Pumping Station Desing - Second Edition by Robert L. Sanks, George Tchobahoglous, Garr M. Jones
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highest
feasible water level.
Air
breaks
are
often
required
for
positive protection
of
potable water.
Ampacity: Current-carrying capacity
in
amperes.
Archimedes screw:
See
helical screw pump.
Axial
flow
pump:
A
pump
in
which
the
impeller
(somewhat
similar
to a
motorboat propeller) moves
the fluid
parallel
to the
pump
shaft.
Backflow
preventer:
A
device installed
in
potable
water
piping
to
prevent
the flow of
nonpotable
water
into
a
potable system.
Background:
The
ambient condition before
a
change
is
made, such
as the
apparent concentration
of a
substance
before
the
substance
is
added
as a
tracer.
Back head
(also
stuffing
box
head):
The
portion
of
the
pump casing attached
to the
volute that houses
the
stuffing
box and
bearings
on an
end-suction
pump.
Barrel (can)
pump:
A
pump inside
a
pipe.
Best
efficiency
point:
The
discharge rate
at
which
an
impeller
of a
given diameter rotating
at a
given
speed operates
at
maximum
efficiency.
Bingham
plastic:
A
material
in
which
flow
occurs
in
a
straight-line relationship with shear stress,
but
only
after
a
certain amount
of
shear stress
is
over-
come.
Blank:
A
solution containing
all the
ingredients
except
the
substance
to be
measured. Also
the
instrumental
reading obtained
from
the
foregoing.
Booster:
A
pump that takes suction
from
a
pressur-
ized piping system
and
discharges,
at a
higher
pres-
sure,
to a
second, isolated piping system.
Boss:
Projection
on a
pipe
fitting to
provide extra
thickness
for a
smaller threaded pipe.
Bowl:
The
casing that contains
the
impeller
of a
verti-
cal
turbine
or
vertical axial
flow
pump.
Brake horsepower:
The
power delivered
to the
pump
shaft.
Bump:
Momentary energization
of a
motor that
causes
it to
rotate
a few
revolutions.
Bus:
A bar
(usually
copper)
that
serves
as the
com-
mon
connection
for
three
or
more electrical circuits.
Casing:
The
impeller housing that directs
the fluid
into
the
impeller
and
thence
to the
discharge
flange
(see also
scroll).
Cavitation:
Vapor bubbles formed
on a
solid surface
(often
an
impeller)
in
contact with
the
liquid.
The
vapor
bubbles occur when
the
pressure
in the
liquid
falls
below
the
vapor pressure.
Centrifugal
pump:
A
rotodynamic pump
in
which
the fluid is
displaced radially
by the
impeller.
Collo-
quial:
Any
rotodynamic pump
in
which
the fluid is
displaced radially, axially,
or by a
combination
of
both.
Characteristic curve:
A
plot
of
head versus dis-
charge rate
for a
pump.
Clear well:
A
basin
of filtered
water
in a
water treat-
ment
plant.
Close
coupled:
A
motor mounted
close
to the
pump
and
in
which
the
pump impeller
is
mounted
on a
specially lengthened motor
shaft.
Closed
impeller:
An
impeller
with vanes enclosed
by
shrouds
on
both sides.
Closed
system:
A
liquid piping system that does
not
include storage open
to the
atmosphere.
Coating:
A
liquid that cures
after
application
to a
sur-
face.
Example: paint (see Lining).
Column:
The
vertical piping through which
a
sus-
pended pump discharges.
Comminutor:
A
machine designed
to cut and
shred
stringy
materials
and
large solids.
It is
sometimes
installed before
the wet
well
of a
sewage pumping
station
to
prevent clogging
of the
pumps.
Condition
point:
A
point
on the
pump characteristic
curve
at
which
the
pump delivers
a
given value
of
flow
at
a
given head.
Conduit
fill: The
amount
of
wires allowed
in a
con-
duit.
The
allowable
is 40% of the
internal cross-sec-
tional area.
