Pumping Station Desing - Second Edition by Robert L. Sanks, George Tchobahoglous, Garr M. Jones
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the
joint venture
is a
day-long retreat attended
by the
involved
personnel
from
both
of the firms and
from
the
client
to
resolve
major
issues
and to
establish
a
close
and
cooperative relationship.
Another
possibility
is to
invite
an
experienced con-
struction manager
to
join
the
joint venture.
The
right
person
may
save considerable expense
by
offering
good advice
on
ease
of
construction
and
practicality.
Design-to-Cost
Design-to-cost
is a
proprietary, computerized man-
agement
system used
by one
consulting
firm for
accurate
cost estimating
and
scheduling
at any
stage
of
design completion. Because
the
potential
for
con-
trolling
costs
is
greatest
in the
early stages
of
design,
the
system
is
extremely
useful.
It
enables
(1)
design-
ers to
focus
immediately
on the
most cost-effective
alternatives;
(2)
clients
to see the
consequences
of
incorporating
special
features;
and (3)
designers, con-
struction
contractors,
and
owners
to
share informa-
tion
that keeps costs under control.
The
system
is
made
possible with
a
database
of
20,000
items
in
which
two
subsystems (continuously upgraded costs
and
scheduling)
are
electronically linked.
In
early
planning
and
design phases, estimators produce con-
ceptual
costs that are,
on the
average, accurate within
an
error range
of
+1
1
to
-3%.
As the
design proceeds,
new
data
are
entered
as
soon
as
available,
and the
accuracy
increases until
the final
estimate (based
on
quantities
of
materials, equipment, person-hours,
location,
and
labor
and
market conditions)
has an
average error
of
only
+7 to
-1%.
The key
element
is
cooperation between
all
persons working
on the
project.
The
program
can be
used anywhere
on a
notebook
computer [10,
U].
The
concept
can be
used
and a
program developed
by
any firm
that keeps good records
of
numerous
and
recent construction costs. Obviously,
the
capability
of
providing accurate costs
from
beginning
to end
helps
to
establish
and
maintain good relationships
between
the
owner
and
designers
and
(during con-
struction)
between
the
contractor, owner,
and
design
firm
—
particularly
when change orders
are
pro-
cessed.
1-11. Avoiding Litigation
In
our
litigious society, nothing
can
ensure complete
protection
from
lawsuits,
but the
precepts that
follow
will
reduce their incidence
and
severity.
Clear,
Fair
Contracts
Describe
clearly both
the
rights
and
responsibilities
of
each appropriate party. Avoid ambiguity
and
one-
sided requirements. Recognize potential problems,
and
provide
for
fair
solutions openly.
More
for
Design,
Less
for
Litigation
The
intelligent application
of
money
for
design
can
promote better coordination between client
and
designer
and
between
the
various design
disci-
plines.
Proper
funding
also allows adequate investi-
gation
of
viable alternatives
and
enough time
for
truly
careful
preparation
and
checking
of
plans
and
specifications
with
a
probable decrease
in the
over-
all
capital cost, with reduced chances
for
errors
and
expensive change orders
and
with improved client
satisfaction.
Partnering
Partnering
is a
voluntary
process
that promotes nonad-
versarial relationships among
the
parties involved
in a
construction project. Partnering
benefits
all
project
participants (owner, contractor,
and
engineer)
by
reducing their exposure
to
disputes
and
litigation
and
by
increasing their productivity.
The
teamwork during
construction
improves quality
and the
chance
of
timely
completion
and
results
in
fewer
lingering dis-
putes.
See
"Partnering.
A
concept
for
success"
[12].
Partnering between owner, engineer,
and
con-
tractor
has
been
tried,
often
with success
but
some-
times with mixed
or
poor
results.
Sincere
efforts
by
each
to be
fair
with
the
others
are the
keystone
to
success.
Resolve
Potential
Claims
as
Change
Orders
Claims that lead
to
litigation
are
simply disputes that
could
not be
resolved
as
change
orders.
The
apparent
ease
of
such
a
solution
is
deceptive
if any of the
fol-
lowing
occurs:
•
Ambiguous contract language
•
Imprecise contract words
or
phrases such
as
"prompt,"
"reasonable,"
"workmanlike,"
and "to the
satisfaction
of the
engineer,"
which will surely
lead
to
different
interpretations
by
different
people
•
Lack
of
communication
and
mutual respect.
