Piping Terms Glossary
A - B - C - D - E - F - G - H - I - J - K - L - M - N - O - P - Q - R - S - T - U - V - W - X - Y - Z
(If you have any to add, please email info@pipingdesigners.com
This
list is intended to include most commonly used abbreviations and acronym
found in Piping Engineering and Design work.
It has been compiled and prepared to aid both the newcomer and others
with a convenient list for mutual use and understanding. If you have any other abbreviations or acronyms you want to add
or feel should be added, please email info@pipingdesigners.com.
Or
A
Absolute - (See ABS)
A
Air – Used to define the commodity in a Line Number
A
Analog signal - This is normally the indication of the existence
of and type signal from some instrument in the plant back to the control
room panel
A
Inlet Nozzle - See Note #1
A
Pipe Anchors – This is a fixed anchor restricting the pipe movement
at a specific support from moving in any (horizontal of vertical) direction.
A/G
Above Ground – The most common use for this abbreviation is on a
P&ID to indicate that portion of a line that is to be or will be above
ground.
ABS
Absolute - Unit of measure. This
term is normally used along with another qualifier as in Absolute Pressure.
AC
Air Conditioner - Equipment designation
AC
Air to Close – This is normally found on a P&ID at a control
valve and indicates that the control valve is a “spring to open and therefore
needs air to close.
AC
Combustion -
ADAPT.
Adaptive control mode -
AFC
Approved For Construction – This is a status indicator for engineering
documents such as Flow Diagrams, Specifications, Drawings, etc.
This indication (note) is normally stamped on a document in red so
that it is very visible. The “Approved” part of the note normally means
that the Client has done the Approving.
AFD
Approved For Design – This is also a status indicator.
But in this case the document is normally an early schematic drawing
such as a P&ID. The “Approval”
is still by the Client.
AG
Above Ground
AGA
American Gas Association
AISC
American Institute of Steel Construction
AISI
American Iron and Steel Institute
ANSI
American National Standards Institute
AO
Air to Open - This is normally found on a P&ID at a control valve
and indicates that the control valve is a “spring to close and therefore
need air to open.
AP
Plant Air – Used to define the commodity in a Line Number
API
American Petroleum Institute
AS
Air Supply – Used to define the commodity in a Line Number
AS
Sprinkler system
ASA
American Standard Association -
ASME
American Society of Mechanical Engineers -
ASTM
American Society for Testing and Materials -
ATM
Atmosphere
AVG.
Average
AWS
American Welding Society -
AWWA
American Waterworks Association -
B
Outlet Nozzle – See Note #1
BA
Base Anchor – This is a type of support often used under piping low
to grade or floor surface. It is
rigidly connects the piping to the paving or floor surface.
BBE
Beveled Both Ends – This is an end prep qualifier for piping fittings
such as reducers and swedges.
BBL
Barrel – This is most commonly used when discussing the plant capacity
(100,000 Bpd) or the capacity of a tank.
It normally refers to a “55 Gallon Barrel” but one should remember
that a barrel actually holds only 42 US gallons.
BBP
Bottom of base plate – The Base Plate in this case is the bottom
ring plate of a vertical vessel support or the bottom plate of a saddle
support of a piece of horizontal equipment.
BC
Bolt Circle – This might be for a flange, a Vertical vessel support
or for a Manhole.
BD
Blow down - – Used to define the commodity in a Line Number
BF
Blind / Blank Flange
BFW
Boiler Feed Water – This is the cleaned, treated, preheated high
pressure water that is pumped into a Boiler to make steam.
BG
Base Guides – This is a type of support under low piping that is
designed to allow the pipe to move back and forth in a specific direction.
BL
Battery limit – This is the invisible boundary around specific portion
of a process plant (i.e.: The Crude Unit Battery Limits)
BLE
Beveled Large End - This is an end prep qualifier for piping fittings
such as reducers and swedges.
BLK
Black
BLVD
Boulevard – As in a type of street
BVLD
Beveled – This would normally refer to the end preparation for pipe
and fittings.
BOF
Bottom of Face of Flange – This would be used as a reference point
clarification when used with an elevation (i.e.: BOF Elev. 109’ - 0”) for
a flange on a vertical line.
BOM
Bill of Material – This term can have two meanings.
First there is the BOM that is included as a part of an individual
document such as a piping isometric. The
second is the summary of the material from all documents or isometrics.
BOP
Bottom of Pipe – This refers to the bottom of a pipe when lying in
the horizontal position.
BS
British Standard
BSE
Beveled Small End - This is an end prep qualifier for piping fittings
such as reducers and swedges.
BTM
Bottom
BTU
British thermal unit - Unit of measure
BW
Butt Weld or Butt Welded – Butt welding means that the end of the
pipe, fitting and/or flange are beveled to a specific contour as defined
by the Code (per different wall thicknesses) then welded together.
