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Introduction
This booklet has been written as an introduction to and a
source of general information on pipe joints.
The flanged joint appears deceptively simple but in fact the
science of flanges and joint sealing is complex and continuously
developing. Sound joints are critical to piping integrity and
plant safety.
A pipe joint thus relies on the skill and application of the fitter
who puts it together. Correct selection of materials, application
of procedures, correct use of tools combined with the fitter’s
skill are all required to ensure a joint of maximum integrity.
But mistakes have happened; choosing the wrong gaskets,
using the wrong studbolts. Such mistakes cannot be ignored.
The purpose of this booklet is therefore to increase understanding
about pipe joints; from pipe specifications and how to
use them, to studbolts and how to identify them.With increased
awareness and knowledge, it is expected that mistakes will be
prevented.
Contents Page
1. Technical Data - Company and National Standards 7
1.1 BP Amoco Engineering Standards 7
1.2 ANSI/API Standards 7
1.3 British Standards 8
1.4 Piping Specifications 9
2. Flanges 11
2.1 Flange Standards 12
2.2 Flange Facings 12
2.3 Flange Face Re-Machining 14
2.4 Flange Types 16
2.5 Flange Specification and Identification 21
2.6 Pipe Flanges - Do’s and Don’ts 22
2.7 Flange Surface Finish and Flange Distortion 23
3. Gaskets 25
3.1 Selection of Gasket Material 25
3.2 Fugitive Emissions 26
3.3 Compatibility with Fluid 27
3.4 Temperature 27
3.5 Internal Pressure 29
3.6 Special Considerations 29
3.7 RTJ (Ring Type Joint) Gaskets 32
3.8 Spiral Wound Gaskets 36
3.9 Sheet Gaskets 43
3.10 Compressed Asbestos Fibre Gasket (CAF) 46
3.11 Gaskets for Lined Pipework 47
3.12 Gaskets - Do’s and Don’ts 49
4. Compact Flanged Joints 51
4.1 Taper-Lok 51
4.2 Graylock Coupling 53
4.3 Other Designs 54
4.4 Compact Flanges Specification and Identification 55
03000785, May 2000 page 3
Contents (cont’d) Page
4.5 Compact Flanges - Do’s and Don’ts 55
4.6 Breaking Joints 56
4.7 Making Joints 58
5. Bolting for Flanges and Covers 61
5.1 Bolt Material Grade 62
5.2 Bolt Thread 62
5.3 Bolt Coating/Plating 63
5.4 Bolt Specification and Identification 65
5.5 Tension Controlled Fasteners - Rotabolt 66
5.6 Hydraulic Bolt Tensioning 70
5.7 Flange and Bolt Protection 72
5.8 Bolting - Do’s and Don’ts 72
5.9 Manual Bolt Tightening 73
5.10 Bolt Tightening - Do’s and Don’ts 77
5.11 Hot Bolting 78
5.12 Restrictions on Hot and Odd Bolting 79
5.13 Insulation Kits for Bolts 80
5.14 Insulating Kit Identification and Specification 84
5.15 Insulating Kits - Do’s and Don’ts 84
6. Spading and Blanking of Flanges 87
7. Screwed Piping Joints 89
7.1 Threaded Joints 89
7.2 Sealing on a Threaded Joint 90
7.3 Table of Thread Jointing Compounds 92
7.4 Screwed Unions 94
7.5 Screwed Joints Specification and Identification 95
7.6 Screwed Joints - Do’s and Don’ts 96
8. Compression Fittings 99
8.1 Compression Fitting Specification and 101
Identification
8.2 Compression Fittings - Do’s and Don’ts 102
page 4 03000785, May 2000
Contents (cont’d) Page
9. Elastomeric O-Ring Seals 105
9.1 Selection of Elastomeric O-Rings 106
9.2 Elastomeric O-Ring Failures 107
9.3 Elastomeric O-Rings - Specification and 108
Identification
9.4 Installation of Elastomeric O-Rings - Do’s and 109
Don’ts
Appendix 1 - Miscellaneous Technical Data 111
1. Bolts Material Specifications 112
2. Hydraulic Bolt Tensioning 113
3. Surface Finish Values for Tongue and Groove Small 113
Male/Female and Ring Joint Facings
4. Chemical Resistance: Selected Elastomers and 114
Plastics
Appendix 2 - Dimensional Data 117
1. ANSI B16.5 Basic Flange Dimensions 118
2. ANSI B16.5 Flange Bolt Hole and Studbolt Dimensions 126
3. Ring Joint Facing and RTJ Gasket Dimensions 133
4. Spades for Raised Face Flanges to Suit ANSI B16.5 140
5. Spades for Ring Type Joint Flanges to Suit ANSI 147
B16.5
6. Normal Wall Thickness for Pipe Schedule Sizes 154
7. Butt Welding Elbows and Return Bends to 156
ANSI B16.9 and ANSI B16.28
8. Butt Welding Reducers, Tees, Lap Joint Stub Ends 157
and Caps to ANSI B16.9
9. Welded and Seamless Pipe, BS 1600 158
10. Table of Gauges 159
11. Decimal Equivalents of Fractions 160
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