Dear all:

My doubt is regarding to a piping line that according to ASME B31 has a Design Pressure established in 6-10% over the Operation Pressure. The Pressure Safety Valves have the Pressure Calibration established under the Operation Pressure.
Is there any interference between these affirmations and the requirements of PED?
Is it correct that the value of Design Pressure is established in 6-10% over the Operation Pressure?
Is there any case where the Design Pressure is established in 20% over the Operation Pressure?

Thank you very much at all