C
Centigrade or Celsius - Unit of measure
C
Clean Drain – This is a system qualifier that would appear on P&ID’s,
Underground and other Drawings to designate the Clean Drain system.
C
Condensate – Used to define the commodity in a Line Number
C
Condensate Nozzle
C
Cradles – The term Cradle, when used on piping drawings normally
refers to a curved section of metal plate (approx 120 degrees) and about
24” (610mm) long. This metal (normally steel) is fitted on the
underside of an insulated line (outside the insulation) at each pipe support
so that the weight of the line at the support does not crush the insulation.
C
Patchboard or matrix board connection -
CC
Corrosion Coupon – This is a piece of metal that is welded to a holder
of some type and placed inside the process fluid.
From time to time the thickness of this is removed and measured to
determine the amount of corrosion taking place in the system itself.
C-C
Centre to Centre – Refers to the type of dimension (i.e.: Center
to Center of two pipes)
CDO
Certified Dimension Outline – This refers to a vendor drawing such
as an Exchanger, a Pump or any other purchased equipment which has been
reviewed by your company, your requirements for modifications have accepted
and incorporated by the Vendor and they have signed (Certified) that they
will build and deliver what is shown on “this” drawing.
CENT
Centigrade - Unit of measure
CFM
Cubic Feet per Minute
CHU
Centigrade Heat Unit
CI
Cast Iron -
cL
Centerline – The centerline is the primary locating reference point
used for the location of all objects such as Pipes Tanks, Vessels, Pumps,
Structural Pipe Supports, Structures, Roads, etc. in Process Plant engineering
and design.
CM
Centimeter -
CO
Chain Operated – This will apply to an operating valve that could
not be located with-in reach and has been fitted with a device that used
a chain from below to open or close.
CO
Clean Out – This is commonly used on underground drawings to indicate
the location of clean-out points for buried systems.
COP
Critical Operating Parameters -
Cr
Chromium – A metal found in some alloy pipe
CrMO
Chrome Moly – A material often used in process plants for higher
pressure and temperature services.
CS
Carbon Steel – The most common material currently used in process
plants such as Refineries and Power Plants.
CS
Cold Spring – This is an indication that action has been taken to
reduce the effect of stress by an expanding line due to the operating temperature. Example: A long line will expand 6” (152 mm)
at normal operation conditions. That
6” (152mm) of growth will result in excessive stress on some point of the
system. You determine that you need
to reduce the excessive stress. To
do this you calculate what the “true” dimension for the long run should
be but you call for the shop (or the Field) to remove one half the expected
growth, in this case 3” (76mm) from the “true” dimension.
This is called “Cold Spring” or “Cold Springing” the line.
CSC
Car Seal Closed – This is normally a designation that appears at
a valve symbol on a P&ID (placed there by the Process Engineer) to indicate
that this valve is to be fitted with a locking device of some sort to prevent
inadvertent or unauthorized opening. This
designation shall be placed on all subsequent piping drawings showing that
valve and the piping material control group may be required to purchase
the device.
CSO
Car Seal Open – Same as CSC but indicated that the valve is to be
in the Open position.
CTR
Center – As in the center of a circle
CU
Cubic
CV
Control Valve – The term “Control Valve” is commonly used for a wide
range of actuator operated valves. The
type of valve body is most often a Globe type but can also be a Ball, Butterfly,
Pinch or other type. The actuator
can be Pneumatic, Solenoid, Electric Motor or other type.
CWP
Construction Work Package – A Construction Work Package is the identification
of and all the paperwork including drawings, material lists, Specifications
and contracts defining a segment of work for an EPCM process plant project. (Example: Underground Piping CWP, Aboveground
Piping CWP, Insulation CWP, Electrical CWP, etc.)
CWR
Cooling Water Return – Used to define the commodity in a Line Number
CYR
Cycle Water Return – Used to define the commodity in a Line Number
CYS
Cycle Water Supply – Used to define the commodity in a Line Number
D
Derivative control mode – Commonly used with instrumentation
D
Digital signal – Commonly used with instrumentation
D
Drain – Used to define the commodity in a Line Number
D
Drain or Draw off Connection - See Note #1
DCS
Distributed Control System – Commonly used with instrumentation
DEG
Degree - Unit of measure
DIA
Diameter -
DIFF
Difference, used in math meaning to Subtract
DIM
Dimension
DIN
Deutsche Industry Norm [German Standard]
DIR
Direct-acting -
DO
Drawing Office -
dP
Delta P, Pressure differential
DRG
Drawing [Not Preferred] see DWG
DS
Dummy Support – A Dummy Support is a stub of pipe 3’ to 7’ long (1
meter to 2 meters long) that is attached to an elbow where a line leaves
the pipe way short of the next support.
The stub will extent to reach the next structural pipe support and
provide support for the line.
