(From 26 May, 2016 to 08 July, 2016)

SUBMITTED BY: RAJ GUPTA

COURSE: B.Tech.

BRANCH: MECHANICAL

YEAR: 3rd year

INSTITUTE:

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

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.

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.

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

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

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.

PROPOSED – PROJECT

COAL HANDLING PLANT FOR 2x660 MW SUPERCRITICAL

THERMAL POWER PLANT, CHHABRA, RAJASTHAN.

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

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)

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.

Layout of CHP- Chhabra

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.

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.

GRADES OF COAL

Mostly E and F grade coal used in India.

Blending with foreign coal is done to get average D grade.

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

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.

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

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

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.

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

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.

Necessary monorails with electric hoist are provided for handling various equipments of

CHP.

Flap Gate

5. STACKER AND STACKER CUM RECLAIMER

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.

Stacking rate of stacker is 2000 tonnes per hour and reclaiming rate of stacker cum reclaimer

is 1000 tonnes per hour.

6. BELT CONVEYER

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

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

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.

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.

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

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.

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.

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).

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.

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.

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.

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.

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.

Mechanical Properties-

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

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

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.

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

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.

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 METAL ARC WELDING

Wire feederWire spool

Power source

Torch Gas

cylinder

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

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

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.

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.

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.

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.

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.

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

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

testing.

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

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

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

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.

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.

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.