Home - www.wermac.orgsearch wermac.org
www.wermac.org
Abbreviations
Piping related Articles

AFC is an abbreviation of Approved For Construction. Approved For Construction means, that eg a piping isometric meets all requirements, and that AFTER release the prefab can begin.

BB is an abbreviation of Bolted Bonnet. A bolted bonnet, or cover of a valve, is fastened (by bolts) to the valve body to complete the pressure-retaining shell.

BBE is an abbreviation of Beveled Both Ends. Beveled Both Ends means that both ends of e.g. a pipe nipple are beveled.
TOE / POE = Treaded One End / Plain One End
TOE / BOE = Treaded One End / Beveled One End
POE / BOE = Plain One End / Beveled One End
TBE = Treaded Both Ends
PBE = Plain Both Ends

BE is an abbreviation of Beveled Ends.
Beveled Ends are applied to all diameters of buttweld pipes, flanges, fittings, valves etc. and will be directly welded (with a small gap 3-4 mm) to each other. Ends are mostly be beveled to angle 30° (+5° / -0°) with a root face of 1.6 mm (± 0.8 mm).

BOM is an abbreviation of Bill Of Materials.
A Bill Of Materials is a detailed item by item tabulated list of the project requirements for piping. It specifies the required item by the reference grade and standard to which it must be made, by the size and its rating. The information on this table is entirely extracted from the material take-off documents.

BW is an abbreviation of Butt Weld(ing).
A Butt Weld is a circumferential butt welded joint, and the most common type of joint employed in the fabrication of welded pipe systems. A butt joint is the most universally used method of joining pipe to itself, fittings, flanges, valves, and other equipment. This welding technique is widely applied in situations where a quality weld desired, and the weld by X-ray technically should be investigated.

CMTR is an abbreviation of Certified Material Test Report.
A Certified Material Test Report attesting that the material is in accordance with specified requirements, including the actual results of all required chemical analyses, tests, and examinations.

CSC is an abbreviation of Car Seal Closed.
Very simply, the terms describe to need to lock (seal) a valve to prevent operation either in the open or closed position. The device to achieve this is a Car Seal (see also CSO).

CSO is an abbreviation of Car Seal Open.
Very simply, the terms describe to need to lock (seal) a valve to prevent operation either in the open or closed position. The device to achieve this is a Car Seal (see also CSC).

CUI is an abbreviation of Corrosion Under Insulation.
In the simplest terms, CUI is any type of corrosion that occurs due to moisture present on the external surface of insulated equipment. The damage/attack can be caused by one of the multiple factors, and can occur in equipment operating at ambient, low, and heated services, depending upon conditions. Moreover, CUI can occur in equipment that is in service, out of service, or in cyclic service.

EFW is an abbreviation of Electric Fusion Welding.
Electric fusion welding steel pipe is electron beam welding, directed impact kinetic energy electron beam, the use of high-speed movement into a hot workpiece to leave the workpiece melting, the formation of the weld. EFW pipes are formed from hot-rolled plates and welded welds. Welding flashes can be removed from the outside or inside using the caulking blade surface. Welding zone can also be heat treatment, so that the weld is not visible. Welded tubes generally have tighter dimensional tolerances than seamless tubes, and if made in the same amount, the cost is lower. Mainly used for dissimilar steel welding sheet or high power density welding, metal welding parts can be quickly heated to high temperatures, melting any refractory metals and alloys. Deep melting welding speed, heat-affected zone is very small, so the impact on the joint performance is small, the joint is almost no deformation. But it has special welding room requirements because of the use of X-ray welding.

ELL is an abbreviation of ELbow.

ERW is an abbreviation of Electric Resistance Welded.
Originally Electric Resistance Welded which contains a solid phase butt weld, was produced using resistance heating to make the longitudinal weld (ERW). Most pipe mills now use high frequency induction heating (HFI) for better control and consistency. However, the product is still often referred to as ERW pipe, even though the weld may have been produced by the HFI process.

ESV is an abbreviation of Emergency Shutdown Valve.
A Emergency Shutdown Valve is an actuated valve designed to stop the flow of a hazarous fluid or external hydrocarbons (gases) upon the detection of a dangerous event.
These valves are the final defence against process misreactions and have a function which requires much more reliable performance than standard remotely operated on-off valves.