Confined
space:
A
space large enough
and so
config-
ured that
a
person
can
bodily enter
and
perform
assigned work;
may
have limited
or
restricted
means
for
entry
or
exit
(e.g.,
tanks, vessels, silos,
storage bins, hoppers, vaults, pipes, trenches greater
than
1.2m
[4 ft]
deep,
and not
designed
for
contin-
uous
employee occupancy) (see permit-required
confined
space).
Control room:
The
superstructure
of a
pumping sta-
tion, which usually includes electrical equipment
and may
also include motors
for
extended
shaft
or
suspended pumps.
Corresponding
point:
One of two or
more points
related
to one
another
by all of the
affinity
laws
applied simultaneously.
C
utter
pump:
A
centrifugal
pump with
a
cutting
blade (attached
to the
impeller) designed
to cut
stringy materials into short segments before
entrance into
the
impeller eye.
Cutwater:
The
leading edge
of the
volute wall that
separates
the
volute
from
the
discharge nozzle.
Minimum clearance between impeller
and
volute
occurs
at the
cutwater.
Dashpot:
A
device
in
which
a fluid
escapement
decreases
the
speed
of
closure
(as of a
valve disc).
Demand:
A
schedule
of
water requirements.
Developed
head:
The
difference
between
the
suction
head
and
discharge head
of an
operating pump.
Diffusers:
Stationary vanes (within
the
casing)
to
provide gradually expanding paths
to
change
the
direction
of flow and
convert liquid velocity into
pressure.
Dirty
water: Water that contains solids such
as
silt
or
sand.
Discharge
flange: The flange at
which liquid
is
expelled
from
the
pump.
Discharge head: Static head plus friction headloss
(in
discharge piping) plus velocity headloss
at the
end of the
discharge piping.
Double
suction:
A
centrifugal
water pump
in
which
the
liquid enters
the
impeller through eyes
on
both
sides
and
thereby reduces
the
force
on
thrust bear-
ings.
Downstream:
In the
direction
of flow.
Drawdown:
The
vertical distance over which
the
sur-
face
of the
pumped liquid
is
lowered during
the
pumping
cycle.
Dresser® coupling:
See
sleeve coupling.
Dry
pit:
See dry
well.
Dry
well:
The
below-grade
structure
of a
pumping
station
in
which
the
pumped
liquid
is
contained
within
piping, valves,
and
pumps.
Dry
well
pump:
A
pump designed
to be
mounted
in a
dry
well
and
requiring
a flooded
suction pipe.
Ductile iron:
A
cast iron alloyed with magnesium
and
heat treated
to
concentrate
the
carbon into nod-
ules
to
obtain ductility
and
high tensile strength.
Uncontrolled high heating makes ductile iron revert
to
brittle
gray cast iron.
Duty: Utilization
and
specific
application
of
equip-
ment,
such
as
operation, standby,
or
emergency.
Duty
cycle: Time-based utilization
and
specific appli-
cation
of
equipment.
Effluent:
Liquid discharged
from
a
pumping station.
Extended
shaft:
Vertical pump
and
motor separately
supported
and
connected
by
means
of
open
shaft-
ing.
Fillet: Concrete
in the
bottom
of the wet
well shaped
to
smooth liquid
flow
into
the
pump suction open-
ings
and to
prevent
the
accumulation
of
solids.
Finished water: Potable, treated water.
Firm
pumping
capacity:
Capacity
of the
pumping
station with
the
largest pump
out of
service
or on
standby.
Flexible coupling:
A
device
to
couple
two
shafts
at a
small
angle.
Flexible pipe coupling:
A
coupling
often
used
at
walls,
and
sometimes elsewhere,
to
couple
two
slightly
misaligned pipes.
Flooded
suction:
Condition
in
which
the
pump
volute
is
below
the low
water level
of the wet
well.
Foot-candle:
The
amount
of
light
falling
on 1 sq ft of
a
spherical
surface
at a
distance
of 1
foot
from
a
standard candle.
Force
main:
Piping, external
to the
station
and filled
with
liquid under pressure, through which
the
sta-
tion
discharges.
Frazil
ice: Crystals
of ice
formed
in
turbulent waters.
French drain:
A
rock-filled
pit or
trench designed
to
allow water
to
seep into surrounding
soil.
Friction head: Equivalent head necessary
to
over-
come
friction
losses through
the
piping,
fittings,
and
valves.
