Contamination Control Glossary of Terms and Definitions
The terms and definitions included in this document generally have/distinctive meanings within the context of contamination control. Terms having a more generic nature are not included in this document; their definitions as found in the American Heritage Dictionary are considered acceptable.
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1 K paint
Paint that requires the application of heat to cure or convert from a liquid to a solid state.
2 K paint
Paint that consists of two components which, when mixed together, react to cure or convert from a liquid to a solid state.
A
abrasion resistance
The ability of a surface to resist wearing due to friction.
abrasive
The hard grit on sandpaper and grinding discs.
absorbance, A (also absorbancy or extinction)
In spectrochemical analysis, the logarithm to the base 10 of the reciprocal of the transmittance. A = log (1/tau)
acid
A corrosive material that reacts chemically as an electron pair acceptor.
activated
Describing an adsorbent whose surface area has been extended through the creation of pores or other internal openings.
activated carbon
An adsorbent of porous structure manufactured by carbonization of organic material and treated by controlled oxidation to increase the microporosity of the adsorbent, consisting mainly of the element carbon in a porous structure. (See also impregnated activated carbon.)
accuracy
The extent to which the value of a quantity indicated by an instrument under test agrees with the accepted value of the quantity.
adhesion
A molecular force exerted across a surface of contact between liquids and solids, or solids and solids, that resists their separation.
adhesion, intercoat
The degree of adherence between successive layers of pain or between the first coat of paint and the underlying primer.
adsorbent
Any solid having the ability to concentrate significant quantities of other substances on its surface. These solids typically include but are not limited to activated carbon or impregnated activated carbon.
adsorber bed (or bed)
A layer of adsorbent contained between two perforated sheets spaced at a specified distance. Also, the assembly of perforated and non-perforated members that comprises the volume into which the adsorbent is packed.
adsorber cell
A modular container for an adsorbent, with provision for sealing to a mounting frame, that can be used singly or in multiples to build a system of any airflow capacity.
aerosol
A gaseous suspension of solid or liquid material, usually between 0.001 µm and 1000 µm in diameter
aerosol generator
An instrument capable of generating particulate matter having appropriate size range (e.g. 0.05 µm to 2 µm) at a constant concentration, which may be produced by thermal, hydraulic, pneumatic, acoustic, or electrostatic means.
aerosol generator, Laskin nozzle type
A system that uses a nozzle to generate a polydisperse aerosol from a liquid, such as DOP, that uses a source of compressed gas as shown in the Echols and Young study, NRL 5929.
aerosol source material
(a) A specified liquid or solid, having known properties, that is transformed into an aerosol for challenge testing. (b) An aerosol used for testing HEPA or ULPA filter media produced from a specified liquid having known properties. Example: dioctyl phthalate (DOP), also known as di(2-ethylhexyl) phthalate (DEHP).
agglomeration
Clumping of particles in the form of loose clusters.
air dry
Allowing paint to dry at ambient (surrounding) temperatures, without the aid of an external heat source.
air ions
Molecular clusters of about ten molecules (water, impurities, etc.) that are bound by polarization forces to a singly charged oxygen or nitrogen molecule.
air knife
A mechanical blowoff device used to prepare the surfaces of automobile bodies or parts for painting. In use, a small amount of compressed air pulls in large values of ambient air to product a high-flow, high-velocity curtain or sheet of air (ionized air if an ionizing bar is used).
air membrane monitor
A porous disc through which air is drawn by use of a vacuum pump. Particles collected on a gridded membrane filter are examined in accordance with ASTM F25, allowing determination of particle sizing and concentration as well as identification of contaminants.
air resistance
The loss of pressure caused by gas moving through the filter medium.
air shower
An air-lock entryway that uses high-velocity jets of filtered air to remove loosely held particles from personnel entering a contamination-controlled area. Loosened particles are removed by filtration in the exhaust/recirculation system in order to prevent contamination by resettling in another area.
airborne particle
Particle suspended in moving or stationary air.
airflow
(a) Movement of air in a given direction with respect to a specified reference plane or other designated physical reference. (b) Movement of all gaseous environmental media (e.g., air, nitrogen, argon).
airflow, nonunidirectional
Airflow that does not qualify as unidirectional because it has a multiplicity of flow directions or multiple-pass circulation (eddies), or both.
airflow, unidirectional
Air flowing in a single direction at the work zone of a clean-air device or clean area. This can be verified by the absence of recirculating or stagnant air at the work zone either by visual methods or other techniques. Formerly referred to as laminar airflow.
airflow rate
The airflow rate expressed as volumetric flow per unit of time.
airlock
An intermediate room or area that is normally ventilated and used to minimize the transfer of airborne contamination from one area to another.
airlock entry
A two-door anteroom used to maintain pressure relationships between adjoining areas. Interlocks may be used to prevent the entry and exit doors from being opened simultaneously.
aliasing
A distortion of frequency data that occurs during digital data acquisition when the sampling rate of the data acquisition hardware is too slow to capture the higher-frequency data that may be present. (an anti-aliasing filter to block out high frequency data may be used to overcome this phenomenon.)
aliquot
One part of a sample that has been divided into equal parts.
AMC
See airborne molecular contamination.
analysis bandwidth
The total relevant frequency range (e.g., 1 to 100 Hz), independent of type of analysis, resolution, or both.
analyte
A sample being analyzed
analytical sample
A portion of material, or component, analyzed.
ancillary
Subordinate, subsidiary, auxiliary, or supplemental activities required to start up or maintain production or process activity.
anemometer
An instrument for measuring airflow velocity.
anemometer, vane
An instrument that measures the velocity of air by mechanically converting the momentum of the air into the rotation or deflection of a vane.
anemometer, rotating vane type
An instrument for measuring air velocity that contains an element that rotates in response to the airflow and converts the rotation to a velocity reading.
anion
A negatively charged atom or group of atoms.
antimicrobial
A compound or formulation used to retard the growth of or to kill microorganisms.
antiseptic
A substance that prevents or inhibits the growth of microorganisms without necessarily killing them. The term antiseptic is usually associated with substances used on humans or animals.
antistatic compound
A chemical substance that is capable of neutralizing a surface charge. NOTE: Most antistatic compounds function via one of the following two properties: a) Electrostatic charge neutralization, in which the surface charge of one polarity is dissipated by applying charged materials of the opposite polarity to the surface. The most effective antistatic compounds in this category are quaternary ammonium chlorides. b) Film formation, in which moisture from the air absorbs onto a film of (nonionic) antistatic compound, thereby dissipating the buildup of charge.
In the microelectronics industry, and wherever else there is concern regarding the presence of ion species, reduction of static through the use of nonionic formulations is preferred.
appearance
The visual quality of a coating, as determined by gloss, distinctness of image (DOI), or tension testing.
AQL
Acceptable quality level. Refers to table of inspection by attributes in ANSI/ASQC Z1.4.
aseptic
The state of having eliminated all detectable viable microorganisms.
as-found data
(a) Data showing the response of an instrument to known standards before adjusting or calibrating the instrument. (b) Measured data indicating status or condition of a process or environment before any remedial or other required actions are taken.
ashing
A method for determining the amount of non-carbon components that remains after combustion.
atomization (aerosolization)
The formation of very small droplets of liquid or particles of powder, as in a paint-spraying process
automatic zone
The area in a paint-spray booth that uses automated spray equipment to apply paint.
averaging
The process of developing the mean average value of a signal.
B
bacteria
One-celled, microscopic organisms lacking chlorophyll that multiply by fission. Bacteria typically measure from 0.2 to 50 µm in diameter.
bacterial spore
A resistant body produced by a vegetative bacterial cell. These spores may be resistant to heat, ultraviolet light, and desiccation, and may remain dormant for extended periods of time.
bactericide
A substance or formulation capable of destroying bacteria.
bacteriostat
A compound or formulation that retards or prevents the growth of bacteria. Bacteriostats act reversibly; when they are removed, cells resume their normal growth patterns.
baffle
A non-perforated member oriented substantially perpendicular to the direction of airflow, connected to a wall or divider of the cell, and having the purpose of preventing wall effect, channeling, or both.
bag
A nonrigid container that may be closed at the top and is used for holding, storing, or carrying something.
bag, autoclave (also biohazard bag)
A type of polymer bag used in steam sterilization applications. Some are printed with an indicator that changes color when processed.
bag, gussetted
A bag made with side or bottom pleats, with dimensions such as 10 x 4 x 16 in., or in the case of bottom gusset, 10 x 16 x 4 in.
bag, outer (also outside double-bag, dust cover)
An additional layer of protective packaging used during storage and transportation. NOTE: The outer bag is removed in the gowning area and has a less-stringent cleanliness requirement than the inner packaging.
band-pass filter
A frequency selective electronic circuit designed to pass—that is, either amplify or not attentuate—all data within a frequency range defined by a nonzero lower and finite upper limiting frequency.
bandwidth, integration
The width of the frequency band over which a measurement is made or a mathematical operation is performed. The amplitudes of vibration are a direction function of the integration bandwidth used; i.e., the greater the bandwidth, the larger the amplitudes.
barrier glove
A glove designed to prevent transmission of materials
base
A corrosive material that reacts chemically as an electron pair donor.
basecoat
A highly pigmented color coat applied prior to a clearcoat as the first step of a two-step, basecoat-clearcoat painting process.
basis weight (or grammage)
The mass of a specified area of materials such as documentation forms or filter media.
