Dictionary of Occupational and Environmental Safety and Health - Part 4 (end) pot

Vincoli, Jeffrey W. "Q-Z"
Lewis' Dictionary of Occupational and Environmental Safety and Health
Edited by Jeffrey W. Vincoli
Boca Raton: CRC Press LLC, 2000
©2000 CRC Press LLC
Q
Q
Quantity or volume of air.
Q factor
See quality factor.
Q fever
An rickettsial infection often seen among
meat and livestock handlers. Can be con-
tracted by inhalation of dust particles that are
infected with the infectious organism. The
organisms are found in the hides of sheep and
cattle. It is contagious between humans and
its symptoms include sudden hay fever, chills,
headache, muscle pain, and coughing.
QA
See quality assurance.
QC
See quality control program and quality cir-
cle.
QLFT
Qualitative fit test.
QNFT
Quantitative fit test.
quack
A pretender to medical skill which he/she
does not possess. One who practices as a

physician or surgeon without adequate experi-
ence or due qualification.
quad map
A topographic map with an approximate scale
of one inch to 2,000 feet; shows physical
features such as wetlands, water bodies,
roadways, mines, and buildings.
quadrant
(1) One-fourth of the circumference of a cir-
cle. (2) An angular dissection of ninety de-
grees. (3) One of the quarters created by two
intersecting lines, roads, streets, vectors, etc.
(4) One of four corresponding parts, or quar-
ters, as of the surface of the abdomen or of the
field of vision.
quadrantanopia
Loss of vision in one fourth of the visual field.
quadriceps
Having four heads.
quadriceps femoris muscle
A muscle group on the anterior thigh consist-
ing of four muscles which flex the hip and
extend the knee: rectus femoris, vastus later-
alis, vastus medialis, and vastus intermedius.
Well-defined quadriceps femoris muscles of the anterior thigh
quadriplegia
A condition in which all four limbs are af-
fected by paralysis.
qualification
The possession by an individual of the quali-

ties, properties, circumstances, natural or ad-
ventitious, which are inherently or legally
necessary to perform a task, fill an office, or
perform a duty or function.
qualification tests
The required tests used to demonstrate that the
design, manufacture, and assembly have re-
sulted in hardware conforming to specifica-
tion requirements.
qualified
Adapted; fitted; entitled; susceptible; compe-
tent; fitting; possessing legal power or capac-
ity; eligible. Applied to one who has taken
the steps to prepare himself/herself for an ap-
pointment of office. One who is adequately
and satisfactorily trained and/or experienced
to perform a function or task.
qualified handicapped individual
Under the Americans with Disabilities Act
(ADA): A handicapped individual who is ca-
pable of performing a specific job with rea-
sonable accommodation.
©2000 CRC Press LLC
qualified operator
A worker having the adequate physical/mental
attributes, training, education, and experience
who has demonstrated that he/she is capable
of safely performing a given task involving
the operation of machinery or equipment with
acceptable quality and quantity.

qualified person
One familiar with the construction and opera-
tion of the equipment and the hazards in-
volved. Note 1: Whether an employee is con-
sidered to be a "qualified person" will depend
upon various circumstances in the workplace.
It is possible and, in fact, likely for an indi-
vidual to be considered "qualified" with re-
gard to certain equipment in the workplace,
but "unqualified" as to other equipment. Note
2: An employee who is undergoing on-the-
job training and who, in the course of such
training, has demonstrated an ability to per-
form duties safely at his/her level of training
and who is under the direct supervision of a
qualified person is considered to be a quali-
fied person for the performance of those du-
ties.
qualified worker
A worker having the adequate physical/mental
attributes, training, education, and experience
who has demonstrated that he/she is capable
of performing a given task using basic tools
with acceptable quality and quantity.
qualifying phase I technology
Under the Clean Air Act (CAA): A techno-
logical system of continuous emission reduc-
tion which achieves a 90 percent reduction in
emissions of sulfur dioxide from the emis-
sions that would have resulted from the use of

fuels which were not subject to treatment
prior to combustion.
qualimeter
An instrument for measuring the quantity of
roentgen rays generated by a Coolidge tube.
qualitative
The characteristic attributes or qualities per-
taining to an exposure based on subjective in-
formation, nonrigorous quantitative data, and
judgment.
qualitative exposure assessment
The identification of contaminants and physi-
cal agents an individual may be exposed to,
and a judgment of the associated hazard based
on the frequency and duration of exposure,
the control measures in effect (engineering,
administrative, and personal protection), the
properties of the stressor, and the manner in
which it is being used/handled.
qualitative risk assessment
An examination of system risk based upon
established criteria that allows the analyst to
evaluate risk levels in relation to other risks or
total system risk.
quality
A condition in which a product satisfies a set
of requirements involving such aspects as
strength, durability, function, appearance, and
user-satisfaction.
quality analysis

An examination or study of product quality
goals.
quality assurance (QA)
(1) A company-wide program that establishes
project policies, procedures, standards, and
guidelines designed to produce an acceptable
level of professional quality. (2) A system of
practices, procedures, and activities that are
taken to provide assurance that the work be-
ing carried out will meet defined standards of
quality. The assessment of the potential for a
procedure to produce sampling results of ade-
quate quality to satisfy the defined objectives.
The primary purpose of a quality assurance
program is to provide the necessary safe-
guards to minimize erroneous sample analy-
ses and to provide a means of detecting errors
when they occur.
quality assurance project plan
As per the Environmental Protection Agency
(EPA): A plan that describes the policy, or-
ganization, functional activities, and quality
assurance and quality control protocols neces-
sary to achieve DQOs dictated by the in-
tended use of the data (RI/FS Guidance).
quality assurance/quality control
According to the U.S. Environmental Protec-
tion Agency (EPA): A system of procedures,
checks, audits, and corrective actions to en-
sure that all EPA research design and per-

formance, environmental monitoring and
sampling, and other technical and reporting
activities are of the highest achievable quality.
©2000 CRC Press LLC
quality circle (QC)
A small group of people involved in a similar
type of work who voluntarily meet on a pre-
determined schedule (e.g., weekly) on paid
time in an attempt to identify, analyze, and
solve some of the problems in their work en-
vironment. Also referred to as quality con-
trol circles and employee participation team.
quality control chart
A chart used for recording data regarding
product quality.
quality control (QC) programs
Establish project activities that apply the poli-
cies, procedures, standards, training, guide-
lines, and systems developed in the QA pro-
gram. QC programs aim to maintain an ac-
ceptable level of project quality through ap-
plication of sound project management prin-
ciples and practices.
quality factor
(1) General. A measure for expressing the
rate of attenuation (sharpness) of time-varying
energy as a function of frequency. Also re-
ferred to as Q factor. (2) Ionizing Radiation.
A modifying factor that is used to derive the
radiation dose equivalent from absorbed dose.

It is a factor by which the absorbed radiation
dose in rad is multiplied to obtain a quantity
that expresses the biological effectiveness of
the absorbed dose in rem. The factor for beta,
gamma, and X-radiation is 1. For alpha parti-
cles and fast neutrons it is 10. Other values
are used for neutrons of other energies and
heavy recoil nuclei. (3) Ionizing Radiation.
The number intended to represent the effec-
tiveness of various types of ionizing radiation
based on relative biological effectiveness or
linear energy transfer, based on the following
values:
X-ray, beta 1
protons, fast neutrons 10
alpha particles 20
quantitation limit
The lowest level at which a chemical may be
accurately and reliably quantified. Usually
equal to the detection limit multiplied by a
factor of 3 to 5, but varies between chemicals
and between samples.
quantitative
The property of anything which can be deter-
mined by measurement and expressed as a
quantity.
quantitative exposure assessment
The procedure of quantitatively determining
an individual's exposure to a health hazard,
employing accepted sampling and analytical

procedures, and assessing the likelihood that
an adverse health effect may occur based on
the sample results.
quantitative risk assessment
An application of statistical techniques to
mathematically identify the level of probable
risk associated with a given hazard, as it re-
lates to total system operation.
quantum
The smallest quantity of energy, responding
to the energy of electromagnetic radiation,
that can be associated with a given phenome-
non.
quantum theory
A theory based on the concept that energy is
radiated intermittently in units of definite
magnitude called quanta and absorbed in like
manner.
quarantine
(1) A place or period of detention of ships
coming from infected or suspected ports. (2)
Restrictions placed on entering or leaving
premises where a case of communicable dis-
ease exists. (3) The application of measures
to prevent contact between persons who are
not infected and persons suspected of being
infected.
quarrel
An altercation, angry dispute, or an exchange
of recriminations, taunts, threats, or accusa-

tions between two persons.
quart
One-fourth of a gallon (946 cc).
quartan
(1) Recurring in 4-day cycles (every third
days). 2) A variety of intermittent fever of
which the paroxysms recur on every third day.
See also malaria.
quarter
The fourth part of anything, especially a year.
©2000 CRC Press LLC
quarter line
A line used to set a boat out where maneuver-
ability is limited.
quarter section
The quarter of a section of land according to
the divisions of a government survey, deter-
mined by dividing the section into four equal
parts by north and south and east and west,
and containing 160 acres (a quarter of a
square mile of land).
quartile
The value of the boundary at the 25th, 50th,
or 75th percentile of a frequency distribution
divided into four parts, each containing a
quarter of the population.
quartz
One of the forms of crystalline silicon diox-
ide. Also referred to as one of the forms of
free silica.

