Definitions

ABSOLUTE VISCOSITY: MEASURE OF INTERNAL RESISTANCE (POISE) P OR SLUGS PER FOOT/SEC

ADHESIVE JOINT: JOINT MADE IN PLASTIC (UPVC)

AIR HARDENED STEEL: STEEL THAT HARDENS DURING COOLING AIR

ALLOY STEEL: STEEL WITH DISTINCTIVE PROPERTIES MINIMUM COMPONENT (SILICON 0.6, COPPER 0.6, MANGANESE 1.65)

ANCHOR: A RIGID RESTRAINT PROVIDING SUBSTANTIALLY FULL FIXATION, IDEALLY NOT ALLOWING TRANSLATIONAL OR ROTATIONAL DISPLACEMENT OF THE PIPE ALONG ANY OF THE THREE REFERENCE AXES. IT IS EMPLOYED FOR PURPOSES OF RESTRAINT BUT USUALLY SERVES EQUALLY WELL AS A RESTRAINT, SUPPORT, OR BRACE.

ANNEALING: USED TO MAKE STEEL SOFT & DUCTILE BY HEATING A METAL TO TEMPERATURE ABOVE CRITICAL TEMPERATURE FOR A PERIOD FOLLOWED BY COOLING @ SUITABLE RATE ACCORDING TO THE PURPOSE

DUCTILITY: MEASURE OF HOW MUCH DEFORMATION BEFORE BREAK (TENSILE TEST)

TOUGHNESS: THE RESISTANCE TO FAILURE OR CRACK

ARC CUTTING: USE OF AN ELECTRIC ARC GENERATED AT THE TIP OF A WELDING ELECTRODE TO CUT METAL.

BACKING RING: A RELATIVELY NARROW, CIRCULAR SECTION PLACED IN BACK OF A BUTTWELDED JOINT PRIOR TO MAKING THE ROOT PASS OF THE WELD. THIS IS DONE TO ACHIEVE A FULL-PENETRATION WELD WHEN THE BACK SIDE OF THE WELD JOINT CANNOT BE ACCESSED.

BOLT TENSIONER: A MECHANICAL DEVICE USED TO TIGHTEN BOLTS BY APPLYING A UNIFORM, CALIBRATED LOAD. IT ATTACHES TO THE END OF THE BOLT, STRETCHES IT BY APPLYING A LOAD, AND THEN PERMITS EASY TURNING DOWN OF THE NUT TO HOLD THE LOAD IN THE BOLT.

BRACE: A DEVICE PRIMARILY INTENDED TO RESIST PIPING DISPLACEMENT DUE TO THE ACTION OF ANY FORCES OTHER THAN THOSE DUE TO THERMAL EXPANSION OR GRAVITY.

COLD SPRING: THE INTENTIONAL STRESSING AND ELASTIC DEFORMATION OF THE PIPING SYSTEM DURING THE ERECTION CYCLE TO PERMIT THE SYSTEM TO ATTAIN MORE FAVORABLE REACTIONS AND STRESSES IN THE OPERATING CONDITION.

CONSTANT-EFFORT SUPPORT: A SUPPORT WHICH IS CAPABLE OF APPLYING A RELATIVELY CONSTANT FORCE AT ANY DISPLACEMENT WITHIN ITS USEFUL OPERATING RANGE (I.E., A COUNTERWEIGHT OR COMPENSATING SPRING DEVICE).

DAMPING DEVICE: A DASHPOT OR OTHER FRICTIONAL DEVICE WHICH INCREASES THE RESISTANCE OF A SYSTEM TO VIBRATION. IT OFFERS HIGH RESISTANCE AGAINST RAPID DISPLACEMENTS CAUSED BY DYNAMIC LOADS, WHILE PERMITTING ESSENTIALLY FREE MOVEMENT UNDER GRADUALLY APPLIED DISPLACEMENT SUCH AS FROM THERMAL EXPANSION.