DW
Drywall -
DWG
Drawing – The most commonly used and the more proper abbreviation
for the term “Drawing”
E
East - As in a direction. Often
used with Coordinate method of defining location or position of in item
of equipment.
E
Voltage signal - Commonly used with instrumentation or Electrical
ECN
Engineering Change Notice – This is a part of the system used to
control and track costs within a “Lump-Sum” contract.
All changes, whether they are Client originated of the result of
late design development is identified, given a “DCN” number, written up,
reviewed through the project approval process.
If the DCN is accepted then the change is made and the cost is added
to (or deducted from) the contract.
ECN
Engineering Charge Number – (Same as DCN)
E-E
End to End – Used to clarify a dimension.
EFW
Electric-Fusion-Welded – Refers to one of the ways that “rolled and
welded” pipe is made.
EL
Elbow – (Not Preferred)
EL
Elevation -
ELB
Elbowlet – (Not Preferred)
ELL
Elbow – (Preferred)
EOL
Elbow-let – A special shaped piping fitting that allows for a branch
attachment onto an elbow and provides built-in reinforcement for the attachment
point.
EOP
End of Pipe – A term used as a part of the dimensional designation
when locating the end of a piece of pipe such as a vent to atmosphere.
EA
Engineer/Architectural - This
can mean a type of company or a type of project.
An AE company or project only does some engineering and then only
produces conceptual drawings. They
cannot and do not produce detailed engineering drawings or bills of materials
because they do not purchase any equipment required to for detailed design.
EPC
Engineering, Procurement & Construction - This can mean a type
of company or a type of project. An EPC Company or Project means a full service capability of Engineering,
Procurement and Construction of the complete process plant.
EPC&C
Engineering, Procurement, Construction and Commissioning - Indicates
type of company or project that is done by one contractor that includes
Engineering, Design, Procurement, Construction and Commissioning (also see
LSTK)
EPCM
Engineering, Procurement & Construction Management - This can
mean a type of company or a type of project.
An EPCM Company or Project means a full service capability of Engineering,
Procurement and the construction portion of the project is executed by Sub-Contractors
under the Management of the EPCM Contractor.
ERW
Electric-Resistance-Welded - Refers to one of the ways that “rolled
and welded” pipe is made.
ES
Electric Supply –
ESS
Emergency Shutdown System –
ESV
Emergency Shutdown Valve – This is used to identify certain valves
that are manually or motor operated that shall be closed in case of a fire,
explosion or Terrorist attack.
ET
Electrically Traced – This indicates a pipe line (or piece of equipment)
that shall be provided with heat tracing via electric resistance cable.
ETA
Estimated Time (of) Arrival – Term used in procurement to indicate
when an item will arrive at a destination.
F
Fahrenheit - Unit of measure relating to temperature
F
Feed Nozzle - See Note #1
(F)
Furnished – Indicated that the
object or item is supplied with something else.
F&D
Faced and Drilled – Means that the indicated surface has been machined
smooth and drilled to accept some other object.
(F&P)
Furnished & Piped – Similar to “Furnished” but is further clarified
to indicate that the required piping is also included as “Furnished”.
FAB
Fabrication – Can be a noun or a verb.
A Fabrication can mean a piping spool that is a “Fabrication”. Or it can be used to say the pipe spool is
in “Fabrication”.
FAHR
Fahrenheit - Unit of measure
FBW
Furnace-Butt-Welded - Refers to one of the ways that “rolled and
welded” pipe is made.
FC
Fail Closed – This means that in case of power failure of loss of
instrument air the valve (or other object) will default to a closed and
safe position.
FCN
Field Charge Number – A system for numeric indexing, identification
and control of changes originating from the field.
FD
Flex-Disc Valve – Normally relates to a type of Gate valve that has
a special design for the disc that is intended to insure a tight closure.
FD&SF
Faced, Drilled and Spot-Faced -
FE
Flanged End – Meaning that an object has flanged connections.
FEED
Front End Engineering & Design - The FEED part of a project would
be characterized as the first twenty percent (20%) to thirty percent (30%)
of the engineering of a project. The
FEED Contractor may have been awarded all or a part of the project. They are now working with the Client (and Licensors
if applicable) to prepare the front end requirements for the project. The
heaviest work load during this FEED part will be in the Process Engineering
group. However, there are some Piping
activities that start at this time (Also see Pre-FEED)
FF
Face to Face – As in Face-to-Face dimension
FF
Flange Face [dimensioning] -
FF
Flat Face (d)
FF
Full Face [of gasket]
FFW
Final Fit Weld - Refers to a piping weld that is to be made in the
field (Point of installation) as opposed to being made in a pipe fabrication
shop. This weld can only be pipe-to-pipe or pipe-to-fitting.
The pipe component is to be fabricated long with (6” to 9”) of extra
length for final field fit-up. This
weld (for this line) is to be made only after all other Field Welds” have
been completed.