Alternative
Dispute
Resolution
The
construction industry
has
developed
a
variety
of
alternative dispute resolution (ADR) procedures
to
avoid
the
time, bitterness,
and
cost
of
resolving disputes
by
litigation. Those that should
be
considered include:
•
Mediation,
a
formal method wherein both parties
negotiate their
differences
before
a
neutral third
party. Mediation
may be
mandated
by the
contract
or
adopted
at the first
irreconcilable dispute.
•
Mini-trials wherein
a
third party acts
as a
judge
and
both sides present their positions
and
answer ques-
tions
from
the
other side
and the
judge.
•
Dispute review board named
by the
parties
at the
start
of the
project.
The
board
thus
becomes
famil-
iar
with
the
project throughout
its
life.
Many
other steps
can be
taken
to
prevent litigation,
but
the
above
are
some
of the
most important.
A
more
extensive discussion
has
been prepared
by
Wilson
[13].
1-12. Library
Every
designer should acquire
an
extensive library
because
no
book, however complete,
can
contain ade-
quate
discussions
of all
topics. Read with caution
and
suspicion, however, because there
are
many mistakes
in
the
literature,
and
some
may
lead
to
blunders
or
poor design. Just because
a
book
is
listed here
or
because
it
carries
a
prestigious label
or a
distinguished
authorship,
do not
assume
it to be
universally authori-
tative
or
correct.
Thoughtful
reading
of
diverse opin-
ions
and
consideration
of the
author's credentials
coupled with your
own
experience
and
expertise
can
often
distinguish between
fact
and
fallacy,
good
and
poor.
The
references
in
these chapters
are
publications
often
found
to be
useful,
but by no
means
are
they
intended
to
include
all of the
useful
literature. Further-
more, inclusion
is not an
endorsement
of
authority
or
assurance
of
freedom
from
error.
Readers must determine their
own
library needs.
Pump sump design, pump testing,
and
vertical turbine
and
propeller
pumps
are
discussed
by
Dicmas [14],
and
pumps, drivers,
and
pump systems
are
covered
in
Pump
Handbook
[15].
Storm water pumping
(a
sub-
ject omitted
in
this text)
is
discussed
in the
Manual
for
Highway
Storm
Water
Pumping Stations,
Volumes
I
and
II
[16]
and
Design
ofWastewater
and
Stormwater
Pumping
Stations
[17].
A
compendium
of
standard
design plans
for
storm water pumping
is
contained
in
the
Pump Station Design Manual
[18].
The
number
of
times books
or
codes
and
standards
are
referenced,
the
title,
and the
context
in
which
the
references
are
given
are
clues
to
their importance. Consulting
firms
must
have
an
extensive library
of
codes
and
specifications.
Because these
are
voluminous
and
frequently
revised,
subscribing
to a
microfiche service
is
definitely
worth-
while
for a
large
office.
For
your convenience, addresses
for
publishers
are
given
in
Appendix
F.
1-13.
Operator
Training
Good operation
is
just
as
important
as
good design.
A
good crew
can
make
a
poor
facility
seem good,
whereas
a
poor crew will make
a
good facility seem
poor. Consequently,
it is in the
long-term interest
of
public utilities
and
agencies
to
spend
the
money neces-
sary
to
send their operators
and
maintenance
staff
to
seminars
and
other training sessions
so
that they
can
learn
how to
operate
and
maintain
the
pumping equip-
ment properly. Training should
be
conducted
(1) by
qualified
representatives
of the
equipment
manufactur-
ers,
(2) at
various seminars conducted
by
manufactur-
ers,
(3) by
in-house training sessions,
and (4)
especially
by
the
engineer responsible
for the
original design.
This last individual
is the
only source
of
information
on
the
operational concepts embodied
in
that design.
Purchasing expensive pumping installations with
sensitive equipment
and
expecting untrained
staff
to
maintain them
is
simply shortsighted.