basis weight
The mass of a specified area of filter medium; also referred to as grammage.
basted
Sewn with long, loose stitches
binder
The ingredient in paint that holds the pigment and other additives in the form of a solid film.
bioburden (or microcount)
A measure of the number of microorganisms resident on or within products and inanimate objects.
biohazard bag
See bag, autoclave.
blank or blank area
A non-perforated area within the perforated portions of a perforated sheet or screen.
blowoff
The removal of particles and fibers from a surface in preparation for the application of paint, using compressed or high-volume, fan-driven air.
body box
A test chamber used to measure the containment properties of a garment set
booth
An enclosure that provides for the supply of fresh filtered air and the removal of contaminated air. NOTE: Booths are used primarily for paint-spray application, but can also be used for other paint-shop processes such as sanding, sealing, and wiping.
bouffant
A puffed-out head covering used to contain the hair of the wearer.
box
A protective portable container for a cassette or contamination-sensitive products.
box, wafer
A carrier that seals wafers and cassettes from the outside environment.
breakthrough
The measurable concentration of a specific contaminant downstream of a filter system, usually expressed in absolute concentration units. NOTE: The ability to detect breakthrough depends on the detection limit of the measurement technique. A breakthrough curve is a continuous plot of contaminant breakthrough vs. time. (See also penetration.)
broadband vibration
Vibration over a broad frequency band; for example, the total amplitude of vibration between 1 and 100 Hz.
building shoes
A dedicated pair of shoes worn by cleanroom personnel within the defined areas of the change room, cleanroom, and peripheral support areas to limit tracking in external contamination on street shoes.
building suit
An undergarment made of 100% polyester or other synthetic fabrics, normally similar to a two-piece jogging suit with either a pullover or zip-up top; worn over personal underwear and under the cleanroom garment.
bypass
The deliberate or unintentional diversion of air around the filter medium in a filtration system.
C
calibrate
To compare the measurement of a standard or instrument of unknown accuracy with another standard or instrument of known accuracy to detect, correlate, report, or minimize by adjustment any variation in the accuracy of the unknown standard or instrument.
calibrated equipment
Test equipment that has been calibrated in accordance with the manufacturer's recommendations or accepted industry practices.
calibration
Comparison of a measurement standard or instrument of unknown accuracy with another standard or instrument of known accuracy to detect, correlate, report, or eliminate by adjustment any variation in the accuracy of the unknown standard or instrument.
capacity
The cumulative amount of contaminant that is removed by a filter system within a specified time period or at a specified efficiency level.
carbon marks
See gel marks.
cassette
An open structure that holds one or more contamination-sensitive products.
catalyst
Any substance of which a small proportion notably affects the rate of a chemical reaction without itself being consumed or undergoing a chemical change. NOTE: Most catalysts accelerate reactions, but a few retard them (inhibitors).
cation
A positively charged atom or group of atoms.
center frequency
The center of the frequency span of a band-pass filter or frequency band. NOTE: ANSI-S1.11 defines standard center frequencies for the more common forms of constant percentage bandwidth.
certificate of calibration
A document provided by the calibration company that certifies the test equipment has been calibrated to a known standard.
certification
The culmination of procedures leading to validation, expressed in the form of written evidence (certificate of compliance) that verification has been accomplished in accordance with specified testing procedures, such as Fed-Std-209 or IEST-RP-CC006 (see pp. 30-32). (See also validation and verification.)
certification organization
An organization providing on-site testing and certification services.
certification technician
A person who has demonstrated proficiency sufficient to meet the criteria for qualification by passing a written and operational examination that assesses the ability of the candidate, as acquired through training and experience, to test and certify cleanrooms and clean-air devices.
CFU
See colony-forming unit.
challenge aerosol
An aerosol derived from the selected aerosol source material and used as the leak-test challenge for filter medium leak-test. Challenge aerosols may be produced by a variety of methods, with the choice determined by the aerosol type and the particle size characteristics.
challenge concentration
The concentration (e.g., mg/m3) of an aerosol (number of particles per unit volume) or gas used to challenge a filter, adsorber, or other air cleaning device under conditions specified for testing such devices.
change room (changing room)
A facility contiguous to the cleanroom to provide for the control of the passage of personnel; donning, doffing, and storage of apparel; and storage of related supplies.
chemical compatibility
The ability of a material to withstand chemical contact with minimal interaction.
chemical degradation
The change in materials that occurs when the materials come into contact with chemicals. Examples: swelling, loss of tensile strength, deformation, and loss of abrasion resistance.
clean workstation
A clean-air device such as a bench or similar enclosure, characterized by having its own supply of filtered air.
clean-air device
A clean bench, clean work station, downflow module, or other equipment designed to control particulate air cleanliness in a localized working area and incorporating, as a minimum, a HEPA filter and a blower.
clean-air device, laminar flow
This term is no longer in use. See clean-air device, unidirectional flow.
clean-air device, unidirectional flow
A clean work station or other device (other than a cleanroom or clean zone) that incorporates one of more HEPA or ULPA filters and one or more motor-blowers for the purpose of supplying unidirectional-flow, clean air to a controlled workspace.
clean-air system
A system designed to maintain the cleanliness of air in a cleanroom or clean zone at or below a specified airborne particulate cleanliness class.
cleaning agent
A liquid that has the ability to aid in removing contaminants from surfaces, usually by dissolution, reducing surface tension, or neutralizing electrostatic charge, or by both reducing surface tension and neutralizing electrostatic charge. Cleaning agents can also be disinfectants. NOTE: To be acceptable for use in cleanrooms and other environmentally controlled areas, cleaning agents should be chemically and physically compatible with the process or product, or both, and should not themselves contribute measurably to the overall burden of contamination.
cleanliness level
(a) A designation indicating the maximum amount of contamination allowed per unit of area or volume or on the defined surface of a component. (b) Measured extent of contamination.
cleanroom
Room within which the number concentration of airborne particles is controlled and classified, and which is designed, constructed and operated in a manner to control the introduction, generation and retention of particles inside the room, as defined in ISO 14644-1.
Note 1: The class of airborne particle concentration is specified.
Note 2: Levels of other cleanliness attributes such as chemical, viable or nanoscale concentrations in the air, and also surface cleanliness in terms of particle, nanoscale, chemical and viable concentrations might also be specified and controlled.
Note 3: Other relevant physical parameters might also be controlled as required, e.g. temperature, humidity, pressure, vibration and electrostatic.
cleanroom, as-built
A cleanroom that is complete and ready for operation, with all services connected and functional, but without production equipment or personnel within the facility.
cleanroom, at-rest
A cleanroom that is complete, with all services functioning and with equipment installed and operable or operating, as specified, but without operating personnel.
cleanroom, operational
A cleanroom in normal operation with all services functioning and with production equipment and personnel, if applicable, present and performing their normal work functions in the facility.
cleanroom, laminar airflow
This term is no longer in use. See cleanroom, unidirectional-airflow..
cleanroom, mixed-airflow
A cleanroom in which the airflow is a mixture of unidirectional and non-unidirectional.
cleanroom, non-unidirectional-airflow
A cleanroom in which airflows exist with a multiplicity of flow directions or multiple-pass circulation (eddies) or both.
cleanroom, turbulent airflow
This term is no longer in use. See cleanroom, non-unidirectional airflow.
cleanroom, unidirectional-airflow
(a) A cleanroom in which airflows have generally parallel streamlines operating in a single direction and with uniform velocity over the cross section. (b) A cleanroom in which the filtered air entering the room makes a single pass through the work area in a parallel-flow pattern, with a minimum of turbulent-flow areas. NOTE: Unidirectional airflow rooms typically have coverage of 80% or more of the area of the ceiling (for vertical flow) or one wall (for horizontal flow) with the HEPA or ULPA filter medium or free-flow area. (Formerly known as laminar airflow cleanrooms.)
unidirectional airflow cleanroom (formerly referred to as laminar airflow cleanroom)
A cleanroom in which the filtered air entering the room makes a single pass through the work area in a parallel-flow pattern, with a minimum of turbulent-flow areas. Unidirectional airflow rooms typically have coverage of 80% or more of the area of the ceiling (for vertical flow) or one wall (for horizontal flow) with the HEPA or ULPA filter medium or free-flow area.
cleanroom, aseptic
A cleanroom operated with strict controls designed to minimize the presence of microorganisms.
cleanroom, nonaseptic
A cleanroom having no requirements regarding the presence of microorganisms.
cleanroom components
The individual fabricated parts that may consist of one or more material types and are used in areas subject to contamination control specifications. Example: filter assemblies.
clean-zone
Defined space within which the number concentration of airborne particles is controlled and classified, and which is constructed and operated in a manner to control the introduction, generation and retention of contaminants inside the space, as defined in ISO 14644-1.
Note 1: The class of airborne particle concentration is specified.
Note 2: Levels of other cleanliness attributes such as chemical, viable or nanoscale concentrations in the air, and also surface cleanliness in terms of particle, nanoscale, chemical and viable concentrations might also be specified and controlled.
Note 3: A clean zone(s) can be a defined space within a cleanroom or might be achieved by a separative device. Such a device can be located inside or outside a cleanroom.
