Hello everyone, can the SIS system be integrated into the DCS system?
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In the on-site process workshop, the equipment requires a safety instrumented system; can it be connected to a DCS to implement emergency operation logic? Thank you
I’ve never encountered this in workshops; in the chemical industry, existing HAZOP analyses are usually used to develop SIS systems based on the resulting ratings.
As an independent safety instrumented system, SIS can communicate with DCS; it is possible to monitor the status of SIS from the DCS, but it is not possible to send commands to it
Yes, the field instruments are connected to the DCS, and they are also fed into the SIS system
First, you need to determine whether you want to add a regular safety interlock circuit or an SIS safety interlock circuit. Normally, whether the additional circuit should be integrated into the SIS is decided through HAZOP and LOPA analyses. If the analysis shows that the level of the additional SIF circuit is SILa and there are no interlocks in the DCS as mitigation measures, then the new interlock can be directly added to the DCS. Others, such as \"although the increased SIF circuit level is SILa, the DCS interlock has already been used as a mitigation measure and cannot be further reduced\" ； Or, when the SIF circuit level is greater than or equal to SIL1, a SIS system must be installed; the SIS should be independent of the DCS (both the controllers, sensing elements, and actuating elements must be independent, unless hazard and operability studies as well as LOPA analyses show that common failure scenarios do not pose a problem), in order to ensure that the SIS circuits can continue to function properly even in the event of failures in the DCS circuits.
The SIS system is an independent safety management system; it can use the DCS common signal sources, but it cannot be integrated into the DCS system.
No, it must be independent of DCS
It’s not possible now; a separation is required, but it was done as an integrated system before. In Lind’s past projects, Pcs7 and failsafe systems were often used together.
Article 13 of the Interim Provisions on the Supervision and Management of Major Hazard Sources of Hazardous Chemicals (**Order No. 40 of the State Administration of Work Safety**) – Major hazard sources of Grade 1 or Grade 2 that involve toxic gases, liquefied gases, or highly toxic liquids shall be equipped with an independent Safety Instrumented System (SIS). Article 5 of the \"Interim Standards for Identifying Major Potential Hazards in Production Safety of Chemical and Hazardous Chemicals Enterprises\": Hazardous chemical storage areas that constitute Class I or Class II major hazard sources involving toxic gases, liquefied gases, or highly toxic liquids, and which do not have an independent safety instrumented system, are considered to pose major potential hazards for accidents. \"Code for Design of Safety Instrumented Systems in Petrochemical Industries\" (GB/T 50770-2013) 5.0.7 A safety instrumented system can implement one or more safety instrument functions, and multiple such functions can make use of the same safety instrumented system. The common areas shall meet the requirements of the highest safety integrity level among the various functions. 6.3 Safety instrument functions of different SIL levels impose specific requirements on the redundancy setup of measuring instruments, emphasizing the independence of SIS instruments from DCS. \"Functional Safety of Safety Instrumented Systems in the Process Industry\" (GB/T 21109): Devices that serve as part of implementing instrument safety functions should not be used for basic process control purposes at the same time, unless it is determined through analysis that the overall risk is acceptable. International standard \"Functional Safety of Electrical/Electronic/Programmable Electronic Safety-Related Systems\" (IEC 61508) – requires that safety-related systems be isolated from other control systems such as DCS to ensure independence and reliability. \"Functional Safety of Safety Instrumented Systems in the Process Industry\" (IEC 61511) – Specifies that SIS systems must have functions that are independent of the DCS, enabling them to carry out safety functions even in the event of a DCS failure. - It is emphasized that SIS and DCS should have physical and logical isolation at both the hardware and software levels.