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Acronyms

Conversion Factors

Numerical Constants

Symbols

Units of Measurement

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Acronyms

Acronym Definition

ACF

Actual Cubic Feet

ACFM

Actual Cubic Feet per Minute

BACT

Best Available Control Technology

BHP

Brake horsepower

BOOS

Burners Out Of Service

BP

Boiling Point

CAA

Clean Air Act

CAAA

Clean Air Act Amendments

CAM

Compliance Assurance Monitoring

CEMS

Continuous Emissions Monitoring System

Cgs

Centimeter-Gram-Second

DACFM

Dry Actual Cubic Feet per Minute

DSCFM

Dry Standard Cubic Feet per Minute

EPA

Environmental Protection Agency

ESP

Electrostatic Precipitator

FIP

Federal Implementation Plan

HAP

Hazardous Air Pollutant

IPA

Isopropyl Alcohol

ITEQ

International Toxic Equivalency Quotient

LAER

Lowest Achievable Emission Rate

LEL

Lower Explosive Limit

MACT

Maximum Achievable Control Technology

MCE

Mixed Cellulose Ester

NAAQS

National Ambient Air Quality Standards

NESHAPs

National Emission Standards for Hazardous Air Pollutants

NSPS

New Source Performance Standards

NSR

New Source Review

OFA

Overfire Air

OTAG

Ozone Transport Assessment group

OTC

Ozone Transport Commission

PSD

Prevention of Significant Deterioration

QA/QC

Quality Assurance/Quality Control

RAP

Reclaimed Asphalt Pavement

RTO

Regenerative Thermal Oxidizer

SCF

Standard Cubic Feet

SCFM

Standard Cubic Feet per Minute

SIP

State Implementation Plan

TEQ

Toxic Equivalency Quotient

U.S. EPA

United States Environmental Protection Agency

VOC

Volatile Organic Compound

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Conversion Factors

American Engineering System

Heat
1 Btu = 252 cal

Length and Distance

1 in. = 2.54 cm
1 ft = 30.48 cm
1 meter = 100 cm
1 meter = 3.2808 ft
1 mile = 5,280 ft

Mass

1 lb_m = 453.6 gm
1 lb_m = 7,000 grains

Mole Equivalents
1 lb mole = 453.6 gm mole

Pressure
(at std. conditions, 68°F)
1 atm = 407 in. W.C. =
14.7 psia = 14.7 lb_f /in.²=
760 mm Hg = 29.92 in. Hg =
101.325 kPa = 33.92 ft W.C.

Temperature
1°C = 1.8°F
°C = (°F 32)/1.8
°F = 32 + 1.8 (°C)
°K = 273 + °C
°K = °R/1.8
°R = 460 + °F
°R = 1.8(°K)

Viscosity

1 micropoise = 10^-4 cp

1 poise = 100 cp

Volume
1 mL = 1 cm³

1 liter = 0.03531 ft³

1 ft³ = 7.481 gal

1 ft³ = 28.32 liter

1 m³ = 35.31 ft³

Volume to Mass
1 mL of pure water = 1 gm

1 gallon of pure water =
8.34 lb_m

1 ft³ of pure water = 62.4 lb_m

Volume (Gas) @ STP
Volume of 1 lb mole of gas
@ STP = 385.4 ft³
(or 385 ft³ rounded)

Volume of 1 gm mole of ideal gas
@ STP = 24.04 liters
(or 24 liters rounded)

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Numerical Constants

Density
Density of city water at standard conditions =
62.4 lb_m/ft³ or 8.34 lb_m/gal

Density of water at 4°C (39.2°F) is 1 gm/cm³

Dissociation
Constant of Water
K_w = 1 × 10^-14 (moles/L)²

Universal Gas Constant, R

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Symbols

SymbolDefinition

A_STP

Fan motor current at standard conditions

A_Actual

Fan motor current at actual conditions

A_Total

Total area of fabric filter bags

BHP

Brake horsepower (total power consumed by the fan)

C_c

Cunningham slip correction factor

C_e

Coefficient of entry

C_p

Pitot tube coefficient (usually assumed to be 0.84)

Cp_x

Heat capacity of compound x at constant pressure

Conc. i_(Dry)

Dry concentration of gas i

Conc. i_{(Measured O2)}

Gas concentration at measured oxygen level

Conc. i_{(Std O2)}

Gas concentration at standard oxygen level

Conc. i_(Wet)

Wet concentration of gas i

c

Average speed of molecules

D

Diameter

D_Fan

Diameter of fan sheave

D_Motor

Diameter of motor sheave

D_c

Diameter of a droplet

D_h

Hydraulic diameter for rectangular duct

D_p

Diffusivity of particles

dv/dy

Velocity gradient

d_pa

Aerodynamic particle diameter

d_pmin

Minimum diameter of particles in a particular size range

d_ps

Stokes particle diameter

d₅₀

Diameter of a median-sized particle

d_15.78

Particle size at 15.78% probability in a lognormal distribution

d_84.13

Particle size at 84.13% probability in a lognormal distribution

E

Voltage

e

Base of the natural logarithm

g

Gravitational acceleration

g_c

Factor used when converting between pounds force and pounds mass

H

Height of a geometric shape ("h" is sometimes used for cylinders). Also, enthalpy

H

Henry's law constant

h

Height of a cylinder. Also, height of a fabric filter bag

h_e

Hood entry loss

I

Motor current

K

Boltzmann constant

K_I

Impaction parameter

K_w

Dissociation constant for water

L

Length of a geometric shape. Also, in the gas stream Reynolds number calculation: linear dimension (usually duct diameter).