Note 4: Other relevant physical parameters might also be controlled as required, e.g. temperature, humidity, pressure, vibration and electrostatic.
cleanroom testing agency
An organization that employs appropriately skilled technicians and specified instrumentation and methods to determine cleanroom cleanliness class. The skill and experience level of the testing agency should be specified by the user or contracting agency.
clearcoat
A clear topcoat of paint containing no pigment or only a transparent pigment or dye required to cover a color basecoat as the second step of a two-step, basecoat-clearcoat painting process.
CMD
See count median diameter.
coalescence
The fusing or flowing together of liquid droplets.
coating
The paint film covering a product.
coefficient of variation
A measure of the width of a distribution, expressed as a percentage, obtained by dividing the standard deviation of the distribution by the mean of the distribution.
coincidence
The presence of two or more particles in the sensing volume of the instrument at the same time, causing the instrument to interpret the combined signal erroneously as resulting from one larger particle.
coincidence loss limit
A particle concentration level, determined by the particle counter manufacturer, that represents the point where the presence of two or more particles simultaneously in the sensing volume of the instrument causes the instrument to interpret the combined signal erroneously as resulting from one larger particle.
collected volatile condensable material (cvcm)
The mass that outgases from a material and subsequently condenses on a collector, expressed as a percentage of the initial specimen mass. The measurement method is defined in ASTM E-595. (See also total mass loss.)
colony-forming unit (CFU)
A microbial cell or aggregate of multiple microbial cells that, when cultivated on solid media, will develop into a single visual colony.
color (topcoat) oven
An oven used to bake the final layer of paint.
comfort suit
See building suit.
concentration
(a) The number of particles per unit volume, at ambient temperature and pressure. (b) The quantity of one substance dispersed in a defined amount of another. NOTE: For airborne molecular contaminants, two common conventions are defined as weight per volume (e.g., µm/m3) or volume per volume (e.g., ppbv).
concentration limit
The particle concentration specified by the manufacturer at which the error due to coincidence is 10% or less. NOTE: Manufacturers may specify concentration limits at error levels other than 10%.
condensable
A substance (other than water) typically having a boiling point above room temperature at atmospheric pressure, capable of condensation on a clean surface
condensation
(a) A process of converting a material in the gaseous phase to a liquid or solid state. (b) An equilibrium process that is favored one way or the other by a chance in temperature, pressure, or both.
condensation nuclei
Small particles, normally within the size range from 0.001 to 0.1 µm radius, upon which water vapor condenses in the atmosphere.
condensation nucleus counter
An instrument for counting airborne particles, in the nanometer size range and larger, by optically detecting droplets formed by condensation of a vapor upon the particles.
constant bandwidth (also narrowband)
A form of analysis or band-pass filter in which the bandwidth is constant and independent of the center frequency.
constant percentage bandwidth (also proportional bandwidth)
A form of analysis or band-pass filter in which the bandwidth is proportional to a center frequency. NOTE: The most common forms of constant percentage bandwidth are octave bands and one-third octave bands, defined in ANSI-S1-11 (see section 2) as 69% and 23% of center frequency bandwidth, respectively.
containment
The ability of a garment set to restrict the migration of potential contaminants from inside the garment set to the ambient environment.
contaminant
Any particulate, molecular, non-particulate, and biological entity that can adversely affect the product or process.
contaminant source rate
The rate at which a contaminant is generated.
contaminate
To reduce the level of quality by the addition of contaminants.
contamination
The result of the addition of contaminants to a material or to any surface within a clean zone.
contamination control
Any organized action taken to control the level of contamination.
controlled
A term used to describe a process or environment in which parameters such as temperature, pressure, humidity, contaminate level and so forth are maintained within specified limits.
controlled environment
An environment in which parameters such as temperature, differential pressure, humidity, and contaminant levels are maintained within specified limits.
convertible film former
Paint that cures through a chemical reaction with the aid of oxygen, heat, or a catalyst.
correlation ratio
(a) The ratio of data obtained from two measurements. The measurements may be from a single environment at different locations or from a single environment using two similar instruments. (b) The ratio of downstream counts to upstream counts with no filter in the test system. NOTE: For sequential counting systems, the correlation ratio represents the differences in the upstream and downstream sampling systems, such as particle losses in sample lines and test duct, diluter (if used), and sample times. For simultaneous counting systems, the correlation ratio represents the same factors as for sequential counting systems, as well as the differences between the different particle counting instruments used upstream and downstream, such as sample flow rate and counting efficiency.
count mean diameter (or number mean diameter)
The average particle size of the number distribution of the aerosol.
count median diameter (CMD) (or number median diameter)
The 50th percentile of the number distribution of the aerosol; i.e., 50% of the particles are smaller than the count median diameter and 50% are larger than the count median diameter.
counting efficiency
The ratio, expressed as a percentage, of a detected concentration of monodisperse particles divided by the actual concentration of particles of a given size or range of sizes.
coveralls (also jumpsuit)
A one-piece, full-length garment that covers the body, generally from the neck to the wrists and ankles.
critical
A term used to describe a parameter whose impact on a product or process renders that product or process useless if the parameter is out of the controlled limits.
crater (fisheye)
A small depression formed in a wet paint film as a result of localized reduction of surface tension, such as might be caused by the presence of silicone or other contaminants.
crossdraft
Air movement in a sideways (horizontal) direction, from supply toward exhaust, within a paint-spray booth.
cure
The process by which paint is converted from liquid or power to a solid state by chemical reaction.
D
decay time
(a) The time required for an electrostatic potential to be reduced to a given percentage (usually 10%) of its initial value. (b) The time interval between two specified values of a variable that decreases with time.
decontamination
The removal of microorganisms, chemical residue, or particulate from liquids, surfaces, air, or other gases.
dedicated shoes
See shoes, building or shoes, dedicated.
degowning
See doffing.
degradation
Undesirable changes, physical or chemical or both, which take place when a material is exposed to certain solids, liquids, or gases or to harmful environmental conditions. Examples: swelling, dissolution, loss of physical strength.
DEHP
See dioctyl phthalate.
DEHS
See dioctyl sebacate.
demonstrated equivalence
Condition where a method of measurement has passed a series of tests to show that it gives results equivalent to those of a standard measurement.
denier
A unit of fineness used to describe synthetic and silk fibers, based on a mass of 1 gram per 9,000 meters of length.
deodorant
A compound or formulation having the ability to counteract undesirable odors.
designated leak
A leak that should be detectable during scanning of a filter. NOTE: When using a photometer, a designated leak is characterized by a standard leak penetration, which is the photometer response when the sampling probe is stationary over a leak, divided by the photometer response upstream of the filter when using a 28.3-L/min (1-ft3/min) photometer. The designate leak is represented as greater than or equal to a value; e.g., 0.010% or 0.050%. When using a discrete-particle counter, a designated leak is characterized by a standard leak penetration and by a designated number of counts chosen to establish statistical probabilities related to its detection.
desorption, thermal (TD) (or thermal extraction)
The removal of volatile material using thermal energy (i.e., heat).
di-2-ethylhexyl (DEHP)
See dioctyl phthalate (DOP).
di(2-ethylhexyl) sebacate (DEHS)
See dioctyl sebacate (DOS).
differential pressure
See pressure, differential.
diffusion, molecular
A process of spontaneous intermixing of different substances, attributable to molecular motion (Brownian motion) and tending to produce uniformity of concentration.
diluter
A device that reduces the particle concentration by the dilution ratio of the device. These devices typically mix a known volume of sample air with a known volume of particle-free or filtered air to achieve the dilution. The ratio of the two volumes is the dilution ratio.
dioctyl phthalate (DOP)
an oily liquid ester C6H4(COOC8H17)2 used chiefly as a plasticizer; bis-(2-ethyl-hexyl) phthalate; CAS# 117-84-0
dioctyl sebacate (DOS)
Dioctyl sebacate (DOS) or di(2-ethylhexyl) sebacate (DEHS); CAS# 122-62-3.
dirt (contaminant)
An undesired inclusion in a paint film, caused by anomalies or disturbances in the painting process.
discharge time
The time necessary for a voltage (due to an electrostatic charge) to decay from an initial value to some arbitrarily chosen final value; used for testing ionizers.
discrete-particle counter (DPC)
An instrument, such as an optical particle counter or condensation nucleus counter, used to count and size discrete particles in air and capable of resolving responses from individual particles.
disinfectant
A chemical or physical agent that destroys or removes vegetative forms of harmful microorganisms when applied to a surface. (USP <1072>). NOTE: A disinfectant may be less effective in destroying bacterial spores. Disinfection does not necessarily sterilize a surface.
distinctness of image (DOI)
The measurement of the clarity of the light image reflected from a painted surface.
DOI
See distinctness of image.
doffing (or degowning)
The act of removing cleanroom garments in a controlled manner to prevent damage and unnecessary contamination of the garments.
donning (or gowning)
The act of putting on cleanroom garments in a precise, prescribed order and manner to avoid compromising the cleanliness and functionality of the contamination controlling protective garment system.
donning gloves
An extra pair of gloves worn to protect the gowning system components from coming into direct contact with the hand to prevent the transfer of skin oil and flakes. May be worn over the work gloves during gowning or used alone for gowning and replaced by work gloves after completion of the gowning procedure.
DOP
See dioctyl phthalate.
dopant
A chemical element that modifies the electrical properties of a semiconductor material.
DOS
See dioctyl sebacate.
downdraft
Air movement in a downward (vertical) direction, from supply toward exhaust.
