For a Hazop analysis at SIL1 level, is it necessary to use a SIS system?
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For a Hazop analysis at SIL1 level, is it necessary to use a SIS system? Do all systems with a SIL rating of 1 or higher require a SIS, or is it only systems with SIL2 or SIL3 that need such a system?
This post was last edited by ZhiGE on 2020-2-5 20:31. SHT 3018-2003 Code for Design of Safety Instrumented Systems in Petrochemical Industries; GBT 50770-2013 Code for Design of Safety Instrumented Systems in Petrochemical Industries: With the frequent occurrence of chemical accidents recently, **the requirements for safety instrumented systems are becoming increasingly stringent. Therefore, design institutes that have reached SIL1 level will directly design safety instrumented systems.
It depends on which system you are using; if it’s a well-known PLC system and all other hardware requirements are met, then it’s acceptable. The PLC can achieve SIL1 by default
It also depends on the manufacturing process; for designs with two key points and one major requirement, SIS is necessary
A SIL1 rating can actually be met by ordinary DCS systems, but the safety supervision authorities don’t see it that way; when it comes to key chemical processes, important chemicals, and major hazard sources, such systems are necessary. You can contact the manufacturer at 15169070869 to discuss this further
Few of the experts who come for inspections by safety authorities truly understand SIS; most of them just memorize standards and regulations, and there’s nothing you can do with such people. My suggestion: If there aren’t many circuits, consider using a small-scale safety PLC, such as Siemens’ 300 series; consult Siemens for the specific models. If there are fewer than ten circuits, and no expansion is planned in the future, they can be built using safety relays. Both the controller and the field instruments must have SIL certificates (although SIL1 does not require certification; having such certificates makes things easier for inspections, as calculations rely on data, and reliable data is crucial). Additionally, there must be SIF calculation documents, so there is no need to worry about inspections.
This post was last edited by Huahua Jianghu on 2020-3-17 at 21:49. According to Document No. 116, SIS systems and other non-SIS systems must be separated. Even if it’s just 1 SIL loop, it still belongs to the SIS system. This is clearly stated in IEC61511. It has little to do with any other circuits. Safety PLCs and conventional PLCs are not the same at all. A verified PLC can certainly be used as an SIS system. SIS is a system concept, while PLC is an electronic and programming format; they are fundamentally two different things. It’s like sensors; verified sensors can be used in SIS systems.
We also need to look at your verification report; if the verification is successful. You don’t need to go on SIS. It’s your process that matters first, not whether it’s a second-tier or first-tier priority.
It is recommended to go straight to the SIS system; otherwise, you might be ruined by some unreasonable \"experts.\"