1. Documentation and Records
Each workshop or unit instrument maintenance team shall establish and maintain the following technical documents and records:
1.1 Instrument equipment master list and digital archive.
1.2 Instrument summary list for each process unit.
1.3 Instrument maintenance and overhaul operating procedures.
1.4 Technical manuals and operation instructions for all installed instruments.
1.5 Maintenance, calibration sheets and calibration records for instruments and accessories.
1.6 Data sheets for throttling elements and control valve sizing calculations.
1.7 Valid certificates for standard calibration instruments.
1.8 Complete instrumentation control system drawings, including:
Equipment list
Instrument installation drawings
Loop diagrams
Wiring diagrams
Interlock logic diagrams
Interlock function charts
P&IDs with control points
Design, installation and handover documents
1.9 A/B class interlock, DCS, UPS, PLC and Industrial PC inventory list.
1.10 Shift handover logs and inspection patrol records.
1.11 Static sealing point register for each unit.
1.12 Monthly and quarterly instrument technical condition reports.
2. Instrument Renewal and Disposal
Requests for renewal or scrapping of instruments must be submitted by the maintenance team, reviewed by the Equipment Department, and approved by relevant company authority.
3. Addition or Removal of Instruments
Any addition, removal, or modification of instrument loops must be applied for by the user unit and approved by the Production and Equipment Department before execution.
4. Fixed Assets
Instrument equipment classified as fixed assets shall be managed according to the company’s fixed asset management system.
5. Instrument Transfer
Transfer of instrument equipment must be approved by the Production and Equipment Department. Transfer of DCS/PLC/ESD spare parts must additionally be filed for record.
6. Reporting Requirements
Each maintenance team shall submit quarterly automation status reports, including:
a) Instrument equipment availability performance indicators.
b) Analysis report of any unit shutdowns caused by instrument failures.
c) Interlock activation/deactivation status report.
7. Annual Summary
An annual inventory and operational performance summary of automation instruments shall be completed at year-end.
8. Major Failures
Major instrument faults affecting key unit operation shall be addressed immediately and reported to the Production and Equipment Department and relevant management.
9. Classification of Instruments
Classification of A/B/C grade instruments shall be implemented according to the company’s metering and instrument classification standards.
10. Interlock System Management
Safety interlock system management shall comply with the company’s safety interlock system management regulations.
11. DCS System Management
DCS system operation and maintenance shall comply with the company’s DCS management procedures.
Instrument Maintenance and Overhaul Procedure
1. Maintenance Categories
Instrument maintenance is categorized into major overhaul, medium overhaul, and minor overhaul:
a) Major Overhaul:
Complete disassembly, cleaning, repair or replacement of major components; full performance testing according to factory inspection standards.
b) Medium Overhaul:
Partial disassembly, repair or replacement of key components; calibration of primary performance parameters.
c) Minor Overhaul:
Routine cleaning, adjustments, troubleshooting and minor repair.
2. Responsibilities
Major and medium overhauls are performed by the instrument maintenance unit; minor repairs are conducted by on-site maintenance personnel.
3. Preparation Work
Before shutdown maintenance, the following must be confirmed and prepared at least one month in advance:
Drawings
Spare parts and consumables
Materials and tools
Personnel allocation
Safety measures
4. Additional Work
Any additional overhaul work must be approved by the Production Operation Department before execution.
5. Acceptance
Critical overhaul items (e.g., interlock verification, DCS loop testing) shall be jointly inspected by the Equipment Department and related responsible personnel. General items may be accepted by the maintenance team.
6. Quality Assurance
Comprehensive quality management shall be implemented throughout the maintenance process, establishing and maintaining a quality assurance system.
7. Safety Requirements
All maintenance activities must follow safety regulations and HSE requirements to ensure safe and orderly operation.
8. Documentation
Inspection, calibration, functional testing, and pressure test records must be completed and archived.
9. Overhaul Summary
After completion of major overhaul, a summary report shall be prepared and submitted to relevant departments.
10. Procedure Compliance
All instrument overhaul work must strictly comply with the approved maintenance procedures.