DPC
See discrete-particle counter.
dry-film hiding
The film thickness of a paint that will completely hide the underlying surface.
dust cover (also outside double-bag)
See bag, outer.
dynamic headspace analysis
The process of thermal desorption of a sample in a flowing gas stream and collecting the outgassing compounds for subsequent analysis.
dwell time
See residence time.
E
e-coat (or electrodeposition or electrocoating)
A painting process that applies a paint film on all surfaces of a metallic object, immersed in a bath of water-thinned paint, when an electric current is passed between the object and another electrode.
effective integration bandwidth
See bandwidth.
efficiency
The fraction of a specific contaminant that is removed by the filter system,usually expressed as a percentage. (See also penetration.)
efficiency curve
A continuous plot of contaminant removal efficiency against time.
electret filter media
Media made of fibers that carry electrical charge on their surfaces.
electrocoating
See e-coat.
electrodeposition
See e-coat.
electromagnetic compatibility (EMC)
The ability of an electronic system or device to: 1) function properly in its intended electromagnetic environment, and 2) not be a source of electromagnetic pollution to its environment. Where the electromagnetic environment is composed of both radiated and conducted energy, EMC has two aspects: susceptibility and emission.
electromagnetic interference (EMI)
Conducted or radiated electrical disturbances that can interfere with equipment operation; these disturbances can occur anywhere in the electromagnetic spectrum, from less than 10 Hz to cosmic rays, including radio, light, and x-rays.
electrostatic charge control (ESCC)
A system of installations, materials, accessories, and procedures that maintains electrostatic effects below the tolerance limits for a given product or process.
electrostatic damage
Damage to a product caused by static electricity resulting from either (1) discharge from a charged conductor, (2) field induction, or 3) self discharge. NOTE: Damage thresholds for each of these causes of failure may differ from product to product.
electrostatic discharge (ESD)
The transfer of electrostatic charge between bodies at different electrostatic potentials, caused by relatively close proximity or direct contact.
electrostatic discharge control (ESDC)
The limitation or elimination of the transfer of electrostatic charge.
electrostatic discharge shield
A barrier or enclosure that limits the passage of current and attenuates an electromagnetic field resulting from an electrostatic discharge.
electrostatic field
(a) A region surrounding a charged object within which another charge will experience a force. (b) A voltage gradient between an electrostatically charged surface and another surface at a different electrostatic potential.
electrostatic field detector
A device used to determine the presence of electrostatic charge.
electrostatic potential
The potential difference (voltage) between a point and an agreed-upon reference point; usually the reference point is considered to be at infinity.
EMC
See electromagnetic compatibility.
EMI
See electromagnetic interference.
enclosure
Physical barrier or barriers separating the localized environment and its surroundings.
end point
The occurrence of the maximum permissible concentration of a specific contaminant in the air downstream of a filter system. Also, the time when a predetermined contaminant penetration of efficiency is reached.
entrapment
The accumulation of foreign material in hidden features of cleanroom garments that is difficult to remove by common methods.
equivalent diameter
The diameter of a reference sphere having known properties and producing the same response in the sensing instrument as a particle being measured. (See also particle size.)
ESCC
See electrostatic charge control.
ESD
See electrostatic discharge.
ESDC
See electrostatic discharge control.
ESD-protective material
Materials capable of dissipating, avoiding, or shielding electrostatic occurrences; generally classified by resistivity as either conductive or static-dissipative.
evaporation
The process by which a material is transformed from the liquid or solid state to the gaseous state. NOTE: This is an equilibrium process that is favored in one direction or the other in response to a change in temperature, pressure, or both.
exponential averaging (also moving averaging)
The process of determining a power spectrum where the most recent record is most heavily weighted to yield the arithmetic mean for the number of averages selected.
exposure time
The period during which a product or witness surface is in direct contact with the environment in a cleanroom or clean zone.
extended-surface filter
A filter in which the effective surface area of the filter medium is greater than the cross-sectional face area of the filter. The increase in area is the result of forming the medium in a characteristic configuration, such as pleats, rigid cells, pockets, bags, or socks. The filter medium is typically made of a material such as air- or wet-laid glass fibers, synthetic polymers, or a cotton-synthetic blend.
extraction, thermal
See desorption, thermal.
F
face velocity
The speed of the airflow across the cross-sectional area (perpendicular to the airflow) of a filter at the upstream side of the filter.
far UV (also vacuum UV)
Ultraviolet radiation with wavelengths less than approximately 280 nm.
fast Fourier transform (FFT)
See Fourier transform, fast.
FFT
See Fourier transform, fast.
field bench tests
Leak tests performed on HEPA or ULPA filters after unpacking at the location of use prior to installation in the clean-air device or cleanroom. A portable test system is used.
filament, continuous
A long strand of synthetic material, usually grouped together in multiples to form a thread or yarn. Continuous filaments contrast with natural threads or yarns of cotton or wool, formed by twisting many short fibers together.
filling
See weft.
film, gas barrier
A film designed with either single or multiple layers of films to prevent gas transmission through the film and onto the product.
film, moisture barrier
A film designed with either single or multiple layers of films to prevent moisture transmission through the film and onto the product.
filter
A device used to remove particulate matter or impurities from a fluid (gas or liquid) flowing through it.
filter, high-efficiency particulate air (HEPA)
An extended-medium, dry-type filter in a rigid frame when tested at rated airflow having a minimum particle collection efficiency of 99.97% (that is, a maximum particle penetration of 0.03%) for 0.3-µm mass median diameter particles of DOP when tested in accordance with MIL-STD-282.
filter, panel
A fixed-medium air filter, in which the airflow velocity at the filter face and within the filter medium is essentially the same. Panel filter media are generally manufactured from metal filaments, spun-glass fibers, or synthetic fibers.
filter, super ultralow-penetration air (ULPA)
An extended-medium, dry-type filter in a rigid frame, made with [CC034.3: "a"] filter medium having a minimum particle collection efficiency of > 99.9999% (i.e., a maximum particle penetration of < 0.00010%) for particles of the most-penetrating particle size (MPPS) when tested at the average medium velocity in the filter in accordance with the methods of IEST-RP-CC021.
filter averaging time (also filter integration time)
The length of time for averaging filtered data. In measuring random data, the averaging time is inversely proportional to the error in the power. For a given error or confidence limit, the required averaging time is inversely proportional to bandwidth; the governing relationship is commonly referred to as the time bandwidth product.
filter flow resistance
Resistance to fluid flow offered by a filter medium, the pressure difference required to give unit flow of a fluid of unit viscosity through a unit cube of filter medium. (See also resistance.)
filter integration time
See filter averaging time.
filter medium
A permeable material that separates solid particles or liquid droplets from a fluid passing through it.
filter pad
A section or element of filter medium (or media), generally supported by a gate-type holding frame, in which the face of internal airflow velocities are essentially the same. Filter pads are generally manufactured from spunglass fibers, paper, or synthetic fibers.
filter resistance
See resistance, filter.
filtered frequency analysis
The continuous, simultaneous analysis of a signal in all relevant frequency bands. As a general rule, this process is performed with the use of parallel filters. It is practical only for obtaining constant-percentage bandwidth spectra.
findings
Nonfabric elements used in the construction of, or as attachments to, cleanroom garments. Examples: snaps, belts, straps, bindings, buckles, and zippers and other closures.
first run
Vehicles or parts that have gone through the complete paint-application process one time and meet final acceptance criteria.
fisheye
See crater.
flat-felled seam
A seam used in garments where two layers of fabric are folded over and interlocked so that edges are not exposed.
float
A matrix of intersecting yarns described by the number of consecutive vertical yarn strands crossed by the number of consecutive horizontal yarn strands, interlocking the warp and weft of a woven fabric.
flocking
Very short or pulverized fiber used to form a velvety layer on the inside of a glove.
flora
The types of microbiological organisms found in an environment.
flow visualization
A method for demonstrating patterns of airflow, either physically (using fog test, aerosol smoke test, strings, or threads) or by computational fluid dynamics.
fogging
(a) A process involving conversion of a liquid to an aerosol mist, generally for purposes of coating a surface with a uniform deposition of the liquid material. (b) A process of decontamination in which the decontamination is administered by means of its conversion to an aerosol.
Fourier transform
The process of transforming data from the time domain to the frequency domain. Signal analyzers use a fast Fourier transform (FFT) algorithm to accomplish this transformation; hence, they are often referred to as FFT analyzers.
Fourier transform, fast (FFT)
A process of transforming data from the time domain to the frequency domain. The algorithm computes discrete frequency components from discrete sampled time domain data.
frequency
The number of full cycle oscillations of vibration per second, expressed in Hertz (Hz).
frequency analysis, synthesized
An analysis in which a constant percentage bandwidth spectrum is fabricated from two or more constant bandwidth fast Fourier transform (FFT) spectra of frequency ranges that differ by increasing orders of magnitude.
frequency domain
Equivalent representations of physical motion, wherein motion is quantified as a set of amplitudes as a function of frequency.
frequency response function
The ratio of the Fourier transform of the output divided by the Fourier transform of the input, as a function of the frequency.
frock
A three-quarter-length garment employing a military collar design and a full front closure with snap adjustment at the neck opening, intended to cover the arms and torso and meet the knees of the wearer; generally used in cleanrooms of less critical air cleanliness classifications
fumigation
A process of decontamination in which the decontaminant is administered in gaseous, smoke, or aerosol form at ambient pressure.
fungi
Any of a major group of saprophytic and parasitic lower plants that lack chlorophyll and include molds, rusts, MutS, mushrooms and yeasts.
fungicide
A substance or formulation capable of destroying fungi.
fungistat
A compound or formulation that retards or prevents the growth of fungi. Fungistats act reversibly; when the fungistats are removed, the cells resume their normal growth patterns.
