Volume 3A GTS

7/30/2019 Volume 3A GTS

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GMR (BADRINATH) HYDRO POWER GENERATION PVT. LTD.

Alaknanda Hydroelectric Project (300 MW)(UTTARAKHAND, INDIA)

BID DOCUMENTS

FOR

Bid No: GBHPL/LOT-5:

Design, Manufacture, Supply, Transportation to Site, Handling, Erection, Testing &Commissioning works of Generators, Turbines, Transformers, GIS equipment,

Control and Protection System, Switching and Auxil iary equipment, EOT Crane and220 kV Pothead yard Equipment etc complete along with Auxi liary Electrical and

Mechanical Equipment

Volume-3A

(General Technical Specifications)

October 2009


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Table of Contents

Volume- 0

Notice Inviting Bids (NIB)

Instructions to Bidders (ITB)

Volume- 1

Information for Bidders

Volume - 2

General Conditions of Contract (GCC)

Volume- 3A

General Technical Specifications (GTS)

Volume- 3B

Particular Technical Specifications (PTS)

Volume- 3C

Technical Data Sheet

Volume- 3D

Quality Assurance and Testing Specification

Volume- 4

Drawings

Volume- 5

Forms and Procedures

Volume- 6

Bill of Quantities (BOQ)


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GENERAL TECHNICAL SPECIFICATIONS


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Alaknanda Hydroelectric Project (300 MW)General Technical Specification Volume 3A(GTS)

GBHPL/LOT-5: Electro-mechanical works i

TABLE OF CONTENTS

1. INTRODUCTION .................................................................................................................. 1

2. TECHNICAL SPECIFICATIONS ......................................................................................... 32.1 Scope of Work ............................................................................................................. 3

2.2 Environmental Conditions ........................................................................................... 4

2.3 Seismic Design ............................................................................................................ 4

2.4 Quality of Water ........................................................................................................... 5

2.5 Units ............................................................................................................................ 5

2.6 General Codes and Standards .................................................................................... 5

2.7 Basic Design standards ............................................................................................... 7

2.8 Manufacturing and Testing Standards ........................................................................ 7

2.9 Material standards ....................................................................................................... 8

2.10 Electrical Standards .................................................................................................... 9

2.11 Design Stress ............................................................................................................ 10

2.11.1 General .......................................................................................................... 10

2.11.2 Stress Limits .................................................................................................. 10

2.12 Reference Drawings and Documents ........................................................................ 11

2.12.1 Drawings and Documents ............................................................................. 11

2.13 Unit model ................................................................................................................. 13

2.14 Past Experience and Performance of Supplier ......................................................... 13

2.15 Materials .................................................................................................................... 13

2.15.1 Test of Materials ............................................................................................ 142.15.2 Trade Names ................................................................................................. 15

2.15.3 Fastenings ..................................................................................................... 15

2.15.4 Forgings ......................................................................................................... 16

2.15.5 Castings ......................................................................................................... 16

2.15.6 Steel Plates ................................................................................................... 18

2.16 Workmanship and Quality Assurance ....................................................................... 18

2.16.1 General .......................................................................................................... 18

2.16.2 Quality Assurance ......................................................................................... 19

2.16.3 Quality Assurance Programme ...................................................................... 19

2.16.4 Quality Assurance Documents ...................................................................... 20

2.16.5 Quality Assurance Plan ................................................................................. 21

2.16.6 Implementation of Quality Assurance Plans .................................................. 21

2.17 Structural Materials ................................................................................................... 23

2.17.1 General .......................................................................................................... 23

2.17.2 Flame Cutting ................................................................................................ 23

2.17.3 Bolts, Nuts, Studs, and Screwed Connections .............................................. 24

2.17.4 Machine Work ................................................................................................ 24

2.17.5 Surface Finishes ............................................................................................ 24

2.17.6 Types of Finishes .......................................................................................... 242.17.7 Unfinished Surfaces ...................................................................................... 25


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GBHPL/LOT-5: Electro-mechanical works ii

2.17.8 Templates and Gauges ................................................................................. 25

2.18 Electric Welding ......................................................................................................... 25

2.18.1 General .......................................................................................................... 25

2.18.2 Preparation for Welding ................................................................................. 25

2.18.3 Welding Codes .............................................................................................. 26

2.18.4 Stress-relieving .............................................................................................. 26

2.18.5 Welders Qualifications ................................................................................... 27

2.18.6 Quality of Welds ............................................................................................ 27

2.18.7 Laminations ................................................................................................... 28

2.18.8 Electrodes ...................................................................................................... 28

2.18.9 Welded Fabrications and Residual Stress Relief ........................................... 28

2.18.10 Non-destructive Tests ............................................................................... 28

2.19 Ladders and Platforms .............................................................................................. 312.19.1 Floor Plates ................................................................................................... 31

2.19.2 Ladders and Stairways .................................................................................. 31

2.19.3 Handrails ....................................................................................................... 31

2.20 Noise ......................................................................................................................... 32

2.21 Identification Plates ................................................................................................... 32

2.21.1 General .......................................................................................................... 32

2.21.2 Manufacturers Nameplates (Rating Plates) .................................................. 33

2.21.3 Functional Plates ........................................................................................... 33

2.21.4 Instruction & Diagram Plates ......................................................................... 33

2.22 Piping, Fitting and Valves .......................................................................................... 33

2.22.1 General Specifications ................................................................................... 33

2.22.2 Water / Air piping ........................................................................................... 35

2.22.3 Oil Piping ....................................................................................................... 37

2.22.4 Fittings ........................................................................................................... 38

2.22.5 Valves ............................................................................................................ 39

2.22.6 Hangers and Supports ................................................................................... 43

2.22.7 Cleaning and Shipping .................................................................................. 44

2.22.8 Testing ........................................................................................................... 45

2.22.9 Insulation ....................................................................................................... 452.22.10 Bolts and Nuts ........................................................................................... 45

2.22.11 Gaskets ..................................................................................................... 45

2.23 Gauges and Instruments ........................................................................................... 45

2.24 Tropicalization ........................................................................................................... 46

2.24.1 Metals ............................................................................................................ 46

2.24.2 Screws, Nuts, springs, Pivots etc. ................................................................. 46

2.24.3 Fabrics, Cork, Paper, etc. .............................................................................. 46

2.24.4 Wood ............................................................................................................. 47

2.24.5 Adhesives ...................................................................................................... 47

2.24.6 Rubber ........................................................................................................... 47

2.24.7 Finishes ......................................................................................................... 47


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GBHPL/LOT-5: Electro-mechanical works iii

2.25 Anti Corrosion Measures ........................................................................................ 48


2.25.2 Surface Preparation for Protective Coating ................................................... 49

2.25.3 Extent of Protective Coating .......................................................................... 49

2.25.4 Shop Protective Coating Application ............................................................. 50

2.25.5 Field Protective Coating Application .............................................................. 51

2.25.6 Colours .......................................................................................................... 51

2.26 General Electrical Requirements ............................................................................... 52

2.26.1 General .......................................................................................................... 52

2.26.2 Power Supplies (Low Voltage) ...................................................................... 54

2.26.3 Standards ...................................................................................................... 55

2.26.4 Colour Code .................................................................................................. 55

2.26.5 Colour coding for mimic diagrams ................................................................. 552.26.6 Electric Motors ............................................................................................... 56