FG
Fuel Gas - Used to define the commodity in a Line Number
FI
Fail Indeterminate - This means that in case of power failure of
loss of instrument air the valve (or other object) will default in place
or current position.
FIV
Fire Isolation Valve – (See ESV)
FL
Fail Locked – (See FI)
FLG
Flange
FLGD
Flanged End
FMU
Fitting Make Up – This means that two or more commonly manufactured
piping fittings or flanges are welded together without any pipe between
the items.
FO
Fail Open - This means that in case of power failure of loss of instrument
air the valve (or other object) will default to an open and safe position.
FOB
Flat on Bottom – A term most commonly used with eccentric reducers
and other non-concentric objects.
FOB
Free on Board – A legal term commonly used in contracts and or procurement
FOB
Freight on Board - A legal term commonly used in contracts and or
procurement
FOT
Flat on Top - A term most commonly used with eccentric reducers or
other non-concentric objects.
FP
Full Port Valve – This term often used with Ball Valves means that
the “Port” or opening in the ball is the same size as the adjoining pipe
inside diameter.
FPT
Female Pipe Thread
FRP
[Glass] Fiber Reinforced Pipe
FS
Base Supports – Indicates a type of secondary support that is normally
used under one side of a Control Valve Manifold.
FS
Far Side
FS
Field Supports – Indicates any of a number of secondary type pipe
supports.
FS
Forged Steel -
FTG
Fitting – This is a universal term that applies to many trades and
trade material (piping, electrical, etc.).
For piping it includes elbows, TEEs and O-Lets.
FV
Full Vacuum
FW
Field Weld – Refers to a weld (normally in piping) that is to be
made in the field (Point of installation) as opposed to being made in a
pipe fabrication shop. This weld can be pipe-to-pipe, pipe-to-fitting or
fitting-to-fitting. The pipe and fitting components on both sides
of this weld are dimensionally correct and no trimming is to be done without
the approval of the Design Office.
FW
Fire Water - Used to define the commodity in a Line Number
G
Gas – Used to define the commodity in a Line Number
G
Glycol – Used to define the commodity in a Line Number
G Gram - Unit of measure
G
Level Gauge or Gauge Glass -
G
Pipe Guides -
GAL
Gallon - Unit of measure
GALV
Galvanized – Rust resistant plating added to metal objects
GO
Gear Operated – Used in conjunction with a valve description.
GPH
Gallon per Hour - Unit of measure
GPM
Gallon per Minute - Unit of measure
GR
Grade – Is commonly used for both Paved or Unpaved surfaces of a
process plant
GS
Gas Supply – Used to define the commodity in a Line Number
GT
Glycol Traced – Commonly used to define a type of heat tracing
GV
Gauge Valve – A valve used for isolation with various types of instruments
H
Hand hole - See Note #1
H
Horizontal – A direction or physical attitude
H
Hot condensate drain - See Note #1
H
Hour – Commonly used with Instruments or units of measure
H
Hydraulic signal - Used to define the commodity in a Line Number
H. PT.
High Point – (see HP)
HDR
Header – May be used when defining a main supply pipe for a utility,
example: HP Steam Header. Or it
can be used to define a physical feature associated with a piping configuration,
example: The Weld-O-Let was used to add a branch to the Header.
HEX
Hexagonal – A shape with six sides
Hg
Mercury - Used to define the commodity in a Line Number
HH
Hand hole - See Note #1
HOA
Hand / Off / Auto – Common electrical terminology for Pump controls
HP
High Point – Used to define the reference for the highest point of
the concrete paving or other service material.
(Also see HPP)
HP
High Pressure -
HP
Horse Power -
HPC
High Pressure Condensate – Used to define the commodity in a Line
Number
HPP
High Point of (finished) Pavement – (See HP)
HPS
High Pressure Steam – Used to define the commodity in a Line Number
HPT
Hose-Pipe Thread -
HR
Hanger Rods – A device that is intended to provide support from above
for an object such as a pipe
HR
Hour - Unit of measure
HS
Hose Station – (See US)
HS
Hydraulic Supply – Used to define the commodity in a Line Number
HTR
Heater – Relates to a type of equipment found on a project
HVAC
Heating Ventilation and Air Conditioning – Can indicate the Profession,
the Equipment or the Work.
I
Current (electrical) signal
I
Inorganic waste – Used to define the commodity in a Line Number
I
Interlock
IA
Instrument Air – Used to define the commodity in a Line Number
IAS
Instrument Air Supply – Used to define the commodity in a Line Number
ID
Inside Diameter – common usage terminology
ID
Internal Diameter – not common usage terminology
IE
Invert Elevation – (See Inv. El.)
IFA
Issued For Approval – This is an indication of “Status” for an engineering
or design document issued as a part of a Process Plant Project. This normally means issued to the Client for the required Approval.