G
garment set (or garment system)
(a) The complete assemblage of body coverings specified for a particular cleanroom application. (b) The entire set of clothing and consumable items used to enclose the wearer and contain sources of human-borne and human-generated contamination. These items include beard covers, bouffants (hair nets), face masks, hoods, garments (including coveralls, shirts, pants, frocks or smocks), cleanroom shoes, safety shoes, shoe covers, cleanroom boots (or booties), glove liners, and gloves. (See also gowning system.)
garment system
See garment set.
garments, cleanroom
Specially designed items of clothing that are worn to prevent or reduce the dispersion of contaminants that may be shed or released by cleanroom personnel. Examples: Coveralls, footwear, shoe covers, gloves, and head covers.
gas chromatography-mass spectrometry (GC-MS)
A single tool for the identification and quantitation of volatile and semivolatile organic compounds in complex mixtures.
gate oxide integrity (GOI)
A measure of the reliability of a thin gate oxide that controls the switching of a transistor.
GC-MS
See gas chromatography-mass spectrometry.
gel marks (or carbon marks)
The result of exposure of molten resin to time and heat that causes the resin to burn. As the burning process continues, the resin breaks free, resulting in clear, brown, or black round markings on the material.
generated particles
Particles not previously present on the surface of a substrate that are generated and released in response to mechanical energy imparted to that surface.
generated particles
Particles that were not previously present on the surface of a substrate, e.g. wipers, but are generated and released in response to mechanical energy imparted to that surface.
generated particles
Particles that are not already present on the surface of a wiper, but that are generated in response to imparting mechanical energy to the wiper.
gloss
The measured amount of light reflected by a painted surface.
gowning
See donning.
GOI
See gate oxide integrity.
gowning system
A set of specified articles of apparel and accessories, together with specifications governing their donning, use, doffing (removal), reprocessing or replacement, and storage, as well as specifications related to the way in which they interact with equipment, fixtures, and facilities. (See also garment set.)
gram-negative bacteria
Bacteria that do not retain the purple color of the crystal violet dye when treated with Gram’s staining technique. Therefore, the saffranin is visible, giving a red or pink color.
gram-positive bacteria
Bacteria that retain the purple color of the crystal violet dye when treated with Gram's staining technique.
Gram's staining technique
A method for staining and classifying bacteria, developed by Dr. Hans C. J. Gram, in which the sample is treated with a solution of iodine potassium iodide, and then with a neutral decolorizing agent, and usually counterstained; bacteria stain either blue (see gram-negative bacteria) or red (see gram-positive bacteria).
grammage
See basis weight.
gravimetric analysis
A standard analytical technique used to determine the mass of a specified material, and commonly used to quantify nonvolatile residue (NVR) in a solvent. The contaminated surface is first rinsed with a clean solvent having a low NVR that has been measured, a standard quantity of solvent is evaporated, and the mass of the substance remaining is determined; this residue—the NVR minus the NVR of the clean solvent—is expressed as mass per unit area of surface
ground
An electrically conducting connection to the earth or to another conducting body that serves in place of the earth.
ground lead
Conductive cabling or a similar device used as a wrist strap or other form of grounding system. In a wrist strap system, the lead connects the cuff with a ground. In a foot strap system, the lead may connect the body-contacting portion to the ground-contacting portion.
ground path
The total system of connecting leads, straps, and surfaces between the controlled body and the ground.
ground straps
A skin-contacting wrist, leg, or ankle strap that rapidly and safely dissipates personnel electrostatic charges to the ground and equalizes electrostatic levels of personnel with that of the work surface. The strap may contain a current-limiting resistor for safety.
H
HEPA (high efficiency particulate air) filter
See filter, high-efficiency particulate air (HEPA).
hiding
See dry-film hiding.
hot spots
Charged islands of material formed when conductive additives are incompletely distributed, such as uneven topical antistat. These hot spots may cause electrostatic discharge (ESD) damage as a result of the electrical potential of charges isolated on them. Another form of hot spot may occur in some apparel constructions when conductive filaments become broken and are no longer in electrical contact with one another.
hot-wire anemometer
See thermoanemometer.
housekeeping, cleanroom
Maintenance or cleaning performed to preserve the specified cleanliness of a cleanroom.
I
impaction (or impingement)
Physical contact of particles with other surfaces in response to the application of an external force.
impactor
A sampling device capable of removing particles from a gaseous suspension using the principle of impaction (impingement).
impactor, cascade
A specific instrument that employs several impactions in series to collect particles of successively smaller sizes.
impregnated activated carbon
A family of carbonaceous substances manufactured by processes that develop adsorptive properties. After activation, this carbonaceous substance is impregnated with a chemical compound or compounds to enhance the adsorption of selected molecular species from air or other gases that are not readily adsorbed physically. (See also activated carbon.)
indexing
Starting or stopping of a cart or carrier operating in an in-line or rotary mode, by manual or electric means.
induced charge
The electrical charge on a conductor produced by isolating the conductor from ground, bringing the conductor near charged object, then momentarily touching the conductor to ground.
inert
Chemically non-reactive with the products or materials at hand or in use.
in-house
A term referring to capabilities that exist within, as opposed to outside of, a company.
inlet flow
The gas that enters the optical particle counter OPC through the gas inlet. Flow rate is expressed as volume per unit time, at ambient temperature and pressure. (See sample flow.)
input/output (I/O) device
A means of transferring contamination-sensitive materials into and out of a minienvironment.
integrated circuit
An interconnected array of discrete devices (transistors, diodes, and capacitors) contained on a single semiconducting substrate to form a complete circuit or multiple circuits.
integration
The incorporation of a minienvironment into the entire production system (including process materials, process equipment, materials-handling equipment, people, and cleanroom).
integration bandwidth
See bandwidth, integration.
intercoat adhesion
See adhesion, intercoat.
interdigital transducer
Two interlocking, comb-shaped, metallic patterns applied to a piezoelectric substrate such as quartz or lithium niobate, used for converting microwave voltages to surface acoustic waves or vice versa.
ionic contamination
Contamination in the form of atoms having electrical charge. Common examples include singly charged atoms (ions) from Group IA (such as sodium and potassium) and Group VIIA (such as fluorine and chlorine) of the periodic table.
isoaxial sampling
See sampling, isoaxial.
isokinetic sampling
See sampling, isokinetic.
isokinetic smoke generator
See isokinetic test aerosol generator.
isolation
The separation of a process or object from the ambient environment.
J
jumpsuit
See coveralls.
K
kGy
See kilogray.
kilogray (kGy)
1000 grays; a standard unit used to measure the absorbed dose of radiation.
knit fabric
Fabric made by interlacing threads in a series of interconnected loops.
L
laminate
A material formed by bonding together two or more layers in order to achieve an effect not otherwise attainable from each of the component layers separately.
laminated fabric
Fabric manufactured from two or more layers of different materials, bonded together to create a single multilayer structure exhibiting a beneficial blend of the properties of the individual layers.
Laskin nozzle
A nozzle used as part of a system to generate a heterogeneous aerosol from a liquid, such as PAO, that uses a source of compressed gas as shown in IEST-RP-CC013.
latent heat
Change of enthalpy during a change of state, usually expressed in J/kg (Btu/lb). Latent heat in substances is absorbed or rejected at constant temperature at any pressure.
LCL penetration
See penetration, lower confidence limit.
leak, bypass
The measure of the direct leakage through metal parts of the cell or the gasket of the cell due to manufacturing defects, bypassing of the adsorbent due to settling of the adsorbent in the bed, or inadequate cell design. The results are reported as percent refrigerant penetration.
leak penetration
When using a photometer, measured leak penetration is the photometer response when the probe is stationary over a leak, divided by the photometer response upstream of the filter. When using a discrete-particle counter, leak penetration is the concentration of partiles counted when the probe is stationary over a leak, divided by the concentration of particles that would be counted upstream of the filter in the same time if the counter could sample upstream. Measured leak penetration depends on the photometer or discrete-particle counter flow rate. The leak can be defined as the portion (percentage) of the test instrument’s sample flow that passes unfiltered through a defect in the filter or filter medium.
leak penetration, standard
The leak penetration that would be measured by a photometer or particle counter with 28.3-L/min (1-ft3/min) sample flow rate when the sample probe is stationary over the leak.
leakage
An artifact of fast Fourier transform (FFT) analysis wherein energy appears to spread throughout the frequency domain, exhibited as the transfer of energy out of one resolution line into other lines.
legging (also upper)
The upper fabric area of a cleanroom boot, which extends over the pant leg or over the ankle and calf of the coverall.
light scattering airborne particle counter (LSAPC)
Instrument capable of counting and sizing single airborne particles and reporting size data in terms of equivalent optical diameter, not geometrical size, by counting the pulses as the particles pass through the sensing volume, by scattered light intensity. Specifications for the LSAPC are given in ISO 21501-4. Sometimes referred to as light scattering discrete airborne particle counter or discrete airborne particle counter.
limited-linting (sometimes referred to as "lint-free")
Term used to describe textiles that have been specially designed, manufactured, and processed (laundered) to achieve minimum levels of particulate and fibrous contaminants. NOTE: Despite technological advances in producing and cleaning textiles for contamination-sensitive applications, these materials are never truly free of all removable "linting" contaminants.
linear averaging (also stable averaging or power averaging)
The process of determining a power spectrum where all records are weighted equally to yield the arithmetic mean for the number of averages selected.
linear spectrum
See rms (linear) spectrum.
lint
Small fibers shed or abraded from textile material.
lower counting limit
The smallest particle size, specified by the manufacturer, at which an optical particle counter (OPC) is capable of 50% counting efficiency.
