Z94.13 - Occupational Health & Safety

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FACE SHIELD. A protective device designed to prevent hazardous substances, dust particles, sharp objects, and other materials from contacting the face.

FACILITY LAYOUT. The act or process of laying out, or planning in detail, to show the arrangement of equipment and other elements of a facility to establish a safe working environment.

FACTOR. In mental measure a hypothetical trait, ability, or component of ability, that underlies and influences performance on two or more tests and hence carries scores on the tests to be correlated. The term  factor- strictly refers to a theoretical variable, derived by a process of factor analysis, from a table of intercorrelations among tests; but it is also commonly used to denote the psychological interpretation given to the variable, i.e., the mental trait assumed to be represented by the variable as verbal ability, numerical ability, etc.

FACTOR ANALYSIS. Any of the several methods of analyzing the intercorrelations among a set of variables such as test scores. Factor analysis attempts to account for the interrelationships in terms of some underlying  factors- preferably fewer in number than the original variables and it reveals how much of the variation in each of the original measures arises from or is associated with each  of the hypothetical factors. Factor analysis has contributed to our understanding of the organization or components of intelligence, aptitudes, and personality and it has pointed the way to the development of  purer- tests of the several components.

FACTOR OF SAFETY (FS). The ratio of ultimate strength of a material or structure to the allowable stress.

FAIL OPERATIONAL FAIL SAFE. A system characteristic that permits continued operation on occurrence of a failure while remaining acceptably safe. A second type of failure results in the system remaining safe, but non-operational.

FAIL OPERATIONAL. A characteristic design that permits continued operation in spite of the occurrence of a discrete failure.

FAIL SAFE. Design of a product or equipment, in such a manner that, when it fails or becomes inoperative it will do so in a safe position or condition.

FAILURE. An inability to perform an intended function.



FAILURE, PRIMARY. The failure which is responsible for a system malfunction.

FAILURE, SECONDARY. A failure which occurs as the consequence of another failure (also dependent failure).

FAILURE ANALYSIS. The logical systematic examination of an item to identify and analyze the cause, mode, and consequence of a real failure.

FAILURE ASSESSMENT. The process by which the cause, effect, responsibility and cost of any reported problem in the system is determined and reported.

FAILURE CRITICAL. A failure which could result in major injury or fatality to people or which could result in major damage to any system or loss of a critical function.

FAILURE MANAGEMENT. Decisions, policies and planning which identify and eliminate or control potential failures and implement corrective or control procedures following real failures.

FAILURE MECHANISM. The physics or chemistry of the failure event, i.e., the cause of the failure.

FAILURE MODE AND EFFECT ANALYSIS (FMEA). A method of analysis used in system safety. The failure or malfunction of each component is identified, along with the mode of failure (e.g., switch jammed  on-). The effects of the failure are traced though the system, and the ultimate effect on the task performance is evaluated.

FAILURE MODE, EFFECT AND CRITICALITY ANALYSIS (FMECA). An extension of an FMEA in which each effect is assigned a criticality index which reflects both the probability of the occurrence of the effect and the seriousness of the effect in terms of loss in performance and/or safety.

FAILURE RATE. The number of failures of an item per unit time (cycles, hours, miles, events, etc., as applicable for the item).

FAINTING. A loss of consciousness as a result of a diminished supply of blood to the brain. Technically called syncope.

FALSE NEGATIVE RATE. The proportion of persons with a disease for whom the screening test for that disease is negative.

FALSE POSITIVE RATE. The proportion of persons without a disease for whom the screening test for that disease is positive.

FATAL ACCIDENT. An accident resulting in the death of one or more persons.

FATALITY. A death resulting from an accident.

FATIGUE. The physical and/or mental responses to an activity which show themselves in a diminished capacity for work.

FAULT HAZARD ANALYSIS. The analysis of hazards or hazard potential situations using fault tree methodology.

FAULT TREE ANALYSIS. A method of analysis used in system safety. An undesired event is selected and all possible  factors that can contribute to the event are diagrammed in sequence in the form of a  tree.-  The branches of the tree are continued until independent events are reached. Probabilities are determined for the independent events and after simplifying the tree, both the probability of the undesired event and the most likely chain of events leading up to it are computed.

FIBROSIS. A reparative or reactive process characterized by the deposition of connective tissue fibers in and around the site of injury.

FINAL POSITION (AFTER AN ACCIDENT). The place where objects or persons involved in the accident finally come to rest without application of power. This is the position before anything is moved to help the injured or remove vehicles or equipment.

