The following requirements apply for the development of the OPC UA Safety technology:

1. Safety communication suitable for Safety Integrity Level up to SIL4 (see IEC 61508) and PL e (see ISO 138491).
2. Combination of SIL 1 – 4 OPC UA Safety devices as well as non-safety devices on one communication network.
3. Implementation of the safety transmission protocol is restricted to the safety layer.
4. The transmission times are monitored by timers implemented in the safety layer.
5. Safety communication meet the requirements of IEC 617843:2017.
6. [RQ4.1] The OPC UA Safety stack is intended for implementation in safety devices exclusively. Exceptions (e.g. for debugging, simulation, testing, and commissioning) shall be discussed with a notified body.