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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)

Abbreviation.	Description
(F&P)	Furnished & Piped
(F)	Furnished
**LL	Liquid Level (* Denotes suffix(es), for high, low, high low, low low, etc.) ie LLLL - Low Low Liquid Level
A
A	Absolute
A	Air
A	Analog signal
A	Inlet Nozzle
A	Pipe Anchors
A/G	Above Ground
ABS	Absolute
AC	Air Conditioner
AC	Air to Close
AC	Combustion
ADAPT.	Adaptive control mode
AFC	Approved For Construction
AFD	Approved For Design
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
AP	Plant Air
API	American Petroleum Institute
AS	Air Supply
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
B	Outlet Nozzle
BA	Base Anchor
BBE	Beveled Both Ends
BBL	Barrel
BBP	Bottom of baseplate
BC	Bolt Circle
BD	Blowdown
BF	Blind / Blank Flange
BFW	Boiler Feed Water
BG	Base Guides
BL	Battery limit
BLE	Beveled Large End
BLK	Black
BLVD	Beveled
BOF	Bottom of Face of Flange
BOM	Bill of Material
BOP	Bottom of Pipe
BS	British Standard
BSE	Bevelled Small End
BTM	Bottom
BTU	British thermal unit
BW	Butt Weld
BW	Butt Welded
C
C	Centirgrade, or Celsius
C	Clean Drain
C	Condensate
C	Condensate Nozzle
C	Cradles
C	Patchboard or matrix board connection
CC	Corrosion Coupon
C-C	Centre to Centre
CDO	Certified Dimension Outline
CENT	Centigrade
CFM	Cubic Feet per Minute
CHU	Centigrade Heat Unit
CI	Cast Iron
cl	Centerline
CM	Centimeter
CO	Chain Operated
CO	Clean Out
COP	Critical Operating Parameters
Cr	Chromium
CrMO	Chrome Moly
CS	Carbon Steel
CS	Cold Spring
CSC	Car Seal Closed
CSC	Car-Sealed Close
CSO	Car Seal Opened
CSO	Car-Sealed Open
CTR	Centerline
CU	Cubic
CV	Control Valve
CWP	Construction Work Package
CWR	Cooling Water Return
CYR	Cycle Water Return
CYS	Cycle Water Supply
D
D	Derivative control mode
D	Digital signal
D	Drain
D	Drain or Drawoff Connection
DCS	Distributed Control System
DEG	Degree
DIA	Diameter
DIFF	Subtract
DIM	Dimension
DIN	Deutsche Industry Norm [German Standard]
DIR	Direct-acting
DO	Drawing Office
dP	Delta P, Pressure differential
DRG	Drawing [Not Preferred]
DS	Dummy Supports
DW	Drywall
DWG	Drawing
E
E	East
E	Voltage signal
ECN	Engineering Charge Number
E-E	End to End
EFW	Electric-Fusion-Welded
EL	Elbow
EL	Elevation
ELB	Elbowlet
ELL	Elbow
EOL	Elbowlet
EOP	End of Pipe
ERW	Electric-Resistance-Welded
ES	Electric Supply
ESS	Emergency Shutdown System
ET	Electrically Traced
ETA	Estimated Time (of) Arrival
F	Diameter
F
F	Fahrenheit
F	Feed Nozzle
F&D	Faced and Drilled
FAB	Fabrication
FAHR	Fahrenheit
FBW	Furnace-Butt-Welded
FC	Fail Closed
FCN	Field Charge Number
FD	Flex-Disc Valve
FD&SF	Faced, Drilled and Spot-Faced
FE	Flanged End
FEED	Front End Engineering Development
FF	Face to Face
FF	Flange Face [dimensioning]
FF	Flat Face(d)
FF	Full Face [of gasket]
FFW	Final Fit Weld
FG	Fuel Gas
FI	Fail Indeterminate
FIV	Fire Isolation Valve
FL	Fail Locked
FLG	Flange
FLGD	Flanged End
FMU	Fitting Make Up
FO	Fail Open
FOB	Flat on Bottom
FOB	Free on Board
FOB	Freight on Board
FOT	Flat on Top
FP	Full Port Valve
FPT	Female Pipe Thread
FRP	[Glass] Fiber Reinforced Pipe
FS	Base Supports
FS	Far Side
FS	Field Supports
FS	Forged Steel
FTG	Fitting
FV	Full Vacuum
FW	Field Weld
FW	Fire Water
G
G	Gas
G	Glycol
G	Grade
G	Gram
G	Level Gauge or Gauge Glass
