Here some of the most common plumbing abbreviations used in the plumbing and heating trade.
ABS – acrylonitrile-butadiene-styrene
AL – aluminum
BG – bathroom group
BT – bath tub
CW – cold water or clothes washer
cm2 – square centimeter(s)
C – degrees Celsius
CI – cast iron
CO – clean out
CPVC – chlorinated polyvinyl chloride
dia – diameter
DF – drinking fountain
DW – dish washer
DWV – Drainage, waste and vent
FD – floor drain
FU – fixture unit
h, hrs – hour(s)
HW – hot water
HWT – hot water tank
in. – inches
ips – iron pipe size
kg/m2 – kilograms per meter squared
Kpa – kilopascals
Kn/m2 – kilonewtons per meter squared
KS – kitchen sink
L – litre(s)
L/s – litres per second
lav – lavatory
lbs – pounds
LT – laundry tray
m – meter(s)
m2 – meters squared
MJ – mechanical joint
mm – millimeters
PE – polyethylene
PEX – crosslinked polyethylene
PP-R – polyvinyl chloride
PRV – pressure relief valve or pressure reducing valve
Psi – pounds per squared inch
Psia – pounds per square inch absolute
Psig – pounds per square inch gauge
RD – roof drain
SH – shower
SJ – slip joint or soldered joint
SS – service sink
T&P – temperature and pressure relief
UR – urinal
WC – water closet (toilet)