MW

Molecular weight

MW_Avg

Average molecular weight

m

Mass

N_Re(g)

Gas stream Reynolds number

n

Number of moles

P

Pressure

P_Absolute

Absolute pressure

P_Actual

Gas pressure at actual conditions

P_Atm

Atmospheric pressure

P_Avg

Average pressure

P_Barometric

Barometric pressure

P_Gauge

Gauge pressure (a relative pressure)

P_Relative

Relative pressure

P_STP

Gas pressure at standard conditions

P_Total

The total pressure of a gas composed of different chemical compounds (the sum of the partial pressures of all component gases)

P_j

Pressure whose value equals j

PM_2.5

Particulate matter less than 2.5 micrometers in diameter

PM₁₀

Particulate matter less than 10 micrometers in diameter

p_f

Power factor (phase relationship between current and voltage waveforms)

Q

Heat required per unit time. Also, volumetric gas flow rate.

R

Universal gas constant

RPM_Fan

Fan speed, revolutions per minute

RPM_Motor

Motor speed, revolutions per minute

r

Radius

SP

Static pressure

Sp. Gr.

Specific gravity

SP_h

Hood static pressure

T

Temperature

T_Absolute

Absolute temperature

T_Actual

Gas temperature at actual conditions

T_Avg

Average gas temperature

T_STP

Gas temperature at standard conditions

T_i

Temperature whose value equals i

TP

Total pressure (the combined static pressure and velocity pressure)

t

Time

V

Volume

V_T=i

Volume at a specific temperature (i)

V_{(T=i, P=j)}

Volume at a specific temperature (i) and pressure (j)

VP

Velocity pressure

v

Gas velocity. Also, in the impaction parameter equation: difference in velocity

v_t

Terminal settling velocity

W

Width of a geometric shape

W.C.

Water column

x

Mole fraction of pollutant in liquid phase

y

Mole fraction of pollutant in gas phase

y*

Mole fraction of pollutant in gas phase in equilibrium with liquid

Greek Symbols

SymbolDefinition

"Change in." For example T means change in temperature

Static pressure drop

Unit shearing stress between adjacent layers of fluid

Collection efficiency

Viscosity of gas or fluid at the prevailing conditions

3.1416

Density

Density at actual conditions

Density of a liquid at a specific temperature (x)

Density at standard conditions

Density at a specific temperature (i)

Gas density at a specific temperature (i) and pressure (j)

Density of water at reference temperature

Density of a gas or fluid

Density of a particle

Standard deviation of particle mass distribution

Kinematic viscosity

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Units of Measurement

Abbrev.Unit

ACFM

Actual cubic feet per minute

atm

Atmosphere

BHP

Brake horsepower

Btu

British thermal unit

°C

Degree Celsius

cal

Calorie

cm

Centimeter

cp

Centipoise

DNm³

Dry standard cubic meter

°F

Degree Fahrenheit

fpm

Feet per minute

ft

Foot

ft W.C.

Feet of water column

gal

Gallon

gm

Gram

gpm

Gallons per minute

gr

Grains

hp

Horsepower

in.

Inch

in. Hg

Inches of mercury

in. W.C.

Inches of water column

°K

Kelvin

kcal

Kilocalorie

kg

Kilogram

kPa

Kilopascal

L

Liter

lb

Pound

lb_f

Pounds force

lb_m

Pounds mass

m

Meter

mi

Mile

min

Minute

mm

Millimeter

mm Hg

Millimeter of mercury

M

Molarity

mPa

Millipascal

µg

Microgram

µm

Micrometer

Nm³/min

Standard cubic meters per minute

nm

Nanometer

N

Normality

Pa

Pascal

p

Poise

ppm

Part per million

ppm(v/v)

(Also ppmv) Part per million calculated as a ratio of the volume of the pollutant divided by the total volume of the sample

ppmvd

Part per million (dry basis)

ppm(w/w)

Part per million calculated as a ratio of the weight of the pollutant divided by the total weight of the sample

psi

Pounds per square inch

psia

Pounds per square inch (absolute)

psig

Pounds per square inch (gauge)

°R

Degree Rankine

rpm

Revolutions per minute

SCFM

Standard cubic feet per minute

sec

Second

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