Preface ...................................................... xiii
1 An Introduction to In-plant Piping and Pipeline
Fitness-for-Service ...................................... 1
Introduction .................................................... 1
What Is Piping? ................................................. 8
Areas Where Corrosion Attacks Piping ............................ 9
The Maximum Acceptable Operating Pressure (MAOP) ................ 9
Assessment Procedure ........................................... 14
Classification of Corroded Regions ............................. 15
External Versus Internal Corrosion ........................... 15
Localized Versus General Corrosion ........................... 15
Interaction of Closely Spaced Areas of Corrosion ............. 16
Circumferential Extent of Damage ............................. 17
Welds, Elbows, and Branch Connections ........................ 17
Corroded Pit Region Interaction Parameters ..................... 18
Methodology .................................................... 19
Determining the Allowable Length of Corrosion .................. 26
Corrosion Allowance ............................................ 27
Assessing Type 3 Flaws ......................................... 28
Burst Test Validation .......................................... 30
Circumferential Corrosion ...................................... 31
Criteria for Circumferential Metal Loss ...................... 31
Methodology of Circumferential Metal Loss .................... 33
Corrosion in Pipe Bends ........................................ 35
Branch Connections and Fittings ................................ 37
Determining a Maximum Allowable Operating Pressure ............. 37
Flaws in Heat Affected Zones of Welds .......................... 38
Example 1-1 .................................................... 39
Example 1-2 .................................................... 43
Checking for the Circumferential Direction Criteria ............ 46
Example 1-3 .................................................... 47
2 An Introduction to Engineering Mechanics of
Piping ..................................................... 50
Piping Criteria ................................................ 51
Stress Categories .............................................. 53
Allowable Stress Range for Secondary Stresses .................. 53
Stresses Acting on Piping Elements ............................. 58
Stress Calculations ............................................ 61
ASME B31.1 Code Stress ....................................... 63
ASME B31.3 Code Stress ....................................... 63
The Pipeline Codes-ASME B31.4 and B31.8 ........................ 65
ASME B31A-Liquid Transportation Pipelines Code ............... 65
ASME B31.8-Gas Transmission and Distribution Pipeline Code ... 66
Flexibility and Stiffness of Piping ............................ 68
Stiffness and Large Piping ..................................... 77
Flexibility Method of Piping Mechanics ......................... 78
Pipe Offsets and Loops ....................................... 79
Pipe Restraints and Anchors .................................. 87
Criteria for Flexibility Analysis .............................. 90
Example Using the Empirical Flexibility Criterion .............. 91
Suggested Criteria for Level of Piping Flexibility Analysis .... 96
Closure ........................................................ 98
3 Fitness-for-Service Topics of Local Thin Areas,
Plain Dents, Dents-Gouges, and Cracks for
Piping .................................................... 100
Useful RSF Equations Using API 579 ............................ 105
Assessment Techniques and Acceptance Criteria ................. 110
Remaining Life Assessment ..................................... 110
Remediation ................................................... 111
In-Service Monitoring ......................................... 111
Documentation ................................................. 111
Damage Mechanisms ............................................. 112
Blisters and Laminations ...................................... 115
Assessment of Local Thin Areas ................................ 116
General Metal Loss Assessment ................................. 117
Individual Point Readings ................................... 121
Thickness Profiles .......................................... 121
Structural Discontinuities .................................. 122
Level 1 Part 4 Acceptance Criteria .......................... 126
Level 2 Assessments ......................................... 127
Level 2 Part 4 Acceptance Criteria .......................... 128
Local Metal Loss Assessment ................................... 129
Determining the LTA Boundary ................................ 132
Level 1 Part 5 Acceptance Criteria .......................... 133
Level 2 Part 5 Acceptance Criteria .......................... 138
Assessing Supplemental Loads ................................ 141
Level 3 Assessments ......................................... 147
Elastic-Plastic Analysis of LTAs ............................ 148
Common Mistakes Made in Level 3 Assessments ................. 152
Performing the Remaining Life Assessment ...................... 154