2.26.7 M.V. AND L.V Switchgear, Cubicles and Panels ........................................... 61

2.26.8 Power and Control Cables ............................................................................. 68

2.26.9 Cubicles and Control Panels ......................................................................... 69

2.26.10 Earthing ..................................................................................................... 71

2.26.11 Alarm Contacts .......................................................................................... 71

2.26.12 Electronic Equipment ................................................................................ 72

2.26.13 Protection Devices .................................................................................... 72

2.27 Equipment Identification: Rating Plates and Nameplates ......................................... 72

2.28 Electrical Instruments, Control Devices and Relays .................................................. 73

2.28.1 General .......................................................................................................... 73

2.28.2 Instruments .................................................................................................... 73

2.28.3 Indicating Lamps ........................................................................................... 74

2.28.4 Miniature Circuit Breakers (MCB) .................................................................. 75

2.28.5 Automatic Semaphore Indicators .................................................................. 75

2.28.6 Push Buttons ................................................................................................. 76

2.28.7 Switches ........................................................................................................ 76

2.28.8 Auxiliary Relays ............................................................................................. 76

2.29 SCADA System ......................................................................................................... 772.29.1 Control boards and panels ............................................................................ 77

2.29.2 Programmable controllers ............................................................................. 78

2.29.3 Power monitoring ........................................................................................... 79

2.29.4 Standards ...................................................................................................... 79

2.30 Network Characteristics ............................................................................................ 80

2.30.1 Protocols and standards ................................................................................ 80

2.30.2 Scalability and future extensions ................................................................... 80

2.30.3 Topology, redundancy and availability .......................................................... 81

2.30.4 Local control cubicles .................................................................................... 81

2.30.5 Plant Control Network .................................................................................... 81

2.30.6 Field Communication Network ....................................................................... 81


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GBHPL/LOT-5: Electro-mechanical works iv

2.30.7 Optical fibre ................................................................................................... 82

2.31 Factory Inspection and Testing ................................................................................. 82


2.31.2 Factory Inspection ......................................................................................... 83

2.31.3 Factory Testing .............................................................................................. 83

2.32 Operation and Maintenance Manuals ....................................................................... 83

2.33 Packing and Transport .............................................................................................. 84

2.33.1 General .......................................................................................................... 84

2.33.2 Packing .......................................................................................................... 85

2.34 Installation and Supervision ...................................................................................... 85

2.34.1 Concreting and Erection Supervision ............................................................ 85

2.34.2 Inspection, Tests on Completion and Commissioning ................................... 86

2.35 Safety ........................................................................................................................ 872.36 Spare parts and tools ................................................................................................ 87

2.36.1 General .......................................................................................................... 87

2.36.2 Specified Spare Parts .................................................................................... 88

2.36.3 Recommended Spare Parts .......................................................................... 88

2.36.4 Tools and Appliances .................................................................................... 88

2.37 Training ..................................................................................................................... 89

2.37.1 General requirements of training ................................................................... 89

2.37.2 Training during engineering / manufacturing phase ...................................... 90

2.37.3 Training during the erection / installation / site work ...................................... 90

2.37.4 Training during the tests on completion phase .............................................. 91


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GBHPL/LOT-5: Electro-mechanical works 1

1. INTRODUCTION

300 MW GMR (Badrinath) Hydro Electric project is located in Chamoli district of the state of

Uttarakhand and is slated to utilize the waters in the upper reaches of Alaknanda River, one

of the main tributary of the River Ganga.

The project is a run of the river type with exploitation of power potential of the Alaknanda

River (maximum reservoir level EL 2903.50 m). The Alaknanda River is diverted to two

intake tunnels by raising a gated barrage across the river downstream of Badrinath. The

intake tunnels connect to two underground desilting chambers which feeds a long head race

tunnel. A surge shaft with a surge chamber is located at the end of head race tunnel.

The underground power house complex comprises 3 vertical axis Pelton turbines with total

installed capacity of 300 MW. The Transformers are placed in a separate cavern parallel to

the power house cavern. Power evacuation is through GIS, XLPE cables, outdoor pot head

equipments connected to two single circuit 220 kV transmission lines.

The following equipments are covered under E&M package.

Turbines

Governing system

Oil pressure system for governing system

Turbine Instrumentation

Main Inlet valves (Spherical type)

Penstock Butterfly valve

Model test requirement

Oil pressure system for Butterfly valve

Main inlet valve instrumentation

Generator Stator

Generator Rotor

Generator braking system

Generator high pressure lubrication system


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Brake dust and carbon dust collecting system

Excitation system

Bus duct and tap off transformers

Generator instrumentation

Generator Step up Transformer

220 kV and 11 kV XLPE cables

Gas insulated switchgear

Outdoor pothead yard equipment

DC system (220V and 48 V )

Digital control system and SCADA

Protection system

Cabling system High voltage switchgear

Low voltage switchgear

Communication system

Illumination system

Electrical workshop

EOT (PH, Penstock and GIS ) cranes

Cooling water system

Dewatering system & Silt Ejection System

HVAC system

Grounding system

Compressed air system

Fire Fighting system

Mechanical workshop

Oil handling System

Elevator


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DG sets

AC distribution system

The terms Owner/Purchaser/Buyer wherever appearing in these Technical Specifications,

Volume 3A, 3B, 3C and 3D documents, mean the Employer and likewise the term Supplier

means the Contractor.

2. TECHNICAL SPECIFICATIONS

2.1 Scope of Work

This specification defines the technical requirements for the design, manufacture, supply,shop assembly; shop testing, inspection, training of Owners engineers, packing, warranty

and delivery of power plant equipments as defined in the commercial part of this document.

The equipment offered shall be complete with all necessary fittings, auxiliary equipment and

all parts that are necessary or usual for their efficient operation. Such parts shall be deemed

within the Suppliers scope whether specifically mentioned or not in the specification.

Requirements of special nature for the equipment are given in respective sections of

Particular Technical Specifications (PTS), as necessary, and will take precedence over

these general technical specifications in case of any contradiction.

The detailed scope of works will be covered in Particular Technical Specifications. The

scope of work is broadly defined as follows:

Detailed design, documents and drawings for approval of client and Engineer

Material specifications and quality plan

Manufacturing and procurement schedule

Equipment delivery schedule and transportation

Installation and construction drawings and documents

Field quality checklists for all equipments.

Project execution schedule

Site storage and material management

Installation, testing and commissioning


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Operation and maintenance manuals

As built drawings

Spare parts and special tools

Training of operating staff, assistance in trouble shooting and maintenance works.

2.2 Environmental Conditions

The environmental conditions at the powerhouse site under which the equipment is required

to operate satisfactory are as follows:

Maximum ambient temperature (C) Exterior 34

Minimum ambient temperature (C) Exterior - 4

Minimum ambient temperature (C) Interior 5

Maximum daily average ambient temperature (C) 25

Maximum relative humidity (%) 100

Maximum water temperature (C) 20

Minimum water temperature (C) 1

Altitude (meters) 2300 m

Seismic zone IV

Average rain fall (mm/year) 800 mm

Number of months with monsoon conditions 3

2.3 Seismic Design

The project is situated in a seismic area and falls within Zone IV of the seismic zoning map

of India incorporated in Indian Standard Criteria for Earthquake Resistant Design of

Structures (IS: 1893 (Part 1): 2002). Value of peak ground acceleration is to be taken as

0.36g for Maximum Considered Earthquake (MCE) and 0.18g for Design Basis Earthquake

(DBE).

