Life Cycle Management of Buried Piping
| The Problem: Although buried piping is subject to significant degradation from various corrosion mechanisms (both externally and internally – see Table below), and has a history of chronic maintenance problems, little attention is paid to it’s inspection and maintenance at most plants. Several critical piping systems contain sections of buried piping, whose failure can adversely impact plant operations. As piping ages, coatings deteriorate, exposed pipe corrodes, and other deterioration mechanisms come into play, which will eventually lead to leaks or possible rupture. Being able to 1) assess the condition of your buried piping, 2) Manage and mitigate its deterioration, and 3) Develop safe and cost effective asset management plans will help minimize unexpected outages and minimize long term costs. |
click on image for larger view
|
Threats to the Structural Integrity of Buried Piping
Time Dependent |
Time Independent |
Stable |
External Corrosion
- General corrosion
- Localized corrosion –pitting, crevice, and intergranular attack
- Microbiologically Influenced corrosion
- Galvanic corrosion
- Environmentally Assisted Cracking, SCC, and corrosion fatigue
- Stray current
|
Mechanical Damage
- 1st, 2nd, or 3rd party
- Installation
- Previously damaged
|
Manufacturing Related
- Defective Pipe Seam
- Defective Pipe
- Wrinkle bend or buckle
- Stripped threads/coupling failure
|
Internal Corrosion
- General corrosion
- Localized corrosion –pitting, crevice, and intergranular attack
- Dealloying
- Microbiologically Influenced corrosion
- Galvanic corrosion
- Environmentally Assisted Cracking, SCC, and corrosion fatigue
|
Incorrect Operations
- Operator error
- Incorrect operating procedure
- Over pressurization
|
Welding Fabrication Related
- Defective pipe girth weld
- Defective long seam weld
|
Fatigue
- Pressure cycling
- Thermal cycling
|
Outside Force
- Earth movements
- Heavy rain, floods
|
Equipment
- Gasket O-ring
- Control/relief equipment malfunctions
- Seal/pump packing failure
- Miscellaneous
|
| Heavy fouling/clogging |
|
|
|
The Solution: SI can generate a site-specific Life Cycle Management (LCM) program for all of the buried piping systems at your plant.
SI’s Buried Pipe LCM Program not only follows the recommendations of the March 2002 EPRI Report, “Life Cycle Management Planning Sourcebooks Volume 2: Buried Large-Diameter Piping,” it expands upon the original premise. SI’s Buried Pipe LCM Program combines the expertise of the pipeline industry with advanced statistical probability distribution tools that predict when mitigation will be necessary. We will then identify the lowest cost alternative and the most cost effective time to initiate action, with our Award Winning Financial Risk Optimization software.
SI uses a 5 Step process to determine the optimal Buried Piping LCM Solution shown in the following Flowchart and described below:
- Collect and review relevant piping, construction, maintenance history, and environmental data.
- Create a comparison between the plant’s piping program and performance, and the industry standards.
- Create a Base Case from the plant’s existing buried piping program, and use SI-developed Statistical Failure Prediction software, to predict the piping’s lifespan without changes to the existent program.
- Generate Alternative Plans to increase the effective lifespan of the plant’s buried piping.
- Use the Statistical Failure Prediction software in concert with SI’s FRO tool to determine the lowest cost alternative and the optimal time to implement the proposed solution.
|
Statistical Failure Prediction Tools
Financial Risk Optimization Analysis
click on image for larger view
|
For more information on SI’s Life Cycle Management of Buried Piping Program, please contact SI.
|