FF is an abbreviation of Flat Face flange.
The Flat Face flange has a gasket surface in the same plane as the bolting circle face. Flat Face does not feature the raised face of heavy duty flanges such as ANSI B 16.5 for example. Applications using flat face flanges are frequently those in which the mating flange or flanged fitting is made from a casting.

FoF is an abbreviation of Flange of Face.
This terminology is used when dimensions have to be given with respect to face of flange.

FFW is an abbreviation of Field Fit Weld.
A field fit weld indicates that the designer has foreseen that the piping may need adjustment in the field so has added an extra length of pipe at a buttweld fitting or flange. The pipe end will be bevelled and welded on site after the installer determines the correct dimensions.

GMAW is an abbreviation of Gas Metal Arc Welding.

GTAW is an abbreviation of Gas Tungsten Arc Welding.

The finished product from a manufacturer (the pipe or fitting mill), is typically traceable to a Heat Number (steel mill identification). A heat typically identifies material produced in the steel mill from one single melt, and the number will be assigned in the steel mill. Chemical analysis is usually reported on a heat basis. Parts of a same heat have the same chemistry.

HAZ is an abbreviation of Heat-Affected Zone.
Cutting processes that use intense heat, like oxyfuel cutting and plasma arc cutting, produce thermal effects near the edge of the cut that lead to microstructural and metallurgical changes in the metal. The portion of a metal work-piece that has been so altered by heat is termed the heat-affected zone or HAZ. All thermal cutting processes create an HAZ in the cut metal.

ISBL is an abbreviation of In Side Battery Limits.
ISBL is functional-based and refers to equipment and other components that are solely dedicated to a single process whether or not the equipment is physically located within the geographical boundaries of the unit.

ITP is an abbreviation of Inspection Test Plan.
An Inspection Test Plan (ITP) is a commonly required document that you'll need to submit with your construction quality control plan. Whether you're working on a private sector or government contract, clients today all want to see your inspection test plan. They want to know exactly what inspections and tests you'll be forming to control quality on their project.

LR is an abbreviation of Long Radius Elbow.
Elbows are split into two groups which define the distance over which they change direction; the center line of one end to the opposite face.
This is known as the "center to face" distance and is equivalent to the radius through which the elbow is bent.
The center to face distance for a Long Radius elbow, abbreviated LR always is 1.1/2 x Nominal Pipe Size (1.1/2D), while the center to face distance for a Short Radius elbow, abbreviated SR even is to nominal pipe size.

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.

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.

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.

NDE is an abbreviation of Non Destructive Examination, also called Non Destructive Testing (NDT).
Non Destructive Examination survey techniques by which we can get an impression of the quality of an item to consider this item without damaging them.
To detect different defects such as cracking and corrosion, there are different methods of testing available like, X-ray, Ultrasonic testing (UT), Magnetic-particle inspection (MT or MPI), Liquid penetrant testing (PT or LPI) etc..

NPS is an abbreviation of Nominal Pipe Size.
Nominal Pipe Size is a North American set of standard sizes for pipes used for high or low pressures and temperatures. The name NPS is based on the earlier "Iron Pipe Size" (IPS) system.

NPT is an abbreviation National Pipe Thread Tapered.
The American National Pipe Thread Tapered, is the best known and most widely used connection where the pipe thread provides both the mechanical joint and the hydraulic seal. NPT has a tapered male and female thread which seals with Teflon® tape or jointing compound.
ASME B1.20.1 covers dimensions and gaging of NPT pipe threads for general purpose applications.

OSBL is an abbreviation of Outside Side Battery Limits.
OSBL refers to systems (equipment pieces and associated components) that support several units. Typical OSBL equipment includes cooling towers, water treatment facilities, tanks farms, etc.

OS&Y is an abbreviation of Outside Screw & Yoke.
A valve design in which the threaded portion of the stem is outside the pressure boundary of the valve. The valve bonnet has a Yoke, which holds a nut through which the rotating stem rises as the valve is opened. The stem part inside the valve is smooth and is sealed so that stem threads are isolated from the flow medium.

