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Pressure Vessel Rerating (Re-certification) - Coggle Diagram
Pressure Vessel Rerating (Re-certification)
Definition and Purpose
Changing
MAWP (Maximum Allowable Working Pressure)
Changing
MAWT (Maximum Allowable Working Temperature)
Revising
corrosion allowances
Optimizing process flow
Facilitating operational improvements
(debottlenecking, throughput)
Addressing changes in service requirements
Establishing lower parameters due to
damage or corrosion
Extending the useful life
of older vessels
Types of Rerating Operations
Pressure Modifications
Uprating:
Increasing MAWP
Derating:
Decreasing MAWP
Temperature Adjustments
Increasing MAWT
Decreasing MAWT
Corrosion Allowance Revisions
Reestablishing corrosion allowances
Leveraging code changes
Calculating remaining life
Regulatory Framework and Code Requirements
Governing Codes and Standards
NBIC Part 3:
Guidance for alterations (including rerates)
ASME Section VIII:
Design requirements and formulas
API 510:
Inspection, repair, alteration, rerating (petroleum/chemical)
Jurisdictional Requirements
State-specific regulations
Local authority approvals
Potential prohibitions (e.g., changing safety factors)
Certification Requirements
ASME certificate for physical alterations
"R" stamp
from the National Board
Stamping responsibility (even without physical changes)
The Rerating Process
Initial Assessment and Feasibility Study
Review of vessel documentation
Evaluation of current condition (inspection, NDE)
Assessment of service history
Technical and code compliance determination
Request and Approval Procedures
Formal request by owner/user
Details of original and proposed parameters
Supporting documentation (calculations, reports)
Approval from regulatory authority
Implementation and Verification
Physical changes by certified organizations
Engineering analysis for no physical changes
Inspections for new conditions
Application of new
stamping or nameplate
Documentation and Engineering Analysis
Required Documentation Package
Original Manufacturer's Data Report
Vessel fabrication drawings
Previous repair/alteration records
Current inspection reports
Engineering calculations
Safety relieving device descriptions
Engineering Analysis and Calculations
Performed by qualified engineers using code formulas
Consideration of all applicable loading
Potential use of specialized software
Assessment of current condition (wall thickness)
Possible Fitness-for-Service assessment (API 579)
Calculation of inspection intervals and remaining life
Stamping and Nameplate Requirements
Stamping Location and Content
Adjacent to original stamping
Minimum character height
Use of specific die stamps or nameplate
Nameplate Information for Rerates (no physical changes)
"
RERATED BY
" and Certificate Holder name
New
MAWP
and temperature values
Date of rerating
National Board "
R
" symbol
Application Responsibility
"
R
" Certificate Holder for design (no physical changes)
"
R
" Certificate Holder for construction (physical changes)
With Inspector knowledge and authorization
Roles and Responsibilities
Owner/User Responsibilities
Initiating the rerating request
Providing necessary documentation
Ensuring jurisdictional compliance
Providing information on new safety devices
"R" Certificate Holder Responsibilities
Performing engineering calculations
Applying stamping or nameplate
Ensuring code compliance
Maintaining documentation
Inspector Role
Reviewing and approving analysis and documentation
Authorizing stamping
Verifying compliance
Documenting the inspection
Special Considerations and Limitations
Code Edition Limitations
Restrictions on older vessels
Rules for using newer code allowable stresses
Conditions for leveraging design margin changes
Material Condition Assessment
Potential need for metallurgical report
UT verification of remaining thickness
Consideration of various damage mechanisms
Jurisdictional Variations
Different requirements for rerates
State-specific constraints
Procedures for non-ASME vessels
Impact of MAWP Changes
Safety and Operational Limits
Pressure Capacity (related to wall thickness, material strength, radius)
Relationship with Design Pressure
Structural and Material Considerations
Impact of Corrosion and Wear
Component Compatibility (nozzles, flanges)
System-Wide Implications
Pressure Relief Device Settings
Process Integration with other components
Engineering and Compliance Costs
Recertification Procedures
Code Compliance Requirements
Long-Term Performance Tradeoffs
Increased MAWP (potential for higher throughput vs. accelerated fatigue)
Decreased MAWP (risk mitigation vs. operational limitations)