by means of conveyor belts in the coal handling plant.

14. COAL TRIVIA
Coal Reserves in India
Coal reserves of 301.56 billion tonnes have been estimated by the Geological Survey of India
(01.04.2014). The reserves have been found mainly in Jharkhand, Odisha, Chhattisgarh, West
Bengal, Madhya Pradesh, Telangana and Maharashtra.
Coal Production
The overall production of Coal for 2014-15 was projected at 630.25 MT. During the period
April to December, 2014 the actual production was 426.7 million tonnes compared to 391.08
million tonnes (MT) during the corresponding period of 2013-14, showing a growth of 9.1%.
Company-wise details of coal production are provided in the table below: -
Coal Dispatch
During the period April, 2014 – December, 2014 Raw Coal dispatch from CIL was 354.33
million tonnes against 341.25 MT during the same period last year, registering a growth of
3.8 % over corresponding period of the previous year.

15. GRADES OF COAL
 Mostly E and F grade coal used in India.
 Blending with foreign coal is done to get average D grade.

16. MAIN COMPONENTS OF COAL HANDLING PLANT
1. WAGON TIPPLER
The wagon tippling system consists of wagon tippler, the wagon positioning equipment,
underground hopper, and feeder below the hopper for evacuating the material unloaded into
the hopper. The wagon tippler consists of a table for positioning the wagon, wagon holding
mechanism, gears and pinions for rotation, drive unit, hydraulic power pack etc. The
unloading cycle starts when the wagon is positioned over the wagon tippler table and the
wagon along with the table rotates and discharges the material into the underground hopper.
The time taken for the unloading operation is about 90 seconds. There are two types of
wagon tipplers viz. rotaside which rotates about 135º and another rotary type which rotates by
180º. The rotaside wagon tipplers are provided in most of the plants in India. The drive for
the rotation will be hydraulic type for smoother operation.
The coal received through Bogie Open Bottom Rapid discharge (BOBR) wagon rakes is
unloaded in underground R.C.C. track hopper. Paddle feeders are employed under track
hopper to scoop the coal and feeding onto underground reclaim conveyors. Belt weigh scales
are provided on these conveyors for measurement of coal flow rate. Standard Design
Criteria/Guidelines for Balance of Plant of Thermal Power Project 2 x (500MW or above)
Section- 2 (Coal Handling Plant) 2-3 Wagon tippler unloading system The coal received from
Box-N wagons is unloaded in underground RCC hoppers by means of rotaside type wagon
tipplers. Side arm chargers are employed for placement of wagons on the tippler table and
removal of empty wagon from tippler table after tippling. Apron feeders are employed under
each wagon tippler for extracting coal from wagon tippler hopper and feeding onto
underground reclaim conveyors. Belt weigh scales are provided on these conveyors for
measurement of coal flow rate. Provision is kept for shunting locomotives for placing the
rakes in position for the side arm charger to handle and begin unloading operation.
BOBR

17. 1.1 WAGON POSITIONING EQUIPMENT
There are different types of wagon positioning equipment like hydraulically operated side
arm charger, beetle charger and shunting locos. The hydraulically operated side arm chargers
are being used in most of the plants in India as this equipment is much faster compared to the
others. The tractive force of the side arm charger shall be suitable for hauling one fully
loaded rake.
1.2 UNLOADING HOPPER
The hopper provided below the wagon tippler could be either RCC type or structural steel
fabricated type. In most of the plants this will be of RCC construction. Suitable liner would
be provided for this hopper depending on the abrasiveness of the material handled. Generally
steel grids of 250 mm square will be provided above the hopper to avoid higher size of
material going through. The higher size material will be removed and broken separately and
then passed through the grid. The grid will be sloping outwards for easy removal of such
larger size material.
1.3 FEEDER BELOW THE HOPPER
The feeder below the hopper could be either vibrating type feeder or apron feeder. The apron
feeder would be more suitable for heavy duty application for taking the impact of the falling
material. The apron feeder will be driven by hydraulic motor for smoother operation.

18. 1.4 RAIL TRACKS
The layout of the rail tracks shall be such that the track will be straight and horizontal for one
rake length on the inhaul side and also on the outhaul side. This would be preferable for
achieving faster unloading rate and the effort required by the side arm charger would also be
minimum. In case it is not possible to have straight length to accommodate one full rake on
either side, then shunting operation will be required using the plant loco and hence it takes
the turnaround time will be more.
Weigh Bridge (In-motion Pit-less) is provided to weigh the coal wagons on receipt before
unloading into the Track Hopper.
1.5 DUST CONTROL SYSTEM
Plain water spray type dust suppression system will be provided for suppressing the dust
generated during the unloading operation. Spray nozzles will be provided at the top of the
wagon tippler and also around the hopper for spraying the water and settling the dust. An
enclosed shed will be provided for the wagon tippler so that the dust will be contained within
and will not be spread to the other parts of the plant.
1.6 CONTROL ROOM
A control room will be provided adjacent to the wagon tippler at an elevated position for
operation and control of the wagon tippling system. The complete view of the unloading
system will be available from this control room.
WEIGH BRIDGE

19. 2. ROTARY BREAKER
Rotary breaker is installed in primary crusher house. The Rotary Breaker is essentially a
large rotating cylinder, powered by an electric motor through a chain reducer drive. These
crushers crush by gravity impact only. The cylinder is fitted with perforated screen plates,
lifting shelves, deflectors and a refuse plow. The size of the screen plate perforations
determines the maximum product size of the coal to be processed. Coal is introduced through
one end of the cylinder known as the ‘feed end’. Product size coal in the feed is first screened
through the perforated screen plates. Larger coal is directed further into the cylinder by the

20. deflectors to the lifting shelves, where it is lifted and dropped onto the screen plates,
shattering on impact. Impacting in this fashion causes fractures along natural cleavage lines
resulting in minimum production of fines in the product passing through the screen plate
openings. Coal that is not product size continues to be lifted and dropped until it passes
through the screen plate. Rock, slate, and other materials that resist breakage and enter the
breaker with the feed eventually flow to the discharge end of the cylinder where they are
ejected by the refuse plough. It must operate at the cylinder R.P.M. listed on the specification
sheet in the manual. Increasing the speed will not increase the capacity of the breaker.
Operating the breaker with increased R.P.M. more than specified will not result in efficiency.
The breaker is enclosed in a fabricated steel casing. Both feed and refuse chutes are necessary
to feed coal to the cylinder and dispose of the rejects. Rotary Breaker achieves reduction by
repeatedly raising the feed material and dropping it against strong, perforated screen plates
around the interior. Adjustable lifter shelves raise the feed material and control the rate of
material movement. This lifting and dropping action effectively crushes soft to medium hard
material, which then passes through the screen openings to a collection hopper below. Hard
rock and uncrushable materials are discharged out the end of the cylinder with the aid of a
discharge plow. The coal coming out of the rotary breaker in our plant is of size (-) 250mm.