Quaternary
The period of geologic time starting 1.6 mil-
lion years ago and continuing to the present
day. It is divided into two epochs: the Pleis-
tocene and the Holocene, with the division
between these two falling approximately
10,000 years before the present. Late Qua-
ternary refers to time between 700,000 years
ago and the present day. Pre-Quaternary re-
fers to any time before 1.6 million years ago.
quaternary
(1) Fourth in a series. (2) Made up of four
elements or radicals.
Queckenstedt's test
When the veins in the neck are compressed on
one or both sides there is a rapid rise in the
pressure of the cerebrospinal fluid of healthy
persons, and this rise quickly disappears when
pressure is taken off the neck. But when there
is a block in the spinal canal the pressure of
the cerebrospinal fluid is affected little or not
at all by the maneuver.
quench tank
A water-filled tank used to cool incinerator
residues or hot materials during industrial
processes.
Quervain's disease
Inflammation of the long abductor and short
extensor tendons of the thumb, with swelling
and tenderness.

questioning technique
A method for analyzing and attempting to
improve work processes, generally by asking
questions such as: a) what is the purpose for
some activity, b) why is a particular sequence
followed, c) why does a particular person
perform that job, and d) is the method being
used to accomplish the task the best possible.
questionnaire
A written set of questions intended to obtain
an individual's responses on his/her attitudes,
issues, etc.
queue
(1) Place a discrete unit in position for se-
quential flow in a single processing channel.
(2) A location from which units may be se-
lected for processing when processing time or
other requisite conditions permit.
queuing theory
A quantitative rule describing the patterns
pertaining to arrivals, service times, and the
sequence in which arrivals are handled.
quick disconnect valve
(1) Breathing Apparatus. A device which
starts the flow of air by inserting of the hose
(which leads from the facepiece) into the
regulator of self-contained breathing appara-
tus, and stops the flow of air by disconnection
of the hose from the regulator. (2) Servicing
and Maintenance. A mechanical device, usu-

ally spring-loaded or under some type of me-
chanical tension, that allows for the quick
connection and/or disconnection of two
structures. Common in many industries, such
as refining, aerospace, the military, etc.
Quick disconnect valves used in the fueling of aircraft allow for
quick and safe connection/disconnection of fuel hose lines
©2000 CRC Press LLC
quickening
(1) A display technique involving the use of
time derivatives for aiding an operator in
tracking or control operations involving mo-
tion. (2) The first perceptible movement of
the fetus in the uterus, appearing usually in
the sixteenth to eighteenth week of pregnancy.
quinine
A white, bitter alkaloid usually obtained from
cinchona. An analgesic, antipyretic, bitter
tonic, and effective antimalarial.
quinquevalent
Pentavalent; having a valence of five.
quinsy
Acute suppurative inflammation of the tonsil
and the surrounding tissue.
quintan
Recurring every 5 days (every fourth day).
quorum
A majority of the entire body. The number of
members who must be present in a delibera-
tive body before business may be transacted.

quotidian
(1) Recurring every day. (2) A form of inter-
mittent malarial fever with daily recurrent
paroxysms.
quotient
A number obtained by division.
quotient verdict
A verdict resulting from an agreement
whereby each juror writes down the amount
of damages to which he/she thinks a party is
entitled and each amount is then added to-
gether and divided by the number of jurors.
QWERTY keyboard
A keyboard with a letter distribution pattern
of QWERTY on the left side of the top row.
See also Dvorak keyboard.
©2000 CRC Press LLC
R
R
(1) Degrees Rankine. (2) See electrical re-
sistance.
R & D
See research and development.
R meter
An instrument for measuring and displaying
the intensity of ionizing radiation in roent-
gens.
R value
See thermal resistance value.
RA

See remedial action. See also return air.
rabbit fever
See tularemia.
rabies
An acute infectious viral disease communi-
cated to man by the bite of an infected animal
and affecting the brain and the nervous sys-
tem. Rabies is transmitted by warm-blooded
animals, especially dogs and foxes. The viru s
i s o f t e n p r e s e n t i n t h e s a l i v a o f a f f e c t e d a n i m a l s
and is trans mit ted chi efl y th ro u gh bi te wou n ds
and occasi on all y th rou gh op en wo un ds or
s ores . After the vi ru s ent ers the bo dy it travel s
alo ng th e nerve tru n k to th e brain . The farther
the bite is from the head, the longer it takes to
reach the brain. The incubation period varies
from 2 weeks to as long as 6 months. The
bitten person must start treatment with antira-
bies vaccine and serum before the virus
reaches the brain. The disease must be pre-
vented because it is always fatal in man. Also
called hydrophobia.
RAC
See risk assessment code.
race
(1) A breakdown of the human species by
certain genetically determined characteristics
such as skin color, bodily proportions, hair
type, and stature. (2) A form of competition
where the purpose is to complete a prescribed

path or function with a minimal time or ahead
of others in the competition.
raceway
A channel designed expressly for holding
wires, cables, or bus bars, with additional
functions (as permitted in applicable codes
and standards). Raceways may be of metal or
insulating material, and the term includes
rigid metal conduit, rigid nonmetallic conduit,
intermediate metal conduit, liquid-tight flexi-
ble metal conduit, flexible metal conduit,
electrical metallic tubing, under floor race-
ways, cellular concrete floor raceways, cellu-
lar metal floor raceways, surface raceways,
wire ways, and bus ways.
RACT
See reasonably achievable control technol-
ogy.
rad
See radiation absorbed dose.
radappertize
To radiate food with ionizing radiation to
sterilize it.
radar
An acronym derived from Radio Detection
and Ranging. A system using emitted and re-
flected electromagnetic energy, principally
radio frequency and microwaves, to detect
and track objects or weather.
radar air traffic control facility (RATCF)

An air traffic control facility, located at a U.S.
Naval or Marine Corps Air Station, utilizing
surveillance, and normally, precision ap-
proach radar and air/ground communication
equipment to provide approach control serv-
ices to aircraft arriving, departing, or transit-
ing the airspace controlled by the facility.
The facility may be operated by the Federal
Aviation Administration (FAA), the United
Sates Navy (USN), the United States Marine
Corp (USMC), or the FAA & USN and serv-
ice may be provided for both civil and mili-
tary airports.
radar air traffic control tower
An airport traffic control tower that uses radar
and nonradar capabilities to provide approach
control services to aircraft arriving, departing,
or transiting airspace controlled by the facil-
ity. It provides radar air traffic control serv-
ices to aircraft operating in the vicinity of one
or more civil and/or military airports in the
terminal area.
©2000 CRC Press LLC
Radar air traffic control operations
radar altimeter
Aircraft instrument that makes use of the re-
flection of radio waves from the ground to
determine the height of the aircraft above the
surface.
radar approach control (RAPCON)

An air traffic control facility, located at a U.S.
Air Force (USAF) base, utilizing surveillance
and, normally, precision approach radar and
air/ground communication equipment to pro-
vide approach control services to aircraft ar-
riving, departing, and transiting the airspace
controlled by the facility. The facility may be
operated by the Federal Aviation Administra-
tion (FAA), or the United States Air Force
(USAF). Service may be provided to both
civil and military airports.
radar approach control tower
An airport traffic control tower (ATCT) that
uses radar and nonradar capabilities to pro-
vide approach control services to aircraft ar-
riving, departing, or transiting airspace con-
trolled by the facility. It provides radar Air
Traffic Control (ATC) services to aircraft op-
erating in the vicinity of one or more civil
and/or military airports in the terminal area In
other words, a radar approach control tower is
an ATCT at which airport traffic control spe-
cialists are permitted to provide radar ap-
proach control service, including extensive
vectoring, as well as to handle takeoffs and
landings. Radar acts can be separated into a
control tower and a radar room.
radar display
The graphic presentation of a radar scan on a
radarscope.