IFB
Issued For Bid - This is an indication of “Status” for an engineering
or design document issued as a part of a Process Plant Project. This normally means a document that is intended for a Contractor
or Sub-Contractor to use to prepare his (her) bid.
IFC
Issued For Construction - This is an indication of “Status” for an
engineering or design document issued as a part of a Process Plant Project. This normally means that the data shown on
the document is complete and approved for fabrication and or construction.
IMP
Imperial – This normally applies to units of measure such as feet
and inches or opposite of metric.
INS
Insulation – Applies to the non-metallic coverings applied to piping
systems or equipment for the conservation or retention of heat or cold.
INST
Instrumentation -
Inv. El.
Invert Elevation – This is the bottom point of the inside diameter
of a Drain system pipe. It is the
point used to set and insure the correct slope of the pipe for drainage.
IPS
Iron Pipe Size -
IRI
Industrial Risk Insurers -
IS
Inside Screw [of valve stem] – Refers to a type of Valve design.
IS&Y
Inside Screw and Yoke - Refers to a type of Valve design.
ISBL
Inside Battery Limits (or Onsite) – Refers to any single or collection
of inter-related and inter-connected process units that performs an integrated
process function. Typically any Onsite Unit could be made to function independently
of another Onsite Unit.
ISO
Isometric drawing - In piping this term refers to a semi-3 dimensional
drawing representation of a pipe line or part of a pipe line. The Isometric should contain ALL the graphics, dimensions, identification
and technical data necessary to purchase material, fabricate, test and install
the displayed piping.
J
Pump out Nozzle - See Note #1
K
Carbonate – Used to define the commodity in a Line Number
K
Kilo, times one thousand, x 1000
KG
Kilo Gram
L
Level Instrument Nozzle - See Note #1
L
Liquid – Used as a qualifier for Process (and other) information. Example: HLL = High Liquid Level)
**LL
Liquid Level (** Denotes suffix (es), for high, low, high high, low
low, etc.) i.e. LLLL - Low Low Liquid Level
L.PT.
Low Point – Often used in defining the other critical elevation point
(see HP) for paving.
LA
Level Alarm – Defines a type of instrument
LB, Lb
Pound weight - Unit of measure
LC
Level Controller - Defines a type of instrument
LC
Lock Closed - Commonly used with valves that must remain closed unless
special authority is granted otherwise.
LG
Level Gauge - Defines a type of instrument
LI
Level Indicator - Defines a type of instrument
LIC
Level Indicating Controller - Defines a type of instrument
LO
Lock Open – Commonly used with valves that must remain open unless
special authority is granted otherwise.
LOL
Low Oxygen Level
LP
Low Point - (See L.PT.)
LP
Low Pressure – Commonly used to define a condition or quality of
a commodity. Example: LP Alarm)
LPC
Low Pressure Condensate - Used to define the commodity in a Line
Number
LPS
Low Pressure Steam - Used to define the commodity in a Line Number
LR
Long Radius [Of Elbow] – LR is equal to 1.5 times the nominal diameter
LS
Level Switch - Defines a type of instrument
LSTK
Lump Sum Turn Key – Indicates the type of company or a project that
is done by one contractor that includes Engineering, Design, Procurement,
Construction and Commissioning (also see EPC&C)
LT
Level Transmitter - Defines a type of instrument
LT
Light-wall [Of Pipe] -
M
Manhole - See Note #1
M
Mega, times one million, x 1 000 000 - Unit of measure
M
Meter - Unit of measure
M
Motor actuator
M
Motorized – Used to indicate that a Valve is “Motorized (Has a motor
operator).
M/C
Machine
MACH
Machined
MATL
Material
MAWP
Maximum Allowable Working Pressure – Most often used with vessels
or piping systems
MAX
Maximum
MAX
Maximum control mode
MCC
Motor Control Center – Defines a building with a collection of electrical
equipment
MFR
Manufacturer
MI
Malleable Iron
MIN
Minimum
MIN
Minimum control mode
MIN
Minute [Of time]
mm
Millimeter
Mo
Molybdenum – An element found in pipe steel.
MOS
Maintenance Override Switch
MP
Medium Pressure
MPC
Medium Pressure Condensate - Used to define the commodity in a Line
Number
MPS
Medium Pressure Steam - Used to define the commodity in a Line Number
MPT
Male Pipe Thread
MS
Mild Steel
MSF
Mill Scale Free – Means that the pipe (or other item) has been or
must be wire brushed or sand blasted.
MSS
Manufacturers' Standardization Society – Applies to the Valve and
Fittings Industry
MT
Magnetic Particle Inspection – (See NDE)
MTO
Material Take Off – Describes both the act of doing the task and
the product of the task.
MW
Manway - See Note #1
N
Nitrogen – Used to define the commodity in a Line Number
N
North – This can be True North, Plant North, Platform North or Magnetic
North.