21. 3. SECONDARY CRUSHER HOUSE
It consists of following major components:
3.1 VIBRATING GRIZZLY FEEDER (VGF)
A vibratory feeder is a device that uses vibration to "feed" material to a process or machine.
The vibrating feeder is used to send shaped and granule materials into crusher evenly, timely
and continuously as well as screen the materials roughly.
Vibrating grizzly type screens provided upstream of the crushers screen out (-) 20 mm coal
from the feed and (+) 20 mm coal is fed to the crushers. A set of rod gates and rack & pinion
gates is provided before screens to permit maintenance of equipment downstream without
affecting the operation of other stream.
The width of vibrating screening feeder shall match to feed the material uniformly over the
entire length of crusher rotor without any deflectors in the feeding chute. There are 4 VGFs in
SCH.
3.2 RING GRANULATOR
There are four ring granulators in SCH. The size of output coal is (-) 20mm.
Ring Granulators are rugged, dependable units, specially designed for continuous high
capacity crushing of ROM coal and other medium hard friable materials. These are ideal
machines for crushing coal to a size suitable for pulverisation, in power stations. The unique
crushing action by combining impact and rolling compression in a Ring Granulator results in
higher output with lower power consumption. They offer better overall economy in terms of
power consumption and maintenance. Ring Granulators are available with operating
capacities from 40 to 1600 tonnes per hour and feed size upto 800 mm. Positive adjustment

22. of clearance between the cage and the path of the rings is provided to compensate for wear
and to adjust or maintain product gradation. Internal parts such as breaker plate, cage bars or
screen plate, crushing rings and liners are made of abrasion and shock resistant steels for
optimum working life.
Frame is fabricated from heavy steel plates with large inspection front and rear doors, fitted
with dust tight seals. Access for further maintenance is provided on the top. Doors on the
sides above the rotor shaft facilitate removal of the rotor without completely dismantling the
machine. Hydraulic door opening arrangement can be provided, if required. Cage Frame is
fabricated from heavy steel plate and supported from heavy hinged cage shaft at top and
provided with adjusting mechanism at the bottom. Cage assembly can be easily moved by a
ratchet wrench and worm gear assembly either towards or away from the path of crushing
rings. Adjustment which can be made while the granulator is in operation provides control
over the product size within permissible limits. The cage hinge bearing is so located that in
any adjusted position all parts of cage face are practically equidistant from the rotor
assembly. This ensures even wear. Tramp iron and uncrushables are prevented from
continuing around and back into the crushing zone by a heavy deflector plate. The debris is
collected in a pocket and removed from access door.
4. JUNCTION TOWER
In a junction tower, chutes and flap gates are provided for dropping coal from one conveyor
to other conveyor and also changing the coal flow stream.
These are used to channelize the route of coal through another belt in case the former is
broken or unhealthy. The flap gates open let the coal pass and if closed stop its movement.
It also contains inline magnetic separator (ILMS) to remove ferrous metal pieces coming
alone with coal.

23. Necessary monorails with electric hoist are provided for handling various equipments of
CHP.
Flap Gate

24. 5. STACKER AND STACKER CUM RECLAIMER

25. Crushed coal is sent to stockyard when coal bunkers are full. Stacking/ reclaiming of coal is
done by bucket wheel type stacker-cum- reclaimer moving on rails. The stacker-cum
reclaimer can stack coal on either sides of the yard conveyor. During stacking mode coal is
fed from conveyors on boom conveyor and while in reclaim mode, boom conveyor
discharges coal on the yard conveyor for feeding coal to bunkers through conveyors and
transfer points. The yard conveyor can be reversible type depending on layout requirement.
When direct unloading from rakes is not in operation, coal is reclaimed by the stacker – cum-
reclaimer and fed to the coal bunkers. Stockpiles provide surge capacity to various parts of
the CHP. ROM coal is delivered with large variations in production rate of tonnes per hour
(tph). A ROM stockpile is used to allow the washplant to be fed coal at lower; constant rate.
A simple stockpile is formed by machinery dumping coal into a pile, either from dump
trucks, pushed into heaps with bulldozers or from conveyor booms. More controlled
stockpiles are formed using stackers to form piles along the length of a conveyor,
and reclaimers to retrieve the coal when required for product loading, etc. Taller and wider
stockpiles reduce the land area required to store a set tonnage of coal. Larger coal stockpiles
have a reduced rate of heat loss, leading to a higher risk of spontaneous combustion.

