Regarding how to interpret the independence of safety instruments as mentioned in Order No. 40,

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I have a question for those experienced in this field: Can the SIS system for major hazard sources of level 1 and 2, such as liquid chlorine storage areas, be shared with the SIS system used for hazardous processes? In the engineering design assessment of one of our projects, it was suggested that the SIS system for major hazard sources such as liquid chlorine storage areas, which are classified as level 1 or 2 hazards, should not be shared with the SIS system used for hazardous processes. The basis for this is Article 13(3) of the Interim Provisions on the Supervision and Management of Major Hazard Sources of Hazardous Chemicals (Order No. 40 issued by the State Administration of Work Safety on 20110815), which stipulates that emergency shutdown devices must be installed for key facilities within major hazard sources, such as toxic gases, highly toxic liquids, and flammable gases ； For facilities handling toxic gases, install emergency leak response devices. For major hazard sources of level 1 or 2 involving toxic gases, liquefied gases, or highly toxic liquids, an independent Safety Instrumented System (SIS) must be installed ； ) Does the independence referred to in Order No. 40 mean independence between the safety instrumented system and the process control system? Or independence between safety instrument systems? I’m not sure how other sea friends understand this independence; those who know could please help clarify it! Thank you!