The forces being caused by Earthquake including hydraulic loads, which may occur

additionally, shall be taken into account for the computations. Stresses resulting after

including these loads shall not exceed permissible stresses.


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The supplier shall design all equipment supplied under this contract to satisfy the seismic

criteria. The supplier shall submit to the purchaser the method of calculation and relevant

codes he intends to use for this purpose.

In addition to the above, IS 1893 shall be adopted for seismic design. Hydrodynamic forces

due to seismic conditions shall be considered on E & M equipment in addition to hydrostatic

loads.

2.4 Quality of Water

Water of Alaknanda River is expected to have high silt content throughout many months of

the year. After award of Contract, water analysis shall be provided by the Purchaser to theSupplier in order to enable the latter to ensure proper operation of the Works under these

conditions. The analysis shall be taken during period of the year representing highest silt

concentration and shall include chemical analysis, type of solids (e.g. Quartz) as well as

suspended solid concentration ppm as a % in function of particle size.

2.5 Units

Metric units according to the latest edition of the relevant International Standards

Organization (ISO) publications shall be used in documents, calculations, correspondence,

drawings, etc. for this Contract.

2.6 General Codes and Standards

Unless another standard is specifically mentioned in these specifications, all materials and

Works used and provided under the Contract and all design calculations and tests shall be in

accordance with the latest edition of the appropriate standards and codes published by the

following issuing authorities where applicable as listed alphabetically in Table 1. Other

standards and recommendations of standard international organizations will be acceptable

provided they ensure equal or higher quality than those specified, and provided, furthermore,

that the Supplier submits for approval detailed standards (in English version) which he

proposes to use.

If requested by the Purchaser the Supplier shall supply at his own expense one copy in

English of any standards which are applicable to the Contract.


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Table 1

Abbreviation Designation

ACI American Concrete Institute

AGMA American Gear Manufacturers Association

AISC American Institute of Steel Construction

AISE Association of Iron and Steel Engineers

AISI American Iron and Steel Institute

ANSI American National Standards Institute

API American Petroleum Institute

ASTM American Society for Testing and Materials

ASME American Society of Mechanical Engineers

AWS American Welding Society

AWWA American Water Works Association

BIS Bureau of Indian Standards

BSI British Standards Institution

CEMA Canadian Electrical Manufacturers Association

CMAA Crane Manufacturers Association of America

CSA Canadian Standards Association

DIN Deutsches Institut fur Normung

EN European Standards

IEC International Electro-technical Commission

IEEE Institute of Electrical and Electronics Engineers

IIW International Institute of Welding

IPCEA Insulated Power Cable Engineers Association

ISA Instrument Society of America (Now International society for

Automation)

ISO International Organization for Standardization


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Abbreviation Designation

J EC Standards of the J apanese Electro-technical Committee

J IS J apan Industrial Standards

NEC National Electrical Code of the U.S.A.

NEMA National Electrical Manufacturers Association (U.S.A.)

NESC National Electrical Safety Code of U.S.A.

NFPA National Fire Protection Association

SAE Society of Automotive Engineers

SSPC Steel Structure Painting Council (Now Society for Protective Coating)

TEMA Tubular Exchangers Manufacturers Association

UL Underwriters Laboratories, Inc. (U.S.A.)

VDE Verband Deutscher Electroingenieure (German equivalent of IEEE)

VDI Verein Deutscher Ingenieure (Society of German Engineers)

2.7 Basic Design standards

ISO System for limits and fits ISO/286-1988

General Tolerances and deviations Part-I ISO/1829-1975

Permissible machining variations in dimensions

without tolerance indication

ISO/2768-1973

Screw threads ISO-68-1998

ISO-262-1998

ISO-724-1998

2.8 Manufacturing and Testing Standards

Standard test methods and definitions for mechanical ASTM-A370-2009


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testing of steel products

Tension testing of metallic materials ISO/82-1959

Standard test method for Notched Bar impact testing of

Metallic materials

ASTM-E23-2007

ISO/83-1976

Bend test for steel ISO/85-1959

Standard test method for Liquid penetrant inspection ASTM-E165-2002

Standard guide for radiographic testing ASTM-E94-2004

Standard practise for Ultrasonic examination of heavy steel

forgings

ASTM-A388 / A388-2008

Standard test method for Guided bend test for ductility of

welds

ASTM-E190-1992(2008)

Welders qualification tests AWS (American welding society)

Group B, DIN EN 287

Preparation of steel surfaces for painting by sandblasting SIS 05-5900

Designation of degree of rusting of paint surfaces DIN-53210

Certificates of material testing DIN-10204

2.9 Material standards

Following standard for supply of material can be adopted subject to specific provision in the

Contract, if any:

a) ASTM (American Society for Testing & Materials),

b) DIN (German Industrial Standards)

c) BSI (British Standards)

d) BIS (Indian Standards)


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e) Material test certificates according to DIN 10204 shall be provided for all important

parts of the equipment such as: steel plates for parts under hydraulic pressure, all

major castings (runner, shut-off valve, etc.), large forgings (turbine and generatorshaft etc.), highly stressed large bolts etc.

f) For less important parts, certificates according to DIN 10204 are acceptable.

g) Materials shall be new and of first-class quality; suitable for the purpose, free from

defects and imperfections, and the classifications and grades in conformance with the

latest issue of the respective ASTM, AISI, DIN, IS or BS standard. Material to other

standards may be used if approval by the Purchaser has been obtained. Material

specifications, including grade or class data, shall be shown on the appropriate detail

drawings submitted for review.

If using stock material not specifically prepared for the supply under this Contract, the

Supplier shall submit evidence that the material complies with approved standards and that

the material is for the intended use.

The Supplier shall indicate in the Technical Data Schedules, the materials and applicable

standards for all major parts of the supply.

The materials shall be carefully selected for the intended purpose and due consideration of

the site conditions and the tropical environment. Higher grade material shall be used where

ordinary material is insufficient.

2.10 Electrical Standards

The following basic standards for electrical works or any other approved standard shall be

applied.

a) BIS (Indian Standards)

b) Standards issued by IEC (International Electro-technical Commission)

c) Standards issued by IEEE (Institute of Electrical and Electronic Engineers)

d) Standards issued by ANSI (American National Standards Institutes)

e) For specific standards refer the Particular Technical Specifications.


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2.11 Design Stress

2.11.1 General

Liberal factors of safety shall be used throughout the design, and especially in the design of

all parts subject to alternating stresses or to shock, including those due to electrical short

circuit faults. The Supplier shall furnish for record of Purchaser complete information,

including computations, regarding the maximum unit stresses used in the design.

2.11.2 Stress Limits

Unless otherwise specified in Technical Specifications, the following shall be the limits for

the Unit stresses:-

a) ALLOWABLE UNIT STRESSES UNDER RUNAWAY CONDITIONS

The maximum unit stress, due to operation at the guaranteed maximum runaway

speed, shall not exceed two-thirds of the yield strength of the material.

b) ALLOWABLE UNIT STRESSES UNDER NORMAL OPERATING CONDITIONS

Under the most severe operating conditions, the unit stresses in the materials shall

not exceed the values shown in Table 2.2 below:-

TABLE 2.2

MATERIAL MAXIMUM UNIT STRESS

IN TENSION IN COMPRESSION

Cast Iron One-tenth of the ultimatestrength

700 kg/cm2

Cast Steel, Alloy CastSteel and Steel Forgings

One fifth of the ultimatestrength or one-third of theyield strength, whichever islower

One-fifth of the ultimatestrength or one-third ofthe yield strength,whichever is lower

Plate Steel for Principalparts subject to hydraulicstresses

One-fourth of the ultimatestrength but not to exceed1050 kg/cm2

One-fourth of theultimate strength but notto exceed 1050 kg/cm2


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i) For other materials not covered in Table 2.2, used in the construction of the

generator, turbine, etc. the maximum stresses in tension or compression due to the

most severe conditions occurring in normal operation shall not exceed 50% yieldstrength. Maximum stresses in shear shall not exceed 210 kg/cm2 for cast iron and

60 percent of the allowable stresses in tension for other materials.

ii) Maximum stress in torsional shear in the turbine and generator shafts shall not

exceed 50 percent of the allowable stress in tension.

iii) For temporary overloads exceeding generator maximum continuous capacity at

unity power factor, unit stresses should not exceeding one half of the yield strength.

c) Maximum stress in tension or compression under normal operation (includingoverload conditions) shall not exceed 40% of minimum yield strength (YS); 50% of

minimum YS under over pressure conditions. 67% of minimum YS under severe

operating conditions (including runaway speed) and 75% of minimum YS under test

pressure condition.

2.12 Reference Drawings and Documents

2.12.1 Drawings and Documents

Works shall be carried out in accordance with the technical specifications and drawings as

well as additional specifications and drawings issued from time to time by the Purchaser.

In case of conflict between a general and more detailed requirement of the specifications,

the latter shall govern.

The following drawings / documents shall be submitted for review and approval:

Transportation Arrangement / Drawings

For all larger pieces of works which, due to their dimensions and/or weight and transport

limitations, will require special means for their transportation, the supplier shall submit

binding loading drawings indicating dimensions, weight etc., of the respective pieces of

works and the necessary trailer for its transportation to the site.

Foundation drawings

The contractor shall submit drawings indicating all essential details such as dimensions,

static and dynamic loads and embedment etc for proper design of the foundations.


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Arrangement drawings

All arrangement drawings shall be drawn to the scale. The general arrangement drawings

shall show the physical arrangement of the works.

The arrangement or layout drawings of electrical, instrumentation and control equipment

shall indicate location of their installation with respect to other equipments in the power

house.

Outline Drawings

The outline drawing shall show all elements and the main dimensions of individual

components where necessary in plan view, cross-section, side and top views.

Installation Drawings

The installation drawings shall provide detailed information on the disposition of various

assemblies. Installation drawing shall also indicate the sequence of installation of the

equipment.

Machining / Component drawings

Complete fabrication, machining drawing with quality plan of the components subjected to

wear shall be provided as per requirement of Purchaser during detail engineering.

Assembly drawing

Assembly / de-assembly drawing of all the components shall be provided with different

views.

Bill of materials

Bill of material covering part name as mentioned in the drawing, tag number, material

specifications, make and size shall be provided. Bill of material in soft copy in MS-Excelformat shall also be provided.

Single Line Diagram

This is a simplified diagram of essential electric works and their interconnections. Each

circuit is represented by a single line. It shall contain all required technical information of the

system represented, e.g. voltage, current, capacity, ratios, etc. as applicable.


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Terminal Diagram

Terminal diagram shall be prepared for all type of terminal boxes, marshalling rack, control

cubicle, switch board, etc and shall show the terminals, internal and external conductors.

Documents

Documents such as all calculations specified in the technical specifications, erection /

installation manual, operation & maintenance manual & quality plan

All above drawings shall be provided in AutoCAD format, MS-word and in MS-Excel format.

Any other drawing which is not specified and required by the Purchaser during detail

engineering shall also be provided.

The Drawings/Data required for the various equipment are indicated atAnnexure-1 and

their respective submission dates shall be proposed by the successful bidder during pre-

award discussions as per the proforma given in Annexure-2 of this document.

2.13 Unit model

A scaled model of section through a unit depicting the details of turbine generator set as

closely as possible shall be supplied by the Contractor. The model should have high quality

of craftsmanship to ensure the inclusion of all major details of the unit set. The details ofmodel may be discussed during detailed engineering and should be approved by the

Employer before acceptance of the same.

2.14 Past Experience and Performance of Suppl ier

The Supplier must have successfully designed, manufactured, type-tested, supplied,

installed and commissioned the system or device in question of equivalent rating or higher.

2.15 Materials

The materials used in the construction of the Works shall be new, of high quality, strength,

ductility, durability, of best engineering practice and suitable for the service to which the

equipment will be subjected, free from defects, imperfections and selected particularly to

meet the duties required of them. The material specification shall be indicated in the

Suppliers detailed drawings. The use of materials liable to be attacked by termites or other

insects shall not be allowed. All workmanship is to be of the highest quality throughout to

ensure smooth and vibration free operation under all possible operating conditions, and the

design, dimensions and materials of all parts are to be such that the stresses to which they


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may be subjected shall not render them liable to distortion or damage under the most severe

conditions encountered in service. Materials not specifically described herein shall be the

most suitable for the purpose and shall comply with the latest specifications of relevantIndian/International Standards. If the Supplier desires for any reason to deviate from or use

materials not covered by these specifications he shall state the exact nature of the deviation

or exception and shall submit for the approval of Purchaser complete specifications for the

materials he proposes to use. All materials, supplies, and articles not manufactured by the

Supplier shall be the products of recognized reputable manufacturers duly approved by the

Purchaser.

2.15.1 Test of Materials

All materials, parts and assemblies thereof entering into the supply to be executed under

these specifications shall be tested, unless otherwise directed, according to the applicable

IS, ASTM standard or as per approved method for the particular type and class of material

as per QAP requirements. The Supplier shall prepare specimens and perform tests and

analysis to demonstrate conformance of the various materials with the applicable

specifications given herein. In case the Supplier desires to use stock materials not

manufactured specifically for the equipment covered by these specifications, he shall submit

satisfactory evidence to Purchaser that such material conforms to the requirements herein

stated, in which case tests on these materials may be waived. Certified mill test reports of

plates will be acceptable. Routine test reports for minor components will be acceptable.

Four certified copies of test reports shall be furnished to Purchaser as soon as possible after

the tests are made. The results of these tests shall be in such form as to provide means of

determining compliance with the applicable specifications for the material tested. When

required, all tests shall be made in the presence of a duly authorized inspector representing

Purchaser. The Supplier shall keep Purchaser informed in advance of the time of startingand of the progress of the work in its various stages so that arrangements can be made for

inspection. No equipment shall be shipped until all tests, analysis and pre-shipment

inspection have been completed and certified copies of test reports have been accepted.

Over and above the inspection and test plan duly approved by the Purchaser, if during detail

engineering any additional inspection is considered necessary, the same will be carried out

and witnessed by the Purchaser. The cost of boarding / lodging and to and fro fare for

witnessing the additional test at Suppliers works shall be borne by the Purchaser.