26. Stacking rate of stacker is 2000 tonnes per hour and reclaiming rate of stacker cum reclaimer
is 1000 tonnes per hour.
6. BELT CONVEYER

27. Through belt conveyer, the coal reaches from wagon tippler to boiler.
4 ply means 4 nylon net in between 2 mm thick rubber coating is used.
Width of belt used is 1400mm or 1600mm.
1400 mm conveyor- 7.5 km
1600 mm conveyor- 9.8 km
Impact idlers reduce the impact on the conveyor belts thereby increasing longevity.
Normal conveyor Idlers (carrying idlers) are the supporting rollers for the conveyor belt on
which the coal laden conveyor belt glides.
Drive pulley is the driver of the conveyor belts;
the prime mover is a motor attached through fluid
coupling so that the starting thrust on the gearbox
is restricted.
RUBBER
LINING
PULLEY
PLUMMER
BLOCK
DRIVE SHAFT

28. 6.1 VERTICAL GRAVITY TAKEUP UNIT
A troughed belt conveyor comprises an endless, rubberized flat belt (a) suspended between
pulleys at either end and supported along its length by a number of rotating idler rollers (b).
The belt is driven via one of the pulleys (usually the head pulley (c)) and the tension in the
belt is maintained by using a sliding pulley (d) which is tied to a gravity take-up unit (e).
The material (f) is loaded onto the conveyor at the tail-end via a chute (g) and is transported
along the carrying-side (h) to the head-end where it discharges into a discharge chute (i)
which guides the product onto the downstream equipment.
Impact idlers (j) are located at the loading point to support the belt where the load impacts
onto the belt as it is dropped down the loading chute.
Once the material has been discharged from the carrying belt, the return belt (k) is guided
back to the tail pulley on return idlers (l).
The impact, carrying and return idlers are spaced at different intervals. On the carrying-side,
the mass of the belt plus the load conveyed is greater than the mass to be supported on the
return-side and thus, for the tension in the conveyor belt (by the take-up and induced by the
drive unit), the idler spacing is selected accordingly. This 'sag' in the belt between the

29. carrying and return idler sets must therefore be designed on the basis of the heaviest load that
the conveyor is to transport.
Snub pulleys (m) are incorporated into the design of a conveyor in order to increase the angle
of wrap (n) of the belt on the drive pulley. The greater wrap angle on the pulley allows more
power to be introduced into the belt as is passes around the drive pulley without slip
occurring. In this way, fewer drives are needed on longer conveyors or conveyors with high
conveying loads.
6.2 HORIZONTAL GRAVITY TAKEUP UNIT
It is used when the height of belt application is less.
6.3 BELT SAFETY DEVICES
6.3.1 Belt Sway Switch
Belt Sway Switch is a protective switch for detecting the meandering (sway or deviation) of
belt conveyors, and sends out an alarm signal and an emergency stop signal. It is suited to be
used for belt breakage prevention and ore falling prevention due to the belt sway. Widely
used in iron and steel, cement and chemical plants, thermal power plants, etc., since it is
essential for safety operation of belt conveyors. Belt sway switches of self-resetting type are
provided at a spacing of 45 m to limit belt sway to permissible extent.

30. 6.3.2 Pull Cord Switch
Pull Cord Switch is an emergency switch to stop the belt conveyor instantly when an accident
happens. The pull cord switch is used as a rope operated safety tripping switch for conveyor
belts, i.e. When the rope is pulled the lever of the pc unit is operated which in turn, actuates a
switch, thereby the conveyor is stopped. The switch lever is manual reset type. Pull chord
stop switches is located on both sides of belt conveyors at a spacing of 20 m along the
walkways for the entire length of conveyors for emergency stopping of conveyor.
6.3.3 Zero Speed Switch
Zero speed switches (ZSS) also known as Speed Actuating Sensing Switches are used to
detect the stoppage or unacceptably slow movement of a rotating shaft. Zero speed switch is a
non-contact (proximity) type electronic switch. It consists of a sensor which senses the
rotation of tail pulley. If there is any problem in the belt conveyor, then the tail pulley
rotation speed will change which will be detected by zero speed switch and the belt will trip.
It is provided at the tail pulley.

31. 6.4 Conveyors leading to crusher house have facility for manual stone picking.
Metal detectors are also provided to detect non-ferrous materials present in the coal before
crushers. Metal detectors work on the principle of transmitting a magnetic field and analyzing
a return signal from the target and environment. The transmitted magnetic field varies in
time, usually at rates of fairly high-pitched audio signals. The magnetic transmitter is in the
form of a transmit coil with a varying electric current flowing through it produced by transmit
electronics. The receiver is in the form of a receive coil connected to receive and signal
processing electronics. The transmit coil and receive coil are sometimes the same coil. The
coils are within a coil housing which is usually simply called “the coil,” and all the
electronics are within the electronics housing attached to the coil via an electric cable and
commonly called the “control box”. This changing transmitted magnetic field causes electric
currents to flow in metal targets. These electric currents are called eddy currents, which in
turn generate a weak magnetic field, but their generated magnetic field is different from the
transmitted magnetic field in shape and strength. It is the altered shape of this regenerated
magnetic field that metal detectors use to detect metal targets. (The different “shape” may be
in the form of a time delay.) The regenerated magnetic field from the eddy currents causes an
alternating voltage signal at the receive coil. This is amplified by the electronics because
relatively deeply buried targets produce signals in the receive coil which can be millions of
times weaker than the signal in the transmit coil, and thus need to be amplified to a
reasonable level for the electronics to be able to process.
7. Dust Control System and Ventilation system
The dust control system is required for control of fugitive dust emissions from dust
generation points such as transfer points, feeders, crushers etc. Dust control is achieved by
dust suppression and extraction system (DE). Dust suppression is achieved by two methods
viz. Plain Water Dust Suppression System (DS) and Dry Fog Type Dust Suppression System
(DFDS).
Metal Detector

32. Ventilation system is provided for all the working areas/ locations/ buildings/ underground
structures of CHP. The required ventilation is achieved by mechanical ventilation system/
pressurised ventilation system depending on the area requirement. The pressurized ventilation
system is capable of pressurizing slightly above atmospheric pressure to prevent ingress of
dust from outside. The MCC/switchgear room areas of coal handling plant are provided with
pressurised ventilation system while other areas have mechanical ventilation. The control
rooms, office room and RIO (Remote Input/ Output) room are provided with air conditioning
system.
7.1 DUST EXTRACTION SYSTEM
Dust collection systems use ventilation principles to capture the dust-filled air-stream and
carry it away from the source through ductwork to the collector. A typical dust collection
system consists of four major components, such as
(1) An exhaust hood to capture dust emissions at the source;
(2) Ductwork to transport the captured dust to a dust collector;
(3) A dust collector to remove the dust from the air;
(4) A fan and motor to provide the necessary exhaust volume and energy
This is used in Bunker silos where the coal is fed from conveyors & falls from a height. The
unsettled dust is sucked through fans installed on the roof through bag filters or cyclonic
separators & the heavier dust particles are fed back to the bunkers.