radar dome
A dome-shaped structure used to protect the
antenna of a radar installation.
radar reflector
A device capable of or intended for reflecting
radar signals.
radarscope
The CRT or other device used to project the
scan of a radar beam for operator viewing.
radial
(1) Pertaining to the radius bone. (2) On a
line directed outward from the center of a cir-
cle. (3) A type of tire usually constructed
with steel belts for added puncture protection
and durability.
radial deviation
A movement of the wrist such that the longi-
tudinal axis of the hand is directed toward the
lateral/radial/thumb side of the forearm.
radial keratotomy
A surgical procedure in which radial incisions
are made in the cornea to improve myopic vi-
sion.
radial nerve
A spinal nerve innervating the upper arm,
forearm, and the dorsal-thumb side of the
hand. Also called musculospiral nerve.
radiale
The uppermost point on the lateral margin of
the leading end of the radius bone.

radiale height
See elbow height.
radiale – stylion length
The linear distance from radiale to stylion
parallel to the long axis of the freely hanging
lower arm. Measured with the individual
standing, the arm hanging naturally at the
side, and the palm facing the thigh. Also re-
ferred to as forearm length and lower arm
length.
radian
A planar angular measure in which the arc
length of the subtended angle at the center of
a circle equals the radius (approximately 57.3
degrees). See also plane angle.
radiance (L)
The value of the ratio of the radian flux to the
solid angle and the perpendicular surface
projection.
©2000 CRC Press LLC
radiant energy
The energy of electromagnetic waves from
sources such as radiowaves, visible light, in-
frared, x-rays, and gamma rays. These waves
do not need molecules to propagate them, and
in a vacuum they travel at nearly 300,000
kilometers per second.
radiant exitance (M)
The radiant flux density leaving a specified
surface.

radiant flux
The rate of flow of radiant power which flows
onto or through a unit area.
radiant flux density
That amount of radiant power which flows
onto or through a unit area.
radiant heat
A form of electromagnetic energy.
radiant heat load
Energy that is transformed into heat when it
strikes an object. The human body can both
emit and receive radiant energy.
radiant heat temperature
The temperature of an object as a result of it
having absorbed radiant energy.
radiant heat transfer
Radiant heat transfer occurs when there is a
large difference between the temperatures of
two surfaces that are exposed to each other
but are not touching.
radiant heating
That heating which occurs solely by radiation.
radiation
(1) Divergence from a common center. (2) A
structure made up of diverging elements, es-
pecially a tract of the central nervous system
made up of diverging fibers. (3) Electromag-
netic waves. The emission and propagation of
energy in the form of waves or corpuscular
emissions of particles through space or

through a material medium; for instance, the
emission and propagation of electromagnetic
waves, electric waves, or other forms of elec-
tromagnetic radiation, as well as ionizing ra-
diation. Sources of radiation include natural
or "background" radiation, such as cosmic
rays from outer space, and the naturally oc-
curring radioactive substances found in the
earth. Manmade radiations result from artifi-
cially produced nuclear reactions in stable
elements which are then changed to radioac-
tive substances. Radiations are particulate
and nonparticulate; that is, that may be made
up of particles such as neutrons and protons
which are fragments of the nuclei of disinte-
grating atoms, or they may consist of electro-
magnetic waves, which have no mass. Par-
ticulate radiations may consist of alpha parti-
cles or beta particles. Most radioactive iso-
topes (radioisotopes) emit particulate radia-
tions and at the same time also release elec-
tromagnetic rays (gamma rays). Both par-
ticulate and nonparticulate radiations are ca-
pable of penetrating and being absorbed into
matter. Alpha particles are the least pene-
trating; beta particles slightly more penetrat-
ing; and the gamma rays, like x-rays, are ca-
pable of completely penetrating the body.
Harmful effects of uncontrolled radiation ex-
posure include serious disturbances of bone

marrow and other blood-forming organs,
burns, and sterility. There may be permanent
damage to the germ plasm or genes, which re-
sults in genetic mutations. The mutations can
be transmitted to future generations. Radia-
tion also may produce harmful effects on the
embryo or fetus, bringing about fetal death or
malformations. Radiation also apparently
shortens the life span of those exposed to it
over a period of time, and predisposes persons
to the development of cataracts. Exposure to
large doses of radiation over a short period of
time produces a group of symptoms known as
the acute radiation syndrome. These symp-
toms include general malaise, nausea, and
vomiting, followed by a period of remission
of symptoms. Later, the patient develops
more severe symptoms such as fever, hemor-
rhage, fluid loss, anemia, and central nervous
system involvement. The symptoms then
gradually subside or become more severe, and
may lead to death.
radiation absorbed dose (rad)
The unit of absorbed dose which is equal to
100 ergs/g. It is a measure of the energy im-
parted to matter by ionizing particles per unit
mass of irradiated material at the point of ex-
posure.
radiation accident
Any accident exposing humans to excessive

radiation or involving the spread of radioac-
©2000 CRC Press LLC
tive materials beyond their intended contain-
ment.
radiation area
An area accessible to individuals, in which
ionizing radiation levels could result in a per-
son receiving a dose equivalent in excess of 5
millirem (equivalent to 0.05 mSv) in 1 hour at
12 inches (30 centimeters) from the source or
from any surface that the radiation penetrates.
radiation dosimetry
A measurement of the amount of ionizing
radiation exposure by individuals, materials,
or equipment at a specific location.
radiation effect
Any of the documented effects from high lev-
els of ionizing radiation exposure, such as hair
loss, cancer, nausea, cataracts, or death. See
also radiation sickness.
radiation fluence
See fluence.
radiation fog
Fog produced over land when radiation cool-
ing reduces the air temperature to or below its
dew point. It is also referred to as ground fog
and valley fog.
radiation hazard
A situation in which persons might receive
ionizing radiation in excess of the applicable

maximum permissible dose or in which radia-
tion damage might be done to materials.
radiation inversion
An increase in temperature with height due to
radiation cooling of the earth's surface. Also
called nocturnal inversion.
radiation length
The mean distance required to reduce the en-
ergy of charged particles by 1/e in passing
through a material.
radiation monitoring
A form of environmental monitoring in which
periodic or continuous measurements are
taken to determine the radiation levels present
in a specific environment.
radiation protection
Any measure to reduce the exposure of hu-
mans and/or equipment to radiation, whether
through legislation, regulations, policies, or
physical measures.
radiation protection guide (RPG)
The total amount of ionizing radiation dose
over certain periods of time that may be per-
mitted to persons whose occupation involves
exposure to such radiation. It is equivalent to
what was formerly called the maximum per-
missible exposure (MPE).
radiation protection officer (RPO)
The person who has been selected and trained
to be responsible for overseeing the ionizing

radiation protection program in a facility.
Also referred to as the radiation safety officer
or RSO.
radiation safety
The study and/or implementation of equip-
ment and procedures to prevent excessive ra-
diation exposure to personnel or radiation re-
lease to the environment.
radiation safety officer (RSO)
See radiation protection officer.
radiation sickness
A self-limiting syndrome characterized by
nausea, vomiting, diarrhea, and psychic de-
pression, following exposure to appreciable
doses of ionizing radiation, particularly to the
abdominal region. Also called radiation syn-
drome.
radiation source
Materials, equipment, or devices that generate
or are capable of generating ionizing radiation
including naturally occurring radioactive ma-
terials, byproduct materials, source materials,
special nuclear materials, fission products,
materials containing induced or deposited ra-
dioactivity, nuclear reactors, radiographic and
fluoroscopic equipment, particle generators
and accelerators, radio frequency generators
such as certain klystrons and magnetrons that
produce x-rays, and high voltage devices that
produce x-rays.