FIRE. Rapid oxidation with the evolution of heat and light.

FIRE ALARM. A device or system (visual, auditory, local or transmitted to other locations, etc.) which signals the presence of a fire to occupants and those who will provide assistance.


FIRE DOORS. Doors rated and tested for resistance to various degrees of fire exposure and utilized to prevent the spread of fire through horizontal and vertical openings. The doors must remain closed normally or be closed automatically in the presence of fire. The degree of resistance required is determined by the type of occupancy, the anticipated fire exposure, and the resistance of the structure in which it is installed.

FIRE EXTINGUISHERS. Devices having characteristics essential to extinguish flame. Fire extinguishers may contain either liquid or dry chemicals, or gases (water, dry chemicals, carbon dioxide, etc.). They are tested and rated to indicate their ability to handle specific classes and sizes of fires. class A extinguishers - For ordinary combustibles, such as wood, paper, and textiles, where quenching-cooling effect is required. class B extinguishers - For flammable liquid and gas fires, such as oil, gasoline, paint, and grease, where oxygen exclusion or flame interruption effect is essential. class C extinguishers - For fires involving energized electrical wiring and equipment where the nonconductive property of the extinguishing agent is of prime importance. class D extinguishers - For fires in combustible metals such as magnesium, potassium, powdered aluminum, zinc, sodium, titanium, zirconium, and lithium.

FIRE PREVENTION. Measures or actions specifically directed toward preventing the inception of fires, and minimizing the severity of fires should they occur.

FIRE (FLAME) PROOF. Material incapable of burning. The term fire-proof- is false. No material is immune to the effects of a fire possessing sufficient intensity and duration. It is commonly, a though erroneously, used synonymously with the term  fire resistive.- Use of the term is discouraged since it is misleading.

FIRE PROTECTION. In its broadest interpretation it embraces all measures in the prevention, detection, and extinguishment of fire; relating to the safeguarding of human life and the preservation of property. In a strict interpretation, it refers to the methods of providing for fire control or fire extinguishment.

FIRE PROTECTION ENGINEERING. The field of engineering concerned with the safeguarding of life and property against loss from fire, explosion, and related hazards. It is concerned with integrated programs involving the design and use of structures, equipment, processes and systems, including the areas of prevention, detection and alarm, and fire control and extinguishment, and gives consideration to functional, economic, and operational factors.

FIRE RESISTIVE. Refers to properties of materials or designs to resist the effects of any fire to which the material or structure may be expected to be subjected.  A building constructed of fire resistive materials can withstand a burnout of its contents without subsequent structural collapse. Fire resistive implies a higher degree of a fire resistance than noncombustible.

FIRE RETARDANT. In general denotes a substantially lower degree of fire resistance than fire resistive. The term is frequently used to refer to materials or structures which are combustible but have been subjected to treatments or surface coverages to prevent or retard ignition or the spread of fire.

FIRE WALL. A fire resistant wall designed to prevent the horizontal spread of fire into adjacent areas, generally self-supporting and designed to maintain its integrity if the structure on either side completely collapses. If a wood roof is involved, the wall must extend through and above the roof.

FIRST AID. The emergency care of a person who is injured or ill, to prevent death or further injury, to relieve pain, and to counteract shock, until medical aid can be obtained.

FIRST AID INJURY. An injury requiring first aid treatment only.

FIT FOR PURPOSE INTENDED. When something sold is useless, or so imperfect that the buyer would not have bought it had he known, the seller has not complied with the statutory warranty against hidden defects and the article cannot be considered  fit for the purpose intended,- unless the warranty has been specifically waived.

FITNESS (OR FIT). Satisfactoriness, suitability or  appropriateness to fulfill the need or use.

FLAME. The visible heat rays which appear when the ignition of a material is reached. Hydrogen is one of the exceptions since the heat rays are not visible.

FLAME (FLASH) ARRESTER. Devices utilized on vents for flammable liquid or gas tanks, storage containers, cans, gas lines or flammable liquid pipelines to prevent flash-back (movement of flame) through the line or into the container when a flammable or explosive mixture is ignited.

FLAME PROPAGATION (SPREAD). The spread of flame throughout a combustible vapor area which may be in a container or across a surface, independently of the ignition source. Generally used in connection with the capability and rate of such movement.


FLAMMABLE. Any substance that is easily ignited, burns intensely, or has a rapid rate of flame spread. The substance may be in the form of an aerosol, a gas, a liquid, or a solid. Flammable and inflammable are identical in meaning; however, the prefix  in- indicates negative in many words and can cause confusion. Flammable, therefore, is the preferred term.


