PipingNotes

Design-Engineering-Construction-Testing & Commissioning of piping

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Category: Definitions

Island Mode

Means the there is outage of some areas in the plant but the main areas still working


Kv coefficient

Tells how much water the valve can pass when it is fully open with pressure drop 1 bar accross it

Unit is m3/hr

Kv= Cv * 0.865


Cv coefficient

Tells how much water the valve can pass when it is fully open with pressure drop 1 psi accross it

The unit is gallon/minute


Water Hammer

Water hammer (also known as fluid hammer, hydraulic shock, or surge) is a pressure surge or shock wave that occurs in a piping system when a fluid (usually liquid, most commonly water) in motion is suddenly forced to stop or change direction rapidly.

This sudden change creates a high-pressure wave that travels back and forth through the pipe at the speed of sound in the fluid, often producing loud banging noises (like a hammer hitting the pipe) and potentially causing serious damage.


YIELD STRENGTH

MINIMUM STRESS WHICH PRODUCE PERMANENT PLASTIC DEFORMATION


WRINKLE

 A DEVIATION OF THE PIPEWALL FROM THE IDEAL CONTOUR OF MORE THAN 15% OF THE NOMINAL WALL THICKNESS PERPENDICULAR TO THE SURFACE.


WATER QUENCHING

RAPID REDUCTION OF METAL TEMPERATURE AFTER A HOT FORMING PROCESS BY USING WATER.


UNIQUE RATING

SPECIFIC RATE FOR FLANGES WHICH EXCEED CLASS 2500 ASME B16.5


UNION

A PIPE CONNECTOR THAT IS MADE OF TWO MATING PIECES, ONE FOR EACH END OF THE TWO PIPES BEING JOINED. THE TWO HALVES OF THE UNION ARE HELD TOGETHER BY A THREADED RING.


TWO-AXIS STOP

A DEVICE WHICH PREVENTS TRANSLATIONAL MOVEMENT IN ONE DIRECTION ALONG EACH OF TWO AXES. A “TWO-AXIS DOUBLE-ACTING STOP” PREVENTS TRANSLATIONAL MOVEMENT IN THE PLANE OF THE AXES WHILE ALLOWING SUCH MOVEMENT NORMAL TO THE PLANE.


STRENGTH

MEASURE OF RESISTANCE TO DEFORMATION, STRENGTH IS INVERSELY PROPORTIONAL TO TOUGHNESS


STEEL RELIEVING (PWHT)

POST WELD HEAT TREATMENT USED TO RELIVE THE TRAPPED ELASTIC STRESS


SPIRAL-WOUND GASKET

A GASKET TYPE FORMED BY ALTERNATELY WINDING STRIPS OF METAL AND SOFT FILLER MATERIAL AROUND A MANDREL


SOCKET-WELD

A PIPE ATTACHMENT DETAIL IN WHICH A PIPE IS INSERTED INTO A RECESSED AREA OF A FITTING, AND THEN FILLET WELDED BETWEEN ITS OUTSIDE DIAMETER AND THE FITTING END.


SUPPORT

A DEVICE USED TO SUSTAIN A PORTION OF PIPING SYSTEM WEIGHT PLUS ANY SUPERIMPOSED VERTICAL LOADINGS


STOP

A DEVICE WHICH PERMITS ROTATION BUT PREVENTS TRANSLATIONAL MOVEMENT IN AT LEAST ONE DIRECTION ALONG ANY DESIRED AXIS. IF TRANSLATION IS PREVENTED IN BOTH DIRECTIONS ALONG THE SAME AXIS, THE TERM “DOUBLING-ACTING STOP” IS PREFERABLY APPLIED. IN COMMON USAGE, A STOP NORMALLY ACTS ALONG THE DIRECTION OF THE PIPE AXIS.


SLAG

A NONMETALLIC BLANKET THAT FORMS ON THE TOP OF THE MOLTEN WELD METAL. IT HELPS TO CONTROL THE TEMPERATURE, THE COOLING RATE, AND ASSISTS IN PREVENTING AND REMOVING IMPURITIES FROM THE WELD METAL.


ROOT PASS

THE FIRST WELD BEAD MADE.


RIGID (SOLID) SUPPORT

A SUPPORT PROVIDING STIFFNESS IN AT LEAST ONE DIRECTION THAT IS COMPARABLE TO THAT OF THE PIPE.


RESTRAINT

ANY DEVICE WHICH PREVENTS, RESISTS, OR LIMITS THE FREE THERMAL MOVEMENT OF PIPING.