33. 7.2 DUST SUPPRESSION SYSTEM
It use water sprays to wet the material so that it generates less dust. Surfactants or chemical
foams are often added to the water into these systems in order to improve performance. A
water spray with surfactant means that a surfactant has been added to the water in order to
lower the surface tension of the water droplets and allow these droplets to spread further over
the material and also to allow deeper penetration into the material. When dust particles are
sprayed with atomized water and the dust particles collide with the water droplets,
agglomerates are formed. These agglomerates become too heavy to remain airborne and
settle. Airborne dust wet suppression systems work on the principle of spraying very small
water droplets into airborne dust. When the small droplets collide with the airborne dust
particles, they stick to each other and fall out of the air to the ground. This collision between
the particles occurs due to three factors involving both the water and the dust particles. As a
dust particle and water particle approach each other, the airflow could move the particle
around the droplet, have a direct hit on the droplet, or barely graze the droplet. It is this factor
that leads us to the second factor, which is that droplets and particles that are of similar sizes
have the best chance of a collision. If a droplet is smaller than the dust particle or vice versa,
then they may never collide and instead just be swept around each other. The last factor is the
dependence of an electrostatic force on a droplet and how the path is affected by this force.
Just like with magnets, similarly charged particles repel each other. Thus it is advantageous to
have the particles either both neutrally charged (so that they neither repel nor attract one
another) or oppositely charged (so that they attract one another) in order to increase the
likelihood of a water and particle collision.

34. 7.3 DRY FOG DUST SUPPRESSION SYSTEM
It uses a special air-atomizing nozzle that produces a very dry fog to agglomerate and remove
airborne dust particles from various material handling and processing operations. This
system utilizes compressed air and plain water to produce these 1-10 micron droplets (true
fog). These ultra-fine water droplets attach (agglomerate) to like size airborne dust particles,
sometimes referred to as PM-10 (particulate matter 10 microns or smaller). Subsequently,
the slightly wetted dust particles become heavy enough to be removed from the air and fall
back into the process. It is important to note that we only wet the dust, not the material. This
result in very low water and power consumption, requiring no expensive chemicals or
significant wetting of the product (always less than 1/2 % by weight, typically no more than
0.1% moisture addition).

35. These systems significantly reduce fugitive dust from a variety of material handling points,
including conveyor transfer points, trippers, reclaimers, crushers, screens, truck dumps,
railcar loading/unloading, ship loaders-unloaders, and ash silo discharge chutes.
8. EMERGENCY RECLAIMING HOPPER (ERH)
When direct unloading from rakes is not in operation, coal is reclaimed by the stacker – cum-
reclaimer and fed to the coal bunkers. Emergency reclaim hopper (ERH) can be provided to
reclaim coal by dumpers when stacker –cum- reclaimer is not in operation. Emergency
reclaim hopper can also be used for blending of Indian coal with foreign coal.
There are sets of gates each comprising of one rod gate and one actuator operated rack &
pinion gate at inlet to each of the vibrating grizzly screens and at inlet to vibro feeders in
emergency reclaim hoppers. Emergency reclaim hoppers with vibro feeders and belt
conveyors complete with conveyor gallery and transfer points for interconnection with
conveyor between crusher house and bunkers. Adequate number of ventilation equipment is
provided for ventilating the emergency reclaim hoppers.
There are 2 ERH for each unit.

36. 9. BUNKER
The ultimate aim of a coal handling plant is to supply coal to boiler. The bunker is the end
point of CHP. The shape of the bunker is like frustum of a pyramid and the coal is fed from
tripper conveyors & falls from a height. It also contains dust extraction system. Then, the coal
passes through a bowl mill where the coal is converted into powdered form.

37. Bowl mills are employed to pulverize the pre-crushed raw coal to the required fineness before
it is admitted into the boiler furnace for combustion. The mill output can be easily varied, as
per the turn down ratio from its minimum to maximum load. The crushed raw coal at a
controlled rate is fed into the revolving bowl of the Bowl Mill. Centrifugal force feeds the
coal uniformly over the replaceable grinding ring where independently spun rolls exert the
required grinding pressure. The rolls do not touch the grinding ring even when the mill is
empty.
This crushed coal is taken away to the furnace through coal pipes with the help of hot and
cold air mixture from primary air fan. P.A. fan takes atmospheric air, a part of which is sent
to air pre-heaters for heating while a part goes directly to the mill for temperature control.

38. 10. COAL SAMPLING UNIT
Coal sampling unit is provided to sample the uncrushed coal. The normal input feed size shall
be considered as (-) 300 mm for coal sampling unit before coal crusher. Coal lump size after
crusher (as fired coal) shall be (-) 20mm.
Detailed chemical analysis, calculation of calorific value of coal sample is carried out and is
confirmed whether it is as per agreement with the coal mines or not.

39. FABRICATION YARD:
All the structures are fabricated from mild steel (IS-2062).
Chemical Composition-
E 250 means that the yield strength of the steel is 250N/mm2
.
For grades E 250 to E 410, there are four sub-qualities (A, BR, B0 and C) and for grades E
450 to E 650, there are two sub-qualities (A and BR). Sub-qualities A, BR, B0 and C indicate
requirement of impact test and mode of de-oxidation as indicated below:
A: Impact test not required, semi-killed/killed
BR: Impact test optional; if required at room temperature; semi-killed/killed
B0: Impact test mandatory at 0°C, semi-killed/killed
C: Impact test mandatory at –20°C, killed
Killed steel is steel that has been completely deoxidized by the addition of an agent before
casting, so that there is practically no evolution of gas during solidification. They are
characterized by a high degree of chemical homogeneity and freedom from gas porosity.