N
North - As in a direction. Often
used with Coordinate method of defining location or position of in item
of equipment.
N
Reboiler Connection - See Note #1
NC
Normally Closed – This is used to designate the normal setting of
a valve.
NDE
Non-Destructive Examination – This refers to a grouping of 5 methods
used to indicate the quality of a weld on vessels or piping.
These are VT, RT, MT, PT, and UT (See: http://www.ndt.net/article/0698/hayes/hayes.htm)
NEMA
National Electrical Manufacturers' Association
NFPA
National Fire Protection Association
NG
Natural Gas – Used to define the commodity in a Line Number
Ni
Nickel
NIC
Not in Contact
NIPP
Swaged Nipple
NLL
Normal Liquid Level
NNF
Normally No Flow
NO
Normally Open
NPS
Nominal Pipe Size
NPSC
Straight pipe thread in pipe couplings
NPSF
Dryseal straight pipe thread (lubricant optional)
NPSH
Net positive suction head
NPSH
Net Positive Suction Head
NPSH
Straight pipe thread for hose couplings and nipples
NPSI
Dryseal internal straight pipe thread
NPSL
Straight pipe thread for locknut and locknut pipe thread
NPSM
Straight pipe threads for mechanical joints
NPT
National Pipe Thread
NPT
Taper Pipe Thread
NPTF
Dryseal taper pipe thread (lubricant optional)
NRS
Near Side
NS
Nitrogen Supply – Used to define the commodity in a Line Number
NV
Needle Valve
O
Electromagnetic or sonic signal
O
Oil – Used to define the commodity in a Line Number
O
Organic Waste Drain
OD
Outside Diameter
Offsite
(See OSBL)
OG
Oxygen – Used to define the commodity in a Line Number
Onsite
(See ISBL)
OP
Operating Valve
OPT
Optimizing control mode
OS
Outside Screw [Valve stem]
OS&Y
Outside Screw and Yoke [Valve stem]
OSBL
Outside Battery Limits (Offsite) -- In a process plant (Refinery,
Chemical, Petrochemical, Power, etc.), any supporting facility that is not
a direct part of the primary or secondary process reaction train or utility
block.
OSHA
Operation Safety and Health Act (USA)
OVHD
Overhead – This is used to define a specific piece of equipment (i.e.:
OVHD Condenser) a specific nozzle on a vessel (i.e.: OVHD Nozzle) of the
product in the line (i.e.: Crude OVHD)
OWD
Oily Water Drain – Used to define the commodity in a Line Number
OX
Oxide - A chemical element
P
All process lines
P
Pneumatic signal
P
Pressure Connection - See Note #1
P
Proportional control mode
P
Purge or flushing device
P&ID
Piping and Instrument Diagram – The primary document produced by
the Process Engineer to define in detail what is required for any process
plant.
PA
Plant Air Supply – Used to define the commodity in a Line Number
PBE
Plain Both Ends [Swage, etc.]
PC
Pressure Controller
PC
Pumped Condensate – Used to define the commodity in a Line Number
PCV
Pressure Control Valve
PE
Plain End [Pipe, etc.]
PFD
Process Flow Diagram – Indicated a preliminary schematic drawing
produced by the Process Engineer to define the simplified process concept. It is the precursor to the P&ID.
PFI
Pipe Fabrication Institute
PG
Pilot Gas – Used to define the commodity in a Line Number
PI
Pressure Indicator – A direct reading gage or indicator.
PIV
Post Indicator Valve – Common type valve used for shut-off of underground
water lines to a fire hydrant or fire Monitor.
PLC
Programmable Logic Controller
PO
Pump Out – Used to define the commodity in a Line Number
POE
Plain One End [Nipple, etc.]
POS
Point of Support
PR
Pressure Regulator
Pre-FEED A
Pre-FEED project is one where someone is conceptually defining a proposed
new project. Many Clients will perform
the Pre-FEED part of a project with their own staff. Clients may also obtain
the services of an engineering company to develop the Pre-FEED project package.
The objective of contracting out the Pre-FEED package is three-fold.
First, the Client may need the expertise of the engineering company
to objectively look at the project goals and determine if it feasible. Second, the Client wants a package that they
can issue to other selected Contractors for bidding purposes. Third, the Client will want the Pre-FEED Contractor
to prepare a realistic estimate of total-installed-cost (TIC) for their
internal requisition for funding and to evaluate the other bids. (Also see FEED)
PRV
Pressure Reducing Valve – This is a valve functional description
not a specific valve manufacturer of specific valve type.
PRV
Pressure Relief Valve – This is a valve functional description not
a specific valve manufacturer of specific valve type.
Lots of companies make valves that are designed to open when the
pressure inside a vessel or system goes above a specific set pressure. (Also see PSV)
PS
Pipe Support – This is a general term and can mean any type of primary
or secondary devices used to hold up pipe.