Indeed,
over
the
long
term, cutting back
on
training sessions will cost
the
utility more because:
(1)
more labor hours will
be
needed
by
poorly trained personnel
to
operate
and
maintain
the
station than would
be
required
by
properly
trained
staff;
(2)
equipment will have
to be
repaired
more
frequently
than
it
would
if it
were properly cared
for
to
begin with;
(3) the
station
can be
kept operating
more
efficiently
and
expensive, critical,
and
relatively
fragile
items such
as
mechanical
seals
and
bearings
for
pumps
are
more likely
to be
properly installed
and
maintained
by
skilled maintenance workers, thereby
reducing replacement parts costs;
(4)
skilled mainte-
nance
staff
can
repair
equipment (for example, they
can
balance pump
shafts
and
impellers)
to a
degree that
minimizes problems such
as
vibration (which always
reduces
the
longevity
of
rotating equipment);
(5)
prop-
erly trained
staff
will probably have
a
better attitude
toward
keeping
the
station neat
and in
good operating
condition;
and (6)
good training will result
in
fewer
accidents
and
missed work
days
—
an
important consid-
eration because water
and
wastewater industries
are
among
the
most hazardous ones
in the
United States.
Large submersible pumps provide
a
good example
of
the
cost-effectiveness
of
good training.
These
large
pumps
are out of
favor
with many public utilities,
but
a
staff
well trained
in
removing
and
repairing them
can
keep them operating with only ordinary
effort
and
little down time provided
the
equipment
is of
high
quality
and the
facilities
are
tailored
for
easy pump
removal
and
replacement (see Sections 25-5
and
27-5).
A
utility with
a
goal
of low
capital expenditure
would
(in
1998)
save
an
estimated construction cost
of
between
1 and 6
million
dollars
for a 1.3
m
3
/s
(30
Mgal/d)
pumping station
if
three
submersible pumps
were used instead
of
three
dry
-pit
pumps (see Figures
29-2
and
29-3). Obviously,
the
cost
of
training would
be
repaid many, many times.
Utilities should also realize that when
the
mainte-
nance
staff
have become skilled
in
repairing complex
equipment,
their market value
is
much higher than that
of
"average"
workers.
If it
does
not
offer
a
competitive
salary appropriate
to the
level
of
skill,
it
will
lose
the
benefits
of its
training program
by
becoming
a
training
center
for
transferees
to
those private industries
and
other public agencies that
do
appreciate
the
worth
of
skillful
mechanics.
1-14.
References
1.
NFPA
101,
Life
Safety
Code, National Fire Protection
Association,
Quincy,
MA.
2.
Papillon
Creek
Wastewater
Treatment
Plant, Omaha,
Nebraska,
HETA 83-440-1537, NIOSH,
U.S.
Department
of
Health
and
Human Services, Atlanta,
GA
(1984).
3.
Criteria
for a
Recommended
Standard.
Working
in
Confined
Spaces, DHEW (NIOSH) Publication
no. 80-
106,
U.S.
Department
of
Health, Education,
and
Welfare,
U.S.
Government Printing
Office,
Washington
DC
(December 1979).
4.
Nevada Revised Statutes,
NRS
625,
and
Nevada
Administrative
Code Board Regulations,
NAC 625
(1994).
5.
Legislature
of the
State
of New
Mexico,
"An act
relating
to
public purchases, amending, repealing
and
enacting certain
sections
of the
procurement
code."
Section 13-1-55 NMSA (1978).
6.
Sanks,
R.
L.,
"How
to
choose
a
consulting engineer,"
Public
Works
120
(10): 125-126
(September 1989).
7.
Shaw,
R.
L.,
"Competing
on
price, again," Civil
Engineering
59
(10):
6
(October 1989).
8.
Whitley,
F,
"Consultant
selection
—
controlling
the
process,"
Public
Works
120
(4):
47^49
(April
1989).
9.
Jones,
G. M.
"Municipal pumping stations,
the
case
for
quality
and
reliability," Pumps
and
Systems
Magazine,
pp.
32, 34,
36-37.
(September 1993).
10.
Pritchard,
M.
T.,
D. S.
Parker,
and A.
Malik.,
"Design-
to-cost with BACPAC." In-house publication, Brown
and
Caldwell, Pleasant Hill,
CA.
11.
Pritchard,
M.
T.,
D. S.
Parker,
and A.
Malik.,
"Keeping
costs
from
creeping,"
Water
Environment
&
Technology
4
(12):
38-39
(December 1992).
12.
AGC.
"Partnering.
