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SANCTIONS:
Actions
taken
against
a
state
or
local
government
for
failure
to
plan
or
to
implement
a
SIP,
such
as
a
ban
on
construction
of
new
sources.
SATEEN:
Cotton
cloth
made
with
a
satin
weave,
expressed
as
warp
sateen
or
filling
sateen.
SATIN
WEAVE:
A
form
of
twill,
except
that
the
points
or
intersection
are
separated
from
one
another
in
a
consistent
or
inconsistent
manner.
SATURATED
AIR:
Air
containing
the
maximum
amount
of
water
vapor
for
a
given
temperature
and
pressure.
SCFM
(STANDARD
CUBIC
FEET
PER
MINUTE):
The
volume
that
a
gas
would
occupy
at
standard
temperature
and
pressure
conditions
(70°
F
and
14.7
PSIA).
See
Gas
Flow
Rate.
SCREW
CONVEYOR:
A
dust
transfer
conveyor
that
uses
a
screw
drive
for
continuous
movement
of
the
material.
SCROLL:
The
general
shape
of
a
centrifugal
fan
housing.
The
formed
piece
to
which
housing
sides
are
welded.
SCRUBBER:
A
device
that
uses
a
liquid
spray
to
remove
aerosol
and
gaseous
pollutants
from
an
air
stream.
The
gases
are
removed
either
by
absorption
or
chemical
reaction.
Solid
and
liquid
particulates
are
removed
through
contact
with
the
spray.
Scrubbers
are
used
for
both
the
measurement
and
control
of
pollution.
SCRUBBER,
GAS:
Any
device
in
which
a
contaminant,
solid
or
gaseous,
is
removed
from
a
gas
stream
by
liquid
droplets.
(Types
include
spray
towers,
packed
towers,
cyclone
scrubbers,
jet
scrubbers,
orifice
scrubbers,
venturi
scrubbers,
impingement
scrubbers
and
mechanical
scrubbers.)
SECONDARY
COLLECTOR:
A
dust
collector
that
is
preceded
by
primary
collector(s).
The
secondary
filter
normally
has
a
higher
filtering
efficiency.
SEEDING:
The
application
of
a
relatively
coarse,
dry
dust
to
a
bag
or
cartridge
before
start-up
to
provide
an
initial
filter
cake
for
immediate
high
efficiency
and
to
protect
bags
from
blinding.
Also,
in
crystallizing,
seeding
is
used
to
start
the
crystallization
process.
SEISMIC
ZONE
4/100
MPH
WIND
LOAD
RATING:
Structural
rating
of
a
dust
collector.
The
equipment
is
designed
to
withstand
the
effects
of
an
earthquake
or
wind
force
as
defined
in
the
Uniform
Building
Code.
SENSIBLE
HEAT:
Any
portion
of
heat
that
effects
a
change
in
a
substance’s
temperature
but
does
not
alter
that
substance’s
state.
SERIES
FANS:
A
combination
of
fans
connected
such
that
the
outlet
of
one
fan
exhausts
into
the
inlet
of
another.
Fans
connected
in
this
manner
are
capable
of
higher
pressures
than
a
single
fan
and
are
used
to
meet
pressure
requirements
greater
than
single
fans.
SERVICE
FACTOR:
The
number
by
which
the
horsepower
rating
is
multiplied
to
determine
the
maximum
safe
load
that
a
motor
may
be
expected
to
carry
continuously.
SETTLING
CHAMBER:
A
dry
collection
device
that
removes
particulate
matter
from
the
gas
stream
by
slowing
down
the
exhaust
gas
velocity.
SHADED-POLE
MOTOR:
A
special
type
of
single-phase
induction
motor.
Low
starting
torque,
low
cost.
Usually
used
on
direct-drive
fans.
SHAFT
SEAL:
A
device
to
limit
gas
leakage
between
the
shaft
and
fan
housing.
SHAKER
BAGHOUSE:
A
baghouse
using
woven
cloth
bags;
cleaning
occurs
by
shaking
bags.
SIC
CODE
(STANDARD
INDUSTRIAL
CLASSIFICATION
CODE):
A
system
used
to
classify
industrial
manufacturing
companies
by
product
and
their
type
of
business.
SI
UNITS:
Systems
International
d’Unites,
International
System
of
Units.
Any
one
of
the
units
of
measure
in
the
international
meter-kilogram-second
system.
SILICONE
FINISH:
A
treatment
of
felted
bags
with
silicone
to
provide
a
slick
finish
for
improved
dust
release.
Most
commonly
used
on
Dacron
polyester
and
fiberglass
bags.
SINGED
FINISH:
A
felted
bag
finish
that
is
designed
to
provide
a
finish
similar
to
calendaring.
The
“hairs”
are
burned
off
to
provide
a
smoother
finish.