Gauge
pressure:
Pressure above standard atmo-
spheric pressure.
Gen-set: Engine generator set.
Gray
iron:
A
brittle cast material principally
of
iron
with
2 to 4%
carbon
and
1%
silicon
by
weight
and
an
ultimate tensile strength
of
140,000
to
410,000
kPa
(20 to 60
ksi), compressive strength
3 to 5
times greater than
tensile
strength, with
negligible
plastic deformation.
Grinder
pump:
A
centrifugal pump with grinder
assembly
on an
extension
of the
shaft,
designed
to
grind solids larger than
a
fraction
of an
inch before
they
contact
the
recessed
impeller.
Grooved-end
pipe coupling:
A
pipe
coupling used
to
make
pipe
fitting and
disassembly easier.
Often
called
a
Victaulic® coupling
(a
trademark name).
Groundwater:
Raw
water obtained
from
wells.
Hazardous location:
Defined
in
Article
500 of
National
Electric
Code (see also Section
25-3).
Heat tracing:
An
electric heat tape wrapped around
a
pipe
or
tube (usually beneath insulation)
to
prevent
freezing.
Hedstrom's
number:
A
dimensionless number
defined
by
Equation
19-5.
Helical
screw
pump
(also
Archimedes
screw):
A
pos-
itive
displacement, inclined, semi-
or
fully
enclosed
screw
for
lifting
liquid
and in
which both suction
and
discharge
are
open
to the
atmosphere.
Hertz: Frequency
in
cycles
per
second.
High service
pump:
A
water pump that discharges
to
a
pressurized piping system, which
may
include
nonisolated, elevated storage.
Home
runs:
Wires running directly back
to the
power source
from
field
devices such
as
lights.
Horizontal
pump:
A
pump mounted with
its
shaft
horizontal.
Hydraulic
radius: Cross-sectional area
of
water
divided
by the
wetted perimeter
of an
open
or
closed conduit.
Impeller:
A
circular casting mounted
on a
rotating
shaft
with vanes
to
accelerate
the fluid.
Impeller eye:
An
opening
in the
impeller
of a
cen-
trifugal
pump through which liquid enters
the
impeller.
Impeller
hub:
The
outside portion
of the
impeller
of
a
centrifugal pump that encloses
the
eye.
Impeller
shroud:
The
outside part
of the
impeller
of
a
centrifugal
pump
to
which
the
vanes
are
attached.
Inrush
(current):
The
temporary surge
of
electrical
current
to a
motor that occurs with
an
across-the-
line
starter.
Intake:
A
structure
from
which
the
pumps take suc-
tion.
Intake basin:
See wet
well.
Invert:
The
inside bottom
of a
pipe.
Jockey
pump:
A
small pump that maintains pressure
in
a
distribution system during periods
of low
demand.
Knee:
A
reduction
in the
gradient
of a
pipeline
or a
change
from
a
positive
to a
negative gradient.
Laminar
flow:
Flow with straight streamlines, i.e.,
without
eddying
or
turbulence.
Laying length:
The
length
of a
piece
of
pipe
or a
fit-
ting
in a
piping system.
Lining:
A
covering applied
or
attached
to a
surface.
Examples: T-Lock®
and
Linabond®.
Lumen:
The
rate
at
which light
from
a
one-candle
source
flows
through
a
unit solid angle
(1
m
2
at 1 m
or
1
ft
2
at 1
ft).
LMJC:
A
measure
of
luminous intensity equal
to one
lumen
per
square meter
or
0.0929
foot-candles.
Mechanical
bar
screen:
A
screen
of
bars, through
which
the
influent
of a
pumping system
flows
before
entrance
to the
pumps, with
a
motorized
cleaning mechanism that delivers
the
screenings
to
a
collector.
Mechanical seal:
An
assembly consisting
of one or
two
pairs
of
polished surfaces,
one of
each pair
mounted
on
(and turning with)
the
shaft
and the
other connected
to the
casing
to
inhibit
the
leakage
of
liquid between
the
casing
and the
shaft.
Micron:
One
thousandth
of a
millimeter
(IxIO
-6
In).