A
concept
for
success,"
Publ.
No.
1205, Associated General Contractors
of
America,
1957
E
Street
N.
W,
Washington,
DC
20006.
13.
Wilson,
R.
L.,
President, Wilson Management Associates,
Inc.,
Glen Head,
NY.
Personal communication (August
1995).
14.
Dicmas,
J.
L.,
Vertical
Turbine,
Mixed
Flow
&
Propeller
Pumps, McGraw-Hill,
New
York (1987).
15.
Karassik,
I.
J.,
W. C.
Krutzsch,
W. H.
Fraser,
and J. P.
Messina, Pump Handbook,
2nd ed.
McGraw-Hill,
New
York
(1985).
16.
Lever,
W. F,
Manual
for
Highway
Storm
Water
Pumping
Stations,
Volumes
I and II,
Report
no.
FHWA-
IP-82-17,
Federal
Highway Administration, National
Technical Information Service, Springfield,
VA
(October 1982).
17.
Design
of
Wastewater
and
Stormwater
Pumping
Stations,
Manual
of
Practice
FD
-4,
Water Environment
Federation, Alexandria,
VA
(1993).
18.
Pump Station Design Manual,
Los
Angeles County
Flood Control District,
Los
Angeles,
CA
(n.d.).
Chapter
2
Nomenclature
MAYO
GOTTLIEBSON
CARL
W. REH
ROBERT
L.
SANKS
CONTRIBUTORS
Roberts.
Benfel!
Earl
L.
Heckman
Stanley
S.
Hong
2-1.
Abbreviations
The
abbreviations given here
are the
same
for
both singular
and
plural.
The
style follows common American
usage. Abbreviations
for
some special disciplines
are
given near
the
beginning
of the
chapter about that subject.
A
Amperes (also amp).
A
Area, usually
the
cross-sectional area
of a
pipe.
a
Acceleration.
a
Acoustic wave
speed.
@
At.
abs
Absolute.
ac
Alternating current.
ac/h
Air
changes
per
hour.
acre-ft
Acre-foot
(43,560
ft
3
).
AF
Adjustable
frequency.
AFD
Adjustable-frequency drive (for electric motors).
AM
Ante meridian (morning).
amp
Ampere (also
A).
amp-h
Ampere-hour.
AN
As
noted.
API
American Petroleum Institute.
ASHRAE American Society
of
Heating Refrigerating
and Air
Conditioning Engineers.
atm
Atmosphere
(=
14.7
lb/in.
2
)
avg
Average.
AWG
American wire gauge.
AWWA
American Water Works Association.
B
Bulk modulus
of
elasticity
of
water.
bee
Best
efficiency
capacity (discharge
at
bep).
bep
Best
efficiency
point.
BHN
Brinell
hardness number
(on the
C-scale
except
as
otherwise noted).
bhp
Brake horsepower.
bhp-h
Brake horsepower-hour.
BHRA
British Hydraulic Research Association.
Btu
British thermal
unit
(the heat required
to
raise
the
temperature
of 1
Ib
of
water
by
I
0
F).
CADD Computer-aided
drafting
and
design.
c One
hundred.
©
Copyrighted.
C
Hazen-Williams
roughness
coefficient.
0
C
Degree Celsius (centigrade) equals
(
0
F-
32)
5
/
9
.
c-c
Center
to
center.
<£-<£
Centerline
to
centerline.
CFD
Computational
fluid
dynamics.
A
numerical means
to
predict
flow
patterns based
on
solving
the
governing equations
in
three dimensions
at
discreet nodes that represent
the flow
space.
See
Section
3-13.
cfm
Cubic
feet
per
minute (also
ft
3
/min).
cfs
See
ft
3
/s.
ckt
bkr
Circuit
breaker,
cm
Centimeter.
cm
2
Square centimeter.
cm
3
Cubic
centimeter,
coef
Coefficient,
cone
Concentration,
cond
Conductivity,
const Constant.
COP
Coefficient
of
performance
(a
ratio
of
electrical
energy input
to
heat energy output).
CPRV
Chlorine pressure reducing valve.
C/S
Constant
speed.
CSO
Combined (wastewater
and
storm water) sewer
overflow
CU
Coefficient
of
utilization used
in
lighting
calculations,
cu ft
Cubic
feet
(also
ft
3
),
cu
in.