G	Pipe Guides
GAL	Gallon
GALV	Galvanized
GO	Gear Operated
GPH	Gallon Per Hour
GPM	Gallon Per Minute
GR	Grade
GS	Gas Supply
GT	Glycol Traced
GV	Gauge Valve
H
H	Handhole
H	Horizontal
H	Hot condensate drain
H	Hour
H	Hydraulic signal
H.PT.	High Point
HDR	Header
HEX	Hexagonal
Hg	Mercury
HH	Handhole
HOA	Hand / Off / Auto
HP	High Point
HP	High Pressure
HP	Horse Power
HPC	High Pressure Condensate
HPP	High Point of Pavement
HPS	High Pressure Steam
HPT	Hose-Pipe Thread
HR	Hanger Rods
HR	Hour
HS	Hose Station
HS	Hydraulic Supply
HTR	Heater
HVAC	Heating Ventilation and Air Conditioning
I
I	Current (electrical) signal
I	Inorganic waste
I	Interlock
IA	Instrument Air
IAS	Instrument Air Supply
ID	Inside Diameter
ID	Internal Diameter
IE	Invert Elevation
IFA	Issued For Approval
IFB	Issued For Bid
IFC	Issued For Construction
IMP	Imperial
INS	Insulation
INST	Instrumentation
IPS	Iron Pipe Size
IRI	Industrial Risk Insurers
IS	Inside Screw [of valve stem]
IS&Y	Inside Screw and Yoke
ISBL	Inside Battery Limits
ISO	Isometric drawing
J
J	Pumpout Nozzle
K
K	Carbonate
K	Kilo, times one thousand, x 1000
KG	Kilo Gram
L
L	Level Instrument Nozzle
L	Liquid
L.PT.	Low Point
LA	Level Alarm
LB, Lb	Pound weight
LC	Level Controller
LC	Lock Closed
LG	Level Guage
LI	Level Indicator
LIC	Level Indicating Controller
LO	Lock Open
LOL	Low Oxygen Level
LP	Low Point
LP	Low Pressure
LPC	Low Pressure Condensate
LPS	Low Pressure Steam
LR	Long Radius [Of Elbow]
LS	Level Switch
LT	Level Transmitter
LT	Light-wall [Of Pipe]
M
M	Manhole
M	Mega, times one million, x 1 000 000
M	Meter
M	Motor actuator
M	Motorized
M/C	Machine
MACH	Machined
MATL	Material
MAWP	Maximum Allowable Working Pressure
MAX	Maximum
MAX	Maximum control mode
MCC	Motor Control Center
MFR	Manufacturer
MI	Malleable Iron
MIN	Minimum
MIN	Minimum control mode
MIN	Minute [Of time]
MM	Millimeter
Mo	Molybdenum
MOS	Maintenance Override Switch
MP	Medium Pressure
MPC	Medium Pressure Condensate
MPS	Medium Pressure Steam
MPT	Male Pipe Thread
MS	Mild Steel
MSF	Mill Scale Free
MSS	Manufacturers' Standardization Society of the Valve and Fittings Industry
MTO	Material Take Off
MW	Manway
N
N	Nitrogen
N	North
N	Reboiler Connection
NC	Normally Closed
NDE	Non-Destructive Examination
NEMA	National Electrical Manufacturers' Association
NFPA	National Fire Protection Association
NG	Natural Gas
Ni	Nickel
NIC	Not in Contact
NIPP	Swaged Nipple
NLL	Normal Liquid Level
NNF	Normally No Flow
NNF	Normally No Flow
NO	Normally Open
NPS	National Pipe Size
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	Non-Rising Stem [Of valve]
NS	Near Side
NS	Nitrogen Supply
NV	Needle Valve
O
O	Electromagnetic or sonic signal
O	Oil
O	Organic Waste Drain
OD	Outside Diameter
OG	Oxygen
OP	Operating Valve
OPT	Optimizing control mode
OS	Outside Screw [Valve stem]
OS&Y	Outside Screw and Yoke [Valve stem]
OSBL	Outside Battery Limits
OSHA	Operation Safety and Health Act
OVHD	Overhead
OWD	Oily Water Drain
OX	Oxide
P
P	All process lines
P	Pneumatic signal
P	Pressure Connection
P	Proportional control mode
P	Purge or flushing device
P&ID	Piping and Instrumentation Diagram
PA	Plant Air Supply
PBE	Plain Both Ends [Swage, etc.]
PC	Pressure Controller
PC	Pumped Condensate
PCV	Pressure Control Valve
PE	Plain End [Pipe, etc.]