radiation standards
Regulations that set maximum exposure limits
for protection of the public from radioactive
materials.
radiation survey
An evaluation of the radiation hazard incident
to the production, use, release, disposal, or
presence of a radioactive material or other
sources of ionizing radiation under a specific
set of conditions. Includes surveys necessary
©2000 CRC Press LLC
to evaluate external exposures to personnel,
surface contamination, and the concentration
of airborne radioactive materials in the facility
and in effluents from the facility, as appropri-
ate.
radiation syndrome
See radiation sickness.
radiation therapy
The use of radiation to treat disease.
radiator
Any device which radiates energy.
radical
An ionic group having one or more charges,
either positive or negative. A group of at-
oms which can enter into a chemical reaction
but which is incapable of existing separately.
See also free radical.
R a d i o A u t o m o b i l e C o m m u n i c a t i o n S y s t e m
A Japanese government/private industry pro-

ject to develop future street/highway vehicle
systems.
radio contact
Aviation. The initial radio call-up to a flight
service station by en route aircraft, which in-
cludes a complete interchange of information
and a termination of the contact.
radio frequency (Rf)
Electromagnetic energy from 30 kHz to 300
GHz.
radioactive
A property of some materials or elements that
is characterized by their spontaneous emission
of radiation.
radioactive contamination
Contamination with radioactive material(s).
radioactive decay
The disintegration of the nucleus of an unsta-
ble nuclide by the spontaneous emission of
charged particles and/or photons.
radioactive decontamination
The removal of contaminating radioactive
materials from a given location.
radioactive device
See radioactive equipment.
radioactive equipment
Equipment or devices that generate, or are
capable of generating, ionizing radiation in-
cluding radiographic and fluoroscopic equip-
ment, particle generators and accelerators, ra-

dio frequency generators such as certain
klystrons and magnetrons that produce x-rays,
and high voltage devices that produce x-rays.
radioactive half-life
That time required for one-half the original
amount of unstable nuclei in a radioactive
sample to decay.
radioactive material
Materials that generate, or are capable of gen-
erating, ionizing radiation including naturally
occurring radioactive materials, byproduct
materials, source materials, special nuclear
materials, fission products, materials con-
taining induced or deposited radioactivity, and
nuclear reactors.
radioactive series
A succession of nuclides, each of which trans-
forms by radioactive disintegration into the
next nuclide until a stable one results.
radioactive substances
Those substances that emit radiation.
radioactive waste
Waste which contains materials that are ra-
dioactive and which must be disposed ac-
cording to regulatory requirements.
radioactivity
The spontaneous emission of radiation, gener-
ally alpha or beta particles often accompanied
by gamma rays, from the nucleus of an unsta-
ble isotope. As a result, the radioactive iso-

tope is converted (or "decays") into the iso-
tope of a different element, which may or may
not be radioactive. Ultimately, as a result of
one or more stages of radioactive decay, a
stable (non-radioactive) end product is
formed. The property of radioactivity occurs
naturally in a number of elements. In general,
the chemical elements of atomic number
above 83 are radioactive. Stable elements that
are not naturally radioactive can be made so
by bombarding isotopes of the element with
high-velocity particles. When an element is
unstable, whether naturally or artificially, the
ratio of protons to neutrons in its atoms is un-
even. Each atom attempts to achieve stability
by giving off particles from its nucleus and
thus it begins to disintegrate, releasing both
nuclear particles and electromagnetic radia-
tions. Since these radiations interact with
matter, including the cells of the body, they
©2000 CRC Press LLC
can be extremely harmful or, under proper
control, extremely useful (in medical therapy,
for example).
radioactivity concentration guide (RCG)
The maximum permissible amount of any
specified radioisotope that may be allowed to
accumulate in the body.
radiobiology
The study of radiation effects on living things.

More specifically, the branch of science con-
cerned with effects of light and of ultraviolet
and ionizing radiations on living tissue or or-
ganisms.
radiocarbon
A radioactive isotope of carbon. The isotope
of mass 14 (
14
C) is used in many diagnostic
procedures and physiologic investigations.
With a half-life of 5568 years, it has provided
a means of determining the age of many an-
cient substances and articles.
radiograph
A picture of an object that is made by passing
ionizing radiation through the object and
photographic film positioned on the opposite
side of the object from the radiation source.
radiographer
The individual who is in attendance at a site
where ionizing radiation sources are being
used and is the user or supervises their use in
industrial radiographic operations. This indi-
vidual is responsible for complying with
regulations and adherence with good practice
during the procedure.
radiography
The use of penetrating radiation such as x-
rays, gamma rays, or neutrons, to make visual
images of the insides of objects. An exami-

nation of humans or animals, or of the struc-
ture of materials by non-destructive methods,
utilizing sealed sources of ionizing radiation
or ionizing radiation-producing machines.
radioisotope
An unstable isotope of an element that disin-
tegrates spontaneously, emitting ionizing ra-
diation, and yielding a different isotope.
radiological health
The art and science of protecting humans,
animals, and the environment from injury or
damage from sources of ionizing radiation
and promoting better health through beneficial
applications of sources of ionizing radiation.
radiology
The branch of medicine that deals with the
diagnostic and therapeutic applications of ra-
diant energy.
radioluminescence
The emission of visible light from ionizing
radiation or the decay of radioactive isotopes
causing the excitation of crystals or phos-
phors.
radiometer
An instrument used to demonstrate the trans-
formation of radiant energy into mechanical
energy.
radiometric unit
A unit of measurement for radiant electro-
magnetic energy in terms of energy or power,

without regard to biological effects.
radiometry
The study or measurement of radiant energy.
radionuclide
Radioactive element that is characterized in
terms of its atomic mass and atomic number
that can be made artificially or can be natu-
rally occurring. They have potentially
mutagenic effects on the human body.
radiosensitive
Term used in describing tissues that are more
easily damaged as the result of exposure to
ionizing radiation.
radiosonde
A balloon-borne instrument that measures and
transmits pressure, temperature, and humidity
to a ground-based receiving station.
radiotherapy
Treatment of ailments by the application of
doses of ionizing radiation from various
sources. The purpose of radiotherapy is to
deliver a definite amount of radiation to a
specific location. The prescribed dosage
should be sufficient to treat a lesion, but not
great enough to damage permanently the
normal tissue surrounding the lesion. Radio-
therapy is often used in conjunction with sur-
gical treatment or with drugs and/or a combi-
nation of both, especially in the treatment of
cancer.

©2000 CRC Press LLC
radium
A chemical element, atomic number 88,
atomic weight, 226, symbol Ra. Radium is
highly radioactive and is found in uranium
minerals. Radium salts emit, in addition to
heat and light, three distinct kinds of radiation
(alpha, beta, and gamma rays) and also a ra-
dioactive gas called radon.
radius
(1) The linear distance from the center of a
circle to its edge. (2) The lateral forearm
bone.
radius of curvature
The radius of a circle whose arc matches a
curve or surface at a given point.
radius of vulnerable zone
The maximum distance from the point of re-
lease of a hazardous substance in which the
airborne concentration could reach the level
of concern under specified weather condi-
tions.
radon
(1) A chemical element formed by the disin-
tegration of radium 226 or radium 224; a
heavy, colorless, odorless and radioactive gas.
(2) An inert gaseous element formed by ra-
dioactive decay of radium atoms in soil or
rocks.
radon daughters

See radon progeny.
radon decay products
A term used to refer collectively to the imme-
diate products of the radon decay chain. These
include Po 218, Pb 214, Bi 214, and Po 214,
which have an average combined half-life of
about thirty minutes.
radon progeny
A term referring collectively to the intermedi-
ate products produced in the radon decay
chain. Also called radon daughters.
raffinate
In solvent extraction, it is that portion of the
mixture which remains undissolved and not
removed by the solvent.
rafter sample
A sample of settled dust that is obtained from
a rafter or other undisturbed surface that will
contain representative particulates that have
settled out of the air. The sample must be
representative of the airborne dust to which
personnel are exposed.
rag top
Transit (slang). Open top trailer covered with
a tarpaulin.
rags
Transit (slang). Bad tires.
rail
A rolled steel shape laid in two parallel lines
to form a track for carrying vehicles with

flanged steel wheels. See also locomotive,
railway, railroad, and train.
rail car
A car designed to carry freight or non-
passenger personnel by rail, and includes a
box car, flat car, gondola car, hopper car, tank
car, and occupied caboose. See also railway
car.
Typical rail car used for hauling freight
rail-highway grade crossing
A location where one or more railroad tracks
cross a public highway, road, or street or a
private roadway, and includes sidewalks and
pathways at or associated with the crossing.
See also grade crossings and highway-rail
crossing.
rail joint bond
Railroad. A metallic connection attached to
adjoining rails to insure electrical conductiv-
ity.
rail ladder
A fixed ladder consisting of side rails joined
at regular intervals by rungs or cleats and
fastened in full length or in sections to a
building, structure, or equipment.
©2000 CRC Press LLC
rail mode
Consists of freight and passenger (including
commuter) railroads. See also rapid rail,
rapid transit rail, transit mode, transit rail-

road, and transit railway.
railbus
A r e l a t i v e l y l i g h t , d i e s e l - p o w e r e d , t w o - a x l e r a i l
v eh icle wi th a bo dy resembl in g that of a bu s .
railing
A vertical barrier erected along exposed sides
of stairways and platforms to prevent falls of
persons. The top member of a railing usually
serves as a handrail.
railroad
(1) A person engaged in transportation by rail.
(2) All forms of non-highway ground trans-
portation that run on rails or electro-magnetic
guide ways, including a) commuter or other
short-haul rail passenger service in a metro-
politan or suburban area, and b) high speed
ground transportation systems that connect
metropolitan areas, without regard to whether
or not they use new technologies not associ-
ated with traditional railroads. Such term
does not include rapid transit operations
within an urban area that are not connected to
the general railroad system of transportation.
(3) Any surface transportation system that
carries passengers, goods, materials, or prop-
erty over rails. See also locomotive, rail,
railway, and train.
railroad accident
An event arising from the operation of a rail-
road which, with minor exceptions results in

