Is there a national standard that requires SIS system to use safety relay?

According to the current situation of the development of functional safety technology in China and the current standards related to functional safety in the process control industry, there is no mandatory standard at present. There are some mandatory standards for mechanical safety.
Some principles and specifications for the design of safety related systems, such as the code for design of safety instrumented systems in petrochemical industry, point out that:
(1) The logic arithmetic unit of safety instrument system can be composed of relay system or programmable electronic system, or it can be mixed.
(2) Redundant or fault-tolerant logic arithmetic units should be used for Level 2 and level 3 safety instrumented systems.
(3) Process interface includes input/output card, sequence event input card, distributor, safety barrier, switch, relay and other related equipment.
(4) The sensor and final actuator connected to the input/output card shall be designed as fail safe, that is, fail safe.
The safety integrity level is the overall assessment of the entire safety loop. It is obvious that even the associated equipment on the loop link, such as relays, also needs the design requirements of fail safe.
At the same time, in the SIS design principles introduced in the reports shared by some experts from design institutes, it is also proposed that the [SIS logic controller] should obtain the functional safety of the national authoritative certification authority.
For the relay applied in the safety circuit of the above safety related system, whether it is the associated equipment applied in the relay system or the process interface in the circuit, the safety relay with self diagnosis function, high diagnosis coverage, low failure probability and authoritative certification is a better choice in terms of design reliability and safety assurance.