Mil:
One
thousandth
of an
inch.
Mixed-flow
pump:
A
pump that produces
a
combina-
tion
of
centrifugal
and
axial
flow
(see Figure
10-8).
Multistage:
Two or
more impellers mounted
on a
common
shaft
housed within casings
for
each
impeller
and
designed
to
deliver liquid
from
the
dis-
charge
of one
casing
to the
suction
of the
other.
Net
positive
suction
head
(also NPSH): Absolute
(total) dynamic head
of the
pumped liquid
at the
suction
eye of a
pump (see also Section
10-4).
Net
positive suction head available:
The
NPSH
at
which
the
pump
in a
given system operates
at a
given
discharge rate.
Net
positive suction head required:
The
minimum
NPSH
at
which
a
pump
can
properly operate
for a
given
discharge rate.
Newton:
A
unit
of
force
in SI
units that accelerates
a
1-kg
mass
1
m/s
2
.
Newtonian
fluid: A fluid
(water,
for
example)
in
which
shear
flow is
proportional
to
shear stress.
Nonclogpump:
A
centrifugal pump designed
to
pump
liquids containing suspended solids
and
stringy
material. (Ed. note:
in
spite
of the
name,
they
often
do
clog.)
Nonoverloading:
The
motor rating that
is not
exceeded
by the
brake horsepower
at any
point
on
the
characteristic curve.
Open
impeller:
An
impeller with vanes
on
only
one
side
of a
single shroud plate.
Open
shaft:
See
extended
shaft.
Open
system:
A
liquid piping system that includes
nonisolated storage open
to the
atmosphere.
Operating
point
(for
pumps):
The
head
and
dis-
charge
at
which
a
pump operates
in a
system;
the
intersection
of the
pump characteristic curve
and
the
system curve.
Packing: Semiplastic material installed
in a
stuffing
box
to
seal
the
shaft
opening
in the
casing
to
restrict
the
leakage
of
liquid
from
the
casing along
the
shaft.
Packing gland:
See
stuffing
box.
Pascal:
A
unit
of
pressure
or
stress
in SI
units
(=
N/m
2
).
Permit-required
confined
space:
A
confined
space
with
one or
more
of the
following characteristics:
(1)
contains
or has the
potential
to
contain
a
hazard-
ous
atmosphere such
as
lack
of
oxygen
(<19.95%)
or
explosive
or
toxic atmosphere;
(2)
contains
a
material that
has the
potential
for
engulfing
an
entrant;
(3) has an
internal configuration such that
an
entrant could
be
trapped
or
asphyxiated
by
inwardly
converging walls
or by a floor
that slopes
downward
and
tapers
to a
smaller cross-section;
or
(4)
contains
any
other recognized serious
safety
or
health hazard.
Pig:
A
device
for
cleaning
the
inside
of a
pipe.
Point: Percentage
efficiency
(of a
pump), e.g.,
2
points equals
2%.
Poppet
valve:
A
spring-loaded valve that operates
automatically
to
relieve excessive pressure.
Potable
water: Drinkable,
finished
water.
Pressure surges
(also
transients
or
water hammer):
Rapid
fluctuations in
pressure
in a
closed piping
system caused
by a
sudden change
in the
velocity
of
liquid
in the
pipe.
Primary
element:
An
element that quantitatively
converts measured variable energy into
a
form
suit-
able
for
measurement.
Prime: Pump casing
and
suction piping completely
filled
with
liquid.
Progressive
cavity:
A
positive displacement pump
with
a
helix rotor
in a flexible,
double helix casing
for
handling liquid with large amounts
of
solids
in
suspension.
Propeller
pump:
An
axial
flow
pump suitable
for
pumping
large volumes
of
liquids without stringy
solids
at low
heads.
Pump:
A
machine that imparts kinetic
and
potential
energy
(from
an
external energy source)
to a
liquid
to
force
a
discharge
from
the
machine.
Pump-down:
An
operation
in
which
the
water level
in
a
sump
is
lowered
as far as
possible
by the
main
pumps
—
generally
to
about
D/4
above
the
last
pump
intake
of
diameter
D.
Pumping station:
A
structure housing pumps, piping,
valves,
and
auxiliary equipment.