one or more of the following circumstances:
a) Any impact between railroad on-track
equipment and an automobile, bus, truck,
motorcycle, bicycle, farm vehicle, pedestrian,
or other highway user at a highway-rail
crossing. b) Any collision, derailment, fire,
explosion, act of God, or other event involv-
ing the operation of railroad on-track equip-
ment, standing or moving, which results in
more than $6,300 in damages to railroad on-
track equipment, signals, track, track struc-
tures, and roadbeds. c) Any event arising
from the operation of a railroad which results
in the death of one or more persons; an injury
to one or more persons (other than railroad
employees) requiring medical treatment. d)
An injury to one or more employees which
requires medical treatment; or results in re-
striction of work or motion for one or more
days, or one or more lost work days, transfer
to another job, termination of employment,
loss of consciousness or any occupational ill-
ness of a railroad employee as diagnosed by a
physician.
railroad and railway electric service
Electricity supplied to railroads and interurban
and street railways, for general railroad use,
including the propulsion of cars or locomo-
tives, where such electricity is supplied under
separate and distinct rate schedules.

railroad car mile
A single railroad car moved a distance of one
mile.
railroad crossing collision
A collision between on-track railroad equip-
ment at a point where tracks intersect.
railroad switching and terminal
A company primarily performing switching
service, furnishing terminal trackage, bridges,
or other facilities such as union freight sta-
tions, operating ferries, or performing any one
or a combination of these functions. It may
coincidentally conduct a regular freight or
passenger service.
railroad switching and terminal establish-
ments
Establishments primarily engaged in the fur-
nishing of terminal facilities for rail passenger
or freight traffic for line-haul service, and in
the movement of railroad cars between termi-
nal yards, industrial sidings, etc. Terminal
companies do not necessarily operate any ve-
hicles themselves, but may operate the sta-
tions and terminals.
railway
A permanent way having one or more rails
which provides a track for trains. See also lo-
comotive, rail, railroad, and train.
railway car
A railway car designed to carry freight, rail-

road personnel, or passengers. This includes
boxcars, covered hopper cars, flatcars, refrig-
erator cars, gondola cars, hopper cars, tanker
cars, cabooses, stock cars, ventilation cars,
and special cars. It also includes on-track
maintenance equipment. See also rail car.
railway gauge
Distance between the rails of a track.
©2000 CRC Press LLC
Railway
railway yard
An area provided with a system of tracks and
associated structures, where railway trains are
assembled, and railway cars are switched,
stored, or serviced.
rain
Precipitation in the form of liquid water drops
that have diameters greater than that of driz-
zle.
rain cap
A sheet-metal fixture which is placed on the
outlet of a stack/vent for preventing rain from
entering. Also called a weather cap.
rain shadow
The region on the leeside of a mountain where
the precipitation is noticeably less than on the
windward side.
rainbow
An arc of concentric colored bands that spans
a section of the sky when rain, fog, or water

spray is present and the sun is positioned at
the observer's back. The colors are those of
the spectrum and are visible due to sunlight
passing through and refracted by the airborne
water molecules.
rainbow passage
A paragraph of text, which when read, results
in the reader making a wide range of facial
movements. This reading can be used for the
talking phase of the respirator fit test protocol.
raking collision
Rail Operations. A collision between parts or
a consist on an adjacent track, or with a
structure such as a bridge.
rales
Abnormal sounds in the respiratory system
indicating some type of pathological condi-
tion.
RAM
See random access memory.
ramp
(1) An inclined roadway connecting roads of
differing levels. (2) A lightly sloped surface
which serves as a mobility aid for handi-
capped individuals or movement of goods to a
different height or level, usually adjacent to a
set of steps or stairs.
ramp metering
(1) The process of facilitating traffic flow on
freeways by regulating the amount of traffic

entering the freeway through the use of con-
trol devices on entrance ramps. (2) The pro-
cedure of equipping a freeway approach ramp
with a metering device and traffic signal that
allow the vehicles to enter the freeway at a
predetermined rate.
ramus
(1) The posterior, vertical portion of the man-
dible. (2) A branch, as of a nerve, vein, or
artery.
rancid
Refers to a musty, rank taste or smell that is
usually associated with fats that have under-
gone decomposition.
Rand formula
An agreement under which employees pay
dues to a union without being required to join
the union.
random
Not deterministic. A variable whose value at
a particular future instant cannot be predicted
exactly.
©2000 CRC Press LLC
random access memory (RAM)
Computing. High-speed memory that holds a
copy of the operating system, any programs
that are currently running on a computer, and
any information that is being processed.
RAM is temporary memory; all information
in RAM is lost when the user turns off the

computer. RAM is resident memory, meas-
ured in bytes or megabytes, of a computer
system that enables and facilitates most of the
system's base functions as well as some
higher level operating functions. It is memory
located in the semiconductor chips in the
computer, not on the hard disk. The more
RAM, the more programs can be run at the
same time and the faster the programs will
run.
random errors
Errors which are the result of uncontrollable
or unknown sources. They are the result of
variation, due to chance, that occurs in moni-
toring despite the effort to control all vari-
ables. They are characterized by the random
occurrence of both positive and negative de-
viations from the mean, and these tend to can-
cel out if the sample size is sufficient.
random noise
An oscillation whose magnitude is not speci-
fied and cannot be predicted with certainty for
any given instance of time.
random process
A collection of all possible sample functions
which might be produced by random phe-
nomena.
random sample
A sample that has been collected in such a
manner that each individual in the population

represented by the sampled individual had an
equal probability of being sampled. This con-
cept can be applied to personnel, work areas,
work shifts, dates, etc. The objective in col-
lecting a random sample is to obtain a sample
which is free of bias.
random signal
See random process.
random variable
A real function whose value is determined
randomly. Also referred to as chance vari-
able and stochastic variable.
randomize
To select or assign randomly.
randomized design
An experimental design in which the subjects
are assigned randomly to groups representing
different conditions or levels of the independ-
ent variable.
range
(1) General. The distance between two ex-
tremes (e.g., the high point and the low point).
(2) Instrumentation. The upper and lower
limits between which an instrument responds
and over which the instrument is calibrated.
The interval between the upper and lower
measuring limits of an instrument.
range-bearing display
See B display.
range of motion (ROM)

The spatial extent through which a combination
of joints, limbs, or links can be normally
moved.
rank
(1) To place a set of scores or other numeric
variables in rank order. (2) The location of a
score in a set of rank-ordered scores. (3) The
maximum number of linearly independent
rows in a matrix.
rank order
A sequence in which objects are organized
sequentially by their quantitative score on
some descriptor, variable, or parameter.
rank order correlation
Any non-parametric correlation test for sig-
nificance between at least ordinal-level paired
observations in a random sample.
Rankine (R)
A temperature scale with zero F at 460º
Rankine. The freezing point of water on this
scale is 491.6ºR and the boiling point is
671.7ºR.
ranking crew member
Rail Operations. An individual in whom the
general charge of the train or yard crew is
vested in accordance with the railroad's oper-
ating rules. Unless otherwise designated by
the railroad, the ranking crew member will be
the assigned locomotive engineer.
RAPCON

See radar approach control.
©2000 CRC Press LLC
RAPF
Recommended assigned protection factor.
rapid eye movement (REM)
Any short, quick movement of the eyes, espe-
cially that occurring during the rapid eye
movement phase of sleep.
rapid eye movement sleep
That phase of sleep during which the eyeballs
can be observed to move rapidly and the EEG
resembles an awake, alert state. Typically
thought to be involved with dreaming.
rapid rail
A subway-type transit vehicle railway oper-
ated on exclusive private rights-of-way with
high-level platform stations. Rapid rail also
may operate on elevated or at grade-level
track separated from other traffic. See also
rail mode, rapid transit rail, transit mode,
transit railroad, and transit railway.
rapid transit
Rail or motorbus transit service operating
completely separate from all modes of trans-
portation on an exclusive right-of-way.
rapid transit rail
Transit service using rail cars driven by elec-
tricity usually drawn from a third rail, config-
ured for passenger traffic and usually operated
on exclusive rights-of-way. It generally uses

longer trains and has longer station spacing
than light rail. See also rail mode, rapid rail,
transit mode, transit railroad, and transit
railway.
rapids
An area of broken, fast flowing water in a
stream, where the slope of the bed increases
(but without a prominent break of slope which
might result in a waterfall), or where a gently
dipping bar of harder rock outcrops.
rapture of the deep/depths
See nitrogen narcosis.
rarefaction
The momentary reduction in pressure during
the trough in a sound wave.
rasp
A machine that grinds waste into a manage-
able material and helps prevent odor.
raster display
A video- or CRT-type display in which the
screen is written in a standard, prepro-
grammed sequence.
ratbite fever
Either of two distinct diseases (Haverhill fe-
ver and sodoku) that may be transmitted to
man by the bite of an infected rat and, less
commonly, by the bite of an infected squirrel,
weasel, dog, cat, or pig.
RATCF
See radar air traffic control facility.

