A
A = (1) acceleration; (2) aperture; (3) area.
A, amp = ampere.
Å = Angstrom.
abs = absolute.
AC,ac = alternating current
acfm = actual cubic feet per
minute.
alt = altitude.
ANSI = American National
Standards Institute.
ASTM = American Society for
Testing and Materials.
asym = asymmetrical.
atm = atmosphere.
B
b = breadth, width.
B = film thickness.
bar = unit of atmospheric pressure.
bara = bar, absolute.
barg = bar gauge.
bbl = barrels
oB”e = Baume degrees.
BHP = brake horsepower.
Bk = Barkometer degrees
bp = boiling point.
Br = Brix degrees.
Btu – British thermal unit.
C
c = (1) specific heat;
(2) volumetric concentration.
C = coefficient.
C = degrees Celsius
ca. = circa.
cal = calorie.
cc = cubic centimeter.
ccm = cubic feet per minute.
cfy = cubic feet per year.
cm = centimeter
cmph = cubic meter per hour.
cp = specific heat, at
constant pressure.
cp or cps = centipoises.
cpm = cycles per minute.
cps = cycles per second.
CPVC = chlorinated polyvinyl chloride.
cs =humid heat.
cv = specific heat, at constant volume
D
d = (1) derivative; (2) differential operator.
D – distillate rate.
D, d or dia = diameter
DC or dc = direct current.
DCS = distributed control system.
deg or o = degrees
DO = dissolved oxygen.
DPDT = double=pole, double=throw.
DPST = double=pole, single=throw
Dv = diffusity of vapor.
E
e = base of natural logarithms.
E = (1) ethylene; (2) energy.
e or exp = exponential function
EL = elastic limit.
emf = electromotive force.
EPA = U.S. Environmental Protection Agency
EPR = ethylenepropylene rubber.
eq = equation.
ERP = enterprise resource planning.
ETFE = ethylenetetrafluoroethylene.
F
f = (1) coefficient of friction;
(2) fugacity.
F = (1) farad; (2) feed rate; (3) force, total load; (4) friction in energy balance.
oF = degrees Fahrenheit.
FEP= fluorinated ethylene propylene.
fl = fluid.
fl oz = fluid ounces.
fp = freezing point.
fpm = feet per minute.
fps = feet per second.
FRP = fiberglass=reinforced plastic.
FS or fs = full scale.
ft = feet.
G
g = (1) gram; (2) acceleration due to gravity.
gc = acceleration of gravity, standard value.
G = free energy, Gibbs; mass velocity.
gal = gallons
g-cal = gram calorie.
g/l = grams per liter.
gpd = gallons per day.
gph = gallons hour.
gpm = gallons per minute.
gr = grain.
H
h = (1) height; (2) hour.
hfg = latent heat.
H = (1) humidity; (2) enthalpy; (3) Henry’s law constant.
Ho = solvent present.
Hp = height equivalent to a theoretical plate.
Hr = humidity, relative.
Ht = height of transfer unit.
HAP = hazardous air pollutant.
HazMat = hazardous materials.
HDPE = high-density polyethylene.
HFP = hexafluoropropylene.
hhv = higher heating value.
hor = horizontal.
Hz = hertz.
hp = horsepower.
HVAC = heating, ventilating and air conditioning.
I
I = moment of inertia.
ID = inside diameter.
in = inch.
in-lb = inch pound.
I/O -= input/output.
IR = infrared.
J
j = heat transfer factor.
J = (a) joule; (2) mechanical equivalent of heat.
K
k = (1) kilo; (2) mass transfer coefficient, individual.
kG = mass transfer coefficient, gas film.
kL = mass transfer coefficient, liquid film
K = (1) equilibrium constant; (2) mass transfer coefficient, overall.
oK = degrees Kelvin.
KG = mass transfer coefficient, on gas-film basis.
KL = mass transfer coefficient, on liquid-film basis.
kc = kilocycles
k-cal = kilogram calories.
kg = kilogram.
kg-m = kilogram meter
kHz = kilohertz.kip = thousand pounds
kip = thousand pounds
kPa = kilopascals.
kVA = kilovolt amperes.
kW = kilowatts.
kWh = kilowatt-hours.
L
l = liter
L = (1) length; (2) liquid rate; (3) mass velocity of liquid.
lb = pound.
LCL = lower control limit.
LDAR = leak detection and repair.
LDPE =low-density polyethylene
LEL = lower explosive limit.
lin = linear.
lm = lumen.
LNG = liquefied natural gas.
LPG = liquefied petroleum gas.
log or log10 = logarithm to base 10.
LP = liquefied petroleum.
lph = liters per hour.
lpm = liters per minute
M
m = (1) meter; (2) mass; (3) mesh; (4) slope of equilibrium curve.
M = (1) molecular weight; (2) mesh.
mA = milliamperes.
MACT = maximum achievable control technology.
mep = mean effective pressure.
MES = manufacturing execution system.