SINGEING:
The
burning
off
of
the
protruding
fibers
from
the
warp
and
filling
yarns
of
the
fabric.
SIP
(STATE
IMPLEMENTATION
PLAN):
Documents
prepared
by
states,
and
submitted
to
EPA
for
approval,
which
identify
actions
and
programs
to
be
undertaken
by
the
state
and
its
subdivisions
to
implement
their
responsibilities
under
the
Clean
Air
Act.
SIZING:
A
protective
coating
applied
to
yarn
to
ensure
safe
handling,
such
as
abrasion-free
during
weaving.
SKRIM:
A
woven
fabric
that
felt
is
needled
onto.
SLIP:
The
percentage
difference
between
synchronous
and
operating
speeds.
SLOT
VELOCITY:
Linear
speed
of
air
through
a
slot
in
a
hood,
expressed
in
Feet
Per
Minute
(FPM).
SMOG:
The
irritating
haze
resulting
from
the
sun’s
effect
on
certain
pollutants
in
the
air,
notably
those
from
automobile
exhaust.
See
Photochemical
Process.
Also
a
mixture
of
fog
and
smoke.
SMOKE:
An
air
suspension
of
aerosol
particles
which
can
be
solid
or
liquid,
formed
from
vaporization
and
condensation,
such
as
welding
smoke,
oil
smoke
from
machining,
etc.
Particles
are
less
than
1
micron
in
diameter.
SO2:
Sulfur
dioxide
is
an
invisible,
nonflammable,
acidic
gas
formed
during
combustion
of
fuel
containing
sulfur.
SO3:Sulfur
trioxide
oxidized
from
SO2;
combines
with
atmospheric
moisture
to
form
sulfuric
acid
mist
(H2SO4).
SOLENOID
VALVE:
Electromechanical
valve
which
initiates
pulsing
action
in
reverse
pulse-jet
cleaning
systems
or
allows
water
to
flow
in
SMOG-HOG®
in-place
cleaning
systems.
An
electrical
signal
energizes
a
coil
that
opens
the
valve
allowing
the
fluid
(air
or
water)
to
flow
through
the
valve
body.
SOOT:
Very
finely
divided
carbon
particles
clustered
together
in
long
chains.
SOUND-POWER
LEVEL:
Acoustic
power
radiating
from
a
sound
source.
Expressed
in
watts
or
decibels.
SOUND-PRESSURE
LEVEL:
The
acoustic
pressure
at
a
point
in
space
where
the
microphone
or
listener’s
ear
is
situated.
Expressed
in
units
of
pressure
or
in
decibels.
SOURCE:
Any
place
or
object
from
which
pollutants
are
released.
SOURCE
CAPTURE:
A
term
used
to
describe
applications
in
which
the
airborne
contaminant
is
picked
up
or
“captured”
directly
at
the
machine
or
process.
Source
capture
applications
involve
the
use
of
ductwork
to
convey
the
contaminated
air
to
the
air-cleaning
device.
Also
sometimes
called
“direct
capture.”
SP
(STATIC
PRESSURE):
Pressure
as
measured
in
all
directions
within
an
airhandling
system,
not
including
the
force
or
pressure
of
air
movement.
SPARK
TRAP:
Device
in
a
duct
system
designed
to
stop
or
extinguish
a
spark
prior
to
entering
a
dust
collector.
Usually
a
dropout
box
in
the
duct
system
or
inlet
plenum
that
contains
baffles
to
create
a
torturous
air
path
which
causes
the
spark
to
quench.
SPECIFIC
GRAVITY:
The
ratio
of
the
weight
or
mass
of
a
given
volume
of
any
substance
to
that
of
an
equal
volume
of
some
other
substance
taken
as
a
standard.
The
ratio
of
the
density
of
any
gas
to
the
density
of
dry
air
at
the
same
temperature
and
pressure
is
the
specific
gravity
of
the
gas.
SPECIFIC
HEAT:
The
ratio
of
the
quantity
of
heat
required
to
raise
a
certain
volume
one
degree
to
that
required
to
raise
an
equal
volume
of
water
one
degree.
SPI:
Society
of
the
Plastics
Industry.
SPLIT-PHASE
MOTOR:
The
most
common
type
of
single-phase
induction
motor.
Moderate
starting
torque,
high-starting
current,
high
breakdown
torque.
Used
on
easy-starting
equipment,
such
as
belt-drive
fans.
SPUN
FABRIC:
Fabric
woven
from
staple
spun
fabric.
SQUIRREL-CAGE
WINDING:
A
permanently
short-circuited
winding,
usually
uninsulated
and
chiefly
used
in
induction
motors,
having
its
conductors
uniformly
distributed
around
the
periphery
of
the
machine
and
joined
by
continuous
end
rings.