ratchet
Marine Operations. A heavy turnbuckle with
cork-screw threads and midships handle,
equipped with pelican hooks on both ends for
the purpose of rapidly tightening up wire
lashings holding the barges of a tow together.
It is widely used on the rivers.
rate
(1) The frequency at which a certain event or
circumstance occurs within a specified or
commonly understood time period. (2) The
quantity of output produced, expressed as ei-
ther per unit time or percent of capac-
ity/normal. (3) See speed. (4) See wage rate
and piece rate. (5) To judge the relative or
absolute amount of some quality of an entity
or process, using some scale or other basis.
rate change
(1) Any alteration in a production time or out-
put standard. (2) Any alteration in worker
compensation, whether time based or output
based.
rate control
The ability to adjust a controlling device as a
function of changes in the velocity of a con-
tinuously moving object or pattern. Also re-
ferred to as first-order control and velocity
control.
rate cutting
An arbitrary reduction in the incentive pay

rate or scale.
rate of decay
Acoustics. The time rate at which the sound
pressure level decreases at a given point and
at a given time after the source is turned off.
rate determination
The study and analysis to decide what a stan-
dard time or incentive pay rate should be.
rate of closure
The rapidity with which different pieces of
information can be integrated into a meaning-
ful pattern. The pattern is initially unknown.
©2000 CRC Press LLC
rate-regulated pipelines
The pipelines included in these segments are
all federally or state rate-regulated pipeline
operations, which are included in the report-
ing company's consolidated financial state-
ments. However, at the reporting company's
option, intrastate pipeline operations may be
included in the U.S. Refining/Marketing
Segment if a) they would comprise less than
5 percent of U.S. Refining/Marketing Seg-
ment net property plant & equipment (PP&E),
revenues, and earnings in the aggregate; and
b) if the inclusion of such pipelines in the
consolidated financial statements adds less
than $100 million to the net PP&E reported
for the U.S. Refining/Marketing Segment.
rate setting

The establishment of standard time values or
any monetary pay scale for a given operation,
based on a rate determination.
rated activity sampling
A more detailed activity sampling in which a
rating is determined for each work element to
establish the work content in addition to that
time occupied by delays and other activities.
rated average element time
See normal element time.
rated load
The maximum static load or force that can be
imposed on the part or structure at any time
during its intended operation and expected
environment.
rated maximum continuous augmented thrust
With respect to turbojet engine type certifica-
tion, means the approved jet thrust that is de-
veloped statically or in flight, in standard at-
mosphere at a specified altitude, with fluid
injection or with the burning of fuel in a sepa-
rate combustion chamber, within the engine
operating limitations established under Part
33 of the Federal Aviation Regulations, and
approved for unrestricted periods of use.
rated maximum continuous thrust
With respect to turbojet engine type certifica-
tion, means the approved jet thrust that is de-
veloped statically or in flight, in standard at-
mosphere at a specified altitude, without fluid

injection and without the burning of fuel in a
separate combustion chamber, within the en-
gine operating limitations established under
Part 33 of the Federal Aviation Regulations,
and approved for unrestricted periods of use.
rated takeoff augmented thrust
With respect to turbojet engine type certifica-
tion, means the approved jet thrust that is de-
veloped statically under standard sea level
conditions, with fluid injection or with the
burning of fuel in a separate combustion
chamber, within the engine operating limita-
tions established under Part 33 of Federal
Aviation Regulations, and limited in use to
periods of not over 5 minutes for takeoff op-
eration.
rated takeoff thrust
With respect to turbojet engine type certifica-
tion, means the approved jet thrust that is de-
veloped statically under standard sea level
conditions, without fluid injection and without
the burning of fuel in a separate combustion
chamber within the engine operating limita-
tions established under Part 33 of the Federal
Aviation Regulations, and limited in use to
periods of not over 5 minutes for takeoff op-
eration.
rating
(1) A statement that, as a part of a certificate,
sets forth special conditions, privileges, or

limitations. (2) That class or level at which an
operator is qualified. (3) That assessment of a
worker's pace or output relative to the stan-
dard pace or output.
rating factor
That level of skill and effort displayed by an
operator during the period of study, based on
100% as normal skill and effort.
rating of perceived effort (RPE)
An individual's estimate of how hard a task is,
in terms of very, very light to very, very hard.
Also known as rate of perceived exertion,
rated perceived exertion, and rating of per-
ceived exertion. See also rating of perceived
exertion scale.
rating of perceived effort scale
A 15-point scale ranging from 6 to 20 which
is used by an individual to report the amount
of effort/exertion he/she is putting forth. Also
referred to as the Borg scale and perceived
exertion scale. See also rating of perceived
effort.
©2000 CRC Press LLC
rating scale
Any rank ordering scale for recording worker
performance.
ratio
A mathematical relationship between two
numerical variables or values in which they
are expressed as a fraction (as A/B) and may

be evaluated as a quotient.
ratio-delay study
A study in which a large number of instanta-
neous work samples are taken randomly.
ratio estimate
The ratio of two population aggregates (to-
tals). For example, "average miles traveled
per vehicle" is the ratio of total miles driven
by all vehicles, over the total number of vehi-
cles. See also estimate ratio and mean.
ratio scale
A basic measurement scale meeting the crite-
ria of an equal-interval scale and in which a
known valid zero exists such that the ratio of
numerical measures can be interpreted as a
ratio of their magnitudes.
rational basis test
Under this test, an appellate court will not
second-guess the legislature as to the wisdom
or rationality of a particular statute if there is a
rational basis for enactment, and if the chal-
lenged law bears a reasonable relationship to
the attainment of some legitimate govern-
mental objective.
rationalization
A defense mechanism in which a person finds
logical reasons (justification) for his/her be-
havior while ignoring the real reasons. It is a
form of self-deception and is unconsciously
employed to make tolerable certain feelings,

behaviors, and motives that would otherwise
be intolerable. Everyone employs rationali-
zation at some time or other and in most in-
stances it is a relatively harmless behavior
pattern. The danger lies in deceiving oneself
habitually so that eventually harmful or de-
structive behavior can be justified in one's
mind. Also, when investigating an accident
or incident, witnesses may tend to rationalize
as time passes. Therefore, the earlier a wit-
ness interview can take place following an ac-
cident event, the better the chance of obtain-
ing more usable testimony.
rattening
An offense on the part of the members of a
trade union involving the taking away and/or
hiding of the tools, clothes, or other property
of a worker in an attempt to compel him/her
to join the union or cease working. In Eng-
land, it is an offense punishable by fine or im-
prisonment.
Raub scale
See computer anxiety scale.
ravine
(1) A long, deep, and narrow hollow in the
earth, worn by a stream or torrent of water.
(2) A long, deep, and narrow hollow or pass
through the mountains.
raw agricultural commodity
According to the Federal Food, Drug, and

Cosmetic Act: Any food in its raw or natural
state, including all fruits that are washed, col-
ored, or otherwise treated in their unpeeled
natural form prior to marketing.
raw material
An unprocessed material or material which
has undergone some preliminary processing
elsewhere which is used as input to a proc-
essing operation.
raw sewage
Untreated wastewater.
rawinsonde observation
A radiosonde observation that includes wind
data.
ray tracing
The calculation of a light ray path through an
optical system.
Rayleigh disk
A thin, lightweight, circular disk made of
sound-reflective material which is mounted at
45° to the incident sound and used to deter-
mine sound wave particle velocity from the
torque induced on the disk.
Raynaud's syndrome
A vascular disorder resulting in the constric-
tion of the blood vessels of the hands due to
cold temperature, emotions, vibration, or un-
known cause. The hands become a bluish-
white color due to lack of blood circulation
and become painful upon exposure to cold. It

is associated with the operation of hand-held
or manually supported or guided machines
©2000 CRC Press LLC
that produce intense vibration in the fre-
quency range of 10 to 1000 Hz. Symptoms
include pain in the fingers, loss of manual
dexterity, stiffness in the joints, radiographi-
cally observable changes in the bones and
joints, whitening and numbness in one or
more fingers of either hand, skin atrophy, and
occasionally gangrene. Also referred to as
Raynaud's disease, dead hands, and vibration
white-hands disease.
RBC
Red blood cell.
RBE
See relative biological effectiveness.
RC
See room criterion curve.
RCC
See rescue coordination center.
RCF
Refractory ceramic fiber.
RCG
See radiation concentration guide.
RCO
See remote communications outlet.
RCRA
See Resource Conservation and Recovery
Act.