Punch
list:
An
itemized list
of
work
the
contractor
must
do to
complete
the job
according
to the
plans,
specifications,
and
change orders before
the
owner
pays
for
substantial completion. Warranty repairs
are
not
considered
part
of the
punch
list.
Radial vane: Impeller with vanes oriented radially
to
the
shaft.
Raw
sewage: Sewage that
has not
been settled
or
treated
in any
manner (except, possibly,
for
screen-
ing
or
grinding).
Raw
water: Nonpotable water that must
be
treated
to
become
finished
water.
Reynolds
number:
A
dimensionless number
defined
by
Equation
3-11.
Root
area:
The
cross-sectional area
of a
bolt calcu-
lated
from
the
diameter
at the
root
of the
threads.
Rotodynamic
pump:
A
mechanical device that pres-
surizes
a fluid by
means
of a
rotating impeller.
Runout:
The
operating condition
for one
pump,
of a
group
of
pumps, operating alone against reduced
dynamic
head. Hence,
the
pump operates beyond
its
bep.
Sail switch:
A
device used
to
indicate
failure
of the
ventilation
system.
A
light paddle (within
an air
duct)
is
kept pushed
up by a
normal
flow of
air,
but
when
air
ceases
to flow, the
paddle
falls,
thereby allowing
a
limit switch
to
open
and
trigger
an
alarm.
Salient
pole:
A
rotor
(in an
electric machine) consist-
ing
of
projecting elements surrounded
by
coils
for
energization.
Scroll:
The
casing enclosing
the
rotor
of a
water turbine.
Secondary
element:
An
element that converts
the
output
of a
primary element (q.v.) into
an
electrical
or
pneumatic signal
for
monitoring
or
control, using
switches
for
discrete signals
and a
transmitter
for
analog signals.
Self
-priming
pump:
A
centrifugal pump that nor-
mally
retains prime
or
automatically
reprimes
itself
when
drawing suction
from
a
liquid pool whose
surface
is
below
the
casing
of the
pump.
Sequent
depth: Depth following
a
hydraulic jump.
Service factor:
A
multiplier that, when applied
to the
rated horsepower, gives
the
load
at
which
an
elec-
tric motor
can be
operated.
Sewage: Domestic wastewater.
May
contain indus-
trial wastewater.
Shaft
sleeve:
A
replaceable cylinder mounted
on
(and
rotating with)
the
pump
shaft
and
extending
through
the
stuffing
box to
protect
the
shaft
from
wear caused
by the
packing.
Shut-off
head:
The
head developed
by a
centrifugal
pump
at
zero discharge rate (against
a
closed dis-
charge valve).
Sleeve coupling:
A
device
to
couple
two
plain-end
pipes together (see Figure 4-3).
Sludge: Residue remaining
after
settling
or
treatment
of
sewage
and raw
water. Usually about
3% or
more
solids concentration
in
suspension.
Slug:
The
unit
of
mass that
is
accelerated
1
ft/s
2
by a
force
of
lib
(-32.171b
m
).
Slug:
The
instantaneous addition
of a
known (usually
large) amount
of a
tracer added
to a fluid.
Snubber:
A
device (such
as a
micropore
filter)
used
to
reduce pressure
fluctuation to
make
a
gauge indi-
cate time-averaged pressure.
Soffit:
The
underside
of a
beam
or the
inside surface
at
the top of a
pipe.
Soft
foot:
A
machine
foot
(or
support) with
a
bottom
surface
not
coplanar with those
of
other
feet
and
requiring compensation
in
shimming
to
avoid twist-
ing
the
machine.
Soft
start: Motor starting
in
which
the
inrush current
is
reduced.
Soldier beam:
A
vertical beam used
to
resist earth
pressure.
Solids
capability:
The
diameter
of the
largest sphere
that
can
pass through
a
pump
from
the
suction
flange
to
the
discharge
flange.
Special:
Any
piece
of
pipe (except
a
full-length
straight section), such
as
short pieces, manifold sec-
tions, elbows, reducers, adapter sections with spe-
cial ends, sections with outlets.
