03. general considerations

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TECHNOLOGYTECHNOLOGY

General ConsiderationsGeneral Considerations

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of Oil and Gas Pipeline Systemof Oil and Gas Pipeline System

Understanding these factors is helpful to permit the designer and/oruser to:

1. Determine the ability of specific material to resist attackDetermine the ability of specific material to resist attack

2. Desi n the s stem to revent attackDesi n the s stem to revent attack

3. Design the system to reduce the rate of attack to anDesign the system to reduce the rate of attack to anacceptableacceptable level when it is not possible to eliminate attacklevel when it is not possible to eliminate attack

, ,Stress Corrosion Cracking , Intergranular Corrosion etc.

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Operating PressuresOperating Pressuresandand Operating TemperaturesOperating Temperatures

owa e opera ng pressures an empera ures o seam ess or we e

corrosion-resistant metallic piping system are calculated by the followingformula :

2ytD

2SETP

o

=

where :

= n erna es gn ressure, ps gS = Applicable allowable stress, psiDo = Outside Diameter (inches) .

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T = tm C = Design thicknessDesign thickness in inchestm = minimum require t ic nessminimum require t ic ness, satis ying requirements or

pressures, and mechanical, corrosion and erosionallowances.

, , .Y = a coefficient having values as follows :

0.4 up to, and including, 1050

F;0.5 for 1100F0.7 for 1150F and above.

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Jointin Techni ueJointin Techni ue

Metallic piping system can be joined by welding, expanding,welding, expanding,threading, or flangingthreading, or flanging.

Certain of the systems have other techniques which are peculiar to theindividual system.

e a erna ve means ava a e, we ngwe ng an expan ng are usua ythe preferred methods for several reasons.

ne o e ma or reasons or e se ec on o one o ese me o s seconomics.economics.

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Metallic Piping SystemMetallic Piping System

Commercial Carbon Steel Piping Systems

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Carbon and Low Alloy SteelsCarbon and Low Alloy SteelsLow Carbon Steels (mild steels)Low Carbon Steels (mild steels)

Corrosion resistanceHigh temperatures

Hi h stresses

Low temperatures

High Carbon SteelsHigh Carbon Steels

Low Carbon Low Alloy SteelsLow Carbon Low Alloy Steels

Mechanical properties

orros on res s anceOxidation resistance

Low temperature ductility

High Carbon Low Alloy SteelsHigh Carbon Low Alloy Steels

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Stainless Steel Piping SystemsStainless Steel Piping Systems

Type 304 304ELC 304L

Type 316 316ELC 316L

Type 347

.

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P pe ne Integr ty ManagementP pe ne Integr ty ManagementSystemSystem

Risk Assessment and Risk Base Analysis

Ten Steps to Effective Pipeline Management

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BlankBlank

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General ConsiderationsGeneral Considerations

as c ques onsas c ques ons : What material shall I use? How shall I join it?

a par s are ava a e as s an ar ca a og ems

How do the materials compare in cost?

Does the material being handles in the pipe have hazardous

properties? (toxic, combustible, explosive)

Operating pressure

Operating temperature

Is heat tracing required?

What are the temperature cycling conditions?

Installation location 3-11


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Advantages:Advantages:

Withstand high and low operating temperatures Can withstand full vacuum over a wide temperature range

Greater tolerance for steam tracin

Readily steam jacketed

Valves are generally supported by the piping system

Less thermal expansion

Does not require protection from sunlight, oxygen or ultraviolet

Easy to static ground

sa vantages:sa vantages:

Atmospheric corrosion may be a problem

Potential for galvanic corrosion exists

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Pipeline SystemPipeline System

Understanding these factors is helpful to permit the designerand/or user to:

Design the system to prevent attack

Design the system to reduce the rate of attack to an acceptable levelwhen it is not possible to eliminate attack completely.

The action and problem to be handled are:

Passivation

a van c corros on Stress corrosion cracking

Intergranular corrosion

.

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Operating Pressures and OperatingOperating Pressures and Operating

TemperaturesTemperatures

Allowable operating pressures and temperatures of seamless or-

the following formula :

ytD

SETP

2

2

=

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03. general considerations

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