Cubic inches (also
in.
3
),
cu
yd
Cubic yards (also
yd
3
),
cwt
One
hundred
pounds,
d
Day.
D
Diameter.
dB
Decibel.
dBA
Decibel-A
scale,
dc
Direct
current,
dia
Diameter.
DIP
Ductile iron
pipe,
do
Ditto.
E
Exponent (e.g.,
3.6
E-6
= 3.6 x
10~
6
).
E
Modulus
of
elasticity
(see
Table
A-IO,
Appendix
A).
E
Efficiency
(sometimes followed
by a
subscript
to
indicate pump, motor, etc.).
ea
Each,
ed
Edition.
Ed.
Editor,
eff
Efficiency,
e.g.
For
example.
EGL
Energy grade
line.
El
Elevation. Also
Elev.
emf
Electromotive force.
ENRCCI Engineering News-Record Construction Cost Index.
E
p
Pump
efficiency.
EPA
See
U.S. EPA.
Eq
Equation.
est
Estimated.
et
al.
And
others.
ETM
Elapsed time meter.
F
Froude number.
0
F
Degrees Fahrenheit.
ff
Following pages.
FFT
Fast Fourier transform (analyzer)
for
vibration analysis.
FLI
Full-load electrical current (see also
/
FL
).
FM
Force main.
fob
Freight
on
board.
fpm
See
ft/min.
fps
See
ft/s.
FRP
Fiberglass-reinforced plastic.
FSK
Frequency
shift
modulation.
ft
Foot
or
feet.
ft
2
Square
feet.
ft
3
Cubic
feet.
ft
• cd
Foot-candles.
ft
•
Ib
Foot-pound.
ft/min
Feet
per
minute.
ft/s
Feet
per
second.
ft
3
/s
Cubic
feet
per
second.
FVNR
Full voltage (nonreversing
for
magnetic motor starters).
g
Acceleration
due to
gravity
(=
9.81
m/s
2
=
32.17
ft/s
2
= 386
in./s
2
).
g
Gram.
g
c
32.17ft-lb
m
/lb
r
s
2
ga
Gauge.
gal
Gallon.
gal/d
• cap
Gallons
per day •
capita.
gal/min
Gallons
per
minute.
GFCI Ground
fault
circuit interrupter
(a
safety
device).
GFI
See
GFCI.
gpcpd Gallons
per
capita
per day
(also gpcd;
see
gal/d
•
cap).
gpm
or GPM See
gal/min.
Grd
Ground.
GTO
Gate
turn-off
thyristor.
h
Hour.
H
or h
Head [usually
in
meters
(feet)
of
water].
h
L
Headloss.
HDPE High-density polyethylene (pipe).
HGL
Hydraulic grade line.
HOA
Hand-off-automatic
(switch).
hp
Horsepower.
hp • h
Horsepower-hour.
H-Q
Head-capacity.
hr
Hour (see
h).
HV
Heating
and
ventilating (also
H&V).
HVAC
Heating, ventilating,
and air
conditioning (also HV&AC).
H-W
Hazen-Williams
(Equations
3-8 and
3-9).
HWL
High water level.
Hz
Hertz (cycles
per
second)
/
Electrical current.
/PL
Full-load current (amperes).
/L
Line current (amperes).
/
e
Phase current (amperes).
I&C
Instrumentation
and
control.
ID
Inside diameter
(mm
[in.]),
i.e. That
is.
IEEE Institute
of
Electrical
and
Electronics Engineers.
IGBT Insulated-gate bipolar transistor (sometimes
found
in AF
drives).
Imp
gal
Imperial
gallon,
in.
Inch.
in.
2
Square
inches,
in. •
Ib
Inch-pound.
IR
Indicating
and
recording (instrument).
ISA
Instrument Society
of
America.
J
Joule.
/
Polar moment
of
inertia.
K
Bulk modulus
of
elasticity
of
water
(B in
Chapter 22).
K
Torsional rigidity
(in
Chapter 22).