PBE is an abbreviation of Plain Both Ends.
Plain Both Ends means that both ends of e.g. a pipe nipple are plain.
TOE / POE = Treaded One End / Plain One End
TOE / BOE = Treaded One End / Beveled One End
POE / BOE = Plain One End / Beveled One End
TBE = Treaded Both Ends
BBE = Beveled Both Ends

PED is an abbreviation of Pressure Equipment Directive arises from the European Community's Programme for the elimination of technical barriers to trade and is formulated under the "New Approach to Technical Harmonisation and Standards".
Its purpose is to harmonise national laws of Member States regarding the design, manufacture, testing and conformity assessment of pressure equipment and assemblies of pressure equipment.
It therefore aims to ensure the free placing on the market and putting into service of the equipment within the
"European Union and the European Economic Area".
Formulated under the New Approach the directive provides for a flexible regulatory environment that does not impose any detailed technical solution. This approach allows European industry to develop new techniques thereby increasing international competitiveness. The pressure equipment directive is one of a series of technical harmonisation directives for machinery, electrical equipment, medical devices, simple pressure vessels, gas appliances etc...

PFD is an abbreviation of Process Flow Diagram.
A Process Flow Diagram is a schematic representation of the flow of fluids within the process as they travel between processing units. This diagram shows flow direction, but has no indication of the instruments and devices needed to control the process or to ensure safe operation.

PI is a mathematical constant that is the ratio of any Euclidean circle's circumference to its diameter. PI is approximately equal to 3.14. Many formulae in mathematics, science, and engineering involve PI, which makes it one of the most important mathematical constants. For instance, the area of a circle is equal to PI times the square of the radius of the circle. pi

PMI is an abbreviation of Positive Material Identification.
Positive Material Identification provides alloy chemistry and grade ID information instantly using a handheld tube-based analyzer without having to transport, alter, or damage the material. PMI is also used to ensure that the parent material in vessels and pipe spools is composed of the correct composition and once the component is welded that the correct filler material was used.

PWHT is an abbreviation of Post Weld Heat Treatment.
Post Weld Heat Treatment is defined as one of heat treatments done after welding/machining to improve the chemical and mechanical properties of weldment or machined surfaces. In concept, PWHT covers many different potential treatments.

RF is an abbreviation of Raised Face, and designed for flanges.
The Raised Face type are the most applied flange type, and is easily to identify. It is referred to as a raised face because the gasket surfaces are raised above the bolting circle face. The height in Pressure Class up to 300 Lbs is approximately 1.6 mm, and in Pressure Class 400 up to 2500 Lbs the height is approximately 6.4 mm. Pressure rating of the flange determines the height of the raised face. The purpose of a RF flange is to concentrate more pressure on a smaller gasket area and thereby increase the pressure containment capability of the joint.

RFC is an abbreviation of Released For Construction.
RFC means that the release for construction (after Approved For Construction) is given...start the project.

RTJ is an abbreviation Ring Type Joint flanges.
Ring Type Joint flanges have grooves cut into their faces which steel ring gaskets. The flanges seal when tightened bolts compress the gasket between the flanges into the grooves, deforming (or coining) the gasket to make intimate contact inside the grooves, creating a metal to metal seal.

SAW is an abbreviation of Sub-merged Arc Welding.
Submerged Arc Welding is a high quality, very high deposition rate welding process.
SAW uses heat generated by an arc formed when an electric current passes between a welding wire and the workpiece. The tip of the welding wire, the arc, and the weld joint are covered by a layer of granular flux. The heat generated by the arc melts the wire, the base metal and the flux. The flux shields the molten pool from atmospheric contamination, cleans impurities from the weld metal, and shapes the weld bead. Depending on the design of the flux, it can also add alloying elements to the weld metal to alter the chemical and mechanical properties of the wel.

SCH is an abbreviation of SCHedule.

SMAW is an abbreviation of Shielded Metal Arc Welding.
Shielded Metal Arc Welding is frequently referred to as stick or covered electrode welding. Stick welding is among the most widely used welding processes.

SMLS is an abbreviation of Seamless pipe or fitting.