RCRA/HWDMS
RCRA Hazardous Waste Data Management
System; includes selective information on
over 324,000 sites which generate, transport,
store, treat, and/or dispose of hazardous waste
as defined by RCRA. Records available in
HWDMS will eventually be transferred to the
RCRIS database.
RCRIS
Resource Conservation and Recovery Infor-
mation System.
rd
See rutherford.
RD
See remedial design.
RDA
See recommended daily allowance.
Re number
See Reynold's number.
reach
(1) A straight-line anthropometric measure
taken along the longitudinal axis of a body
extremity. (2) The capability of achieving a
certain point in space through any self-
directed orientation of limbs. (3) A work
element involving the use of any combination
of flexion, extension, or other joint move-
ments to attain a point in space for some op-
eration. (4) A certain area of a river, usually a
straight section.

reach envelope
The volume or solid bounded proximally by
the body, clothing surface, or proximal reach
and by the distal boundary in any direction
which an individual or robotic device can at-
tain by any combination or postures, rotations,
flexion, and/or extension movements under
specified conditions.
reach from wall, maximum
The distance from a wall to the tip of the mid-
dle finger. Measured with the individual's
back and the contralateral shoulder pressed
against the wall, the shoulder of the arm being
measured held as far forward as possible, with
the arm and hand extended horizontally.
reaction time
The time required for a person to react to a
stimulus.
reaction time delay
A time factor used in the modeling of man-
machine systems to simulate the human reac-
tion to an event.
reactionless tool
Any tool which compensates internally for
forces or torques induced as a result of its ac-
tions such that there is essentially no external
force or torque applied to the user.
reactive
Materials which by themselves or in contact
with water or other non-compatible materials

are readily capable of detonation, explosive
decomposition or explosive reaction at normal
temperatures and pressures, as well as those
materials that are sensitive to mechanical or
localized shock at normal temperatures and
pressures.
reactive muffler
Acoustics. A type of muffler used to reduce
noise emissions from an engine, such as that
from an automobile exhaust system.
©2000 CRC Press LLC
reactivity
A measure of the tendency to undergo a
chemical change or reaction with the release
of energy. It is the susceptibility of materials
to release energy.
read-out
A meter reading or other form for displaying
visual information to an individual. See also
call-out.
read the water
To navigate by visual observation of the water
surface; not recommended for newcomers.
readability
A quality of text or numbers which allows
groups of related alphanumeric characters to
be easily discerned and recognized as words
or number sequences.
readily accessible
Capable of being reached quickly for opera-

tion, renewal, or inspections, without requir-
ing those to whom ready access is required to
climb over or remove obstacles or to resort to
portable ladders, chairs, etc. See also acces-
sible.
readiness potential
A change in cortical potential in the motor
cortex just prior to a planned, volitional
movement.
readiness time
That period of time necessary for a system to
be prepared from a specified, inactive state to
a state in which it is stabilized and can per-
form its intended function.
reading point
See breakpoint.
reading radius
The distance from the front of the eyeball to
the object or display to be read.
reading speed
The number of words of text read per minute
by an individual.
reagent
A substance that produces a chemical reaction
that can be used to detect, measure, or pro-
duce another substance.
reagent blank
Materials used in sample analysis are evalu-
ated as reagent blanks to determine their con-
tribution, if any, to the analytical result.

real ear attenuation at threshold (REAT)
A methodology for determining the attenua-
tion provided by a hearing protection device
fitted in a prescribed manner on a group of
normal wearers.
real-ear protection at threshold
The mean value in decibels of the occluded
threshold of audibility (hearing protector in
place) minus the open threshold of audibility
(ears open and uncovered) for all listeners on
all trials under otherwise identical test condi-
tions.
real time
(1) General. Having essentially no percepti-
ble delay between the occurrence of an event
and the knowledge of the event at another lo-
cation. Also, having a control system which
delivers the necessary inputs to the system
being controlled at or prior to the times they
are required. (2) Instrumentation. An in-
strument that responds to and indicates a
contaminant concentration or level of a physi-
cal agent as changes are occurring.
realistic job preview (RJP)
A pre-employment description or new-
employee orientation in which accurate and
precise information about the job is related to
the individual.
realizable
Pertaining to a component or system which is

physically manufactured, not merely theoreti-
cal.
realization rate
That proportion or percentage of actual annual
hours worked by all employees in a workplace
or company compared to the planned or ex-
pected normal annual hours to be worked.
rear axle capacity
The factor and/or Society of Automotive En-
gineers (SAE) recommended maximum load
that a rear axle assembly is designed to carry
as rated at the ground and expressed in
pounds.
rear end collision
(1) A collision in which one vehicle collides
with the rear of another vehicle. (2) A colli-
sion in which the trains or locomotives in-
volved are traveling in the same direction on
the same track. (3) A collision of the front of
©2000 CRC Press LLC
one vehicle with the rear of another vehicle.
Also called rear-end.
rear extremity
Transit. The rearmost point on a vehicle
when the vehicle's cargo doors, tailgate, or
other permanent structure are positioned as
they normally are when the vehicle is being
driven. Non-structural protrusions such as tail
lights, hinges, and latches are deleted from the
determination of the rearmost point.

rear overhang
Transit. The distance from the center of the
rear axle to the end of the frame.
rear projection
Pertaining to a display which is presented to
one side of a translucent screen for viewing
from the other side.
rearrange tow
Maritime. To shift barges in tow.
reasonable accommodation
Under the Americans with Disabilities Act
(ADA), that modification to the workplace or
other environment which enables a qualified
handicapped individual to work in a given
situation and does not impose an undue hard-
ship on an employer.
reasonable act
Such as may fairly, justly, and reasonably be
required of a party.
reasonable and probable cause
Such grounds as to justify anyone suspecting
another person of a crime, and placing him or
her in custody based on those grounds. It is a
suspicion founded upon circumstances suffi-
ciently strong to cause a reasonable person to
believe that a charge is true.
reasonable care
Law. Such a degree of care, precaution, or
diligence as may fairly and properly be ex-
pected or required, having regard to the nature

of the action, or of the subject matter, and the
circumstances surrounding the transaction. It
is such care as an ordinary prudent person
would exercise under the conditions existing
at the time he/she is called upon to act. Sub-
stantially synonymous with ordinary care or
due care. It should be noted that a "high de-
gree of care" is not the legal equivalent of rea-
sonable care. It is that degree of care which a
very cautious, careful, and prudent person
would exercise under the same or similar cir-
cumstances; a degree of care commensurate
with the risk of danger. See also ordinary
care.
reasonable cause
A basis for arrest without warrant exists when
the facts would lead a person of ordinary care
and prudence to believe and conscientiously
entertain an honest and strong suspicion that
the person subject to the arrest is guilty of
committing a crime. See also reasonable and
probable cause.
reasonable compensation
The sum which would reasonably compensate
a person for injuries, for pain and suffering,
and for past, present, and future expenses rea-
sonably necessary or incidental to his/her ef-
forts to alleviate injuries and all pecuniary
losses suffered, or to be suffered, as a result of
an inability to engage in his/her usual occu-

pation.
reasonable diligence
OSHA’s expectation that an employer is li-
able for conditions or practices which should
reasonably have been known of and/or taking
preventive actions. OSHA believes employ-
ers have an affirmative duty to monitor its
workplace safety and become knowledgeable
of all hazards that may be present there.
reasonable doubt
The standard used to determine the guilt or
innocence of a person criminally charged. To
be guilty of a crime, one must be proved
guilty "beyond a reasonable doubt." Reason-
able doubt which will justify acquittal is
doubt based on reason and arising from evi-
dence or lack of evidence, and it is doubt
which a reasonable man or woman might en-
tertain, and it is not fanciful doubt, is not
imagined doubt, and it is not doubt that a juror
might conjure up to avoid performing an un-
pleasant task or duty. Reasonable doubt is
such doubt as would cause a prudent person to
hesitate before acting in matters of importance
to themselves. It is doubt based on reason
which arises from evidence or lack of evi-
dence.
reasonable force
That degree of force which is not excessive
and is appropriate in protecting oneself and/or