40. Mechanical Properties-

41. Types of I-section Beams Used
1. Indian Standard Medium Beam (ISMB) -Beams will be designated by –
Web size x Flange size
2. Universal Beam (UB) -The depth of a UB is greater than its width and difference is quite
big, making it easy to spot. The increased depth results in higher loading capabilities than
UCs; however there is not always enough space to use a UB.
Beams will be designated by–
Web size x Flange size x Unit Weight
3. Narrow Parallel Beam (NPB) - Beams will be designated by–
Web size x Flange size x Unit Weight

42. Types of Angles Used
1. Indian Standard Equal Angle (ISA) - Length of both legs are equal.
Designated By- Leg1 size x Leg2 size x Thickness
2. Indian Standard Unequal Angle (ISUA) - Length of both legs are unequal.
Designated By- Leg1 size x Leg2 size x Thickness

43. Types of Channels Used
1. Sloping Flange Channel- Designated by– Web size X Flange size
2. Parallel Flange Channel- Designated by– Web size X Flange size
Plates- Plates will be designated by Thickness.

44. TYPES OF WELDING USED
1. Shielded Metal Arc Welding (SMAW) - In this process, the heat is generated by
an electric arc between base metal and a consumable electrode. In this process electrode
movement is manually controlled hence it is termed as manual metal arc welding. This
process is extensively used for depositing weld metal because it is easy to deposit the molten
weld metal at right place where it is required and it doesn’t need separate shielding. This
process is commonly used for welding of the metals, which are comparatively less sensitive
to the atmospheric gases. This process can use both AC and DC. The constant current DC
power source is invariably used with all types of electrode (basic, rutile and cellulosic)
irrespective of base metal (ferrous and non-ferrous). However, AC can be unsuitable for
certain types of electrodes and base materials. Therefore, AC should be used in light of
manufacturer’s recommendations for the electrode application. In case of DC welding, heat
liberated at anode is generally greater than the arc column and cathode side. The amount of
heat generated at the anode and cathode may differ appreciably depending upon the flux
composition of coating, base metal, polarity and the nature of arc plasma. In case of DC
welding, polarity determines the distribution of the heat generated at the cathode and anode
and accordingly the melting rate of electrode and penetration into the base metal are affected.
PURPOSE OF FLUX COATING –
1. Gas shielding of arc
2. Stabilizes the arc
3. Provides slag blanket
4. Alloying element will improve the mechanical properties
5. Gives good appearance & penetration
6. Welding in all positions is easy
7. Compensates for oxidation loss
Electrode Designation- E-6013
E- Electrode
60- Ultimate tensile strength of electrode is 60000psi
1- Welding position
3- Coating conditions

45. 2.Metal Inert Gas Welding (MIG) -This process is based on the principle of
developing weld by melting faying surfaces of the base metal using heat produced by a
welding arc established between base metal and a consumable electrode. Welding arc and
weld pool are well protected by a jet of shielding inactive gas coming out of the nozzle and
forming a shroud around the arc and weld. MIG weld is not considered as clean as TIG weld.
Difference in cleanliness of the weld produced by MIG and TIG welding is primarily
attributed to the variation in effectiveness of shielding gas to protect the weld pool in case of
above two processes. Effectiveness of shielding in two processes is mainly determined by
two characteristics of the welding arc namely stability of the welding arc and length of arc
besides other welding related parameters such as type of shielding gas, flow rate of shielding
gas, distance between nozzle and work-price. The MIG arc is relatively longer and less stable
than TIG arc. Difference in stability of two welding arcs is primarily due to the fact that in
MIG arc is established between base metal and consumable electrode (which is consumed
continuously during welding) while TIG welding arc is established between base metal and
non-consumable tungsten electrode.
Consumption of the electrode during welding slightly decreases the stability of the arc.
Therefore, shielding of the weld pool in MIGW is not as effective as in TIGW. Metal inert
gas process is similar to TIG welding except that it uses the automatically fed consumable
electrode therefore it offers high deposition rate and so it suits for good quality weld joints
required for industrial fabrication (Fig. 17.1). Consumable electrode is fed automatically
while torch is controlled either manual or automatically. Therefore, this process is found
more suitable for welding of comparatively thicker plates of reactive metals (Al, Mg,
Stainless steel). The quality of weld joints of these metals otherwise is adversely affected by
atmospheric gases at high temperature. The arc and weld pool are both shielded by CO2 gas
flowing from the gun.

46. MODES OF METAL TRANSFER-
• Short Circuit Transfer
• Globular Transfer
• Spray transfer
GMAW wires- 1. Copper coated solid mild steel wires
2. Wire dia. Ranges from 0.8 to 2.0 mm
3. Standard spool dia. 300 mm
Functions of Copper coating:
1. Avoids rusting of the wire.
2. Better feedability.
3. Improved current pick-up.
NOTE- Copper content in the weld should not exceed 0.5%.
Poor copper coating results in feeding, arc instability problems.
Electrode Designation- ER 70S-6
ER- Electric welding rod or filler
70- Ultimate tensile Strength of electrode is 70000 psi
GAS METALARC WELDING
Wire feeder
Wire spool
Power source
Torch Gas
cylinder

47. S- Solid wire
6- Chemical composition of the wire
3. Submerged Arc Welding (SAW) – Submerged arc welding (SAW) process uses
heat generated by an electric arc established between a bare consumable electrode wire and
the work piece. Since in this process, welding arc and the weld pool are completely
submerged under cover of granular fusible and molten flux therefore it is called so. During
welding, granular flux is melted using heat generated by arc and forms cover of molten flux
layer which in turn avoids spatter tendency and prevents accessibility of atmospheric gases to
the arc zone and the weld pool. The molten flux reacts with the impurities in the molten weld
metal to form slag which floats over the surface of the weld metal. Layer of slag over the
molten weld metal results:
 Increased protection of weld metal from atmospheric gas contamination and so
improved properties of weld joint
 Reduced cooling rate of weld metal and HAZ owing to shielding of the weld pool by
molten flux and solidified slag in turn leads to a) smoother weld bead and b) reduced
the cracking tendency of hardenable steel
SAW is known to be a high current (sometimes even greater 1000A) welding process that is
mostly used for joining of heavy sections and thick plates as it offers deep penetration with
high deposition rate and so high welding speed. High welding current can be applied in this
process owing to three reason a) absence of spatter, b) reduced possibility of air entrainment
in arc zone as molten flux and slag form shield the weld metal c) large diameter electrode.
Continuous feeding of granular flux around the weld arc from flux hopper provides shielding