M
make-up air
Air introduced into a recirculated air system to ventilate, pressurize, and replace exhaust air.
manual zone
The area within a paint-spray booth in which the application of paint is performed by people.
margin
A solid (not perforated) area at the side, at the end of, or around the perforated area of a perforated sheet or screen.
masking
The application of paint-impermeable tape or other impervious material, or both, to protect designated area(s) of the product from being coated with paint.
mass mean diameter of aerosol
The particle diameter size that is the average particle size of the mass distribution of the aerosol. Typically, since the mass of a particle varies as the cube of its diameter, most of the mass of an aerosol tends to be in the larger sizes, resulting in the mass mean being larger than its count or number mean.
mass median diameter (MMD) of aerosol
The particle diameter size that is the 50th percentile of the mass distribution of the aerosol; i.e., 50% of the mass of the aerosol is made up of particles smaller than the mass median diameter and 50% of the mass of the aerosol is made up of particles larger than the mass median diameter.
Material Safety Data Sheet (MSDS)
A document prepared by a chemical or material manufacturer, describing the composition, reactivity, properties, and hazards of a chemical or material along with recommended safeguards for handling, storage, and use.
maximum hold averaging (also peak-hold or continuous peak averaging)
The process of determining a maximum signal value from an ensemble of magnitude values. In spectral analysis, maximum hold averaging results in the envelope of spectral amplitudes that are not exceeded during the measurement session.
mean time between failures (MTBF)
The average time (in hours) equipment performed intended function prior to failure.
mechanical leak
See leak, mechanical.
medium (plural: media)
The filtering material in a filter; an adsorbent or chemisorbent used to remove airborne molecular contaminants. Alternatively, a material containing an adsorbent or chemisorbent.
meniscus
The concave curve of a liquid surface in a graduated or narrow tube.
metallic paint
Paint that contains small flakes of metal or mica (or both) in addition to any pigments that are present.
microbiological clean area
A defined space with a filtered air supply that is designed to accommodate the performance of activities for which the control of viable particles is essential.
microcount
See bioburden.
micrometer (µm)
A unit of length in the metric system equal to one-millionth (10-6) of a meter (approximately 0.00003937 inch; 25 micrometers is approximately 0.001 in.).
micron
Obsolete equivalent to the accepted term, micrometer. The term micron was abolished by the 13th General Conference on Weights and Measures in 1967.
mil
A unit of length in the English (U.S. customary) system, commonly used in measuring paint film thickness, equal to one-thousandth of an inch (25.4 µm).
minienvironment
A localized environment created by an enclosure to isolate a product or process from the surrounding environment.
mixed-airflow cleanroom
See cleanroom, mixed airflow.
modal testing
Testing that is performed to obtain the frequency response functions of process tools or structures. These functions provide information about natural frequencies and characteristic shapes (mode shapes).
modification
Making of a limited change in something.
monitor wafer
A semiconductor wafer used as a witness plate.
monitoring
Observations made by measurement in accordance with a defined method and plan to provide evidence of the performance of an installation. NOTE: This information may be used to detect trends in the operational state and to provide process support.
monodisperse
A distribution in which the coefficient of variation of particle size is 5% or less.
monodisperse particles
See polystyrene latex (PSL) spheres.
monotone
Painted with a single color (versus two-tone).
morphology
The characteristic shape, color and consistency of a microbial colony when cultivated on various solid media.
most-penetrating particle size (MPPS)
The particle size at which a given filter has its highest penetration (or lowest efficiency); i.e., the worst-case particle size with respect to filtration efficiency. From filtration theory, the efficiency is higher for particle sizes smaller or larger than the MPPS. In practice, the MPPS of a filter is considered to be within a measured size range typical in commercial instruments rather than at one unique particle size.
MSDS
See Material Safety Data Sheet.
MTBF
See mean time between failures.
N
narrowband vibration
Vibration over a narrow frequency band; for example, the amplitude of vibration between 1 and 1.25 Hz (a 0.25 Hertz-wide band).
national metrology institute (NMI)
An organization providing national or international primary test standards used in the unbroken chain of traceability of test equipment. NOTE: Traceability to national metrology institute standards does not always require the use of the NMI of the country in which a calibration laboratory is located.
natural frequency
The frequency or frequencies at which a body vibrates as a result of its own physical characteristics (for example, mass and stiffness) when the body is excited.
n-dope
To introduce an impurity (dopant) into the crystal lattice of a semiconductor to modify its electronic properties; for example, adding phosphorous to silicon to make the material n-type.
NMI
See national metrology institute.
noise floor (threshold)
The voltage output of a transducer and associated electronics that is not related to motion of the transducer. The noise floor (threshold) determines the minimum amplitude of motion that can be measured by a transducer-amplifier system.
nominal bandwidth
See resolution bandwidth.
nonconvertible film former
Paint that dries through the simple evaporation of a volatile liquid.
noncorrosive, nonstaining
Terms applied to formulations to indicate that they should have a minimal effect on the integrity or appearance of surfaces with which they come in contact.
nonionic
A term used to describe compounds and formulations that do not possess charged materials.
nonunidirectional airflow
See airflow, nonunidirectional.
nonunidirectional-airflow cleanroom
See cleanroom, nonunidirectional-airflow.
nonvolatile residue (NVR)
(a) Matter that remains after the solvent containing such matter has been filtered and evaporated at a specified temperature. (b) Any solid or liquid phase remaining after the evaporation of a volatile liquid from a solution. NOTE: NVR is generally expressed in units of mass per unit volume of liquid. If the volatile liquid was used to remove soluble contamination from a specific area of surface, the NVR units may be expressed as mass per unit area.
nonwoven fabric
A flat, flexible, porous sheet structure produced by interlocking layers or networks of fibers or filaments (bonded together thermally, mechanically, or chemi-cally) or by perforating films.
number mean diameter
See count mean diameter.
number median diameter
See count median diameter.
NVR
See nonvolatile residue.
NVR deposition rate
See nonvolatile residue (NVR ) deposition rate.
NVR deposition rate level
See nonvolatile residue (NVR ) deposition rate level.
O
observed penetration
See penetration, observed.
octave
The interval between two frequencies having a ratio of 2 to 1.
offgassing
See outgassing.
offset voltage
(a) The voltage that will accumulate upon an initially uncharged isolated conductive plate when that plate is exposed to an ionized air environment. (b) A voltage produced on an isolated conductive plate, in an ionized environment, when an unequal number of positive and negative ions exist on the plate.
one-third octave
The interval between two frequencies having a ratio of 1.26 to 1 (the cube root of 2).
ongoing training
A continuing program of continuing education of qualified personnel.
onsite testing and certification
Testing and certification of equipment at the location of usage.
opacity
The capacity of a fabric to inhibit the passage of light and prevent visual recognition of images, as related to personal modesty.
OPC
See particle counter, optical.
operational cleanroom
See cleanroom, operational.
organic
A substance based on carbon and also containing hydrogen, with or without oxygen, nitrogen, or other elements.
organic vapors
Vapors containing organic molecules that originate from solid or liquid organic materials inside or outside the cleanroom, due to outgassing, evaporation of solvents, combustion, chemical reactions, or other sources.
out-of-tolerance
Exceeding the values of an error permitted by specifications or regulations for a given measuring instrument.
outside double-bag (also dust cover)
See bag, outer.
overspray
That portion of the atomized paint that does not contact the part during the painting process. Most of it is exhausted from the booth, but some is deposited on surfaces within the spray booth or the exhaust components.
owner
The company or organization that has the ultimate responsibility for achieving established strategic and fiscal objectives through operation of the cleanroom. (See also user.)
P
PAC
See particle percent area coverage.
paint
A material which, when applied to a surface as a liquid or powder and cured, forms a solid film that is decorative or protective, or both. Paints generally contain a binder, solvent(s), and pigment(s). Other materials may be incorporated to impart special properties to the paint film. Some examples of such additives are rust inhibitors, light stabilizers, and softening agents (plasticizers).
paint kitchen (also paint-mix room)
Area where paints are stored, mixed, and dispensed.
paint-mix room
See paint kitchen.
paint spray
The atomization or breakup of paint into tiny droplets of liquid or particles of powder, usually caused by turbulence in an airstream, centrifugal force, or a sudden drop in pressure.
paint-shop cleanroom
The portion of the paint shop, generally isolated by various methods and encompassing the paint-spray booths, where controls and restrictions are imposed on the size and concentration of airborne particles in order to prevent dirt defects.
paint-spray apparel
A set of specified limited-linting articles of clothing and accessories, typically used in paint shops.