SRC
(SPARK-RESISTANT
CONSTRUCTION):
AMCA
standard
of
guidelines
for
general
methods
of
fan
construction
when
handling
potentially
explosive
or
flammable
particles,
fumes
or
vapors.
SSPC:
Steel
Structures
Painting
Council.
STACK:
A
smokestack.
Vertical
pipe
or
flue
designed
to
exhaust
gases.
STANDARD
AIR
DENSITY:
0.075
lbs./ft3.
Corresponds
approximately
to
dry
air
at
70°F
and
29.92
in.
Hg.
STARTING
TORQUE:
The
torque
produced
by
a
motor
as
it
begins
to
turn
from
a
standstill
and
accelerate.
Sometimes
called
locked
rotor
torque.
STATIC
BALANCE:
The
mechanical
balance
of
a
rotating
part
or
assembly
by
adding
weights
to
counter-balance
gravitational
rotating
of
the
part
without
power
driving
it.
STATIC
PRESSURE:
The
pressure
exerted
in
all
directions
by
a
fluid.
For
a
fluid
in
motion,
it
is
measured
perpendicular
to
the
direction
of
flow,
expressed
in
inches
of
water.
STATIC
PRESSURE,
COLD:
The
pressure
caused
by
the
resistance
to
air
flow
through
the
system
if
the
gas
were
at
standard
conditions
or
colder,
if
this
is
a
possibility.
STATIC
PRESSURE,
FAN:
The
static
pressure
for
which
a
fan
is
to
be
selected
based
on
system
calculations:
Fan
SP
=
SP
outlet
–
SP
inlet
–
VP
inlet
STATIC
PRESSURE,
HOT:
The
pressure
caused
by
the
resistance
to
air
flow
through
the
system
at
actual
conditions.
Measured
in
inches
of
water
(WG).
STATOR:
The
stationary
parts
of
a
magnetic
circuit
with
associated
windings.
STREAMLINE
FLOW:
Fluid
flow
in
which
the
velocity
pressure
and
fluid
density
of
a
given
particle
remains
constant
with
time.
STEL
(SHORT-TERM
EXPOSURE
LIMIT):
The
employee’s
15-minute
time
weighted
average
exposure
which
cannot
be
exceeded
at
any
time.
STEL
is
set
by
OSHA
for
each
pollutant
and
expressed
in
terms
of
ppm
or
mg/m.
STOICHIOMETRIC
AIR:
The
exact
quantity
of
air
required
to
combine
with
the
given
fuel
so
that
the
ensuing
combustion
reaction
is
perfect
and
no
free
oxygen
or
unburned
constituents
remain.
In
reality,
air
in
excess
of
the
stoichiometric
ratio
is
usually
provided
to
encourage
complete
combustion
of
the
fuel.
SULFUR
DIOXIDE
(SO2):
A
heavy,
pungent,
colorless
air
pollutant
formed
primarily
by
the
combustion
of
fossil
fuels.
It
is
a
respiratory
irritant,
especially
for
asthmatics
and
is
the
major
precursor
to
the
formation
of
acid
rain.
SULFUR
OXIDES:
Pungent,
colorless
gases
formed
primarily
by
the
combustion
of
fossil
fuels;
considered
major
air
pollutants.
Sulfur
oxides
may
damage
the
respiratory
tract
as
well
as
vegetation.
SURGE
LIMIT:
That
point
near
the
peak
of
the
pressure
curve
which
corresponds
to
the
minimum
flow
at
which
the
fan
can
be
operated
without
instability.
SWSI:
Single-Width,
Single-Inlet
Centrifugal
Fan.
SYNCHRONOUS
SPEED:
Rated
motor
speed
expressed
in
RPM.
Synchronous
speed
=
120
x
frequency,
divided
by
number
of
poles.
SYSTEM:
A
series
of
ducts,
conduits,
elbows,
filters,
diffusers,
etc.,
designed
to
guide
the
flow
of
air,
gas
or
vapor
to
and
from
one
or
more
locations.
A
fan
provides
the
energy
necessary
to
overcome
the
system’s
resistance
to
flow,
and
causes
air
or
gas
to
flow
through
the
system.
SYSTEM
CURVE:
Graphic
presentation
of
the
pressure
versus
volume
flow
rate
characteristics
of
a
particular
system.
SYSTEM
EFFECT:
The
effect
on
the
performance
of
a
fan
resulting
from
the
difference
between
the
fan
inlet
and
outlet
connections
to
the
actual
system,
and
the
standardized
connections
used
in
laboratory
tests
to
obtain
fan
performance
ratings.
SYSTEM
GAS
VOLUME:
All
gases
flowing
through
the
exhaust
gas
system
(including
excess
air,
scavenger
air,
leakage
air).
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