0
K
Degree Kelvin
(=
0
C
+
273.2).
kc
Kilocycles,
kcal
Kilocalorie.
kcmil
A
unit
of
conductor area equal
to the
diameter
of a
wire
in
mils
squared,
kg
Kilogram,
kip
Kilopound (1000
Ib).
km
Kilometer.
kPa
Kilopascals
(1000
N/m
2
).
ksi
Kilopounds
(1000
Ib)
per
square inch.
kV
Kilovolt.
kVA
Kilovolt ampere.
kVAR
Reactive kilovolt
ampere,
kW
Kilowatt
(1000
watts).
kW - h
Kilowatt-hour.
L
Liter.
Ib
Pound (means
lb
f
in
this volume).
lb
f
Pound
force
=
lb
m
glg
c
\
numerically (not dimensionally) equals
lb
m
.
In
this volume
lb
f
is
writ-
ten
Ib.
lb
m
Pound mass
(=
lb
f
-
gjg).
lb/ft
2
Pounds
per
square foot.
lb/ft
3
Pounds
per
cubic foot.
L/d • cap
Liters
per day •
capita.
LEL
Lower explosion limit.
LF
Linear
feet
(also
lin
ft).
In
Natural
logarithm,
log
Logarithm
to
base
10.
LPG
Liquid petroleum
gas
(either propane
or
butane;
specify
which).
LWL
Low
water
level,
m
Meter(s).
m
2
Square meters.
m
3
Cubic meters.
mA
Milliampere.
max
Maximum.
MCC
Motor control center.
MCM Now
kcmil.
A
unit
of
conductor area equal
to the
diameter
of a
wire
in
mils squared.
MCP
Motor circuit protector.
Mfr
Manufacturer,
mg
Milligram.
Mgal
Million gallons.
Mgal/d
Million gallons
per
day.
mgd
or MGD See
Mgal/d.
mg/L
Milligrams
per
liter.
mi
Mile.
mi/h
Miles
per
hour.
mil
1/1000
in. or
0.025
mm or 25
microns.
min
Minimum.
min
Minute.
ml
Milliliter.
mm
Millimeter.
mol
Mole.
mph
See
mi/h.
mV
Millivolts.
N
Newton (the force required
to
accelerate
1 kg of
mass
1
m/s
2
).
n
Manning roughness
coefficient
(Equation 3-17).
NA
Not
applicable.
NC
Normally closed (electrical switch).
n.d.
No
date.
NEC
National Electrical Code.
NEMA
National Electrical Manufacturers Association.
NO
Normally open (electrical switch).
No.
Number.
NPS
Nominal pipe size.
NPSH
Net
positive suction head (q.v. Section 2-2).
NPSH
A
Net
positive suction head available (q.v. Section 2-2).
NPSH
R
Net
positive suction head required (q.v. Section 2-2).
NRS
Nonrising
stem (for valves).
n
s
Specific
speed.
NTU
Nephelometric turbidity units.
OC
Overcurrent.
OD
Outside diameter.
O&M
Operation
and
maintenance.
OSHA Occupational
Safety
and
Health Administration.
OS&Y
Outside screw
and
yoke (indicates
a
rising stem
in a
valve).
oz
Ounce.
p
Pole
(electrical).
p,
pp
Page, pages.
Pa
Pascal (N/m
2
).
PAM
Pulse amplitude modulated.
pcf
See
lb/ft
3
.
Pf
Power factor.
P&ID
Process
and
instrumentation diagram.
PIR
Peak
influent
rate.
PLC
Programmable logic controller.
PM
Post meridian (afternoon).
ppb
Parts
per
billion.
ppm
Parts
per
million.
PRV
Pressure reducing valve.
PS
Pumping station.
psi
Pounds
per
square inch (also
lb/in.
2
).
psia Pounds
per
square inch absolute (pressure above vacuum, also
lb/in.
2
abs).
psig Pounds
per
square inch gauge (pressure above atmospheric, also
lb/in.
2
ga).
PTC
Positive temperature
coefficient
thermistor.
PVC
Polyvinyl chloride.
PWM
Pulse width modulated.
Q
Flowrate, capacity,
or
discharge.
q.v.
Which see.
0
R
Degrees
Rankine
(=
0
F
+
491.7).
R
Electrical resistance
(in
ohms).
R
Hydraulic radius (wetted area/wetted perimeter).
R
Reynolds number.
®
Registered trademark (see also
™).
rad
Radian.
RCP
Reinforced concrete pipe.