48. to the weld pool from atmospheric gases and control of weld metal composition through
presence of alloying element in flux. Complete cover of the molten flux around electrode tip
and the welding pool during the actual welding operation produces weld joint without spatter
and smoke.
Functions of Flux-
• Provide shielding to the weld zone
• Control chemistry of the weld metal
• Scavenging of impurities
• Provide good mechanical properties
• Provide arc stability
• Produce self-peeling slag
SAW Flux / Filler Metal Designation- F7A2-EL8
F indicates a submerged arc welding flux
7 indicates the ultimate tensile strength (in increments of 10000 psi)
A indicates condition of heat treatment (A for as welded and P for post weld heat treatment)
2 indicates the temperature in -20°F at which the impact strength of the weld metal meets or
exceeds 20 ft-lbs
EL8 – Wire
E – For Electrode
L – Indicates for Low Manganese
8 Stands for .08% C
Oxy-acetylene Cutting-
Oxy-fuel cutting uses a combination of fuel gases and oxygen to cut metals. A variety of
different fuels may be utilized, although the most common is acetylene. Other gases utilized
include natural gas, propane, hydrogen, propylene, liquefied petroleum gas (LPG), and
combinations of these gases. Oxy-fuel cutting begins by using a torch to heat a metal to its
kindling temperature. This is the lowest temperature at which the metal in question will
spontaneously ignite. At this point, a stream of oxygen is trained onto the metal, in turn
burning it into a metal oxide. This new metal oxide then flows out and away from the intact
material being utilized. Any leftover slag can be wiped or tapped away. It’s actually the heat

49. produced by the metal oxide and its contact with the rest of the material which actively
continues the cutting process. The torch itself only heats the metal to begin the process.
Since oxidation of the metal is a vital part of the oxyacetylene cutting process, this process is
not suitable for metals that do not oxidise readily, such as copper, brass, stainless steel etc.
Low-carbon steels are easily cut by the oxyacetylene cutting process, but special techniques
are required for the oxyacetylene cutting of many other metals.

50. QUALITY CONTROL/QUALITY ASSURANCE
DEPARTMENT
QUALITY POLICY-
Quality management at L&T begins with a company-wide drive to improve customer
satisfaction by supporting the customers' business goals. Effective processes are developed
for everything from research, development and product implementation, to sales and
customer support. The objective is to create high-quality products and services and
implement ongoing improvements that will meet or exceed customer needs.
L&T is committed to continuous improvement of its business processes by implementing
globally accepted standards such as ISO 9001:2008, ISO 14000: 2004 and OHSAS
18001:2007. The Company's operating sites implement the appropriate quality policies
dependent upon locations, types of products or services provided and prevailing regulatory
requirements.

51. Quality is the key component which propels performance and defines leadership traits. At
L&T Construction, Quality Standards have been internalised and documented in Quality
Assurance manuals. L&T Construction recognizes the crucial significance of the human
element in ensuring quality. Structured training programmes ensure that every L&T
employee is conscious of his/her role and responsibility in extending L&T Construction’s
tradition of leadership through quality. A commitment to safety springs from a concern for
the individual worker – every one of the thousands braving the rigours of construction at
numerous project sites. L&T, Metallurgical and Material Handling IC has a well-established
and documented Quality Management System (QMS) and is taking appropriate steps to
improve its effectiveness in accordance with the requirements of ISO 9001:2008. Relevant
procedures established clearly specify the criteria and methods for effective operation, control
and necessary resources and information to support the operation and monitoring of these
processes.
QUALITY IMPLEMENTATION AT SITE
L&T, Metallurgical and Material Handling IC has established procedure for monitoring,
measuring and analyzing of these processes and to take necessary actions to achieve planned
results and continual improvement of these processes. It has also maintained relevant
procedures to identify and exercise required control over outsourced processes, if any.
Systems and procedures have been established for implementing the requisites at all stages of
construction and they are accredited to the International standards of ISO 9001:2008, ISO
14001:2004 and OHSAS 18001:2007. L&T continues to maintain the trail blazing tradition
of meeting the stringent quality standards and adherence to time schedules in all the projects.

52. NON-DESTRUCTIVE WELDING TESTS:
1. LIQUID PENETRANT TEST-
 In penetrant testing, a liquid with high surface wetting characteristics is applied to the
surface of a component under test.
 The penetrant “penetrates” into surface breaking discontinuities via capillary action
and other mechanisms.
 Excess penetrant is removed from the surface and a developer is applied to pull
trapped penetrant back on the surface.
 With good inspection technique, visual indications of any discontinuities present
become apparent.
Basic Process of PT
Almost any material that has a relatively smooth, nonporous surface on which discontinuities
or defects can be inspected through penetrant testing.
All defects that are open to the surface can be detected via penetrant test such as cracks,
porosity, undercut, overlap, lack of fusion, lack of penetration.
2. ULTRASONIC TESTING- Ultrasonic waves are of frequency greater than 20000 Hz.
These can be generated by piezoelectric transducer which converts electrical energy into
mechanical vibrations.
High frequency sound waves are very directional, and they will travel through a medium (like
a piece of steel or plastic) until they encounter a boundary with another medium (like air), at
which point they reflect back to their source. By analyzing these reflections it is possible to
measure the thickness of a test piece, or find evidence of cracks or other hidden internal
flaws.