PAO
See poly-alpha-olefin.
particle, airborne
See airborne particle.
particle burden
The number of particles in the relevant size range per unit area of surface.
particle concentration
The number of individual particles per unit volume of air.
particle count
The number of particles detected in a given volume of air (or time period for a stable instrument sample flow rate). The number may be determined by counting discrete particles using a particle counter, or it may be deduced by calibration of a monotonic response (such as the photometric calibration of a condensation nucleus counter) of the instrument to a known concentration standard.
particle counter
An instrument capable of resolving responses from individual particles.
particle counter, airborne
An instrument for continuous counting of airborne particles larger than a given threshold size. The sensing means may be optical, electrical, aerodynamic, etc.
particle counter, optical (OPC)
A light-scattering instrument with display or recording means to count and size discrete particles in air and other gases.
particle deposition
The portion of the transient particle population that does not remain airborne, typically with respect to a specified period of time, under the influence of ambient airflow conditions, air and surface temperatures, and localized electrostatic charges.
particle deposition rate
The number of particles deposited on a surface per unit of time
particle percent area coverage (PAC)
Fraction of the surface that is covered by particles, reported as total particle project area divided by total surface area.
particle size
(a) The apparent maximum linear dimension of the particle in the plane of observation, as observed with an optical microscope; or the equivalent diameter of a particle detected by automatic instrumentation. Current particle size range of interest can vary upward from sizes smaller than 0.1 µm. (b) For calibration, size is the mean diameter of the monodisperse particles. For applications, size is the diameter of a reference sphere having known properties and producing the same response in the optical particle counter (OPC) as the particle being measured.
pass-through
An opening in a wall between two rooms through which something (such as materials) may be passed.
pass-through washer
A washing machine with two doors, which provides for the loading of soiled garments outside of the clean-room and removal of cleaned garments inside of the cleanroom.
pathogen
A microorganism capable of causing disease.
peak-to-peak value
The absolute sum of positive and negative peak amplitudes
pencil hardness
A measure of the hardness or cure of a paint film.
penetration, observed
The penetration calculated from observed counts.
penetration, true mean
The penetration that would be calculated from the averages of observed upstream and downstream counts, if tests were repeated indefinitely.
penetration, lower confidence limit (LCL)
The 95% upper confidence limit (UCL) penetration and 95% lower confidence limit (LCL) penetration are values statistically calculated from the observed counts. There is a 95% confidence that the true mean penetration is between the UCL and LCL penetrations.
penetration, upper confidence limit (UCL)
The 95% upper confidence limit (UCL) penetration and 95% lower confidence limit (LCL) penetration are values statistically calculated from the observed counts. There is a 95% confidence that the true mean penetration is between the UCL and LCL penetrations.
penetrometer
A self-contained instrument for the determination of penetration characteristics of very high-efficiency filter medium and filter units with thermally generated DOP, in accordance with MIL-STD-282.
penetrometer
An instrument for determining penetration characteristics of very high-efficiency filtration media and filter units, using thermally generated challenge aerosol in accordance with Mil-Std-282.
percent elongation
The percent increase in the dimension of the material in the direction of stress at the point of failure.
percent nonvolatile (also percent solids or weight solids)
The percent by weight of the solid (nonliquid) components in a paint.
periodic vibration
Vibration characterized as a set of amplitude values that recur after a given interval known as the period of motion.
permeability
A quantitative measure of the ability of a material to transfer mass (solid, liquid or gaseous) through its pores or capillaries, or both, under the influence of a pressure gradient.
photometer
See aerosol photometer.
photometer response time constant
The time it takes for the photometer reading to reach 63% of its final value when there is a step change in aerosol concentration at the probe inlet (i.e., the time constant of the exponential response of the photometer). The response time is a function of the photometer design, the photometer scale used (e.g., full scale equals 0.1%), and the sampling system.
physisorption
attraction of an adsorbate, e.g. contaminants, to the surface of an adsorbent caused mainly by van der Waals forces and electrostatic forces
pigment
Finely ground powders in paint that give it its color.
pitot tube
A device used to determine the velocity pressure of a unidirectional airstream by simultaneously measuring its static pressure and total pressure.
placket (or zipper placket)
A strip of material that completely covers the outside surface of a closed zipper.
pod
A box containing a cassette of wafers that is used in conjunction with a standard mechanical interface (SMIF); the box isolates the cassette of wafers and maintains the integrity of the minienvironment.
point of contact
Designated individual in an organization who has the responsibility for assuring that contractual contamination control requirements are met. This position serves as a focal point for all activities concerning contamination control.
polydisperse DOP
See dioctyl phthalate (DOP), polydisperse.
polymer
A high-molecular-weight substance, natural or synthetic, whose structure can be represented by repeated small units.
polystyrene latex (PSL) spheres (also polystyrene microspheres or monodisperse particles)
(a) A common type of highly uniform spheres or a suspension thereof used to generate a monodisperse solid aerosol that is useful for characterizing and calibrating an optical particle counter (OPC) or for leak-testing filters where other aerosols may contaminate the filters in an unacceptable manner. (b) Polymer spheres composed of polystyrene or a similar polymer, sometimes abbreviated “PSL,” having a refractive index of 1.58-1.61 and a distribution in which the coefficient of variation is 5% or less. (c) Test aerosol made using solid, monodisperse polystyrene particles of a known size. NOTE: Polystyrene latex do not contain natural rubber latex, which has been shown to potentially cause allergic reactions on contact with skin.
polystyrene microspheres
See polystyrene latex (PSL) spheres.
porosity
The ratio of the combined volume of all of the pores in a material to the overall volume of the material.
power spectral density (PSD)
The mean squared amplitude (displacement, velocity, or acceleration) per unit frequency of a waveform. In denoting an acceleration PSD, the units are expressed in g2/Hz.
power spectrum
The mean squared amplitude (displacement, velocity, or acceleration) of a waveform as a function of frequency. In denoting an acceleration power spectrum, the units are expressed as gravitational constant squared, g2.
power wash
A multistage cleaning machine or structure through which material is transported, using some form of conveyor system, in which the material is cleaned and conditioned.
precision
The closeness of agreement between values obtained by repeated measurements of the same quantity under the identical conditions; also known as repeatability or reproducibility.
pre-filter
An air filter fitted upstream of another filter to reduce the challenge on that filter.
pre-gowning
The required procedures between entering the building and entering the change room to begin the gowning procedure.
prep area (decontamination area)
A preparation cleanroom or clean zone that typically is less clean than the operational cleanroom and in which preliminary cleaning procedures are performed before entry into the operational cleanroom.
pressure, differential
(a) The difference in pressure between two points of a system, which may be separated by a solid or fluid barrier. (b) The difference in pressure caused by resistance to fluid flow across a device, pipe, or duct, such as in a paint circulation system. For air, the units are pascals (SI) or inches water gauge (English). For liquids, the units are bars (SI) or pounds per square inch (English).
pressure, velocity
(a) The impact pressure associated with the velocity of a flowing fluid. It is related to the kinetic energy per unit volume of the flow. (b) The pressure resulting from a moving airstream, as determined from pitot-tube reading, equivalent to the total pressure less the static pressure.
pressure drop
The difference in pressure between two points in an airflow system upstream and downstream of a filter system.
primary barrier
See primary surface.
primary surface (also primary barrier)
A surface that is in direct contact with the product.
primer
Undercoat paints that are typically used to prepare the product surface for topcoating. The word primer is often used when referring to many types of sprayable undercoats such as primers, primer-surfacers, and primer-fillers.
probing
See scanning.
process tool
Vibration-sensitive equipment, including lithography equipment, scanning electron microscopes, inspection equipment, and metrology equipment.
processing, garment
(a) Procedures performed to meet cleanliness and usability specifications for apparel and accessories for use in a controlled environment. (b) Cleaning and packaging of cleanroom garments to meet required cleanliness specifications.
proficiency
Demonstration of specified level of technical ability.
production aid
A device, such as a jig, bracket, or clamp, used to hold or support parts or keep them in proper position for painting.
production pack
The smallest sealed product unit of measure that would be received by the end user.
PSD
See power spectral density.
PSL
See polystyrene latex (PSL) spheres.
pyrogen
A substance capable of producing a fever. Common pyrogens are endotoxins, a class of lipopolysaccharides that comprise the outer wall of Gram-negative bacteria and are themselves by-products of cell metabolism.
Q
qualifications
Documented training, skills, and proficiency that should be met or complied with for a given requirement.
R
raglan sleeve
A sleeve attached to a modified armhole with slanted seams extending from underarm to neck.
random vibration
Vibration that is not periodic in nature. Because the term frequency cannot be rigorously applied to random motion, the amplitude of random vibration can only be specified in terms of a probability function.
releasable particles
Particles present on the surface of a substrate that are readily releasable from there by wetting the surface with a liquid, but without imparting mechanical energy to the substrate.
recirculated air
That portion of cleanroom air that is recirculated through the air-handling equipment.
Recommended Practice (RP)
A published document that provides technical guidance, philosophy, or preferred procedures regarding a given topic.
relative humidity (r.h.)
