Specialized Engineering Scope And Case Studies

Asset protection have always been a high priority and important aspect from customers. Fire and Gas System (FGS) have always been the crucial safeguard system and various procedures have been taken in place to handle flammable and toxic materials.

EXEN have a well versed experienced in Fire and Gas and services cover from feasibility and mapping study, identify the suitable detectors location, up to providing a working 2D and 3D model for detectors location with proven engineering calculations references.

Various risk-based approach software’s have been developed to accommodate this, and the evolution of software have been steadily changing. Our in-house engineers are capable to design and provide a 2D and 3D modeling which provides a key decision to define an accurate detectors placement, as well as to provide detail justification of distance and coverage.

Fire and Gas (F&G) Mapping Study and Design Experiences
  • Terengganu Crude OI Terminal (TCOT) and Onshore Slug Catcher (OSC) F&G Mapping and Implementation for Petronas Carigali Sdn Bhd
  • Peninsular Malaysia Operation (PMO) Wide F&G Mapping and Implementation for Petronas Carigali Sdn Bhd – Dulang Platform, Duyong Platform, Angsi Platform, Abu Cluster Platform
  • EPCC for FGS and Telecommunication Works for Interconnecting Facilities for RAPID Package 14, Pengerang
  • Bintulu Crude Oil Terminal (BCOT) FGS Enhancement Project for Petronas Carigali Sdn Bhd.

Nur Amnanie have more than 10 years experiences in Oil & Gas and Petrochemical industry. She has been involved in various Instrumentation and Fire and Gas development project and well versed on developing the 2D and 3D FGS mapping study with our in-house software

Fitness for Service (FFS) is quantitative engineering evaluation that are performed to demonstrate the structural integrity of an in-service component containing flaw or damage and to determine the fitness of the equipment for continued service.

It allows the user to make ‘Run-Repair-Replace’ decisions to ensure that the pressurized equipment containing flaws, which have been identified by the assessment, can continue to operate safely.

Assessment can be done for following flaw / damage mechanism:

  • Brittle Fracture
  • Corrosion / Erosion
  • Crack like Flaws
  • Fire Damage
  • Creep Damage
  • Mechanical Damage
Levels Of Assessment Technique And Acceptance Criteria
Level 1
  • Intended to provide conservative screening criteria that can be utilized with a minimum amount of inspection or component information
  • Produce most conservative results.
  • Can be performed by either plant inspection or engineering personnel
Level 2
  • More detailed evaluation that produce results that are more precise than level 1 assessment
  • Similar information with level 1 is required, but more detailed calculation is used in the evaluation
  • Typically conducted by plant engineers / engineering specialist
Level 3
  • Most detailed evaluation that produce more precise results than level 2 assessment
  • Typically used when criteria required for level 1 & 2 assessment do not meet
  • Require use of other numerical techniques such as finite element method.
  • Primarily intended for use by engineering specialist.

If the results of a fitness-for-service assessment indicate that the equipment is suitable for the current operating conditions, the equipment can continue to be operated at these conditions provided suitable monitoring/inspection programs are established. On the other hand, If the results of the assessment indicate that the equipment is not suitable for the current operating conditions, following options are provided to user:

  • To rerate the equipment based on calculation methods are provided
  • Suggestion for remediation based on the damage mechanism or flaw type
  • To advice method for in-service monitoring.



To assess and analyse strength of Coil B 48” Outlet header of steam superheater F-3301 (located inside S-Chem Plant, Jubail, KSA) to ensure it is safe and fit for continue operation.


Based on the inspection reports and site visit performed, the flaw and damage type were identified and the assessment method required is selected (general metal loss). Data regarding the component such as equipment design data, maintenance and operational history, expected future service and data specific to FFS assessment (flaw size, state of stress at the location of flaw, material properties) were obtained. 3D laser scanning was used in order to create 3D model (see Figure 1) of the component for use in analysis software (CAESAR II) and the model was verified using dimensional survey.

The component was first assessed for using level 1 method, which evaluate the component subjected to internal pressure. For the assessment, 15-point thickness readings were measured and coefficient of variation (COV) was calculated. Since COV calculated (1.833%) was less than 10%, therefore the average thickness found in the thickness readings can be used as average thickness of the component for analysis. Minimum required thickness based on current design data was then calculated. The average thickness readings can be used

Average Thickness 36.187 mm
Coefficient of Variance (COV) 1.833%
Minimum required thickness 23.495 mm
Calculated MAWP 0.4025 MPa
Component MAWP 0.206 MPa

to calculate MAWP of the component based on existing wall thickness.

Since the thickness measured is larger than minimum required thickness calculated, the equipment meets the acceptance criteria based on level 1 assessment method for general metal loss. For level 2 assessment, additional parameters were considered such as the Future Corrosion Allowance (FCA) and remaining strength factor (RSF) of the component. In addition, flexibility analysis assessment of the component is done using CAESAR II software, which include the modification of new supports system.

Figure 1: 3D model for 48” Outlet Header

From the point thickness reading, the remaining life, Rlife evaluation can be calculated based on worst case corrosion rate (0.1mm/year) and readings of current thickness using following equation:

From the calculation, it was determined that the remaining life of the component is 114 years.


Based on the results from the assessment, the equipment was found to be fit for continued service. Following recommendations were provided to ensure the component can continue to operate:

  1. Visual inspection and in-service monitoring need to be done monthly to make sure the component operate in normal condition
  2. System temperature need to be maintained below maximum design temperature (927 oC) to ensure the component doesn’t experience any creep damage
  3. Any significant changes in service condition (pressure, temperature, fluid content etc) shall be documented.

Ir Mursyidi have more than 15 years experiences and work as a principal and specialist for inspection in Oil & Gas and Petrochemical industry. He has been involved and well versed in API inspector and safety related works and actively being a certified API Trainer.

Hairi Hafiezie have more than 10 years experiences in Oil & Gas and Petrochemical industry. He is the focal person for fitness for service engineering in EXEN and have experiences as a rotating and reliability mechanical engineer.