Introduction
The Pipeline Toolbox is home to many tools and calculators. The PLTB User’s Guide presents information, guidelines, and procedures for use during design, construction, operations, and integrity tasks for field or office applications.
The Steel Pipeline Design & Stress Analysis module is intended to provide adequate analysis for public safety under all conditions encountered in the gas industry. Conditions that may cause additional stress in any part of a line or its appurtenances shall be provided for, using good engineering practice. Examples of such conditions include long self-supported spans, unstable ground, mechanical or sonic vibration, weight of special attachments, outside induced stresses, stresses caused by temperature differences, and the soil and temperature conditions.
Module/Applications
- Bending Stress and Deflection
- Bending Stress-Caused by Fluid Flowing Around Pipeline
- Buoyancy Analysis & Concrete Coating Requirements
- Buoyancy Analysis & Concrete Weights Spacing
- Design Pressure – Steel Pipe
- Flume Design – Rational Method
- Hoop and Longitudinal
- Internal Pressure % SMYS
- Linear Thermal Pipeline Expansion
- Maximum Allowable Pipe Span Length
- Maximum Impact Load & Penetration Depth
- Pipe Anchor Force Analysis
- Requirements to Move Unpressured Pipe
- Restrained Pipeline Stress Analysis
- Thrust at Blow-Off
- Unrestrained Pipeline Stress Analysis
- Wall Thickness – Steel Pipe
References
- ASME B31.8 – Gas Transmission and Distribution Piping Systems
- API 5L, API 5LS and API 5LX – Specification of Pipe Grade
- ASTM – Various – Weld Joint Factor
- CFR Code Part 192
- USDA-SCS Modified (Permissible Velocity of Water and Soil Erodibility)
- FHWA-HEC
- Pipeline Rules of Thumb Handbook
- Timoshenko, S – Theory of Elasticity Anchor Force
FAQ
-
Restrained versus Unrestrained Pipe (Difference in Gas vs. Liquid)?
ASME B31.4 liquid and B31.8 gas codes include calculations for the net longitudinal compressive stress that must be applied only for a restrained line that equates to a low (less than 2%) longitudinal strain. This stress status is characteristic to underground pipelines located some distance away from above ground piping facilities.
Unrestrained lines means those above ground sections of piping without axial restraint as with buried pipe with soil. In others words the soil exerts substantial axial restraint, but not fully restrained. Check Out
-
What is the Maximum Span Length of rev1?
Regarding span factors with and without water are based on bending stress and deflection. Larger diameter pipe spans require saddles for stability. Many standards that require pipes to be filled with water are based on bending and shear stresses not to exceed 1,500 psi and a deflection between supports not exceed 0.1 inches. Check Out
-
What is the model used for Thrust at Blow-Off?
Appendix of Definitions
- Actual Pipe Size
- The measurement is equal to the outside diameter of the pipe.
- Bend Radius
- The radius corresponding to the curvature of the bent specimen or bent area of a formed part, measured on the inside of a bend or on the centerline of the tube, as defined.
- Casing
- Pipe used as a structural retainer for the exterior walls of water, gas, oil well, or other application; also used as a structural interior retainer for another pipe commonly seen in oilfield applications.
- Coefficient of Thermal Expansion
- A physical property value representing the change in length per unit length, the change in area per unit area, or the change in volume per unit volume per one-degree increase in temperature.
- Diameter
- The distance between one edge of a circle and the other as measured on a straight line through the center of the circle.
- Electric Resistance Weld
- A method of manufacturing steel pipe in which a flat ribbon of steel is cold-formed by rolls; electrical current is then used to weld the edges together. This pipe can be normally produced in sizes from NPS 1/8 through NPS 26.
- Expanded Pipe
- Pipe which has been enlarged circumferentially by mechanical or hydraulic pressure.
- Fatigue
- The tendency for a metal to break under conditions of repeated cyclic stressing;
stresses that are considerably below the ultimate tensile strength.
- Fracture Stress
- The maximum principal true stress (fracture load divided by fracture area).
- Grade
- A class of steel defining amongst others, chemistry, tensile strength, and yield strength requirements.
- Hydrostatic Test
- A mill test that is normally required by specifications. The ends of the pipe are sealed, and high-pressure water is applied into the pipe at predetermined pressure for a specific period of time as required by the various specifications.
- Inside Diameter (ID)
- The distance of a straight line passing through the center of a pipe from one inside pipe wall to the opposite inside wall.
- Joint
- The point in a piping system at which a connection is made; joints connect pipe, fittings, and valves to form a system. Also, a single length of pipe can be called a joint.
- KIP
- Unit of weight equal to 1,000 pounds dead weight.
- KIS
- K equals I,000, thus the term is actually K (1,000) psi. The P has been dropped, and KSI is the new term. (i.e. 50 KSI = 50,000 psi).
- Modulus of Elasticity
- The slope of the elastic portion of the stress-strain curve in mechanical testing. The stress is divided by the unit elongation. The tensile or compressive elastic modulus is called Young’s modulus; the torsional elastic modulus is known as the shear modulus or modulus of rigidity.
- Outside Diameter
- The distance of a straight line passing through the center of the pipe from one outside rim of the pipe to its opposite outside rim.
- PSI
- Pounds per Square Inch.
- PSIG
- Pounds per Square Gauge.
- Radius
- The distance of a straight line from the center of the circle to its edge.
- Stress
- The load per unit of area. Ordinarily, stress-strain curves do not show the true stress
(load divided by area at that moment), but a fictitious value obtained by always using the original area.
- Tensile Strength
- The value obtained by dividing the maximum load observed during tensile straining until breakage occurs by the specimen cross-sectional area before straining. Also called ultimate strength.
- Yield Strength
- The stress at which a material exhibits a specified limiting deviation from proportionality of stress to strain. An offset of 0.2 percent is used for many metals such as steel, aluminum base, and magnesium base alloys, while a 0.5 percent total elongation under load is frequently used for copper alloys.