Specific
speed:
A
characteristic number
for a
geo-
metrically similar
series
of
pumps operating under
similar conditions. Called
the
"type
number"
in
Europe (see Table 10-1
and
Figure
10-8).
Speed:
Usually
specific
in
this text
for the
velocity
of
propagation
of a
pressure wave.
Spike:
A
known addition
to the
concentration
of a
substance being analyzed; also
a
sudden change
in
a
variable.
Split
case:
A
two-piece casing bolted together
for
ease
in
providing access
to the
rotating assembly
and
all
internal passages.
Spool:
A
section
of
flanged
pipe shorter than
a
stan-
dard length.
Static discharge head:
The
vertical distance
from
the
center
of the
pump casing
to the
surface
of the
liq-
uid
at the
point
of
discharge.
Static head:
See
total static head.
Static suction head:
The
vertical distance
from
the
centerline
of the
pump casing
to the
surface
of
the
liquid being pumped;
the
casing must
be
below
the
liquid level
(h
s
in
Figure
10-2).
Static suction
lift:
The
vertical distance
from
the
centerline
of the
pump casing down
to the
surface
of
the
liquid being pumped;
the
casing must
be
above
the
liquid level (see
h
s
in
Figure
10-3).
Steady
bearing:
A
bearing between
the
pump
and the
motor
for the
lateral support
of
extended
shafting.
Stuffing
box:
An
assembly containing packing
or a
mechanical seal through which
the
pump
shaft
passes.
Submersible
pump:
A
pump
or
pump
and
motor suit-
able
for
fully
submerged operation.
Suction
elbow:
Any
elbow that
is
connected
to the
suction
flange of a
pump
or an
elbow, bolted
to the
floor
of
a wet
well, that engages
a
submersible
pump.
Suction
flare or
bell:
A flaring
entrance
fitting to the
pump
suction piping.
Suction
head:
See
static suction head
and net
posi-
tive
suction head.
Suction
lift:
See
static suction
lift.
Sump:
See
wet
well.
Surface
water:
Raw
water obtained
from
streams,
lakes,
or
reservoirs.
Suspended:
A
pump
in
which
the
impeller
is
sus-
pended below
the
liquid level
on a
vertical
shaft
supported
from
a
motor above
the
liquid.
System head curve: Curve
of
total dynamic head
(q.v.)
versus
flow for all flowrates
within
the
capa-
bility
of the
pumping station.
Therm:
100,000
Btu.
Total
dynamic head
(TDH):
The
total head
at
which
a
pump operates
at any
given discharge rate (see
Figure 10-2).
Total
static head:
The
difference
in
elevation
between
the
surface
of the
pool
from
which
the
pump
draws water
and the
surface
of the
pool into
which
the
outlet discharges (see Figure 10-2).
Trash
basket:
A
basket with bars
or
screens through
which
influent
of a
pumping station
flows
before
entering
the
liquid
pool
in the wet
well
to
prevent
large solids
from
entering
the
pumps.
Tremie
concrete: Concrete placed under water
through
a
tube that discharges under
the
surface
of
the
concrete being deposited.
Tubercles: Rough deposits (formed inside
of a
pipe)
that
greatly increase resistance
to flow.
Turbulent
flow:
Flow
in
which
the
streamlines
are
unsteady
and the
motion
at a fixed
point vanes
in a
random manner.
Type
number:
See
specific
speed.
Umbrella:
An
extension fastened
to a
pipe
flare to
form
an
entrance similar
to a
trumpet bell.
Upstream:
Opposite
to the
direction
of flow.
Varmeter:
A
wattmeter corrected
for
power factor.
Velocity:
In
pipe
flow, the
average velocity
of the
fluid.
Velocity
head:
The
kinetic energy
in a
moving liquid;
the
average
is
v
2
/2g.
Vertical
pump:
A
pump with
a
vertical
shaft.
Vertical
turbine:
A
centrifugal pump
usually
with
multistage
impellers
and
bowls
in a
vertical column.
It is
suitable
for
pumping
from
wells
and
sumps.
Victaulic®
coupling:
See
grooved-end coupling.
Volute:
A
centrifugal pump casing that provides
a
gradually
expanding liquid path
to
change
the
direction
of flow and
convert velocity
to
pressure.
