Difference Between MAWP and Design Pressure (2024)

MAWP vs Design Pressure

When equipment is designed, MAWP, or Maximum Allowable Working Pressure, and design pressure are very much taken into account.

In designing equipment, it is seen that it sustains the stress imposed on it from the external and the internal pressures. This pressure is termed as design pressure. The design pressure of any vessel or equipment is determined from its maximum operating pressure which is generally increased by some margin for balancing the probable pressure surge.

MAWP is the maximum pressure at which the vessel or equipment is allowed to function at a specific temperature. The mechanical design, which is based on Material of Construction (MOC) and thickness of the vessel is taken into account in MAWP.

One of the main differences between Maximum Allowable Working Pressure and design pressure is that the latter one is always equal or less than the MAWP of the vessel or equipment. The PSV set pressure is based on design pressure, and it can be equal to the MAWP but not higher.

Design pressure is the condition of coincident temperature and pressure that is expected in a normal condition. Maximum Allowable Working Pressure is the maximum pressure that is permissible at the top of the equipment or vessel in normal operating conditions.

The MAWP will be changing with time because of corrosion and vessel fatigue. Design pressure depends on the kind of system (fuel, water, steam, etc.) that is used in the vessels. Both the design pressure and MAWP have many applications in steam drums, boilers, piping, and different types of pressure vessels.

Summary:

1.In designing equipment, it is seen that it sustains the stress imposed on it from the external and the internal pressures, and this pressure is termed as design pressure.
2.MAWP is the maximum pressure at which the vessel or equipment is allowed to function at a specific temperature.
3.Design pressure is the condition of coincident temperature and pressure that is expected in a normal condition.
4.Maximum Allowable Working Pressure is the maximum pressure that is permissible at the top of the equipment or vessel in normal operating conditions.
5.One of the main differences between Maximum Allowable Working Pressure and design pressure is that the latter one is always equal or less than MAWP of the vessel or equipment.
6.The MAWP will be changing with time because of corrosion and vessel fatigue. Design pressure depends on the kind of system (fuel, water, steam, etc.) that is used in the vessels.