I was just curious to know what risk reduction factor (RRF) most companies usually allocate to Pressure relief devices, and if this factor (RRF) is dependent on the specific type of PRD (conventional, balanced bellows, pilots, conservation vents and explosion hatches).
Also, the probability of failure on demand (PFD) of a PRD is the inverse of its RRF. Therefore, if the PFD of a PRD is 0.0001, this does mean, its RRF should be 10000?
If true, while conducting a PHA, a single PRD with an PFD of 0.0001, should reduce a risk by 10000.
Please let me know what your thoughts are about the statements above.