MI = melt index.
micron = micrometer.
min = minutes.
mi = milliliters.
mm = millimeters.
mol = mole.
mp = melting point.
Mpa = Mega Pascal.
mps or m/s = meters per second.
mR = milliroentgens.
ms = milliseconds.
MSDS = material safety data sheet.
MTBF = mean time between failures.
mm = millimicron.
N
n = (1) rate of rotation; (2) nano.
N = (1) Newton, unit of force; (2) number.
N0 = Avogadro’s number.
Np = number of plates.
Nt = number of transfer units.
nm = nanometer.
NDT = nondestructive testing.
NEMA = National Electric Manufacturers’ Association.
NESHAP = National Emission Standard for Hazardous Air Pollutants.
NSPS = New Source Performance Standards.
O
OD = outside diameter.
ohm = unit of electrical resistance.
OSHA = U.S. Occupational Safety and Health Administration.
oz = ounce.
P
p = (1) pressure; (2) pico.
P = power.
Pa = Pascal, a unit of pressure.
Pas = Pascal-second.
pct = percent.
PD = positive displacement.
pf = picofarad.
PF or pf = power factor.
PFA = perfluoroalkoxy.
pH = acidity index.
PI = proportional and integral.
P&ID = piping and instrument diagram.
PLC = programmable logic controller.
PMVE = perfluororomethylvinyl ether.
ppb = parts per billion.
ppm = parts per million.
ppt = parts per trillion.
psi = pounds per square inch.
psia = pounds per square inch, absolute pressure.
psid = pounds per square inch, differential pressure.
psig = pounds per square inch, gauge pressure.
PTFE = polytetrafluoroethylene.
PVC = polyvinyl chloride.
PVDC = polyvinylidene chloride.
PVDF = polyvinylidene fluoride.
Q
q = (1) volumetric rate of flow; (2) rate of heat transfer; (3) thermal condition of feed.
Q = quantity of heat transferred.
qt = quart.
R
r = (1) radius.
R = (1) gas constant; (2) production rate; (3) reflux ratio; (4) thermal resistance.
RH = hydraulic radius.
RR = reduction ratio.
rev = revolution.
Re = Reynolds number.
RH = relative humidity.
RI = refractive index.
rms = root mean square.
rpm = revolutions per minute.
rps = revolutions per second.
RTD = resistance temperature detector.
S
s = (1) second; (2) entropy, per unit weight; (3) specific surface.
S = (1) cross section; (2) entropy; (3) solubility.
sec = second.
sat = saturated.
scfm = standard cubic feet per minute.
SG, SpG or sp gr = specific gravity.
sq = square.
sr = steradian.
std = standard.
T
t = (1) ton; (2) temperature; (3) time.
T = temperature.
TFE = tetrafluorethylene.
T.S. = tensile strength.
oTw = Twadell degrees of liquid density.
U
u = (1) local velocity; (2) internal energy per unit weight.
U = (1) energy in general; (2) overall heat transfer coefficient; (3) internal energy.
UEL = upper explosive limit.
UHSDS = ultra-high-speed deluge system.
UPV = unfired pressure vessel.
V
v = (1) velocity; (2) specific volume.
vH = humid volume.
V = (1) volts; (2) vapor rate; (3) total or per mole volume.
Va =acoustic velocity.
Vert = vertical.
W
w = (1) width; (2) mass flowrate.
W = (1) free moisture content; (2) residue, waste, bottoms; (3) work; (4) weight, quantity of matter.
We =work, external.
Wb = weber.
WI = wobble index.
wt = weight.
X
x = (1) distance in direction of flow; (2) mole fraction, in liquid.
xv = fraction by volume.
xw = fraction by weight.
X = (1) reactance; (2) mole ratio, in liquid.
Y
y = depth.
Y = mole ratio, in vapor.
yd = yard.
yr = year.
Z
z = compressibility.
Z = distance above datum plane.
Greek letter symbols
α (alpha) = (1) angle; (2) coefficient of expansion, linear; (3) diffusivity, thermal; (4) absorpitivity for radiation; (5) relative volatility; (6) specific cake resistance.
β (beta) = coefficient of expansion, volumetric.
γ (gamma) = activity coefficient, molal basis.
Γ (capital gamma) = weight rate of flow per unit of breadth.
Δ (capital delta) = difference or change.
ε (epsilon) = emissivity.
η (eta) = efficiency.
κ (kappa) = specific heats.
λ (lambda) = latent heat of evaporation.
μ (mu) = viscosity, absolute.
1/μ = fluidity.
μ/ω = viscosity, relative to water.
v (nu) = viscosity, kinematic.
ρ (rho) = density.
σ (sigma) = (1) surface tension; (2) Stefan-Boltzmann constant.
τ (tau) = (1) time; (2) tractive force per unit.
Φψ or χ (phi, psi or chi) = function.
ω (omega) = (1) solid angle; (2) velocity, angular.
