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Case Study: A Successful Start: Qualitative Risk-Based Inspection of a Greenfield Project

Posted On:November 9, 2015 Updated On:September 26, 2023
Case Studies

Learn how we helped a greenfield petrochemical complex successfully establish a proper integrity program prior to startup.

The Challenge

Greenfield projects, which are undeveloped construction sites, are often designed and built without operations, maintenance, or integrity in mind. However, a petrochemical complex located in Al Jubail, Saudi Arabia, had three goals when it came to its new site:

  1. It required that a proper integrity program be set up prior to the facility’s startup.
  2. Site management needed to ensure that its piping and equipment were in compliance with the Occupational Safety and Health Administration’s (OSHA) Process Safety Management (PSM) standards.
  3. The facility wanted to utilize a strategic, risk-based approach to planning inspections, while mitigating the need to manage a highly intensive quantitative risk model.

Pinnacle's Solution

With these challenges in mind, the operator requested that Pinnacle build a qualitative Risk-Based Inspection (RBI) program for ongoing management. In response, Pinnacle recommended the following strategies for the greenfield project:

  • Streamline the use of documentation and data required to build the integrity program by working with the engineering, procurement and construction (EPC) company to leverage already existing documents.
  • Build a qualitative risk-based methodology that employs Recognized and Generally Accepted Good Engineering Practices (RAGAGEP) and best-in-class risk assessment applications. Pinnacle also advised setting up accounts for all Process Safety Management (PSM) regulated assets, which minimizes the need for overly-intensive data management that is typical in quantitative risk models.
  • Work with the facility remotely to perform baseline Condition Monitoring Location (CML) assignment inspections for the PSM assets.

After presenting its objectives and goals to the operator, Pinnacle implemented the following:

Phase 1 (Unit Systemization):

Pinnacle first built an asset and piping classification structure by systemizing and circuitizing the units’ piping and fixed equipment. This methodology was customized for the project, but it laid the foundation for flagging each asset as PSM or non-PSM, and also prepared for the risk-based assessment.

Phase Two (Consequence of Failure Assessment):

Once the classification effort was completed, Pinnacle customized a consequence of failure assessment that accounted for the flammability of the service; the toxicity and environmental effects of release; and financial implications for operations upon release. Each of these were defined by using RAGAGEP, and a conservative approach was taken to set triggers that assigned each asset into buckets based on these categories.

Phase Three (Corrosion/Damage Assessment):

To assess the probability of failure for the risk calculation, Pinnacle performed a damage/corrosion analysis on each of the PSM regulated assets, including an assignment of potential damage mechanisms and their projected rates and/or susceptibilities. This analysis accounted for all the design basis for the unit and utilized the process breakdown, contaminant levels, operating conditions, metallurgy, startup/shutdown procedures, the presence of insulation, and whether the asset had been Post Weld Heat Treated, to develop the model.

Phase Four (Development of RBI Plans):

Based on Pinnacle’s customized, qualitative approach to risk assessment for this project, a probability of failure and consequence of failure rating were assigned to each asset and an overall risk level was calculated. This risk level was then coupled with the pertinent damage mechanism(s), as determined by the corrosion/damage assessment, to develop an inspection plan for each asset, including an inspection method, the extent of method application and an inspection interval.

Phase Five (Development of Inspection Drawings):

To alleviate field sketching and streamline the work process, Pinnacle utilized the construction isometrics generated by the EPC company to develop piping inspection drawings for the PSM piping, per the already determined piping circuits. Using the corrosion model and risk calculations, Pinnacle then made recommendations on how many CMLs should be assigned to each asset. The facility personnel were then tasked with assigning the CMLs in the field based on accessibility and also performing baseline inspections. These drawings were sent back to Pinnacle, where the assigned CMLs were updated on the CAD drawings.

Results

As a result of Pinnacle’s program implementation, a total of 1,598 fixed equipment and associated piping, which is roughly 80 percent of the assets at the facility, were listed as having high consequence, mostly due to high flammability and financial implications upon loss of containment. The consequence distribution is as follows:

Consequence Level

% Distribution

Low3%
Medium16%
High81%

In addition, the damage mechanisms that were recognized throughout the facility through the damage/corrosion study are provided:

 

Environmentally Assisted Cracking

  • CL-SCC (External Chloride Stress Corrosion Cracking)
  • Caustic Stress Corrosion Cracking
  • CUI CL-SCC (CUI Chloride Stress Corrosion Cracking)
  • Wet H2S Damage (HIC/SOHIC)

External Loss of Thickness

  • Atmospheric External Corrosion
  • Corrosion Under Insulation (CUI)

Internal Loss of Thickness

  • Boiler Water Condensate Corrosion
  • Caustic Corrosion
  • Cooling Water Corrosion
  • High Temp H2/H2S Corrosion
  • Sour Water (Acidic) Corrosion
  • Sulfuric Acid Corrosion

Internal Loss of Thickness

  • Creep/Stress Rupture
  • Living Failure
  • Mechanical Fatigue
  • Refractory Degradation
  • Thermal Fatigue

Based on the consequence evaluation and damage projections, the following risk profiles were produced as a percentage of the overall assets falling in each damage type (mechanical and metallurgical failure not included):

 

Internal Thinning

Cracking

External Thinning

High.03%21.0%0.0%
Medium High3.7%24.2%53.8%
Medium78.4%50.8%37.9%
Medium Low16.1%4.0%7.9%
Low1.6%0.0%0.3%

These results were then used to drive strategic inspection plans, per the damage mechanisms and risk category, producing specific inspection methodologies and intervals. In the end, this facility received a foundational integrity program for its fixed equipment and piping, including a qualitative risk-based approach to managing its inspections. The results include:

Reduced Risk of Loss of Containment Events:

From startup, this facility is now performing targeted inspections to mitigate the probability of specific loss of containment events. This translates to finding damage areas before it leads to an event, and being able to plan repairs, replacements, and necessary design changes proactively, rather than reactively.

Optimized Inspection Costs:

Due to the facility’s risk-driven inspection program, site management can be confident that it is directing its inspection budget to the right assets and activities.

Regulation Compliance:

This facility wanted to ensure it was inspecting its assets in accordance with OSHA’s PSM guidelines. Per the systematic approach, the facility can be confident that is accounting for assets, classifying them, and assessing the assets’ risk, which ultimately leads to compliance.

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