RCR
Room cavity ratio used
in
lighting calculations.
rev/min Revolutions
per
minute.
rev/s Revolutions
per
second.
RMPDR Recommended minimum pump discharge
rate.
RMS
Root mean square
(an
average
of
70.7%
of
peak value
in a
sinusoidal waveform).
rpm
or RPM See
rev/min.
rps
or RPS See
rev/s.
RS
Raw
sewage (the older term,
"sewage,"
is now
replaced
by
"wastewater").
RTP
Reinforced
thermosetting
polyester (the modern acronym
for
fiberglass
or
FRP).
RVNR
Reduced voltage nonreversing (for magnetic motor starters).
RW
Raw
wastewater.
s
Second.
SCADA Supervisory control
and
data acquisition.
scfm
Standard cubic
feet
per
minute.
Sch
Schedule (for pipe).
SCR
Silicon controlled
rectifier.
SDR
Average outside diameter
of a
pipe divided
by
minimum wall thickness.
sec
Second (see
s).
SF
Service factor.
shp
Shaft
horsepower.
SI
System International (for metric units).
sp gr
Specific
gravity.
sq
Square.
sq ft
Square
foot
or
feet
(also
ft
2
).
sq
in.
Square inch
or
inches (also
in.
2
).
ss
Stainless steel.
Std
Standard.
t
Thickness.
t
Time.
TDH
Total dynamic head
(=
static head
+
friction
head
+
other losses).
TDS
Total dissolved solids.
TEFC Totally enclosed,
fan
cooled
(motor).
temp Temperature.
TIR
Totalizing, indicating,
and
recording (instrument).
™
As a
superscript, trademark (see also (D).
Typ
Typical, typically.
UL
Underwriters Laboratory.
URV
Upper range value.
U.S. United States
or
U.S. customary units.
U.S.
EPA
United States Environmental Protection Agency.
V
Volts.
V
Volume.
V
L
Line-to-line voltage.
VQ
Phase voltage.
v
Velocity.
VA
Volt-ampere.
VAR
Reactive volt
ampere.
VCP
Vitrified
clay pipe.
VFD
Variable-frequency drive (also
AFD
[adjustable-frequency
drive]).
2-2.
Definitions
The
following
list
of
terms
is not
intended
to be
com-
plete
but to
contain only commonly used terms that
might
be
unfamiliar
to
some readers. Some terms
for
special disciplines
are
contained
at the
beginning
of
the
chapter about that subject.
Absolute pressure: Gauge pressure plus standard
atmospheric pressure.
Affinity
laws:
A set of
equations
or
laws governing
the
operation (discharge, head, power)
of a
single
centrifugal
pump operated
at
different
speeds
or, by
close approximation, governing
the
relationship
of
operation
of
pumps
or
impellers
of
different
sizes
operated under dynamically similar conditions (see
Section
10-3).
Air
break:
An air gap in a
liquid system intended
to
ensure against back siphonage.
The
discharge into
free
atmosphere must
be
located well above
the
viz.
Namely.
V/S
Variable speed.
vs.
Versus.
VTSH Vertical turbine, solids-handling (pump).
W
Watt.
WC
Water column (pressure
in
meters
[or
feet]
of
water).
WEF
Water Environment Federation.
W
-
h
Watt-hour.
W •
hM
Watt
hour meter.
whp
Water horsepower.
WPCF Water Pollution Control Federation (now Water Environment Federation).
WR
2
Inertia
of
moving parts
in
pump
and
driver.
wt
Weight.
XS
Extra strong (pipe).
XXS
Double extra strong (pipe).
yd
Yard.
yr
Year.
7
Specific
weight.
e
Absolute pipe roughness (inches
or
millimeters).
JUL
Dynamic viscosity.
IJL
Poisson's
ratio.
v
Kinematic viscosity.
p
Density.
S
Sum, summation.
T
Shearing stress.
c()
Phase (electrical current).
CD
Rotational speed (usually
rev/min).
U
Ohms (resistance).
>
Equal
to or
greater than.
<
Equal
to or
less than.
>
Greater than.
<
Less than.
—
or
=
Approximately equals.
~
or ~
Approximately
(prefix).
±
Approximately
(suffix).
0
Cent.
$
Dollar.
As
a
superscript,
feet.
"
As a
superscript, inches.
%
Percent.
Times (multiplication).