SR is an abbreviation of Short Radius Elbow.
Elbows are split into two groups which define the distance over which they change direction; the center line of one end to the opposite face. This is known as the "center to face" distance and is equivalent to the radius through which the elbow is bent. The center to face distance for a Short Radius elbow is even to nominal pipe size, while the center to face distance for a Long Radius elbow abbreviated LR always is 1.1/2 x Nominal Pipe Size (1.1/2D).

SST is an abbreviation of Stainless STeel.
Stainless is a term coined early in the development of these steels for cutlery applications. It was adopted as a generic name for these steels and now covers a wide range of steel types and grades for corrosion or oxidation resistant applications.
Stainless steel contains a maximum of 1.2% carbon, a minimum of 10.5% chromium and other alloying elements. The presence of chromium confers on stainless steel its principal quality: its corrosion resistance.
The alloying elements, depending on their percentages, give stainless steels their physical, chemical and mechanical properties. The presence of alloying elements is the starting point for obtaining the desired properties, various production processes facilitating this. The carbon and iron steel base, together with the addition of various alloying elements, provide the balance of each grade and dertermine which stainless "family" it belongs.
The most frequently used alloying elements are: nickel, molybdenum, titanium, niobium, manganese, nitrogen, copper, silicon, aluminium and vanadium.

SW is an abbreviation of Socket Weld(ing).
A Socket Weld is a pipe attachment detail in which a pipe is inserted into a recessed area of a valve, fitting or flange. Socket Weld fittings are mainly used for small pipe diameters (Small Bore Piping); generally for piping whose nominal diameter is NPS 2 or smaller. To join pipe to valves and fittings or to other sections of pipe, fillet-type seal welds be used.

TBE is an abbreviation of Threaded Both Ends.
Treaded Both Ends means that both ends of e.g. a pipe nipple are threaded.
TOE / POE = Treaded One End / Plain One End
TOE / BOE = Treaded One End / Beveled One End
POE / BOE = Plain One End / Beveled One End
BBE = Beveled Both Ends
PBE = Plain Both Ends

TIG is an abbreviation of Tungsten Inert Gas.
Tungsten Inert Gas welding also known as GTAW is a process that produces an electric arc maintained between a nonconsumable tungsten electrode and the part to be welded. The heat-affected zone, the molten metal and the tungsten electrode are all shielded from atmospheric contamination by a blanket of inert gas fed through the GTAW torch. Inert gas (usually Argon) is inactive or deficient in active chemical properties. The shielding gas serves to blanket the weld and exclude the active properties in the surrounding air. Inert gases such as Argon and Helium do not chemically react or combine with other gases. They pose no odor and are transparent, permitting the the welder maximum visibility of the arc.

TofG is an abbreviation of Time of Flight Diffraction.
Time-of-Flight Diffraction Ultrasonic Testing is among the most modern testing methods for the detection of imperfections and defects in materials. Conventional Ultrasonic Testing uses sound reflection. ToFD testing measures the time-of-flight of an ultrasonic pulse to determine the position of a reflector. The application of this method is fast and extremely accurate. This has resulted in an increasing popularity over the last few years.

TOS is an abbreviation of Top Of Steel.

WPQ is an abbreviation of Welder Performance Qualification.
The Welder Performance Qualification document is required by all codes for all welders. It details and summarizes the following information:

Indicates the WPS referenced during the qualification test Identifies the welder by name and/or clock number Lists what the essential parameters were during this test Reports the results of the required qualification tests Specifies qualified limits for welder

For most codes there is a time limit associated with the welder qualification test. However, the American Welding Society provides an unlimited qualification period if certain conditions are met. As with the WPS and WPQR, each code has a recommended format.

WPS is an abbreviation of Welding Procedure Specification.
The Welding Procedure Specification is a required document for all code welding. Your customer either directly or indirectly specifies to what code your company must qualify. The WPS outlines all of the parameters required to perform your welding operation.
In short the WPS is the recipe for your welding operation. It describes the welding process or processes used, the base materials used, the joint design and geometry, gases and flow rates, welding position and includes all of the process conditions and variables. Each code has a recommended format.

WT is an abbreviation of Wall Thickness.
The Wall Thickness in piping terms is defined as schedule (SCH or S).

XXS is an abbreviation of EXtra EXtra Strong.

Go to Top of Page