Vortex
impeller:
A
recessed impeller that creates
a
vortex
in the
casing
to
induce
flow. The
liquid
flows
over
the
impeller,
not
through
it.
Wastewater:
Water-borne wastes (including sewage)
from
households, businesses,
and
industry.
Water
hammer:
Rapid, severe,
and
often
destructive
changes
in
pressure
in a
piping system caused
by a
sudden change
of
liquid velocity.
Water
horsepower:
The
power delivered
by the
pump
to the
liquid being discharged
(=
pound
of fluid per
minute
x
feet
of
head/33,000).
Water
lance:
A
long, light pipe used
for
directing
a
water
jet at the
desired point
of
delivery.
Water
seal: Clear water supplied under pressure
to
the
packing
or
mechanical seal
of a
pump
to
lubri-
cate, cool,
and flush the
packing
or
seal. (Grease
or
oil is
sometimes used
in
place
of
water.)
Wear
rings: Removable, replaceable metallic
rings
on
the
casing and/or impeller
at the
impeller hub.
Wet
pit:
See
wet
well.
Wet
well:
The
below-grade
compartment
of a
pump-
ing
station into which
the
liquid
flows and
from
which
the
pumps draw suction. Also
"pump
intake
basin"
and
"sump."
Wet
well
pump:
A
pump designed
to be
directly
immersed
in the
liquid.
Withstand rating: Capability
of an
electrical device
to
withstand
a
short circuit without damage long
enough
to
trip
the
protective devices.
Wrought pipe
fittings:
Pipe
fittings
formed
by
forg-
ing,
piercing, hammering, welding, rolling, bending,
pressing,
or
extruding
(or by a
combination
of
these).
2-3. Symbols
Some
of the
symbols shown
in
Tables
2-1 to 2-6 are
standard; others
are
typical, though
not
necessarily
universal. Except
for
Table
2-4,
which
is
reproduced
from
drawings
by
Brown
and
Caldwell Consultants,
the
tables
are
reproduced here
by the
courtesy
of
Greeley
and
Hansen Engineers.
2-4. Supplementary
Reading
1.
Lyons,
J.
L.,
and C. L.
Askland,
Jr.,
Encyclopedia
of
Valves,
Van
Nostrand
Reinhold,
New
York
(1975).
Table
2-1.
Single-Line
Piping
Symbols
Pipe fittings
Symbol
Description
Symbol
Description
CrossTee
Cross (branch
up)Tee
(branch
up)
45°
elbowTee
(branch down)
45°
elbow
(up)Side
outlet
tee
(up)
45°
elbow
(down)Reducer
LateralEccentric reducer (Elevation)
90°
elbowUnion,
screwed
90°
elbow
(up)Sleeve
coupling
90°
elbow
(down)Sleeve
coupling (harnessed)
45°
elbow (long
radius)Meter
(identify
type)
90°
elbow (long
radius)Venturi
meter
Base
elbowExpansion
joint, metal bellows
Side outlet elbow
(up)Expansion
joint,
rubber
bellows
Side outlet elbow (down)
Strainer
Pipe
fittings
Symbol
Description Symbol Description
Duplex
strainerThermostat
Flame trap
Pressure gauge
Lube
oil filter
Water
level alarm
Scale
trape
Vent
Thermometer
Valves
Stem
relative
to
plane Pipe joints
Perpendicular
Parallel Description Symbol Description
GateFlange
ButterflyBell
and
spigot
Eccentric
plugMechanical
joint
Eccentric plug
(alternate)Mechanical
joint, restrained
Cone Bell
and
ball
Ball
Wall
fittings
Symbol
Description
Check,
swing
Wall
sleeve, caulked
Globe
Wall
sleeve, annular seal
Angle
Wall
pipe,
flange
&
flange,
Jj
1166
wa
yintermediate
collar
Wall
pipe, bell
&
bell, intermediate
Flapcollar
Wall
pipe, mechanical joint
Diaphragm
Wall
pipe, mechanical joint,
Auto
air and
vacuum release intermediate
collar
Auto
air
release
Auto
vacuum
release
Hose (bibb)
Valve,
manual operation
Control valve with hydraulic, pneumatic
or
electric actuator
Table 2-2.