The MAWP Approach ........................................... 154
The Thickness Approach ...................................... 155
Material Property Data ........................................ 157
Material Property Data Required for Assessment .............. 157
Crack-like Flaws .............................................. 169
Remediation of Crack Defects ................................ 177
Grooves, Plain Dents, and Dents with Gouges ................... 179
Plain Dents ................................................... 179
Dents and Gouge Combination Type Flaws ........................ 181
Example 3-1: API 579 Example 5.11.1 Revisited ................. 184
Example 3-2: Dents and Gouge Combination Example .............. 186
Example 3-3: Testing for General Metal Loss ................... 189
Example 3-4: Surface Crack-Like Flaw in a Pipe ................ 190
4 Fitness-for-Service for Brittle Fracture
Concerns ................................................. 201
Introduction .................................................. 201
Brittle Fracture Concepts ..................................... 203
Defect ...................................................... 203
Stress ...................................................... 204
Toughness ................................................... 205
Definitions ................................................... 208
Safe Operation at Low Temperatures Existing Equipment ......... 209
Safe Operating Envelopes .................................... 209
Example 4-1: Determining the Basic MAT and Constructing the
MAT Curve ................................................... 213
Determining the MAT Using Fracture Mechanics .................. 217
Variations to MAT ............................................. 218
Considering the Maximum Allowable Working Pressure .......... 218
Material That Is Already Impact Tested ...................... 218
Pressure Reduction .......................................... 219
Charpy Exemption Pitfalls-Words of Caution .................... 219
Welding ....................................................... 220
Considerations for Design Codes Other Than ASME ............... 220
Selecting Materials and Defining Impact Requirements - New
Piping and Components ....................................... 221
Use Good Quality Steel in the Base Case ..................... 222
Impact Test Temperature ..................................... 222
Determining the CET ......................................... 223
Shock Chilling .............................................. 227
Hydrosatic Test Temperature Minus 10.8°F (6°C) for a 2 in.
or Thinner Pipe ........................................... 227
Managing Potential CET Violations ............................. 228
Cases of Brittle Fracture ..................................... 228
Transient Thermal Stresses .................................... 229
Example 4-2: Thermal Transients in a Pressure Relief Piping
System ...................................................... 232
5 Piping Support Systems for Process Plants ........ 237
Spring Supports ............................................... 237
Variable Springs ............................................ 238
Constant Springs ............................................ 243
Piping Nozzle Loads on Rotating Equipment ..................... 253
Pump Nozzle Loads ........................................... 253
Piping Layout Schemes for Rotating Equipment ................ 256
Compressor Nozzle Loads ..................................... 261
Nozzle Stiffness and Elastic End Conditions ................... 265
Piping Systems Without Springs ................................ 269
Fluid Forces Acting on Piping Systems ......................... 274
Nozzle Movements and Thermal Displacement ..................... 279
Example 5.1: Thermal Movements in a Vessel Skirt .............. 290
Example 5-2: Residual Temperatures in a Branch Pipe ........... 297
Residual Heat Transfer Through Pipe Shoes ..................... 302
Example 5-3: Heat Transfer Through a Pipe Shoe ................ 304
Example 5-4: Emergency Constant Spring Replacement ............ 305
Example 5-5: Pipe Header Simple Support ....................... 310
6 Piping Maintenance and Repairs ...................... 323
Leaking Pipe Flanges and Hot Bolting .......................... 323
Leak Sealing by Banding Flange or Wire Seal Peripheral Seal
Repair ...................................................... 324
Bolted Pipe Clamps ............................................ 324
Flange Insert Clamps (Insert Ring or Tongue Clamps) ........... 329
Simple Pipe Clamps with Single Plane Lug Plates ............. 331
Clamp Bolts ................................................. 334
Two Planar Clamps ........................................... 336
Elbow Clamps ................................................ 340
Mitered Elbow Clamps ........................................ 343
Clamps with Thrust Loads ...................................... 345
Shear Pins and Serrated Teeth Connections ................... 345
Sealants ...................................................... 348
Sealant Material Considerations ............................. 349
Re-injection of Leak Seal Repairs ........................... 352