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All material, packages receiving at site shall be in good condition without any defects and

meet the duties required there in. All packages receiving at site (Part of scope of supply)

shall be informed to Purchaser for the inspection before use.

2.15.2 Trade Names

When, as described in these specifications, certain Works, articles, materials and / or

manufacturing processes have been named by their trade names or by their catalogue name

or number, these designations are meant to be followed by the words or approved equal

even if they are not included in the text.

The Supplier may substitute other Works, articles, materials and/or fabrication processes

subject to the approval of the Purchaser, provided these are equivalent in quality and type to

those indicated and/or specified. It will be the Suppliers responsibility to demonstrate and

prove to the Purchaser the quality and suitability of the proposed alternatives.

2.15.3 Fastenings

Nuts, bolts, studs and washers for incorporation in the Works shall conform to the

requirements of the appropriate standard. Where non-standard fasteners are used in the

Works, appropriate tools, including wrenches, taps and dies, shall be provided. Nuts and

bolts for pressure parts shall be of the best quality bright steel, machined on the shank and

under the head and nut.

All washers shall be included under the Contract, including locking devices and anti-vibration

arrangements, which shall be subject to the approval of the Purchaser. Taper washers shall

be fitted where necessary. Where there is a risk of corrosion, bolts and studs shall be

finished flush with the surface of the nuts. Bolts, except for high strength friction grip bolts,

shall be designed so that, with the nuts fully tightened, the stress intensity at the bottom of

the thread shall not exceed one half of the yield point of the material under all conditions.

Connections employing high strength friction grip bolts as per ASTM A325 or A490 shall

follow the requirements of Specification for Structural J oints Using ASTM A325 or A490

Bolts as given in the AISC Manual of Steel Construction. Bolts, nuts and screws which are

subject to frequent adjustment, frequent removal or immersion in the course of operation

shall be made of corrosion-resistant steel or bronze. The material of stainless steel bolts

and nuts shall be selected to prevent galling. Spring type washers will not be permitted

where they may damage any protective coatings.


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2.15.4 Forgings

Forgings in excess of 150 mm in diameter shall be subjected to examination internally for the

detection of flaws and to heat treatment for the relief of residual stresses. Particulars of the

heat treatment proposed for all forgings, and in each case the name of the proposed maker,

shall be submitted to the Purchaser for approval.

Each forging incorporated into the Works shall be clearly stamped with the heat number

readily visible. All such forgings shall be jointly examined at the place of manufacture by the

Purchaser and by a representative of the Supplier during the heat treatment and shall be

examined by the latest non-destructive methods for the detection of defects.

2.15.5 Castings

Steel castings shall conform to the following requirements:

a) General

Castings shall be free from injurious defects and shall be free of foundry irregularities such

as projections, ridges, hollows, honey-combing, pock marks, or chip marks, so that they will

not require surface smoothing operations in the field prior to painting. The location of existing

defects shall be determined, and they shall be completely removed to sound metal. Thestructure of the castings shall be homogeneous and free from excessive non-metallic

inclusions. An excessive segregation of impurities or alloys at critical points in a casting will

be cause for its rejection. All castings involving welded fabrication shall be stress-relieved.

b) Inspection

Castings of main parts, including all those subject to hydraulic pressure and all castings

which underwent major repair, shall be radio graphically examined as specified. Other

castings shall be tested using radiographic, ultrasonic, dye penetration, magnetic particle orany other standard non-destructive test method approved by the Purchaser. The Purchaser

has the right to ask the Supplier to carry out non-destructive tests to determine:

The presence of defects;

The maximum extent of defects;

That the area to be welded is satisfactorily prepared;

That the repairs are satisfactory.

The costs incurred by such tests shall be at the Suppliers expense.


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The Supplier shall notify Purchaser in ample time to have an inspector present at the

foundry, if Purchaser so desires, when the castings are cleaned and defects chipped to

sound metal, before any repair welding is done. After the repairs of castings, same shall beheat-treated.

Test pieces for tension and bend test specimens shall be removed from the castings at the

time of inspection. Certified copies of the test reports shall be furnished as specified in

clause 2.9.1. The Supplier shall make non-destructive tests for important load carrying

castings as appropriate prior to final machining. Radiographic or magnetic particle

inspection, ultrasonic or other non-destructive tests may be required by Purchaser when it is

desired to make such tests as a means of judging acceptability of castings which contain

defects of apparent borderline seriousness or to determine that repair welds have been

properly made. Any such tests shall be at the expense of the Supplier.

c) Repair Welding

No repairs of major defects shall be made to castings without prior approval from Purchaser.

Defects shall be considered major when the depth of the cavity properly prepared for

welding exceeds 20 percent of the effective wall thickness or 25 millimeters, whichever is

smaller. Acceptance criteria shall be CCH 70-3 class 3.

Welding of defects shall be performed only by welders or welding operators qualified in

accordance with clause 2.12.1(d) and shall conform to the best modern welding practice.

If the removal of metal to uncover a crack or remove a defect reduces the stress-resisting

cross-section of the casting to such an extent that the computed unit stress in the remaining

metal is more than 30 percent in excess of the allowable stress, the casting may, at the

option of Purchaser, be rejected.

Casting repairs by welding of major defects at any stage of manufacture after the first heat

treatment (annealing) shall be stress-relieved. Minor defects or imperfection that will not

ultimately impair the strength or service ability of the castings, may be repaired by welding in

accordance with accepted commercial casting practice without securing approval. However,

an accumulation of minor defects which in the opinion of Purchaser casts serious doubt as to

the general quality of the casting may constitute cause for rejection.

Before proceeding to repair any major defect a written report shall be submitted to the

Purchaser in which the fault is fully described, together with diagrams, photographs and

reports of metallurgical tests, when applicable, as well as with the description of the

proposed repair method.


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d) Dimensions

Thicknesses and other dimensions of the castings shall conform substantially to the

dimensions on the drawings and shall not be reduced by shop or foundry practices to the

extent that the resulting stresses in the metal will exceed the stresses allowed under these

specifications. Castings shall not be warped or otherwise distorted, nor shall their

dimensions be oversize to such an extent as to interfere with proper fit with other parts.

e) Finish

i) Surface finishes shall be indicated on the detail drawings and shall conform to the

requirements of ANSI B46.1 "Surface Roughness, Waviness and Lay", or other

approved equal standard. Also refer clause 2.11(f).

ii) All parts shall be free from burrs, sharp edge and imperfections in cutting, machining and

welding. All visible parts shall receive special attention in order to ensure aesthetic

appearance of the completed machine.

2.15.6 Steel Plates

Rolled steel plates which are to be used in the fabrication of pressure vessels or parts that

are subject to internal pressure and are encased in concrete, and rolled steel plates forming

large highly stressed weldments shall be tested for laminations at the place of manufacture

in accordance with ASTM A435. Mill sheets for all plates shall be supplied.

2.16 Workmanship and Quality Assurance

2.16.1 General

a) Workmanship shall be of the highest grade and in accordance with the best modern

practice for the manufacture of high-grade machinery, not withstanding any omissions

from these specifications or drawings. All work shall be performed by workmen skilled

in their various trades.

b) Machining of renewable parts shall be accurate and to specified dimensions so that

replacements made according to the drawings may be readily installed and are inter-

changeable among unit and spares. The Supplier shall maintain in storage for at least

10 years, at his own expense, sufficient templates, gauges, patterns, or other records

to enable him to make repair and replacement parts. All special gauges and templates

necessary for field erection shall become the property of Purchaser. All measurements


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and dimensions given on drawings submitted for approval shall be expressed in the

metric system (millimeters, meters).

