Piping Related Abbreviations (M)

MAOP is an abbreviation of Maximum Allowable Operating Pressure.
The Maximum Allowable Operating Pressure is the maximum pressure that can be safely operated by a pipeline. The thickness of the wall, pipe outer diameter, and Specified Minimum Yield Stress are used to calculate the MAOP of a pipe.

MAWP is an abbreviation of Maximum Allowable Working Pressure.
The Maximum Allowable Working Pressure of a boiler carrying the ASME Code symbol or of a pressure vessel carrying the ASME or API-ASME symbol shall be determined by the applicable sections of the code under which it was constructed and stamped. Subject to the concurrence of the enforcement authority at the point of installation, such a boiler or pressure vessel may be rerated in accordance with the rules of a later edition of the ASME Code and in accordance with the rules of the National Board Inspection Code or API 510, as applicable.
For example; the maximum allowable working pressure of a steam boiler is an absolute restriction of pressure within psig unit for a steam boiler is allowed to run. The ASME BPV Code (American Society of Mechanical Engineers Boiler and Pressure Vessel) says that absolutely no steam boiler should be run at a pressure above the MAWP with the exception of the safety valve is operated to discharge excessive pressure. Steam boiler has some technical terms that be generally used. One of them is MAWP (Maximum Allowable Working Pressure) which means that all of working pressure at the pressure part shall not exceed MAWP.

MIG is an abbreviation of Metal Inert Gas.
Metal Inert Gas or Gas Metal Arc Welding (GMAW) is frequently referred to as MIG welding. MIG welding is a commonly used high deposition rate welding process. Wire is continuously fed from a spool. MIG welding is therefore referred to as a semiautomatic welding process.

MOV is an abbreviation of Motor Operated Valve.
A motor operated valve uses an electric motor to open and close the valve. The motor is connected to the valve stem, which moves the closing element of the valve to change the flow of fluid through the valve when the motor is activated.

MPI is an abbreviation of Magnetic Particle Inspection.
It is a nondestructive examination method to locate surface and subsurface discontinuities in ferromagnetic materials. The presence of discontinuities is detected by the use of finely divided ferromagnetic particles applied over the surface. Some of these magnetic particles are gathered and held by the magnetic leakage field created by the discontinuity. The particles gathered at the surface form an outline of the discontinuity and generally indicate its location, size, shape, and extent.

MSS is an abbreviation of Manufacturers Standardization Society.

MTO is an abbreviation of Material Take-Off.
A final material take-off is a accurate list of ALL the required piping items of a project in tabulated form.