Last updated: Mon 01 Jul 2024, 21:25 UTC+8

This skill is used for:

Layers of protection

Before going into each type of safety assessment, we need to acknowledge there are many layers of safety protection. The onion diagram on the right is typically used to depict these safety protection layers.

  1. Process
  2. Basic process controls
  3. Alarms and operator intervention
  4. Safety instrumented system (trips)
  5. Physical protection (relief devices)
  6. Physical containment (bunds)
  7. Fire and gas system
  8. Emergency response

Let’s go through one by one in sequence.

https://www.thesafetymaster.com/wp-content/uploads/2021/11/LOPA.png

https://www.assetintegrityengineering.com/wp-content/uploads/2016/07/Swiss-Cheese-Model.png

Layer 1: Process

Layer 2: Basic process controls

Layer 3: Alarms and operator intervention

Layer 4: Safety instrumented system or SIS (trips)

Layer 5: Physical protection (relief devices)