2.16.2 Quality Assurance

In general terms, the Supplier quality assurance program must be in compliance with ISO

9001 standards. The Purchaser reserves the right to verify the document pertaining to the

Suppliers quality assurance program, as well as the application of the same in the

manufacturing plant.

In general the assembly of all the equipment components shall be carried out in the

Supplier's workshops so that it shall be possible to perform inspections, tests, etc. that will

ensure a subsequent satisfactory operation. Exceptions to this rule shall only be possible

upon the Purchaser's consent.

The Purchaser's authorized representatives shall have the right of access to the plant and to

inspect and verify the quality of materials used in the manufacturing process.

2.16.3 Quality Assurance Programme

To ensure that the equipment under the scope of this contract whether manufactured or

performed within the Suppliers Works or at his Sub-Contractors premises or at the

Purchaser's site or at any other place of Work are in accordance with the specifications, the

Supplier shall adopt suitable quality assurance programme to control such activities at all

necessary points. Such programmes shall be outlined by the Supplier and shall be got

approved from the Purchaser. A quality assurance programme of the Supplier shall generally

cover the following:

a) His organisational structure for the management and implementation of the proposed

quality assurance programme.

b) Documentation control system.

c) Qualification data of Suppliers key personnel.

d) The procedure for purchase of materials, parts, components and selection of Sub-

Suppliers service including vendor analysis, source inspection, incoming raw-

material inspection, testing, verification of materials purchased, etc.

e) System for identification and traceability of parts/components

products/instruments/control devices etc.


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f) System for process control, fabrication and assembly control during shop

manufacturing and site erection.

g) System for inspection and testing when parts/components/raw

material/instruments/control devices are received, during manufacture and during

final product/equipment/assembly inspection and testing.

h) Control of calibration and testing of measuring and testing equipments.

i) System of documentation to indicate conformance or non conformance of product to

specifications, inspection and test status. Also control of non-conforming items and

system for corrective actions.

j) System for handling, storage, packaging and delivery.

k) System for maintenance of quality records.

l) System for quality audit.

m) System for authorising release of manufactured product to Purchaser.

2.16.4 Quality Assurance Documents

The Supplier shall be required to submit the following Quality Assurance Documents for

approval of the Purchaser:

a) All Non-Destructive Examination procedures, stress relief and weld repair procedure

actually used during fabrication.

b) Welder and welding operator qualification certificates.

c) Welder identification list, listing welder's and welding operator's qualification

procedure and welding identification symbols.

d) Material mill test reports on components as specified by the specification.

e) The inspection plan with verification, inspection plan check points, verification

sketches, if used, and methods used to verify that the inspection and testing points in

the inspection plan were performed satisfactorily.

f) Sketches and drawings used for indicating the method of traceability of the

radiographs to the location on the equipment.

g) Non-Destructive Examination result reports including radiography interpretation

reports.


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h) Stress relief time temperature charts.

i) Factory test results for testing required as per applicable codes and standards

referred in the specification.

j) Inspection reports duly signed by Quality Assurance personnel of the Purchaser and

Supplier for the agreed inspection hold points. During the course of inspection, the

following will also be recorded:

i) Any important repair work carried out or to be carried out to make the job

acceptable.

ii) The repair work remains part of the accepted product quality.

2.16.5 Quality Assurance Plan

A quality assurance plan detailing specific control procedure proposed to be adopted for

controlling the quality characteristics relevant to each item of equipment shall be furnished.

These shall include but not be limited to following to ensure conformance of equipment

specifications and relevant codes/standards.

a) Material test of raw material.

b) Non destructive examination as approved by Purchaser.

c) Component Inspection and tests.

d) Assembly Inspection and tests.

e) Pressure test/high voltage dielectric and other test

f) Operational tests

g) Functional and Performance tests as applicable.

2.16.6 Implementation of Quality Assurance Plans

a) Detailed shop inspection/testing schedule shall be submitted by Supplier to

Purchaser. Quality assurance plan shall take into account various provisions of

specifications.

b) Non destructive examination shall be carried out for the principal parts of materials

and the weld seams of fabricated components in accordance with the requirements

of A.S.M.E. code sections and A.S.T.M. standards as per Appendix 2.2 or as

approved.


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c) The Supplier shall give his own quality assurance plan with details and Purchaser

hold points, keeping in view specification requirements, codes/standards provisions

and Suppliers practices for approval by Purchaser.

d) Notice for inspection shall be submitted to Purchaser thirty (30) days prior to

proposed date for inspection as per provisions of Conditions of Contract.

e) Material mill certificates and material identification record for important components

shall be submitted after completion of fabrication.

f) Electrical tests i.e. dielectric loss measurement, insulation resistance, dielectric tests

and other tests as per specifications and applicable codes and standards shall be

conducted during various stages of manufacture.

g) Purchaser may appoint third party inspectors for inspection and testing to ensure that

provisions of specifications and applicable codes and standards are complied with.

Supplier shall extend all facilities for conduct of such inspections and tests and

ensure intimation of programme for inspection and tests to third party inspectors as

directed by Purchaser.

h) The test and inspection certificates shall be submitted to Purchaser prior to shipment

of components/assembly concerned.

i) To ensure implementation of quality assurance plan, all inspection and tests on

various material, components, assembly and equipment shall be sub-divided into

following categories:

i) Tests by vendor/sub-Contractors inspector, inspection certificates to be

submitted to Purchaser.

ii) Tests by manufacturer's inspector at his or vendor/sub-Contractors works

and test certificates to be submitted to Purchaser.

iii) Tests by manufacturer's inspector and witness by Purchaser's inspector on

purchasers request.

iv) Tests by manufacturer's inspector and witness by Purchaser's inspector and

at Purchaser's option by third party inspector as well.

v) All Inspection/tests are subject to Purchaser's review.

j) Quality assurance plan shall be offered for all equipment covered under the contract

including equipments such as static excitation equipment.


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k) In so far as practical, provisions and guidelines of ISO 9001 will be applicable and

implemented for quality control and assurance.

l) Supplier shall furnish his proposed quality plan for all major components to

Purchaser for approval.

2.17 Structural Materials

2.17.1 General

Structural materials may be straightened by methods which will not result in injury, sharp

kinks or bends which shall be cause for rejection. Finished members shall be free from kinks

or bends. Shearing shall be done accurately and all portion of the work neatly finished.Corners shall be square and true unless otherwise shown on the drawing.

Re-entrant cuts shall be made in a workmanlike manner. Where they cannot be made by

shearing, a rectangular punch may be used. Re-entrant cuts shall be filleted, unless

otherwise approved by Purchaser.

Bends, except for minor details, shall be made by approved dies or bending tools. When

heating is required for the satisfactory working of the metal, it shall be allowed to cool under

conditions that will not destroy the original properties.

Steel with welds other than those definitely indicated on the shop drawings, or specified or

otherwise called for, will not be acceptable. All bolts, nuts, and screws shall be tight.

The ends of all pipes shall have all burrs removed.