one's property. When such force is used, a
©2000 CRC Press LLC
person is justified and is not criminally liable,
nor is he/she liable in tort.
reasonable grounds
Reasonable grounds within a statute author-
izing an arrest without a warrant by an officer
who has reasonable grounds for believing that
a person to be arrested has committed a
criminal offense means substantially probable
cause.
reasonable man doctrine
The standard which one must observe to
avoid liability for negligence is the standard
of the reasonable man under all circum-
stances, including the foreseeability of harm
to another person (such as a plaintiff).
reasonably available control technology (RACT)
The lowest emissions limit that a particular
source is capable of meeting by the applica-
tion of control technology that is both rea-
sonably available, as well as technologically
and economically feasible. RACT is usually
applied to existing sources in nonattainment
areas and in most cases is less stringent than
new source performance standards.
REAT
See real ear attenuation at threshold.
reboot
Computing. The act of restarting a computer

by reloading the operating system. You can
reboot some computers by pressing the
RESET
button. On all personal computers, the user
can reboot or "warm boot" by pressing the
CTRL+ALT+DEL keys on the keyboard (press
all keys at the same time).
rebuild
A complete repair of a component with the
objective of returning it as nearly as possible
to its original and/or performance characteris-
tics.
rebuilt caboose
A caboose that has undergone overhaul which
has been identified by the railroad as a capital
expense under Interstate Commerce Commis-
sion accounting standards.
rebuilt locomotive
A locomotive that has undergone overhaul
which has been identified by the railroad as a
capital expense under Interstate Commerce
Commission accounting standards.
rebuilt passenger car
A passenger car that has undergone overhaul
which has been identified by the railroad as a
capital expense under Interstate Commerce
Commission accounting standards.
rebuttable presumption against registration
(RPAR)
See special review.

recall
(1) A statement by a manufacturer or dis-
tributor of some item that it may have one or
more defects and should be returned for re-
placement or repair. (2) To access informa-
tion stored in memory and output that infor-
mation.
receiver
A device on a locomotive, so placed that it is
in position to be influenced inductively or
actuated by an automatic train stop, train con-
trol, or cab signal roadway element.
receiver coil
Concentric layers of insulated wire wound
around the core of a receiver of an automatic
train stop, train control, or cab signal device
on a locomotive.
receiver operating characteristic (ROC)
A graphical presentation of detector perform-
ance in signal detection theory, including the
combined effects of sensitivity and response
bias on operator performance. See also signal
detection theory.
receiving
That organization or those activities involved
in the receipt and distribution within the plant
of raw materials, equipment, and supplies
from external sources.
receiving waters
A river, lake, ocean, stream, or other water-

course into which wastewater or treated efflu-
ent is discharged.
recency error
An error due to recent events which bias a
rating or other measure. Also called recency
of events error.
receptacle
(1) General, Electrical. A contact device in-
stalled at the outlet for the connection of a
single attachment plug. (2) Single Receptacle.
A single contact device with no other contact
©2000 CRC Press LLC
device on the same yoke. (3) Multiple Re-
ceptacle. A single device containing two or
more receptacles. (4) Transit – Freight. A
containment vessel for receiving and holding
materials, including any means of closing.
receptacle outlet
An outlet where one or more receptacles are
installed.
reception minimum altitude
The lowest altitude at which an intersection
can be determined.
receptive field
A region of the skin, retina, or other structure
having an extended sensory apparatus within
which appropriate stimulation affects the re-
sponse of a given sensory neuron.
receptor
Binding site that has a high affinity for a par-

ticular ligand. Receptors interact with bio-
logically endogenous ligands, facilitating in-
tracellular communication. Many chemicals
interact with receptors, producing a variety of
toxic effects.
recessed
Pertaining to any device or object which is
embedded, either entirely or in part, within
another structure such that the device or ob-
ject is still visible.
recharge
The process by which water is added to a zone
of saturation, usually by percolation from the
soil surface, e.g., the recharge of an aquifer.
recharge area
A land area in which water reaches to the
zone of saturation from surface infiltration,
e.g., an area where rainwater soaks through
the earth to reach an aquifer.
reciprocal color temperature
A chromaticity measure which more nearly
provides equal perceptible divisions of color
temperature.
reciprocating pedal
A foot-operated device which operates as a
member of a pair of pedals by moving in op-
posing directions about a common shaft with
a rotational capability limited by the pedal ra-
dial motion.
reckless endangerment

A statutory offense committed by creating a
substantial risk of death or serious injury to
another.
reckless homicide
A species of statutory homicide in some states
characterized by a willful and wanton disre-
gard of consequences and resulting in death.
In some states, it may amount to manslaugh-
ter.
reckless misconduct
A person is guilty of reckless misconduct
when he/she intentionally does an act, or fails
to do an act in violation of his/her duty, with
knowledge of the serious danger to others in-
volved in it or of facts which would disclose
such danger to a reasonable person.
reclamation
The restoration of land, water, or waste mate-
rials to usefulness through methods such as
sanitary landfill, wastewater treatment, or
material recovery.
Reclamation Act
The Reclamation Act of 1902 authorized the
Secretary of the Interior to locate, construct,
operate, and maintain works for the storage,
diversion, and development of waters for the
reclamation of arid and semiarid lands in the
Western States.
reclining
Pertaining to a posture involving an interme-

diate position between sitting and lying in
which the posterior aspect of the body is
against some reference surface, with the torso
approximately between 45° and horizontal,
and some degree of flexion of the hips and
knees.
recognition
The process in which an observer interprets or
computer process matches with data in mem-
ory the information available from a stimulus
or object to arrive at a conclusion about the
stimulus or object.
recognition time
That temporal interval required for a particu-
lar stimulus to be recognized.
recognized hazard
Any hazard declared by OSHA to be such, as
well as any hazard known or suspected to ex-
ist within a workplace by management. This
©2000 CRC Press LLC
concept of "recognized hazard" is a critical
element in the OSHA compliance process, es-
pecially with regard to the employer's General
Duty under Section 5(a)(1) of the OSHAct.
The contention is that a hazard must first be
"recognized" as such before any attempts can
be made to remove or control it. However, it
must be clearly understood that ignorance of a
hazard or hazardous condition does not ele-
vate the responsibility to eliminate or control

it. OSHA has clearly established a position
that places this burden of knowledge directly
on the employer. If the employer should have
known or, with the practice of reasonable
diligence, could have known about the hazard,
then the employer is still required to and obli-
gated to control or remove the hazard. See
also General Duty Clause.
recombinant bacterium
A type of microorganism whose genetic
makeup has been deliberately altered by in-
troduction of new genetic elements.
recombinant DNA (rDNA)
The new DNA that is formed by combining
pieces of DNA from different organisms or
cells.
recommended daily allowance (RDA)
That amount of a specified mineral, vitamin, or
other substance which is recommended for
normal health.
recommended exposure limit (REL)
An occupational exposure limit recommended
by NIOSH as being protective of worker
health over a working lifetime.
recommended maximum contaminant level
(RMCL)
The maximum level of a contaminant in
drinking water at which no known or antici-
pated adverse affect on human health would
occur, and which includes an adequate margin

of safety. Recommended levels are non-
enforceable health goals. See maximum con-
taminant level.
recompression therapy
The treatment for decompression sickness
using a hyperbaric chamber to increase the
ambient pressure.
reconciling items
Items where accounting practices vary for
handling these expenses as a result of local
ordinances and conditions. Reconciling items
include depreciation and amortization, interest
payments, leases and rentals. They are called
reconciling items because they are needed to
provide an overall total that is consistent with
local published reports.
reconstructed source
An existing facility in which components are
replaced to such an extent that the fixed capi-
tal cost of the new components exceeds 50
percent of the capital cost that would be re-
quired to construct a comparable entirely new
facility. New source performance standards
may be applied to sources which are recon-
structed after the proposal of the standard if it
is technologically and economically feasible
to meet the standard.
record of decision (ROD)
A public document that explains which
cleanup alternative(s) will be used at National

Priorities List sites where, under CERCLA,
Trust Funds pay for the cleanup.
recordable occupational injuries and illnesses
Under OSHA 29 CFR 1904.12(c), any occu-
pational injuries or illnesses which result in:
a) fatalities, regardless of the time be-
tween the injury and death, or the
length of the illness; or
b) lost workday cases, other than fatalities,
that result in lost workdays; or
c) nonfatal cases without lost workdays
which result in transfer to another job
or termination of employment, or re-
quire medical treatment (other than first
aid) or involve loss of consciousness or
restriction of work or motion. This
category also includes any diagnosed
occupational illnesses which are re-
ported to the employer but are not clas-
sified as fatalities or lost workday
cases.
recording thermometer
A thermometer with a recording device used
to obtain a permanent record of temperature.
records retention policy
A systematic procedure for the retention and
destruction of an organization’s documents.
Retention periods may be driven by business
considerations and not requirements of law.
Failure to retain documents in the face of dis-

covery in litigation can result in evidentiary