Regulations on the Management of Automated Interlock Protection in Refining and Chemical Enterprises

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Regulations on the Management of Automation Interlock Protection in Refining and Chemical Enterprises Article 1 These regulations are formulated to ensure the safe and stable operation of refining and chemical plants, to strengthen the management of automation interlock protection for plant equipment (hereinafter referred to as interlocks), and to enable the plants to operate under controlled conditions. Article 2 These provisions apply to the refining and chemical enterprises affiliated with joint-stock companies. Article 3: Regional branches must designate the competent department responsible for interlocking management at both the company and factory levels ； Responsible for organizing the technical and equipment management departments to review applications for interlock deactivation/reactivation as well as applications for interlock changes ； Responsible for supervising and inspecting the implementation process of interlock management regulations ； Responsible for establishing the interlock management ledger. Article 4: The fourth workshop (unit) is responsible for submitting requests to disable/reactivate interlocks as well as to make changes to them ； Responsible for establishing and maintaining the interlock management records for this workshop (unit). Article 5: The instrument maintenance unit is responsible for the actual implementation of interlock disconnection, activation, and modification, as well as the maintenance of records related to instrument interlocks. Article 6 Interlocks are divided into the following three levels: (1) Level 1 interlock: An interlock that causes one or more sets of equipment to stop operating. (II) Secondary interlock: The interlock action causes a partial or complete shutdown of the device’s specific section, and its impact is less extensive than that of primary interlock. (III) Level 3 interlocking: The interlocking action causes localized shutdown of a section, and its impact is less severe than that of level 2 interlocking. – 61 – Article 7: Interlocking is managed on a hierarchical basis; level 1 interlocking is managed by the regional branch, while levels 2 and 3 interlocking are managed by the factory (workshop). Article 8: Work procedures for interlock deactivation/reactivation or interlock modification: The process workshop (plant) submits an application for interlock deactivation/reactivation or interlock modification (fill out the application form, see Appendix 1). After it is reviewed and approved by the technical and equipment management departments and signed off by the chief engineer, the production operation department verifies the system conditions. The instrumentation maintenance unit then fills out the work order (see Appendix 2) and carries out the work according to it. Article 9: The work order shall include a work plan, an implementation scheme, and inspection confirmations. Article 10: Before disabling/enabling or modifying interlocks, the workshop (plant) must conduct a risk assessment and establish corresponding preventive measures and emergency response plans, which shall be filled in the application form for disabling/enabling interlocks and the application form for modifying interlocks. Article 11: The disconnection and activation of the interlock switches (automatic/manual, normal/bypass) on the operation panel must be carried out in accordance with work order procedures, with confirmation by the process and instrumentation teams prior to their activation or disconnection. Operations within the workshop (plant) are carried out in accordance with the process operation procedures and the contents of the process cards. During operation, the shift leader must provide supervision, while the Production Operations Department is responsible for verifying the external conditions. Article 12: The status of interlock disactivation on the equipment must be clearly communicated by the duty operator as part of the handover procedures, and records must be kept. Additionally, the plans for dealing with the risks arising from interlock disactivation should be incorporated into the regular plan management system. Article 13: Before the unit is put into operation, the workshop (unit) and instrument maintenance units shall conduct tests on the interlock functions, fill out the \"Interlock Test Confirmation Form\" (see Appendix 3), and the branch factory shall organize relevant departments to inspect the interlock system. Article 14: After an interlocking action occurs, the cause must be identified, and confirmation must be obtained before it is put back into use. Article 15: Regional branches shall establish hierarchical interlocking management ledgers. The process workshop (unit) shall promptly record the disconnection, activation, and changes of interlocks. The entity responsible for implementing the interlocking system regularly reports on the status of its activation, deactivation, and modifications to the higher-level management department. Article 16: The list of interlock alarm set values must be managed as controlled documents. The factory affiliated with the regional branch is responsible for revising the list of interlock alarm setpoints for that unit. The list of interlock alarm setpoints is revised every three years ； In the event of changes during the revision period, the department in charge of the branch plant shall issue them to the workshops (units) in the form of controlled documents. Article 17: The department in charge of interlocking shall regularly inspect and evaluate the interlocking management and implementation in subordinate units. Article 18 These provisions shall be interpreted by the Refining and Sales Branch and the Chemicals and Sales Branch of the joint-stock company. Article 19 These provisions shall come into force as of the date of issuance. - 63 – Appendix 1: Application Form for Starting/Stopping Interlocks (Example) Device (Equipment) Name: Name of the interlock; Level; Reason for starting/stopping; Risk assessment; Emergency response plan; Safety requirements. The production conditions required for operating the interlock must be met, and instrument operators must carefully check and confirm that the instrument system is functioning properly ； When activating or disabling interlocks, supervision and process personnel must be involved ； When disabling interlock, it must be under the unified command and coordination of the plant dispatcher. Content, signature date, application unit, approval from the factory’s mechanical department, review by the factory’s technical department, and approval by factory management. Note: Any information that cannot be filled in the form should be written on an attached sheet and submitted together for approval. - 64 - Appendix II: Work Order (Example) Device Name: Interlock Name: Level Process Workshop Opinion: Signature: Control Room Opinion: Signature: Inspection and Confirmation Items: Person in charge, Time 1. Confirm the risk assessment of interlock factors and emergency response plans. 2. Review the circuit diagrams, interlock wiring diagrams, and interlock logic diagrams. 3. Confirm the dashboard number. 4. Check whether the power supply for this interlock is functioning. 5. Check whether the interlock alarm setter is powered. 6. Check to confirm whether power is supplied to the relay. 7. Check and confirm the terminal number or interlock switch of the interlock that is to be removed or shorted. 8. Check and confirm the on/off status of the signal contact under normal operating conditions. 9. Check the short-circuit wire for poor contact or breaks. Note: ⑴ Mark “√” after confirming it is correct. ⑵Operations can be carried out only after the confirmation letter is completed. Instrument Operation Procedures: Person who carries out the procedure (signature): Time of execution: Process supervisor, Instrument supervisor. Approver: – 65 – Appendix 3: Interlock Test Confirmation Form (example) Name of the unit/device: Name or tag number of the interlock circuit; Normal operation, Abnormal operation. Name or tag number of the interlock circuit; Normal operation, Abnormal operation. Person who carries out the procedure: Date: Supervisor: Date: Process technician: Date: Inspector: Date: