Piping Vocabulary

two-valve system with vent to atmosphere to stop flow

Double block and bleed

a permanent open spacer installed between two flanges connected to a thick plate of metal that can be rotated to stop piping flow

Figure-eight (spectacle) blind

pipe fitting used to mate against cast equipment using a gasket that covers the entire flange face.

Flat face flange

A group of corrosion-resistant nickel alloys, characterized by high resistance to hydrochloric, sulfuric, phosphoric, acetic, and fromic acids, to media containing ions of chlorine and fluorine, and to many organic media.

Hastaloy

type of piping to keep the conveyed fluid hot in which the fluid is conveyed through the inner pipe and a heating medium is conveyed through the jacked (the outer pipe).

Jacketed piping

A pictorial representation of a piping system in three dimensions. Drawing is not to Scale, does not show size of piping or components.

Piping isometric drawing (Iso)

inspection method used to find defects in plates and welds and determine pipe and tube wall thickness

Radiographic (x-ray) testing

The exterior wall of a vessel.

Shell

Sketches that include information necessary for selection, use, and need for periodic inspection of materials used to make vessels.

Vessel design sheets

An economical butt-weld branch connection, used when the branch is much smaller than the main pipe.

Weldolet

(American Society of Mechanical Engineers) promotes the art, science & practice of multidisciplinary engineering around the globe.

ASME

design code that governs vessels with pressures higher than 15 psig

ASME Code Section VIII

substance with a low pH (<7) capable of burning or corroding by chemical action

Acid

material consisting of two or more metals or metal and a nonmetal

Alloy

steel with 18% chromium and 8% nickel that is resistance to both rusting and corrosion.

Austenitic (Stainless) Steels

plate for covering or closing the end of a pipe to gain a complete shutoff in piping.

Blind

physical connection of two objects by a copper wire to prevent fire hazards.

Bonding

family of alloys of copper (60%-90%) and zing (remaining portion)

Brass

Materials with hardness but little tensile strength, which break without significant deformation (e.g., ceramics and glass).

Brittle

type of piping connection in which the parts to be joined are beveled and welded together

Butt-welded piping

constitutes most piping in process units because it is economical and has a wide temperature range. Made from low-carbon steel.

Carbon steel piping

a hard, relatively brittle alloy with a higher proportion of carbon than steel has, cast in a mold and used for conveying nonflammable fluids.

Cast iron pipe

In a galvanic cell, the location of the positive pole to allow the circuit to be complete. In cathodic protection, this is the protected metal.

Cathode

technique used to control the corrosion of a metal surface by making it the cathode of an electrochemical cell.

Cathodic Protection

substance with a high pH (>7) capable of burning or corroding by chemical action

Caustic

type of steel that has a certain quantity of chromium, which withstands corrosion very well.

Chromium Steels

a measure of a materials change in length or volume with temperature

Coefficient of expansion

family of allows that contains copper and zinc.

Copper Alloys

electrochemical reaction between metal surfaces and fluids that results in the gradual wearing away of the metal

Corrosion

70% copper, 30% nickel

Cupronickel

the maximum pressure that the system that can be exposed to and sets the system relief valve at the same pressure

Design pressure

Materials that can be easily molded or shaped without breaking or losing toughness (e.g., copper, iron or gold)

Ductile

a measure of a material's ability to undergo permanent deformation before breaking (e.g., stretching metal into a wire).

Ductility

inspection method to identify cracks or imperfections, which show up as a bright red line.

Dye penetrant testing

pipe fitting that looks like an "L" or partial "C" and used to route piping around bends.

Elbow

Loss of ductility of a material, making it brittle.

Embrittlement

A National Pipe Thread Taper (NPT) subset, receives another tapered

Female pipe thread

specified using pound ratings (or lb. ratings) - 150, 300, 600, 900, 1500 and 2500, which refers to the maximum allowable non-shock pressure (psig).

Fitting pressure ratings

disc, collar, or ring that attaches to pipe with the purpose of providing increased support for strength, blocking off a pipeline, or implementing the attachment of more items.

Flange

A mechanical seal which fills the space between tow "less-than-perfect" mating surfaces by filling irregularities, generally to prevent leakage from or into the joined objects, often made from rubber or plastic.

Gasket

additional pressure in a system relative to atmospheric pressure. It is a convenient pressure measurement for most practical applications. Often expressed in units of "psig."

Gauge pressure

procedure to connect an object to the earth using a copper wire and connected to a grounding rod or grounding device.

Grounding

type of piping to keep the conveyed fluid hot in which the fluid is conveyed through the outer pipe and the heating medium is conveyed through the inner pipe.

Gutted piping

inspection method that uses tapping to determine metal thickness by sound and feel.

Hammer testing

measure of how resistant a material is to permanent deformation. Test readings indicate strength and ductility.

Hardness

type of alloy steel that has larger quantities of secondary metals (10% or more) to produce a steel that is satisfactory for most services.

High-Alloy Steels

inside diameter

I.D.

An alloy with a relatively small amount of the secondary material (e.g., carbon-, moly-, and chrome alloys).

Low Alloy

type of alloy that steel that provides better mechanical properties or greater resistance to corrosion that carbon steel through the inclusion of small quantities of secondary metals (less than 10%).