Clamp Example 1 ............................................... 352
Clamp Example 2 ............................................... 354
Clamp Example 3 ............................................... 360
Repairs Involving Hot Work .................................... 363
Lap Patches ................................................. 363
Example of a Lap Patch ...................................... 365
Welding Caps ................................................ 366
Welded-on Nozzle ............................................ 367
Full Encirclement Sleeves ................................... 368
Full Encirclement Welded Sleeve Without End Plates .......... 369
Full Encirclement Repair with End Plates on Straight Pipe
Section ................................................... 372
Full Encirclement Repair with End Plates at an Elbow ........ 373
Full Encirclement Repair with End Plates at a Branch
Connection ................................................ 374
Required End Plate Thickness Without Pressure Thrust Load ... 375
Required End Plate Thickness Considering Pressure Thrust
Load ...................................................... 376
Thermal Stress Criteria in Welded Enclosure Designs ......... 378
Welded Full Encirclement Sleeve on Straight Section of
Pipe with End Plates ...................................... 383
Welded Partial Leak Containment Box ......................... 390
Equipment Isolation Repairs—Stoppling ......................... 393
Equipment Isolation Repairs by Freeze Sealing ................. 396
Safety Considerations of Freeze Sealing ..................... 398
Failure Experiences with Freeze Sealing ..................... 399
Closure—Threaded Connections .................................. 399
Example of a Bolt-up Problem in a Plant ....................... 400
Example of Clamp Design Using Shear Pins for Thrust Forces .... 402
7 Hot Tapping (Pressure Tapping) and Freezing ...... 414
The Hot Tap Process ........................................... 416
Assessing the Feasibility of Hot Tapping ...................... 419
Special Considerations for Welded-on (Hot Work) Hot Taps ...... 420
Hot Tap Design Considerations ................................. 422
Wall Thickness of Header Pipe ................................. 424
LMT Approach for Process Piping ............................. 424
Maximum Allowable Pressure for Pipelines .................... 426
Example: Calculating the Maximum Allowable Pressure for Hot
Tapping ................................................... 427
Test Pressure and Temperature ................................. 427
Summary Procedures .......................................... 433
The Hot Tap Package ........................................... 439
Freeze Sealing ................................................ 440
Example 7-1: Area Replacement Calculation for a Hot Tap ....... 442
8 Pipeline Fitness-f or-Service, Repair, and
Maintenance-Selected Topics .......................... 449
Useful RSF Equations Using API 579 Methodologies .............. 449
API 579 Criteria Modified to Pipelines ........................ 456
Example: Pipeline LTA Assessment ............................ 456
Limitations of RSTRENG ...................................... 469
Another Actual Field Example ................................ 470
Grooves, Plain Dents, and Dents with Gouges and Crack-like
Defects ..................................................... 472
Pipeline Protection ........................................... 472
Cathodic Protection ......................................... 472
Pigging Technology .......................................... 473
Launching and Retrieving Pigs ............................... 477
Repair Options for Pipelines .................................. 483
Metal Sleeves ............................................... 483
Composite or Nonmetallic Sleeves ............................ 486
Other Types of Repairs ...................................... 486
Grit Blasting of Operating Pipelines ........................ 487
Typical Example of Grit Blast (Abrasive Blast) of an
Operating Pipeline ........................................ 487
Hydrogen Attack ............................................... 492
Soil-Structure Interaction Abnormality of Pipe Bowing ......... 492
Tie-in Temperatures ......................................... 496
Thermal Expansion of Buried Pipelines ......................... 496
Soil Resistance Equations ................................. 497
Forces and Stresses Induced in Buried Pipe .................... 500
Allowable Stress for Buried Pipelines ..................... 501
Finding the Location of the Virtual Anchor ................ 501
Example Problem of Buried Pipe .............................. 502
Restraining Bowing of Pipelines ............................... 502
Example of Pipeline Bowing .................................. 505
Permissible Bending of Pipelines ............................ 505
Appendix A Properties of Pipe ................................ 509
Appendix В Weights of Pipe Materials ......................... 516
Appendix С Formulas for Pipe, Internal Huid, and Insulation
Weights ........................................... 543
Index ......................................................... 551
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