MAP ,MAWP 1

[kandula1]

Hi,
Can anyone explain me difference between MAWP and MAP?

 

[TomBarsh]

As far as ASME Section VIII Division 1 goes, see definition of MAWP in Appendix 3. This Code does not define or use the term MAP but the concept is the same as the basis for "calculated test pressure" as defined in Appendix 3. Other Codes probably have same definitions.

MAWP ("maximum allowable working pressure") is maximum pressure based on allowable stress at design temperature, reduced for the pressure due to the operating liquid acting on the component or vessel, and in the corroded condition.

MAP ("maximum allowable pressure") is maximum pressure based on allowable stress at ambient ("cold") temperature, it is assumed there is no operating liquid acting, and component is in new condition. This is sometimes referred to as "new and cold".

 

[kandula1]

Thankyou Tom its clear for me know.
Regarding Impact testing i have an issue in compress which i am finding difficulty to understand.
I have a vessel with 2900Psi int pressure and 100F
NO EXT TEMP/PRESSURE.I am using SA-106-B pipe (2.3440 THK)SA-516-70 Heads.customer wants an MDMT of 20F so now should i raise my MDMT to 20F from -20F.And if i dont impact test i have a warning message stating that Rated MDMT 40F is higher than Design MDMT 20F?

can you explain me this

 

[vesselfab]

THE THICKNESS OF 2.344 IN THE MATERIAL LISTED IS EXEMPT FROM IMPACTS DOWN TO +40*F. +20*F IS LOWER TEMP THAN +40*F

YES YOUR MDMT SHOULD BE +20 INSTEAD OF -20

IMPACTS ARE REQUIRED

YOU COULD PROBABLY GO TO NORMALIZED MATERIAL TO GET RID OF REQUIRED IMPACTS, BUT CHECK TO MAKE SURE