PS
Pre-Spring – This is the technique of adding a small amount to the
dimension of an actual length of pipe required to reach from point “A” to
point “B”. This practice is to compensate fro systems
in cryogenic service where the pipe would shrink due to the negative coefficient
of expansion.
PS
Process Sewer - Used to define the commodity or service in a Line
Number
PSI
Pound per Square Inch – Defines a unit of measure related to pressure.
PSIA
Pound per Square Inch Absolute - Defines a unit of measure related
to pressure.
PSIG
Pound per Square Inch Gage - Defines a unit of measure related to
pressure.
PSV
Pressure Safety Valve – (also see PRV)
PT
Pressure Tap – Sometimes used to define the future purpose of a valved
and plugged connection.
PT
(Liquid) Penetrate Inspection – (See NDE)
PU
Pick-Ups – Used to define a type of secondary pipe support. This method (short length of Angle Iron and “U” Bolts) uses a larger
size pipe to provide support for a smaller pipe line.
Pup
A “Pup” piece is a short length of pipe required between two fittings,
a fitting and a flange or between two flanges to make-up a required dimensional
distance.
PW
Potable Water – Used to define the commodity in a Line Number
PWHT
Post Weld Heat Treated – This is the action of applying heat to piping
to relieve stress built up in the material due to the welding during fabrication.
R
Automatic-reset control mode – Used in the electrical and controls
systems.
R
Radius -
R
Reflux Nozzle - See Note #1
R
Reset - Used in the electrical and controls systems.
R
Reset of fail-locked device - Used in the electrical and controls
systems.
R
Resistance (signal) - Used in the electrical and controls systems.
R/L
Random Length – Often used in the purchase of pipe.
Single Random Length = 20 feet (+/-) 7meters (+/-). Double Random Length = 40 feet (+/-) 14 meters
(+/-)
RED
Reducer – Used in Concentric Reducer (Conc Red) or Eccentric Reducer
(Ecc Red)
RED
Reducing -
REF
Reference -
REQ
Requisition – Term used in Procurement activities or the actual document.
REQ
Required -
REV
Reverse-acting -
RF
Raised Face – A type of flange face.
RFI
Request for Information - Term used in Procurement activities or
the actual document.
RFP
Request for Purchase - Term used in Procurement activities or the
actual document.
RFQ
Request for Quote - Term used in Procurement activities or the actual
document.
RJ
Ring Joint – (see RJT) -
RPM
Revolutions per Minute -
RS
Rising Stem [Of valve] -
RT
Reducing Tee -
RT
Radiographic Inspection – (See NDE)
RTD
Resistance (-type) temperature detector -
RTJ
Ring Type Joint – A type of flange facing/gasket
RW
Raw Water – Used to define the commodity in a Line Number
S
Pipe Shoes – A device used under Hot Insulated pipes to raise the
pipe up off the primary pipe support level thus protects the insulation.
S
Solenoid actuator -
S
South - As in a direction. Often
used with Coordinate method of defining location or position of in item
of equipment.
S
Steam or Sample Connection - See Note #1
S
Storm Water Drain – Used to define the commodity in a Line Number
S.G.
Specific Gravity -
SAE
Society of Automotive Engineers -
SC
Sample Connection -
SC
Steam Condensate – Used to define the commodity in a Line Number
SCH
Schedule [Of pipe] – Relates to the wall thickness of pipe
SCRD
Screwed – Method of joining some types of pipe, fittings and valves.
SCV
Sample Point Valve -
SCV/T
Sample Point Valve with Thief -
SD
Shut Down -
SECT
Section – A “View” in mechanical drafting (similar to Elevation used
in Architectural drafting)
SF
Spot-Faced – The machining-off the back side of an object (i.e.:
a flange) to provide a true flat surface for the bolt head or nut.
Si
Silicon -
SKT
Socket - Method of joining some types of pipe, fittings and valves.
SMLS
Seamless – A type of pipe
SO
Slip-On – A type of flange
SO
Steam Out – See Note #1
SOL
Sock-o-let – A device used to make an integral reinforced branch
for socket-weld (size) pipe
SP
Sample Point -
SP
Set Point -
SP
Standard Practice [MSS term] -
SP
Steam Pressure -
Spec
Specification – A narrative description for the requirements of almost
anything
Spool In
piping a "Spool" is a contiguous fabricated part if an isometric
or a pipe line.
Example: a spool can be small such as a flange, an elbow and another
flange. Or it can be large such as a contiguous fabricated configuration
not to exceed the designated shipping size set for the project.