53. In ultrasonic testing, an ultrasound transducer connected to a diagnostic machine is passed
over the object being inspected. The transducer is typically separated from the test object by a
couplant (such as oil) or by water, as in immersion testing.
Two methods of receiving the ultrasound waveform:
 Reflection
 Through Transmission
Principle:
LEFT: A probe sends a sound wave into a test material. There are two indications, one from
the initial pulse of the probe, and the second due to the back wall echo.
RIGHT: A defect creates a third indication and simultaneously reduces the amplitude of the
back wall indication. The depth of the defect is determined by the ratio D/Ep.
In reflection (or pulse-echo) mode, the transducer performs both the sending and the
receiving of the pulsed waves as the "sound" is reflected back to the device. Reflected
ultrasound comes from an interface, such as the back wall of the object or from an
imperfection within the object. The diagnostic machine displays these results in the form of a
signal with amplitude representing the intensity of the reflection and the distance,
representing the arrival time of the reflection.
In attenuation (or through-transmission) mode, a transmitter sends ultrasound through one
surface, and a separate receiver detects the amount that has reached it on another surface after
traveling through the medium. Imperfections or other conditions in the space between the
transmitter and receiver reduce the amount of sound transmitted, thus revealing their
presence. Using the couplant increases the efficiency of the process by reducing the losses in
the ultrasonic wave energy due to separation between the surfaces.

54. One of the most useful characteristics of ultrasonic testing is its ability to determine the exact
position of a discontinuity in a weld. This testing method requires a high level of operator
training and competence and is dependent on the establishment and application of suitable
testing procedures. This testing method can be used on ferrous and nonferrous materials, is
often suited for testing thicker sections accessible from one side only, and can often detect
finer lines or plainer defects which may not be as readily detected by radiographic testing.
3. RADIOGRAPHIC TESTING-
Penetrating radiation is passed through a weld, onto a photographic film, resulting in an
image of the object's internal structure being deposited on the film. The amount of energy
absorbed by the object depends on its thickness and density. Energy not absorbed by the
object will cause exposure of the radiographic film. These areas will be dark when the film is
developed. Areas of the film exposed to less energy remain lighter. Therefore, areas of the
object where the thickness has been changed by discontinuities, such as porosity or cracks,
will appear as dark outlines on the film. Inclusions of low density, such as slag, will appear as
dark areas on the film while inclusions of high density, such as tungsten, will appear as light
areas. All discontinuities are detected by viewing shape and variation in density of the
processed film.
Radiographic testing can provide a permanent film record of weld quality that is relatively
easy to interpret by trained personnel. This testing method is usually suited to having access
to both sides of the welded joint (with the exception of double wall signal image techniques
used on some pipe work). Although this is a slow and expensive method of non-destructive
testing, it is a positive method for detecting porosity, inclusions, cracks, and voids in the
interior of welds. It is essential that qualified personnel conduct radiographic interpretation
since false interpretation of radiographs can be expensive and interfere seriously with
productivity. There are obvious safety considerations when conducting radiographic testing.
X-ray and gamma radiation is invisible to the naked eye and can have serious health and

55. safety implications. Only suitably trained and qualified personnel should practice this type of
testing.

56. WELDERS’ QUALIFICATION TEST-
ASME Section IX relates to qualification of welders, welding operators, brazers and brazing
operators and the procedures that they employ in welding and brazing.
It is divided in two parts, part QW gives requirements for welding and part QB contains
requirements for brazing.
The purpose of welding procedure specification (WPS) and procedure qualification records
(PQR) is to determine that the weldment proposed for construction is capable of providing
the required properties for its intended application.
WPS is intended to provide direction for the welder and lists the variables, both essential and
non-essential and the acceptable ranges of these variables when using the WPS.
It is presumed that welder or welding operator performing the welding procedure
qualification test is skilled workman so that welding procedure qualification test establishes
the properties of weldment and not the skill of the welder.
The purpose of performance qualification is to determine if the welder is able to deposit
sound metal or the welding operator is able to operate welding equipment properly.
Part QW is divided into 4 articles.
Article I -Welding general requirements
Article II-Welding procedure qualifications
Article III-Welding performance qualifications
Article IV-Welding data
Acceptance Criterion-
 Visual examination acceptance criteria
 Weld should show complete penetration and fusion
 Bend test acceptance criteria
 No open discontinuities in the weld or HAZ greater than 1/8-in.
 Radiographic acceptance criteria
 Linear Indications
o Any type of crack, incomplete fusion, or incomplete penetration
o Elongated slag with a length greater than
 1/8-in. for t equal to 3/8-in. or less
 1/3t for t over 3/8-in. up to 2 1/4-in.
 3/4-in. for t over 21/4-in.
o Group slag should have an aggregate length no greater than t in a 12t length
 Exception is when the distance between successive imperfections is
6L where L is the length on the longest imperfection
 Rounded Indications
o Maximum dimension shall be 20% of t or 1/8-in. whichever is smaller

57.  For material less than 1/8-in only 12 rounded indications can be
present per 6-in. of weld
 For material greater 1/8-in. and greater the acceptance criteria is
provided in Appendix I
Welder Qualification Positions-
In general,
1G or 1F is called flat positions
2G or 2F is called horizontal and circumferential
3G or 3F is called vertical position
4G or4F is called overhead position
Position 5G is only in welds in pipes. It is a position when pipe axis is held horizontal and
circumferential seam is welded without rotating. In a way it is combination of 1G, 3G & 4G.
Position 6G is also for the pipes when pipe axis is at 45 deg. to horizontal plane and
circumferential seam is welded without rotating the pipe. It is combination of all positions.
Plate groove positions- 1G, 2G, 3G, and 4G
Pipe groove positions- 1G, 2G, 5G, and 6G
Plate fillet positions- 1F, 2F, 3F and 4F
Pipe fillet positions- 1F, 2F, 2FR, 4F, and 5F

