For every single SIL 1/2/3 or 4 safeguard, the following actions are performed in accordance with IEC 61511 or IEC 61508;
- Identification of safeguard. It is wise to make a schematic drawing with all the relevant sensors, components and final elements.
- Verifying the functionality of the safeguard.
- Determine whether the safeguard is separated from the system.
- Check against the architectural requirements (eg is one valve sufficient?).
- Check to the probabilistic requirements (calculation of probability of failure on demand).
- Check for systematic faults.
It is highly recommended to make taylor-made test procedures during design phase.