According to IEC standards, a Safety Integrity Level (SIL) may be defined for a safety-related or safety instrumented system (SIS) with reference to a certain safety function.
A valve alone, for example, may not be considered as a system, because it can not accomplish any safety function and then a SIL may not be defined for just the valve itself.
The same is valid, of course, for an actuator alone or a solenoid valve alone.
If a SIL value is pubblished, it refers to a specific valve + actuator + control logic configuration (that constitutes a system) and a specific safety function (e.g.: emergency shut-down rather than blow off or pressure release...).
In order to calculate the SIL of your system (against the safety function of interest) from the single components' data, you must go back to the relevant failure rate (