PFD	Process Flow Diagram
PFI	Pipe Fabrication Institute
PG	Pilot Gas
PI	Pressure Indicator
PIV	Post Indicator Valve
PLC	Programmable Logic Controller
PO	Pump Out
POE	Plain One End [Nipple, etc.]
POS	Point of Support
PR	Pressure Regulator
PRV	Pressure Reducing Valve
PRV	Pressure Relief Valve
PS	Pipe Support
PS	Pre-Spring
PS	Process Sewer
PSI	Pound per Square Inch
PSIA	Pound per Square Inch Absolute
PSIG	Pound per Square Inch Gage
PSV	Pressure Safety Valve
PT	Pressure Trap
PU	Pick-Ups
PW	Potable Water
PWHT	Post Weld Heat Treated
R
R	Automatic-reset control mode
R	Radius
R	Reflux Nozzle
R	Reset
R	Reset of fail-locked device
R	Resistance (signal)
R/L	Random Length
RED	Reducer
RED	Reducing
REF	Reference
REQ	Requesition
REQ	Required
REV	Reverse-acting
RF	Raised Face
RFI	Request for Information
RFP	Request For Purchase
RFQ	Request For Quote
RJ	Ring Joint
RPM	Revolutions Per Minute
RS	Rising Stem [Of valve]
RT	Reducing Tee
RTD	Resistance (-type) temperature detector
RTJ	Ring Type Joint
RW	Raw Water
S
S	Pipe Shoes
S	Solenoid actuator
S	South
S	Steam
S	Steam or Sample Connection
S	Storm Water Drain
S.G.	Specific Gravity
SAE	Society of Automotive Engineers
SC	Sample Connection
SC	Steam Condensaate
SCH	Schedule [Of pipe]
SCRD	Screwed
SCV	Sample Point Valve
SCV/T	Sample Point Valve with Thief
SD	Shut Down
SECT	Section
SF	Spot-Faced
Si	Silicon
SKT	Socket
SMLS	Seamless
SO	Slip-On
SO	Steam Out
SOL	Sockolet
SP	Sample Point
SP	Set Point
SP	Standard Practice [MSS term]
SP	Steam Pressure
Spec	Specification
SQ	Square
SQ.RT	Square Root
SR	Short Radius [Of Elbow]
SS	Sanitary Sewer
SS	Spring Supports
SS	Stainless Steel
SS	Steam Supply
SSO	Intermittent hot process drain
SST	Stainless Steel
SSV	Soft Seat Valve
ST	Steam Traced
ST	Steam Tracing
ST	Steam Trap
ST	Support Trunnions
STD	Standard
STM	Steam
STR	Straight
STS	Storm Sewer
SW	Socket Welding
SWG	Swage
SWG	Swaged Nipple
SWP	Standard Working Pressure
SWP	Steam Working Pressure
T
T	Temperature
T	Temperature Connection
T	Threaded
T	Trap
T&C	Threaded and Coupled [Pipe]
T/F.F	Tangent to Face of Flange
T/T	Tangent to Tangent
TB	Traced Valve Body
TBB	Traced Body & Bonnet
TBE	Threaded Both Ends
TC	Temperature Controller
TC	Test Connection
TE	Threaded End
TEF	Teflon
TEMA	Tubular Exchanger Manufacturers' Association
TGT	Tangent
TL	Tangent Line
TLE	Thread Large End
TOC	Top of Concrete
TOE	Threaded One End [Nipple or Swage]
TOL	Threadolet
TOP	Top of Pipe
TOS	Top of Steel
TOS	Top of Support
TPI	Threads Per Inch
TS	Twin Seal
TSE	Thread Small End
TSE	Threaded Small End
TSO	Tight Shut Off
TYP	Typical
U
U/G	Underground
UA	Utility Air
UDD	Utility Distribution Diagram
UFD	Utility Flow Diagram
UG	Underground
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
V
V	Valve
V	Vanadium
V	Vapor Outlet or Vent Connection
V	Vent
V	Vertical
VB	Vortex Breaker
Vert	Vertical
W
W	Relief Valve Nozzle
W	Water
W	West
W/	With
WC	Water Column
WE	Welded End
WGT	Weight
WLD	Weld(ed)
WN	Welding Neck
WOG	Water, Oil and Gas
WOL	Weldolet
WP	Working Point
WP	Working Pressure
WS	Water Supply
WT	Weight
X
X	Multiply
X	Unclassified acuator
XH	Extra-Heavy
XS	Extra-Strong
XXH	Double Extra Heavy
XXS	Double-Extra-Strong