SIS SYSTEM
A Safety Instrumented System (SIS) is a dedicated safety layer independent of process control systems (e.g., DCS), designed to detect potential hazardous conditions (overpressure, overtemperat
A Safety Instrumented System (SIS) is a dedicated safety layer independent of process control systems (e.g., DCS), designed to detect potential hazardous conditions (overpressure, overtemperat
English:
A Safety Instrumented System (SIS) is a dedicated safety layer independent of process control systems (e.g., DCS),
designed to detect potential hazardous conditions (overpressure,
overtemperature, etc.) and initiate protective actions (emergency
shutdown, venting) to return the process to a safe state, reducing risk
to an acceptable level. It complies with IEC 61511 and quantifies safety performance via SIL (Safety Integrity Level).
层级 | 组件与功能 |
传感器层 | 冗余安全仪表（压力变送器、温度开关、火焰探测器） → 诊断危险工况 |
逻辑控制器层 | SIL认证逻辑解算器（如三重模件冗余TMR） → 执行安全逻辑运算 |
执行器层 | 安全关断阀、泄放阀、电机停机单元 → 实施物理保护动作 |
工程接口层 | 编程工作站（管理安全逻辑、SIL验算） + 事件顺序记录（SOE） |
English:
Functional Safety Compliance: Mandatory adherence to IEC 61511 with SIL certification (SIL 1-4).
Fail-Safe Design: Inherent failure to a safe state (e.g., de-energized valve closure).
High Availability: Hardware redundancy (sensors/controllers/power) + ≥99% online diagnostic coverage.
Independence: Physically/logically isolated from DCS to prevent common-cause failures.
Lifecycle Management: Full safety lifecycle coverage (design, installation, operation, maintenance, decommissioning).
Reactor Safety Interlocks: Overpressure emergency venting, runaway temperature quenching
Flammable Gas Protection: Leak detection triggering isolation & inerting
Combustion Management: Burner management systems (BMS) for furnace/boiler flame failure shutdown (FGS)
Pressure Relief Backup: SIS-actuated venting if pressure safety valve (PSV) fails
Feature | Safety Instrumented System (SIS) | Basic Process Control System (BPCS) | Fire & Gas System (F&G) |
Primary Goal | Risk reduction (safety functions) | Process stability (continuous operation) | Personnel/asset protection |
Standard | IEC 61511 | ISA-88/ISA-95 | NFPA 72/EN 54 |
Failure Response | Fail-to-safe | Fail-to-alarm/maintain | Alarm + activate suppression |
SIL Requirement | SIL 1-4 (mandatory) | Not applicable | SIL 1-2 (optional) |
English:
Smart SIS: AI-driven predictive maintenance (e.g., valve stroke time analysis) reducing PFD (Probability of Failure on Demand).
Enhanced Cybersecurity: Integration of IEC 62443 to defend against OT-targeted attacks.
Cloud-Based Safety Audits: Remote SIL verification and compliance management.
Integrated SIS/BPCS Architecture: Shared infrastructure with DCS (while maintaining functional isolation).