2.17.2 Flame Cutting

Low carbon structural steel may be cut by machine-guided or hand-guided torches instead of

shears or saws. Flame cutting of material other than low carbon structural steel shall be

subject to the approval of Purchaser and, where proposed, shall be definitely indicated on

shop drawings submitted by the Supplier. Where the torch is machine-guided, no chipping or

grinding will be required except to remove slag and sharp edges.

Flame gouging will be permitted as a preparation for welding. Where the torch is hand-

guided, the cut shall be chipped, cut, or machined to sound metal except where material is

not to be welded, in which case the burrs and rough edges alone shall be removed.


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2.17.3 Bol ts, Nuts, Studs, and Screwed Connections

All threads shall be clean and accurately cut before assembling. Screwed parts shall be

lightly lubricated or coated with jointing compound as may be applicable before connection.

All screwed connections shall be made without the use of force sufficient to permanently

deform the material. Threads shall be metric.

2.17.4 Machine Work

Unless otherwise shown on the approved shop drawings, all allowances, tolerances, and

gauges for metal fits shall conform to ANSI Standard B.4.1 for the class of it as shown or

otherwise required. Sufficient machining allowance shall be left on placing pads to ensure

true surface of solid material. Finished contact or bearing surfaces shall be true and exact to

ensure full contact.

All machined parts shall be accurately machined and like parts shall be interchangeable.

Drilled holes for bolts shall be accurately located and drilled to templates when necessary or

specified. The holes for fit-up bolts or dowels shall be carefully reamed and the bolt or dowel

shall enter with a light driving fit. Bolt and screw threads shall conform to ISO standard 68.

2.17.5 Surface Finishes

Surfaces to be machine-finished shall be indicated on the shop drawings by symbols which

conform to ANSI B46.1. Values of roughness height are specified in microns as "average

deviation from the mean surface". Values of roughness, width and waviness height are not

specified but shall be consistent with the general type of finish as specified by the roughness

height. Compliance with the specified surface will be compared to roughness comparison

specimens.

2.17.6 Types of Finishes

Surfaces which are to be machined to dimensions where the tolerance is 0.5 mm or greater

shall have a maximum roughness value of 12.5 microns.

Stationary mating surfaces, where reasonably accurate positioning of the members or a

moderately tight joint is desired, shall have a maximum roughness value of 6.3 microns.

Surfaces in sliding or rotating contact, where motion is slow and loads are light, shall have a

maximum roughness value of 3.2 microns.


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Surfaces in sliding or rotating contact, when loads and speeds are moderate, shall have a

maximum roughness value of 1.6 microns.

Surfaces in sliding or rotating contact where loads are heavy and / or the motion is rapid,

shall have a maximum roughness value of 0.8 microns.

2.17.7 Unfinished Surfaces

So far as practicable, all work shall be laid out to secure proper matching of adjoining

unfinished surfaces. Where there is a large discrepancy between adjoining unfinished

surfaces, they shall be chipped and ground or machined to secure reasonable alignment.

Unfinished surfaces shall be true to the lines and dimensions shown on the drawings and

shall be chipped or ground free from projections or rough spots. Depressions or holes not

affecting the strength or usefulness of the parts may be filled in a manner approved by

Purchaser.

2.17.8 Templates and Gauges

All parts that may require renewal shall be made to template and gauge so that original and

spare parts will be interchangeable. All special gauges and templates necessary for site

erection and runner maintenance shall become the property of Purchaser as specified in

PTS.

2.18 Electric Welding

Electric welding shall conform to the following requirements:

2.18.1 General

All welding shall be performed by the electric-arc method, by a process that excludes the

atmosphere from the molten metal, and where practicable, using automatic machines.

Complete procedures for both shop and field welds shall be submitted for approval.

2.18.2 Preparation for Welding

Members to be joined by welding shall be cut accurately to size, with edges sheared, flame-

cut, or machined to suit the required type of welding and to allow thorough penetration and

good fusion of the weld with the base metal. The cut surfaces shall be free of all visible

defects such as laminations, surface defects caused by shearing or flame cutting operations,

or any other injurious defects. The surfaces of plates to be welded shall be free from rust,

grease, and other foreign matter along the edges prepared for welding.


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All welds exposed to water flow shall be ground to a smooth and even surface flush with the

adjacent plate.

2.18.3 Welding Codes

All welding for the fabrication of principal stress-carrying parts shall be in accordance with

Part UW of Section VIII of the American Society of Mechanical Engineers (ASME) "Boiler

and Pressure Vessel Code", with the exceptions regarding stress-relieving stated below. All

welding for the fabrication of less important parts shall be in accordance with the applicable

requirements of paragraphs 401 through 403 and 406 through 410 of the "Standard Code for

Arc and Gas Welding in Building Construction" of the American Welding Society (AWS) or

other equal approved standard.

2.18.4 Stress-relieving

Important Parts

For principal stress carrying parts, localized stress- relieving will not be permitted

for shop-welded parts. All weld-fabricated parts except minor parts, those where

stress is not important, or those which are specifically exempted from stress-

relieving shall be stress-relieved as a unit prior to final machining. Radiographic

and ultrasonic examination of welds will be required, as specifically stated in these

Specifications, and when, in the opinion of Purchaser, doubt exists as to the quality

of certain welds. Any such radiographic and ultrasonic inspection shall be at the

expense of the Supplier. The Supplier shall furnish all special materials,

equipments, or techniques required for pre-heating or post-heating of members to

be joined by field welding.

The design and construction of welded joints shall conform to the applicable

requirements of the ASME Boiler and Pressure Vessel Code, Section VIII. Machineparts, including all parts directly and permanently attached to the turbine distributor

or spherical valve shall be stress-relieved prior to final machining.

The stress-relieving furnace shall be equipped with suitable recording

thermometers to record the temperature of the furnace and parts during the heating

and cooling of the parts. All temperature records shall be submitted to Purchaser

for record. Localized stress-relieving will not be permitted for shop welded parts.

Field welding of stress-relieved parts will not be permitted.


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LESS IMPORTANT PARTS - The fabrication of less important parts, such as wheel

pit liners and oil sump tank shall be in accordance with the applicable requirements

of Paragraphs 401 to 403 and 406 to 410 of the American Welding Society. Stress-relieving of such parts will not be required.

2.18.5 Welders Qualifications

For welding of principal stress-carrying parts, the qualification of welding procedures,

welders, and welding operators assigned to work covered by these specifications shall

conform to the requirements of Section IX of the ASME "Boiler and Pressure Vessel Code",

Welding & Brazing Qualifications and, Section VIII Part UW, Requirements for Pressure

Vessels Fabricated by Welding. For welding of less important parts/ structural steel parts,the qualifications of welding procedures, welders, and welding operators shall conform to

AWS Section D1.1 - 75 Section 5B A "Standard Qualification Procedure".

If at anytime, in the opinion of the concerned engineer, work of any welder or welding

operator appears questionable, such operator will be required to pass additional qualification

tests to determine his ability to perform the type of work on which he is engaged. All such

additional qualification tests for welding operators and the physical test of the welded

specimens shall be made in the presence of Purchasers inspector. All expenses in

connection with making such qualification tests for welders and welding operators shall be

borne by the Supplier.

