ASME SECTION VIII DIV 1 stated an 10 % allowable over pressure over set pressure to achieve full lift of a single relief valve for blocked case . If i set the set pressure as maximum allowable working pressure(MAWP), the accumulation and over pressure is same and it is 10% over MAWP.
My question is, the system is designed for MAWP and we are allowing an accumulation of 10% over MAWP to achieve full lift. How does the system can take this excess pressure over MAWP , if at all thickness is governed by only MAWP at co incident temperature.
For example my system is designed for a pressure of 10 kgsc and 120 degree Celsius. and thickness calculations done accordingly. I want to protect the system for blocked case, i installed a single relief vale with a set pressure of 10 kgsc. As i said ASME SECTION VIII DIV 1 allows an accumulation of 10% over MAWP for full lift, for this example it is 11 kgsc. But my system is designed ( Thickness calculation) for only 10 kgsc, how can the system will take 11 kgsc pressure ??