GB/T 42595-2023
Basic requirements for repair of pressure equipment (English Version)
- Standard No.
- GB/T 42595-2023
- Language
- Chinese, Available in English version
- Release Date
- 2023
- Published By
- General Administration of Quality Supervision, Inspection and Quarantine of the People‘s Republic of China
- Latest
- GB/T 42595-2023
- Scope
- This document specifies the classification, basic requirements and workflow for the repair of in-service pressure equipment such as boilers, pressure vessels and pressure pipes. This document is applicable to the repair of pressure equipment in the special equipment catalogue, and can be used as a reference for the repair of pressure equipment outside the special equipment catalogue.
- Introduction
Interpretation of the core content of the standard
Definition of key terms
Pressure equipment repair refers to various repair activities carried out to restore the safety functions of equipment such as boilers, pressure vessels and pressure pipelines that have safety hazards, technical degradation or failures.
- Temporary repair: Transitional measures to maintain short-term safe use
- Permanent repair: Repair that completely restores the original performance of the equipment
Repair method Technical features Typical application Welding repair Packing/surfacing/Replacement of pipe sections Repair of defects in pressure vessel body Mechanical repair Thread repair/mechanical clamp Repair of pipe connection parts Non-metallic repair Composite material repair Pipeline lining repair Repair classification management system
The standard innovatively established a three-level classification system:
- Class A repair: Major repair requiring supervisory inspection (as defined by TSG regulations)
- Class B repair: Major repair not requiring supervisory inspection
- Class C repair: Routine maintenance repair
Typical case: Repair of pressure vessel in a chemical plant
A company discovered cracks in the shell of a hydrogenation reactor and it was confirmed to be a Class A repair after evaluation. According to the standard requirements:
- The original design unit shall review the repair plan
- Handle the notification procedures for special equipment
- Accept supervision and inspection during the implementation process
- Finally obtain the "Supervision and Inspection Certificate"
Key points of quality control in the whole process
Six-stage work flow
- Preparation: Qualification review/notification processing
- Data collection: Design/inspection/operation data
- Defect analysis: Cause diagnosis/repairability assessment
- Scheme formulation: Contains 11 necessary elements
- Construction implementation: Execute according to the approved plan
- Acceptance archiving: Files are saved until the equipment is scrapped
Responsible entity Core responsibilities Document requirements User Qualification confirmation/process supervision Keep the repair plan for 15 years Repair unit Plan preparation/quality control Submit complete construction records Inspection agency Grade A supervision inspection Issue supervision inspection certificate HSE risk control system
The standard innovatively introduces the HSE double prevention mechanism:
Environmental Factor Identification (Appendix A)
- Waste gas/wastewater emission control
- Energy resource consumption monitoring
- Hazardous chemical management
Job Hazard Analysis (Appendix B)
- 164-item risk identification checklist
- Confined space operation control
- Special work permit management
Typical control measures: Welding operations must be equipped with ventilation equipment, confined space gas detection must be conducted once every 2 hours, and double life ropes must be set up for high-altitude operations.
Comparative Analysis of Technological Development
Technical Dimension Traditional Practice Requirements of this Standard Defect Assessment Empirical Judgment Based on GB/T30579 Damage Pattern Recognition Repair Verification Conventional Inspection Advanced Nondestructive Testing such as TOFD (NB/T47013) Life Assessment Simple Verification Risk Inspection Based on GB/T26610 Implementation Suggestions
- Establish a repair case library: accumulate typical defect treatment solutions
- Carry out special training: focus on training Appendix B risk control measures
- Improve the document system: standardize file management according to Chapter 7 of the standard
- Apply digital tools: develop a repair process management system
Note: For irreversible damage such as hydrogen embrittlement and intergranular corrosion, the standard clearly prohibits repair and should be directly scrapped and updated.
GB/T 42595-2023 history
- 2023 GB/T 42595-2023 Basic requirements for repair of pressure equipment