Low-Alloy Steels

relatively inexpensive material that is low in carbon, sulfur, and phosphorus and used for most plant applications.

Low-Carbon Steel

inspection method used to detect surface or near surface flaws by dusting iron powder over an induced magnetic field, and defects become outlined by the iron powder.

Magnetic particle inspection

A National Pipe Thread Taper (NPT) subset, is inserted into a receiving tapered threaded connection.

Male pipe thread

the opening to vessel, used as an access point for inspection or performing maintenance.

Manway

A group of nickel alloys, primarily composed of nickel (up to 67%) an copper, with small amounts of iron, manganese, carbon, and silicon. Stronger than pure nickel and resistant to corrosion by many agents, including rapidly flowing seawater.

Monel

group of alloys that contains large amounts of nickel and is used around chemical plant where stainless steel is unsatisfactory.

Nickel Alloys

means "in name only".

Nominal

North American set of standard sizes for pipes used for high or low pressures and temperatures.

Nominal Pipe Size (NPS)

metal that contains little or no iron (e.g., nickel alloys, copper alloys).

Nonferrous Alloys

A stub-pipe that is shop-welded to a vessel to facilitate welding a connecting pipe in the field.

Nozzle

outside diameter

O.D.

a physical object that has a self-reinforced end intended to be welded onto a hole in the wall of a pipe or piping component. The other end is to be connected to another pipe or piping component.

Olet (pronounced O-LET)

Device used for measuring flow rate, for reducing pressure or for restricting flow (in the latter two cases it is often called a restriction plate).

Orifice plate

Interaction between oxygen molecules and other substances (e.g., metal). With iron, this process causes rust.

Oxidation

Thick piece of metal inserted between flanges to stop piping flow.

Paddle blind

The area of the outside of the pipe, expressed in square feet per foot or pipe.

Pipe external surface area

A joint or connector, as an elbow, union, or tee, used to connect two or more pipes in a pipe system.

Pipe fitting

A bracket, clamp, clip, or loop used to suspend or support pipes by transferring the load of the pipe and conveyed material to a supporting structure.

Pipe hanger

A fitting, consisting of a short piece of pipe of small diameter, usually provided with a male pipe threat at each end, for connecting two other fittings.

Pipe nipple

The approximate diameter of a pipe, specified using nominal size.

Pipe size

Prefabricated components of a piping system, including the pipes, flanges and fittings, fabricated before they are delivered to the construction area. Prefabrication allows more rapid field pipe assembly.

Pipe spool

the thickness of the pipe wall, measured in inches, or similar unit, generally specified by pipe schedule.

Pipe wall thickness

weight of water that could fit inside one foot of pipe, expressed in pounds per foot (or similar unit).

Pipe water weight

weight of pipe in pounds per foot (or similar unit).

Pipe weight

System of pipes used to convey all kinds of fluid materials (liquids and gases).

Piping

A two-dimensional drawing of a three-dimensional object, using tow or more additional drawings to show additional views of the object. Drawing is to scale, including representation of piping and components.

Piping orthometric drawing (Ortho)

pipe fitting used to join pipe to other flanged equipment, pipe, etc. and has a gasket that fits inside the bolted area.

Raised face flange

pipe fitting used to join pipe to other fanged equipment, pipe, etc. that uses a metal ring as a gasket.

Ring joint flange

Standard (pipe schedule)

STD

Highly active metals used to prevent a less active material surface from corroding, created from a metal alloy with a more negative electrochemical potential than the other metal it will be used to protect (e.g., zinc, magnesium, or aluminum alloys).

Sacrificial anode

type of piping connection in which a pipe is inserted into a larger fitting before being welded with a fillet weld.

Socket-welded piping

a branch connection fitting, which utilizes the basic weldolet design configuration with a socket weld outlet.

Sockolet

Storage vessel used for high-pressure fluids or compressed gases with a very strong structure and no weak points. Shaped like a large ball.

Spherical tank

Storage vessel shaped like an ellipsoid, commonly seen in water towers.

Spheroidal tank

a measure of the maximum load that a material can take before it permanently deforms or breaks.

Strength

mechanical-chemical type of deterioration.

Stress-Corrosion Cracking

pipe fitting that looks like the letter "T", used to make branch connections.

Tee

the pressure to which pipelines, boilers, vessels, etc. are tested for strength and leaks before being placed into service.

Test pressure

a branch connection fitting, which utilizes the basic weldolet design configuration with a threaded outlet.

Threadolet

ability of a material to absorb energy and permanently deform without breaking.

Toughness

type of piping that keeps conveyed fluid hot by wrapping copper tubing around process pipe and covering with heat transfer cement or insulation and passing low-pressure steam or hot oil through the tubing.

Traced piping

A caliper equipped with an adjustable or removable leg to permit use of the caliper in narrow or confined spaces.

Transfer caliper

Inspection method used to measure metal thickness through a drilled hole.

Trepanning

An opening that allows air, gas, or liquid to pass out of or into a confined space.

Vent

most common form of inspection, performed visually.

Visual inspection

ability to be welded. Many metals and thermoplastics can be welded, but some are easier to weld than others.

Weldability

Extra strong (pipe schedule)

XS

Double extra-strong (pipe schedule)

XXS

short for the Latin phrase exempli gratia--- means "for example." An easy way to remember is to treat it as an abbreviation of "example given"

e.g.