SQ
Square -
SQ.RT
Square Root -
SR
Short Radius [Of Elbow] -
SS
Sanitary Sewer – Used to define the commodity in a Line Number
SS
Spring Supports -
SS
Stainless Steel -
SS
Steam Supply – Used to define the commodity in a Line Number
SSO
Intermittent hot process drain – Used to define the commodity in
a Line Number
SST
Stainless Steel -
SSV
Soft Seat Valve -
ST
Steam Traced -
ST
Steam Tracing -
ST
Steam Trap -
ST
Support Trunnions -
STD
Standard -
STM
Steam – Used to define the commodity in a Line Number
STR
Straight -
STS
Storm Sewer – Used to define the commodity in a Line Number
SW
Socket Welding -
SWG
Swage -
SWG
Swaged Nipple -
SWP
Standard Working Pressure -
SWP
Steam Working Pressure -
T
Temperature -
T
Temperature Connection - See Note #1
T
Threaded -
T
Trap -
T&C
Threaded and Coupled [Pipe] – Pipe purchased from the supplier with
both ends threaded and a coupling installed on one end (only) of each length.
T/F.F
Tangent to Face of Flange -
T/T
Tangent to Tangent – Used define the distance of the straight side
of a vessel.
TB
Traced Valve Body – Term used where Heat Tracing is used for process
lines or equipment.
TBB
Traced Body & Bonnet - Term used where Heat Tracing is used for
process lines or equipment.
TBE
Thread Both Ends - Used with Swedge Nipples
TC
Temperature Controller -
TC
Test Connection -
TE
Threaded End -
TEF
Teflon -
TEMA
Tubular Exchanger Manufacturers' Association -
TGT
Tangent -
TI
Temperature Indicator – Indicates a direct reading gage or indicator.
TL
Tangent Line – Indicates the point on a cylindrical vessel where
the straight side intersects the curvature of the knuckle radius of the
head.
TLE
Thread Large End – Used with Swedge Nipples
TOC
Top of Concrete -
TOE
Threaded One End [Nipple or Swege] -
TOL
Thread-o-let - A device used to make an integral reinforced branch
for Threaded (size) pipe
TOP
Top of Pipe -
TOS
Top of Steel -
TOS
Top of Support -
TPI
Threads per Inch -
TS
Twin Seal – A type of Gate Valve.
TSE
Thread Small End - Used with Swedge Nipples
TSE
Threaded Small End - Used with Swedge Nipples
TYP. Typical -
U/G
Underground – A type of drawing or a buried piping system
UA
Utility Air – Used to define the commodity in a Line Number
UDD
Utility Distribution Diagram – A Plot Plan oriented drawing showing
the main distribution headers with all the branches in the proper sequence.
UFD
Utility Flow Diagram – Similar to a (process) P&ID but used for
the drawing use to define the generation of a plant utility service (Steam,
Plant Air, Cooling Water, etc.).
UG
Underground – (See U/G)
UNC
Unified Coarse [Bolt thread] -
UNF
Unified Fine [Bolt thread] -
UNO
Unless Noted Otherwise -
UNS
Unified Selected [Bolt thread] -
UON
Unless Otherwise Noted -
US
Utility Station – A collection of multiple services (Steam, Plant
Air, Plant Water, Nitrogen, etc.) arranged in locations at grade or on platforms
for use by maintenance and clean-up.
UT
Ultrasonic Inspection – (See NDE)
V
Valve -
V
Vanadium – An element found in some piping materials
V
Vapor Outlet or Vent Connection - See Note #1
V
Vent – Used to define the commodity in a Line Number
V
Vertical -
VB
Vortex Breaker – A device fabricated and installed inside a vessel
as a part of the pump suction nozzle to prevent the formation of a Vortex.
Vert
Vertical –
VT
Visual Inspection – (See NDE)
W
Relief Valve Nozzle - See Note #1
W
Water – Used to define the commodity in a Line Number
W
West – As in the direction. Often
used with Coordinate method of defining location or position of in item
of equipment.
W/
With -
WC
Water Column – A piping configuration that allows for the attachment
of multiple level and pressure instruments on a Tank or Vessel.
WE
Welded End – Often used with a valve to indicate the type of end
connections.
WGT
Weight -
WLD
Weld(ed) -
WN
Welding Neck – Indicated the type of Flange
WOG
Water, Oil and Gas -
WOL
Weld-o-let – A self reinforced branch fitting for butt weld continuation
WP
Working Point – Used on drawings with sloping pipe lines to indicate
the point where key information is given (Locating coordinates and elevations).
WP
Working Pressure -
WS
Water Supply – Used to define the commodity in a Line Number
WT
Weight -
x
Multiply -
X
Unclassified actuator – Used with instruments
XH
Extra-Heavy – Refers to the Wall Schedule of pipe
XS
Extra-Strong – (See XH)
XXH
Double Extra Heavy - Refers to the
Wall Schedule of pipe
XXS
Double-Extra-Strong – (See XXH)
#1 This Abbreviation is intended to indicate the specific
purpose or function for a nozzle on a vessel. However, the use of this specific letter for
this specific purpose or function is not universal throughout the engineering
community.