Mechanical
Symbols
3
Fixture
symbols
Symbol Description Symbol Description
Floor
drainWater
heater
Area
drainLavatory
Roof
drainSink
Compressed
air
outletShower
stall
Gas
outletUrinal
Vacuum
outletWater
closet
Hose
bibbWater
closet,
wall hung
Drinking fountain
Electric
water
cooler
Piping symbols
Symbol
Description
Symbol
Description
StormFire
protection
Fire
sprinkler
Soil
WasteDrum
trap
DrainP-trap
VentRunning
trap
Acid
wasteBackflow
preventer
Acid
ventCleanout
(exposed
pipe)
Service
waterCleanout
(floor
or
grade)
Cold
waterHeating
water supply
Effluent
waterHeating
water return
Hot
water
(potable)Cooling
water supply
Hot
water circulating
(potable)Cooling
water return
Compressed
airChilled
water supply
Vacuum
Chilled water return
Symbol
Description Symbol Description
Low-pressure steam
Three-way
control valve
Low-pressure
condesate*
<
P
>
:
P^umatic
*
(E): electric
Medium-pressure
steam
Contro
,
valye
*
(P): pneumatic
Medium-pressure
condensate*
(E): electric
High-pressure
steamPipe
guide
High-pressure
condensatePipe
anchor
Fuel
oil
supplyFloat
and
thermostatic
trap
Fuel
oil
returnThermostatic
trap
Boiler feedExpansion joint
Natural
gasExpansion
joint (harnessed)
Liquefied
petroleum
gasPipe
flow
direction
Refrigerant
liquidPipe
pitch down with respect
to flow
Refrigerant
suctionPipe
pitch
up
with respect
to flow
Condensate pump discharge Pipe capped
Miscellaneous
symbols
Symbol
Description Symbol Description
Unit
heater
INV
EL
Invert elevation
Convection
IEL
Centerline elevation
Cabinet
heater
CFM
Cubic
feet
per
minute
Thermostat
MBH
Thousand
Btu/hour
*
(P): pneumatic
*
(E): electric
VD
Volume damper
Humidostat
*
(P): pneumatic
TC
Temperature control
*
(E): electric
NTS
Not to
scale
BD/EL
Bottom
of
duct elevation
p
Pneumatic
TD/EL
Top of
duct elevation
E
Electric
a
After
Greeley
and
Hansen
Engineers.
Table
2-3.
Heating,
Ventilating,
and Air
Conditioning
Symbols?
Symbol
Description
Symbol
Description
Duct
width
x
depth
(first
dimension
isNegative
pressure duct section; asterisk
dimension
seen)represents
service designation
Inclined
rise
(with
respect
to air flow)Round
duct with transition
to
rectangular
duct
Inclined drop
(with
respect
to air flow)
Splitter
damper
Volume
damper
(shaft
parallel
to
paper)
Turning
vanes
Volume
damper
(shaft
perpendicular
to
paper)Deflecting damper
with
rod and
lock
>D
Extractor
with
rod and
lock
Automatic
opposed blade control damper
(POD) pneumatic; (MOD) electric
Supply
duct down (positive pressure)
Register
or
grille
(face
perpendicular
to
paper);
asterisk
represents
equipment
Exhaust
or
retum
duct
down
(negative
i
designationP
ressure
)
:
M
Flexible duct connection
Register
or
grille (face parallel
to
paper);
asterisk represents equipment
:
M
designationAccess
doors
in
duct
Equipment designations
Register
Grille
Outside
air
intake
Ceiling register
Ceiling grille
Single
inlet
fan
(plan view)
Rectangular
ceiling
diffuser
(size
given
refers
to
neck
size)Outlet
air
direction
/^
Inlet
air
direction
Round
ceiling
differ
(size
given
refers
Direction rf
^
flow
jn
duct
_
to
neck
size)
ri
Service designations
DA
Outside
air
Positive pressure duct section; asterisk
S
Supply
air
represents
service designation
E
Exhaust
air
R
Return
air
a
After
Greeley
and
Hansen
Engineers.