FLAMMABLE LIQUIDS. Any liquid having a flash point below 100ºF (37.8ºC), except any mixture having components with flash points of 100ºF (37.8ºC) or higher, the total of which makeup 99 percent or more of the total volume of the mixture. Flammable liquids shall be known as Class I liquids. Class I liquids are divided into three classes as follows: (i) Class IA shall include liquids having flash points below 73ºF (22.8ºC) and having a boiling point below 100ºF (37.8ºC); (ii) Class IB shall include liquids having flash points below 73ºF (22.8ºC) and having a boiling point at or above 100ºF (37.8ºC); (iii) Class IC shall include liquids having flash points at or above 73ºF (22.8ºC) and having a boiling point below 100ºF (37.8ºC).

FLAMMABLE VAPOR. A concentration, by volume, of vapors in air from a flammable liquid within the lower and upper flammable limits.

FLASH BURN. Injury or destruction of body tissue caused by exposure to a flash or sudden release of intense radiant heat.

FLASH POINT. The lowest temperature of a liquid at which it gives off sufficient vapors to form an ignitible mixture with the air near the surface of the liquid or within the vessel used. The flash point can be determined by the open cup or the closed cup method. The latter is commonly used to determine the classification of liquids which flash in the ordinary temperature range.

FLUX. Usually refers to a substance used to clean surfaces and promote fusion in soldering. However, fluxes of various chemical nature are used in the smelting of ores in the ceramic industry, in assaying silver and gold ores, and in other endeavors. The most common fluxes are silica, various silicates, lime, sodium and potassium carbonate and litharge and red lead in the ceramic industry.

FOAM. A fluid aggregate of gas- or air-filled bubbles formed by chemical or mechanical means that will float on the surface of flammable liquids or flow over solid surfaces. The foam functions to blanket and extinguish fires and/or to prevent ignition of the material.

FOLLICULITIS. Inflammation of a hair follicle or follicles.


FOOT CANDLE. A measure of illuminance produced on a surface all points of which are 1 foot from a directionally uniform point of 1 candela.  That illuminance is 1 lumen/ft2 or 1 footcandle. (Editor's Note: Under SI, illuminance is measured in terms of lux units, where 1 lx = 1 lm/m2 x cd x sr where, m = meter; cd =candela; sr = steradian for solid angle. To convert: 1 footcandle = 1.076 391 lx.)

FORCED EXPIRATORY FLOW (FEF200-1200). The average rate of flow for a specified portion of the forced expiratory volume, usually between 200 and 1200 ml.

FORCED EXPIRATORY VOLUME (QUALIFIED BY SUBSCRIPT INDICATING THE TIME INTERVAL IN SECONDS, FEVT). Volume of gas exhaled over a given time interval with expiration as forceful as possible.

FORCED EXPIRATORY VOLUME PERCENTAGE EXPIRED (FEVT%). Forced expiratory volume expressed as a percentage of the forced vital capacity.  (FEVt/FVC) x 100

FORCED MID-EXPIRATORY FLOW (FEF25-75%). The average rate of flow during the middle half of the forced expiratory volume.

FORCED VITAL CAPACITY (FVC). The vital capacity performed with maximum inspiration and expiration as forceful and rapid as possible.

FORESEEABILITY. The legal theory that a person may be held liable for actions that result in injury or damage only where the person was able to foresee dangers and risks that could reasonably be anticipated.

FOUR-TO-ONE RATIO. An arbitrary ratio frequently used in the comparison of the indirect costs of an accident to the direct costs. Generally considered obsolete since no fixed ratio exists among various types of exposures.

FREQUENCY (IN CYCLES PER SECOND, OR CPS, HERTZ, OR HZ). The time rate of repetition of a periodic phenomenon. The frequency is the reciprocal of the period. It  defines- pitch or the highness or lowness of sound.

FROSTBITE. A freezing injury of the skin due to exposure to extreme cold. It may be recognized by whitening of the skin and loss of sensation. It is treated by rapid thawing. Deep frostbite with freezing of tissues deep to the skin generally results in dry gangrene.

FUME. Solid particles generated by condensation from the gaseous state, generally after volatilization from molten metals. A fume is formed when a volatilized solid, such as metal, condenses in cool air. The solid particles that make up a fume are extremely fine, usually less than 1 µm 1.122(0.001mm). In most cases, the hot material reacts with the air to form an oxide.

FUNCTIONAL DISEASE. Disease in which some change in function of the body or its parts occurs without changes in structure. Usually refers to psychiatric diseases.

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