62. Refer below figure that gives performance qualification position and diameter limits.

63. EHS DEPARTMENT
GENERAL EHS RULES & REGULATIONS:
1. No workmen below 18 years and above 58 years of age shall be engaged for a job.
2. All workmen shall be screened before engaging them on the job. Physical fitness of
the person to certain critical jobs like working at height or other dangerous locations
is to be ensured before engaging the person on work. The final decision rests with the
site management to reject any person on the ground of physical fitness.
3. Visitors can enter the site after EHS induction with the visitor pass. He should be
provided safety helmet & safety shoes; also he should be accompanied with the
responsible person of that area.
4. Smoking is strictly prohibited at workplace.
5. Subcontractors shall ensure adequate supervision at workplaces. They shall ensure
that all persons working under them shall not create any hazard to self or to the
coworkers.
6. Nobody is allowed to enter the site without wearing safety helmet. Chinstrap of safety
helmet shall be always on.
7. No one is allowed to work at or more than two meter height without wearing full body
harness and anchoring the lanyard of full body harness to firm support preferably at
shoulder level.
8. No one is allowed to enter into workplace and work at site without adequate foot
protection (including female worker).
9. Usage of eye protection equipment shall be ensured when workmen are engaged for
grinding, chipping, welding and gas cutting. For other jobs, as and when site safety
coordinator insists eye protection has to be provided.
10. All PPEs like shoes, helmet, full body harness etc. shall be arranged before starting
the job as per recommendation of the EHSO.
11. Rigid barrication must be provided around the excavated pits, and barrication shall be
maintained till the backfilling is done. Safe approach is to be ensured into every
excavation.
12. Adequate illumination at workplace shall be ensured before starting the job at night.
13. All the dangerous moving parts of the portable/fixed machinery being used shall be
adequately guarded.
14. Ladders being used at site shall be adequately secured at bottom and top. Ladder shall
not be used as work platforms.
15. Erection zone and dismantling zone shall be barricaded and nobody will be allowed to
stand under the suspended loads.
16. Horseplay is completely prohibited at workplace. Running at site is completely
prohibited except in case of emergency.
17. Other than the electrician possessing B license with red helmet, no one is allowed to
carry out electrical connection, repairs on electrical equipment or other job related
thereto.

64. 18. Inserting of bare wires for tapping the power from electrical socket is completely
prohibited.
19. All major, minor accidents, near misses and unhygienic conditions must be reported.
20. All scaffoldings/work platforms shall meet the requirement. The width of the working
platform and fall protection arrangement shall be maintained as per the standard.
21. All tools and tackles shall be inspected before use. Defects are to be reported
immediately. No lifting tool & tackle to be used unless it is certified by the concerned
Engineer Incharge/P & M engineer.
22. Good housekeeping is to be maintained. Passage shall not be blocked with materials.
Material like bricks shall not be stacked to the dangerous height at workplace.
23. Debris, scrap and other material is to be cleared then and there from the workplace
and at the time of closing of work everyday.
24. Contractors shall ensure that all their workmen are following safe practices while
travelling in the company’s transport and staying at company’s accommodations.
25. Adequate firefighting equipment shall be made available at workplace and persons are
to be trained in firefighting techniques with the coordination of EHSO.
26. All the unsafe conditions, unsafe act identified by the contractors, reported by site
supervisor and/or safety personnel to be corrected on priority basis.
27. No children shall be allowed to enter the workplace.
28. Workwomen are not allowed to work at high risk areas.
29. Other than the Driver/operator, no one shall travel in a tractor/toughrider etc.
30. Wherever the vehicle/equipment has to work near or pass through the overhead
electrical lines, the goal post shall be installed.
31. Identity card should always be displayed and shown when demanded.
32. Any person found to be interfering with or misusing fixtures, fittings or equipment
provided in the interest of health, safety and welfare would be excluded from site.(
like using helmet and fire bucket for carrying the material, removing the handrails,
etc.)
33. Visitors must use safety helmet before entering the site.
34. Safety signs and notices must be displayed and followed.
35. Transistor radios or personal stereos/Walkman must not be used.
36. All site personnel, for their own safety and for the safety of others, are required to
fully comply with the agreed safety systems/procedures and working method.
37. Consumption of alcohol and drugs is prohibited.
38. No person is to operate any mechanical/electrical equipment unless they have been
authorized and have been certified as competent.
39. No worker should enter the site with lungies and dhotis.
40. Nobody should sit/sleep on the floor edges.
41. Don’t enter inside the room where there is no light.
42. Don’t take shelter under the vehicle or in an electrical installation rooms.
43. Look for warnings signs, caution boards and other notices.
44. Must be aware about the locations of the first aid canter, fire extinguisher, emergency
assembly point and emergency siren.
45. No floor opening, floor edges should be left unguarded.

65. 46. Training is must for all scaffolders and only trained scaffolders should make
platforms.
47. Don’t keep loose materials at height.
48. Permission should be taken for all earthworks from P&M Department.
49. Those who are violating the safety norms will be penalized.
50. Female workers should not be engaged on work between 7.P.M. to 8 A.M.
51. Physical fitness check shall be carried out for crane operators & drivers.
52. PPE shall be provided to visitors at gate.
53. No smoking sign boards shall be kept at flammable and combustible material storage
places.
54. Debris, scrap and other materials shall be disposed daily at closing hours of the day by
the same crew.
55. Environment poster shall be displayed at site as and when required depending upon
the activities in progress.
56. Fire points should be placed at all required areas.
ENVIRONMENT, HEALTH AND SAFTEY POLICY:
L&T and its employees are committed to protecting the environment and the health & safety
of fellow employees, customers, and the public by adhering to stringent regulatory and
industry standards across all facilities, encouraging pollution prevention, and striving towards
continual improvement.
L&T seeks to go beyond compliance with regulatory standards in pursuit of excellence in
environmental, health and safety management practices, as an integral part of its total quality
management system - a healthier today and a safer tomorrow. L&T's corporate management
has enunciated policies that emphasize EHS through structured and well-defined procedures
at every stage of construction that protect the environment. The Company's global operational
policies and standards support its commitment to continuous improvement and serve as a
solid foundation for the EHS management processes. The business units build upon this
foundation with programs tailored to their respective culture and work environment to strive
toward L&T's ultimate vision of zero injuries and zero adverse environmental impact.
At L&T, Environment, Health & Safety (EHS) is given the highest priority. The EHS policy
enunciated by the Corporate Management lays emphasis on Environment, Health and Safety
through a structured approach and well defined practices.