EXPANSION JOINT: A FLEXIBLE PRESSURE-CONTAINING COMPONENT OF A PIPING SYSTEM WHICH IS DESIGNED TO ABSORB THERMAL MOVEMENT.

GUIDE: A DEVICE PREVENTING ROTATION ABOUT ONE OR MORE AXES DUE TO BENDING MOMENT OR TORSION. IN COMMON USAGE, A GUIDE NORMALLY PERMITS TRANSLATION ALONG THE PIPE AXIS BUT PREVENTS TRANSLATION PERPENDICULAR TO THE PIPE AXIS.

HANGER: A SUPPORT BY WHICH PIPING IS SUSPENDED FROM A STRUCTURE OR OTHER FIXED POINT LOCATED ABOVE IT, AND WHICH FUNCTIONS BY CARRYING THE PIPING LOAD IN TENSION.

LIMIT STOP: A DEVICE WHICH RESTRICTS TRANSLATIONAL MOVEMENT TO A LIMITED AMOUNT IN ONE DIRECTION ALONG ANY SINGLE AXIS. PARALLELING THE VARIOUS STOPS, THERE MAY ALSO BE: DOUBLE-ACTING LIMIT STOPS, TWO-AXIS LIMIT STOPS, ETC.

PIPE: IS A TUBE WITH A ROUND CROSS SECTION CONFORMING TO THE DIMENSIONAL REQUIREMENTS FOR NOMINAL PIPE SIZE AS TABULATED IN ASME B36.10M, TABLE 1, AND ASME B36.19M, TABLE 1. FOR SPECIAL PIPE HAVING A DIAMETER NOT LISTED IN THESE TABLES, AND ALSO FOR ROUND TUBE, THE NOMINAL DIAMETER CORRESPONDS WITH THE OUTSIDE DIAMETER

PIPE JOINT: THIS WORD HAS TWO MEANINGS DEPENDING ON THE CONTEXT.

(A) THE INTERFACE BETWEEN TWO COMPONENTS, SUCH AS AT A WELD,FLANGE, OR THREADS.

(B) IN PIPELINE APPLICATIONS, A SINGLE SECTION OF STRAIGHT PIPE BEFORE BEING WELDED INTO A LONGER SECTION.

PRE-HEATING: USED TO CONTROL THE FORMATION OF H2 CRACKS

RADIOGRAPHY: THE USE OF RADIANT ENERGY IN THE FORM OF NEUTRONS, X-RAYS OR GAMMA RAYS FOR THE NONDESTRUCTIVE EXAMINATION OF OPAQUE OBJECTS. IT PRODUCES GRAPHICAL RECORDS ON SENSITIZED FILMS WHICH INDICATE THE COMPARATIVE SOUNDNESS OF THE OBJECT BEING TESTED.

RESILIENT OR FLEXIBLE SUPPORT: A SUPPORT WHICH INCLUDES ONE OR MORE LARGELY ELASTIC MEMBERS (I.E., A SPRING).

RESTING OR SLIDING SUPPORT: A DEVICE FOR PROVIDING SUPPORT FROM BENEATH THE PIPING, BUT OFFERING NO RESISTANCE OTHER THAN FRICTIONAL TO HORIZONTAL MOTION.

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

RIGID (SOLID) SUPPORT: A SUPPORT PROVIDING STIFFNESS IN AT LEAST ONE DIRECTION THAT IS COMPARABLE TO THAT OF THE PIPE.

ROOT PASS: THE FIRST WELD BEAD MADE.

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.

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.

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

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.

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

STEEL RELIEVING (PWHT): POST WELD HEAT TREATMENT USED TO RELIVE THE TRAPPED ELASTIC STRESS

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

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.

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.

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

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

WELD: A LOCALIZED UNION OF METAL ACHIEVED IN PLASTIC AND MOLTEN STATES, WITH OR WITHOUT THE ADDITION OF FILLER METAL OR APPLICATION OF PRESSURE.

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

YIELD STRENGTH: MINIMUM STRESS WHICH PRODUCE PERMANENT PLASTIC DEFORMATION