2.18.6 Quality of Welds

The design of welded joints and the welding procedures for both field welds and shop welds,

in addition to conforming to the requirements set forth in the applicable code and/or in these

Specifications, shall meet the following requirements for workmanship and visual quality:

i) Butt welds shall be slightly convex, of uniform height, and shall have fullpenetration.

ii) Fillet welds shall be of specified size, with full throat and with legs of equal length.

iii) Repair chipping, or grinding of welds shall be done in such a manner as not to

gouge, groove, or reduce the base metal thickness.


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2.18.7 Laminations

Any plate in which lamination has been discovered after cutting shall be rejected unless the

laminated portion of plate is local and can be cut out and replaced by welding of a new

sound plate in the cut-out area.

In such cases the Purchasers approval for repairs will be required. Where such repairs are

authorized the welds of the repairs shall be ground smooth to assure neat appearance.

2.18.8 Electrodes

The Supplier shall indicate on all detail drawings the type, size and material of electrodes he

proposes to be used for shop and / or field welding. Field welding electrodes will be providedby the Supplier.

2.18.9 Welded Fabrications and Residual Stress Relief

All parts manufactured using welding methods, except those in which the stresses are not

important, shall be designed, manufactured and inspected according to the ASME Boiler

and Pressure Vessel Code, Section VIII, Requirements for Unfired Pressure Vessels

Fabricated by Welding or equivalent. Welds shall be balanced in so far as practical to

minimize distortion and residual stresses. The requirements of welding methods shall besubmitted for approval.

2.18.10 Non-destruct ive Tests

Unless otherwise requested by the Supplier and approved by the Purchaser, all non-

destructive testing of materials shall be carried out in accordance with the following

specifications:

Radiographic methods ASME Section VIII, division - 1 UW51 (welds)

ASTM E446, E186 and E280 (castings)

Ultrasonic methods ASME Section VIII, Appendix 12 (welds)

ASTM A418 and A388 (forgings)

Magnetic particle methods ASTM E709

Liquid penetrant methods ASTM E165

The Supplier shall supply the Purchaser with procedure sheets and test data confirming the

effectiveness and validity of each method he proposes to use.


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All inspection and non-destructive testing requirements must be clearly specified on the

drawings.

Radiographic Inspection

Radiographic inspection with X-ray machines or radioactive isotopes will be permitted.

Limitations on the use of each method are outlined in ASTM and ASME standards. X-ray

machines shall be used in preference to isotope cameras whenever possible. Single control

kilovoltmilliampere X-ray machines shall not be used without the express approval of the

Purchaser.

All welds of components subjected to penstock hydrostatic pressure and welds of other

important stress-carrying parts shall be 100% radiographically inspected where practical in

the opinion of the purchaser. For other welds minimum 20% radiography to be carried out.

Final decision on acceptability shall rest with the Purchaser. Radiographic plates will only be

accepted if they comply with the conditions specified in the ASME Code, Section VIII. All

welds which are rejected on the basis of the ASME Code, Section VIII or other, shall be

repaired or replaced by an acceptable weld. Where radiographic inspection is not practical,

other non-destructive testing such as ultrasonic, dye-penetrant, magnetic particle, or a

combination of tests, shall be used. The results shall be submitted to Purchaser for record

purposes.

Ultrasonic Inspections

Ultrasonic Inspection of cast, forged and welded parts will be acceptable if an inspection

program is presented together with evidence to prove the validity of the proposed method, all

subject to the Purchasers prior approval.

Whenever radiographic inspection of welds is not possible, such as certain angular and

back-plated welds, the Supplier shall demonstrate the validity of ultrasonic methods byinspecting a test sample which has been prepared by identical methods and checked by

radiography.

Ultrasonic testing shall only by acceptable if it is carried out with equipment of recognized

brand. Welds, castings and forgings shall be inspected by direct contact of the probe with

the surface.

Under special conditions, ultrasonic inspection by immersion of forged parts may be

required. Whenever angled probing is used, the angle of incidence shall be suitable for the

thickness of the part, and shall be as recommended in ASTM and ASME standards.


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Equipment shall be calibrated regularly on a test sample prepared as described above, or on

a test sample containing flaws similar to those being sought. The ultrasonic method shall not

be used until technical literature describing the process, proposed methods, equipmentsensitivity, probes, etc. is submitted to the Purchaser together with proof of the competence

of the Suppliers technicians.

Inspection reports and supporting drawings, sketches or photographs shall be submitted to

the Purchaser, together with all details needed to reproduce accurately any ultrasonic test at

any time.

The final decision on acceptance rests with the Purchaser.

Complementary Inspection

Complementary inspections of castings, forgings and welded joints may be carried out using

liquid penetrant and magnetic particle methods. These methods shall conform to the

requirements of ASTM E165 and ASTM E709.

These methods are only acceptable for detection of flaws on the surfaces of components or

on welds. Striations and irregularities shall be removed before testing.

For liquid penetrant testing, the surface shall be conditioned or effectively cleaned before the

application of the penetrant.

Magnetic particle examination shall be so conducted that surface deterioration or burning

does not occur at electrode contact points. Current intensity and duration of application and

orientation of the magnetic field shall be as specified in the standards. A magnetic field

meter shall be used regularly. Provision shall be made for demagnetization of components if

residual magnetism is a potential problem. Final acceptance rests with the Purchaser.

Special Inspection

For all components fabricated with segments joined by full penetration butt welds, the

inspection requirements shall be specified on the drawings and submitted for the

Purchasers approval.

Ultrasonic inspection shall be done when radiographic inspection cannot be performed

and/or where the design standards allow it. Non destructive testing shall be performed after

heat treatments.

When the verifications specified on the drawings are partial, the Supplier shall perform them

at the locations specified by the Purchaser. When defects are found, the necessity of repair


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will be evaluated by the Purchaser allowing for the level the stresses may reach in that spot

and for the severity of the defects.

The repair work shall be done by gouging to defect-free metal, as conformed by a non-

destructive inspection. Repair welding will be allowed only if the defect has been eliminated

to the satisfaction of the Purchaser. The repaired welds will be checked again according to a

procedure approved by the Purchaser.

2.19 Ladders and Platforms

2.19.1 Floor Plates

Floor plates shall be chequered steel plates with a minimum plate thickness excluding raisedpattern of not less than 8 mm. Edges of plates shall be planed and joints shall be cut where

practicable so as to maintain continuity of pattern.

2.19.2 Ladders and Stairways

Steel ladders or stairways shall be provided where necessary to access for operation and

maintenance of the equipment. Ladders shall not exceed 7.5 m in length and suitable

platforms with handrails shall be provided between each length.

Where a ladder does not extend above a floor or platform level, hand grips or other suitable

means of support shall be provided. Protective cages shall be provided for ladders longer

than 4.5 m. Ladder rungs shall not be less than 20 mm diameter and stringers not less than

400 mm apart. Stairways shall be provided with handrails and shall have a slope not greater

than 45.

2.19.3 Handrails

Handrails shall be provided wherever necessary for the safety of personnel. The handrails

shall consist of at least two horizontal tubular members approximately 35 mm diameter

mounted on tubular or flat bar upright. The handrail shall be approximately 1100 mm above

finished floor level.

The handrails and supports shall be designed to withstand vertical and horizontal uniformly

distributed loads of 750 N/m applied simultaneously on the top of the railing. Openings in

the handrails shall be closed by removable chains.


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2.20 Noise

The noise level caused by the installed Works shall n

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