The table lists functions that appear in most oil, gas, refining and chemical plants. Targets come from your own hazard analysis; architectures shown are common starting points, not rules.
| Equipment | Function | Typical initiator | Typical action | Common architecture | Review points |
|---|---|---|---|---|---|
| Separator | High-high pressure | 2oo3 pressure transmitters | Close inlet shutdown valve | 2oo3 / safety PLC / 1oo1 or 1oo2 valves | Relief valve sizing for blow-by; valve stroke time against process safety time |
| Separator | Low-low level | Level transmitters | Close liquid outlet | 1oo2 or 2oo3 / 1oo1 valve | Downstream blow-by case |
| Compressor | High-high suction scrubber level | 2oo3 level transmitters | Trip compressor, close suction | 2oo3 / PLC / motor trip + valve | Level measurement independence from control |
| Compressor | Machinery protection | Vibration, axial displacement | Trip driver | Dedicated monitoring system | Integration with the safety PLC; bypass during start-up |
| Fired heater | Flame failure | Flame scanners | Close fuel double block, open vent | 1oo2 scanners / BMS logic / 1oo2 valves | Scanner self-check; purge permissive |
| Fired heater | Low pass flow | Flow transmitters per pass | Trip fuel | 1oo2 or 2oo3 per pass | Coking and erosion of flow elements |
| Reactor | High-high temperature | 2oo3 temperature transmitters | Stop feed, start emergency cooling | 2oo3 / SIL 3 PLC / 1oo2 valves with partial stroke | Thermowell response time; runaway kinetics |
| Storage tank | Overfill | Independent radar or switch | Close receipt valve, stop pump | 1oo1 / PLC / 1oo1 valve | Independence from tank gauging; energise-to-trip MOV supply |
| Pipeline / HIPPS | High-high pressure | 2oo3 pressure transmitters | Close two valves in series fast | 2oo3 / SIL 3 logic / 1oo2 fast-acting valves | Closure time; settle-out pressure; downstream design |
| Pump | Low-low suction level | Level transmitter | Stop pump | 1oo1 or 1oo2 | Dry-running scenario severity |
In First Out AI
Six of these are worked examples (separator, compressor scrubber, fired heater, reactor, tank, batch charging interlock) with LOPA scenarios, HAZOP nodes and a C&E matrix: open the demo project to see them connected.
Written for First Out AI as engineering guidance. It supports engineering work and does not replace it; check every value against your standards, certificates and company rules with a competent functional safety engineer.