The ratio of the amount of water vapor in the air (at a specific temperature) to the maximum amount that the air could hold at that temperature, expressed as a percentage.
releasable particles
Particles present on the surface of a substrate that are readily releasable there from by wetting the substrate with a liquid, but without imparting mechanical energy to the substrate.
representative upstream sample
A sample of the aerosol upstream of the filter that is being leak-tested, used to set the 100% point of aphotometer or to calculate values for discrete-particle counter scanning. In factory test systems, in field bench test systems, and in unidirectional, clean-air devices, a method of obtaining a representative upstream sample should be built into the device by the device manufacturer.
residue
Any substance remaining on a surface after the surface has been cleaned.
resin
Typically, a thick and sticky substance of natural of synthetic origin used as a binder in paint.
resistance, filter
The pressure drop across a filter under known conditions of flow, temperature, etc., commonly expressed in units of: Pascals (N/m2), mm water gauge, inches w.g., or psi (lb/in.2).
resistivity
A measure of the ability of a paint film to conduct electricity.
resolution
A measure of the ability of a particle counter to differentiate between particles of different sizes; also, the range of sizes an instrument would ascribe to a particular particle if its size were determined repeatedly.
resolution bandwidth (also nominal bandwidth)
The spacing between center frequencies.
resolution lines
The number of discrete linear data bands provided by a signal analyzer for a given measurement frequency band width. For example, for an 800-line analyzer measuring a frequency band width that is 100 Hz wide, each line of data band has a resolution equal to 100/800 or 1/8 Hz.
resolution, particle size
The capability of a particle-sizing device to discriminate between particles that are similar in size; expressed as the ratio of the minimum size differential required to indicate a size change to the size of the particle being measured.
rework
(a) Parts which, found unable to meet final acceptance criteria, have been or will be reprocessed through a repair cycle or paint application. (b) The process of preparing defective painted parts for repainting, typically by removing surface defects by sanding or other means.
RFI
See radio frequency interference.
r.h.
See relative humidity.
rms
See root-mean-square value.
rms (linear) spectrum
The rms (mean) amplitude (displacement, velocity, or acceleration) of a waveform as a function of frequency.
root-mean-square value (rms)
The amplitude of continuous motion or voltage with equal energy, compared to the signal being analyzed. It is calculated by squaring all of the values, adding the squares together, dividing the total by the number of values to obtain the mean, and then taking the square root of the result. In the case of simple harmonic motion, the rms value is equal to: the square root of 2 divided by 2, multiplied by the value of the maximum single amplitude. NOTE: The rms value of random vibration, for example, is not equal to the rms value of simple harmonic motion.
root-sum-square value (rss)
A value derived by squaring numerical quantities, adding them together, and then taking the square root of the sum.
RP
See Recommended Practice.
rss
See root-sum-square value.
S
sample acquisition time
The time that the particle counter accumulates counts before automatically resetting to zero and restarting counting.
sample flow
The gas that passes through the sensing volume of the particle counter. The sample flow may be a portion of the inlet flow. Flow rate is expressed as volume per unit time, at ambient temperature and pressure. (See also inlet flow.)
sampling, isoaxial
A sampling condition in which the direction of the airflow into the sample probe inlet is the same as that of the unidirectional airflow being sampled.
sampling, isokinetic
A sampling condition in which the mean velocity of the air entering the sample probe is the same as the mean velocity of the unidirectional airflow at that locations.
sanitizer
a) A chemical agent that reduces the number of vegetative bacteria, some enveloped viruses, and some fungi on hard, nonporous surfaces by 99.9% (3-logs). b) A substance that reduces the number of microbial contaminants to a level that is considered safe.
scanning (also probing)
A method for disclosing leaks in HEPA and ULPA filters whereby the inlet of the sampling probe of an aerosol photometer or discrete-particle counter is moved in a series of parallel, slightly overlapping strokes across the test area at a distance of approximately 2.5 cm (1 in.) from the filter face and at a rate based on the leak penetration to be detected and the upstream concentration of the challenge aerosol.
secondary surface
A surface that is not in contact with the product, but which indirectly affects the product.
seeding
Agglomeration of pigment or resin particles in the paint.
semiquantification
An analysis technique in which the response factors for all unknown compounds are assumed to be the same as the standard reference compound.
sensible heat
Heat associated with a change in temperature; specific heat exchange of temperature; in contrast to a heat interchange in which a change of state (latent heat) occurs.
sensing volume
The portion of the illuminated region through which the aerosol passes and from which scattered light is collected by the detector.
sensor
A device designed to respond to a physical stimulus (e.g. temperature, illumination, and pressure) and transmit a resulting signal for interpretation, or measurement, or for operating a control.
sequential counting system
(a) A system that uses a single detector to determine the concentrations of the test aerosol, both upstream and downstream of the filter medium, by alternating the sampling locations of the detector. (b) Test systems in which particles are counted by the same counter or counters both upstream and downstream of the filter. The counters are sequentially connected to either side of the filter, once or several times. Sequential counting systems are characterized by the need for stable aerosol and by reduced problems in correlating counters.
set-in sleeve
A sleeve attached to an armhole of a garment with a vertical seam.
settling
Collecting of paint solids in the circulation system due to an inadequate circulation flow rate or aggregation.
shedding
The generation and release of particles from the filter system into an airflow.
shelf life
The estimated length of time that a product or formulation can be stored before it loses its effectiveness.
shoe cleaner, mechanical
An electrically operated device that contains rotating or oscillating brushes and a vacuum collection system. When a shoe or boot is placed into the device and slowly moved fore and aft, the brushes help to remove dust and dirt from the tops, bottoms, and sides of the shoes, while the vacuum system collects and contains the dirt.
shoe cover
A disposable or reusable cover worn over street shoes within defined boundaries of the change room, cleanroom, and support area to minimize the transfer of contamination from street shoes.
shoes, building or dedicated
Footwear or shoes compatible with an environment or process that are maintained solely within that environment. Typically these will only leave the environment for cleaning or replacement.
signal-to-noise ratio
The ratio between the output signal of a transducer and its noise floor.
significant surface
Any surface of an item or product that is required to meet established cleanliness level requirements.
silhouette
A partition or partial wall used to reduce the size of the open of the entrance or exitways from paint booths and tunnels.
simple harmonic vibration
See vibration, simple harmonic.
simultaneous counting system
Test system in which particles are counted simultaneously upstream of the filter, with a counter or counters dedicated to upstream counting, and downstream of the filter, with a counter or counters dedicated to downstream counting. Simultaneous counting systems are characterized by reduced need for stable challenge aerosol concentration and by difficulty in correlating counters.
single-particle counter
See discrete-particle counter.
SMIF
See standard mechanical interface.
snood cap (also snood)
A net or fabric bag worn to hold the hair at the back of the head, and tied behind the head.
solids
The nonvolatile components of the paint that remain on the surface of the product being painted.
solvent
(a) A substance that dissolves another to form a solution. (b) The liquid portion of the paint, in which the soluble components are dissolved and which evaporates to leave a film of dry solids.
solvent rub
Determination of the solvent resistance or cure of a paint film by rubbing the surface with a solvent-dampened cloth and evaluating the appearance of the surface.
SOP
See standard operating procedure.
sporicide
A substance or formulation capable of destroying bacterial spores.
stability
The resistance of paint to change in viscosity or in potential for seeding, over tie, due to variation in environmental conditions such as temperature and humidity.
standard leak penetration
See leak penetration, standard.
standard mechanical interface (SMIF)
The connecting plate that mates with the bottom of a pod or carrier; mechanical device that transports a cassette of wafers into and out of a minienvironment.
standard operating procedure (SOP)
A prescribed and established method to be followed when performing a designated operation.
static electricity
An electrical charge at rest. The electrical charge is due to the transfer of electrons within a body (polarization) or from one body to another.
static-dissipative garments
Body coverings specifically designed or treated to prevent buildup of electrostatic charge.
sterile
a) The condition of lacking all forms of microbiological life. b) Free from bacteria or other microbiological life.
sterilization
A physical or chemical process that completely destroys or eliminates all forms of microbial life.
stiffness
Resistance to bending when flexural stress is applied.
sublimation
The evaporation of a solid directly to the gaseous state without passing through the liquid state.
substrate
The base material of a product that is to be painted. Examples: steel, aluminum, fiberglass.
super ULPA (ultra-low penetration air) filter
See filter, super ultralow-penetration air.
surface contaminant
Any unwanted substance present in or on a surface.
surface resistivity
An inverse measure of the conductivity of a material, equal to the ratio of the potential gradient to the current per unit width of the surface, with the potential gradient measured in the direction of current flow in the material. Surface resistivity is numerically equal to the surface resistance between two electrodes forming opposite sides of a square of the material. The size of the square is irrelevant over a wide range of sizes. Surface resistivity is expressed in units of ohms per square (Ω/n).
synthesized frequency analysis
See frequency analysis, synthesized.
T
tack cloth (or tack rag)
A wiping cloth, typically treated with a nondrying tackifier, that is used to remove particles and fibers from a surface.
tack mat
A disposable or washable floor mat with a sticky surface which, when stepped upon, removes particles from the portion of the shoe or boot sole with which it comes in contact.
tack-off (process)
The means used to remove particles and fibers from a surface that is to be painted.
target compound
A contaminant detrimental to the manufacturing process, either by itself or in combination with other compounds.
TD
See desorption, thermal.
temperature control zone
A cleanroom, or portion thereof, in which temperature is uniquely controlled.
tensile strength
The maximum tensile stress that a material can withstand while being stretched before rupture, calculated as the maximum force applied divided by the original cross-sectional area of the test specimen, and expressed in units of stress (e.g., megapascals, MPa, or pounds per square inch, psi).
tension (ten-see-own)
The smoothness of a painted surface as determined by evaluation of the resolution of an image of increasingly closer parallel lines reflected from its surface (the smoother the surface, the higher the resolution)
test
A procedure undertaken in accordance with a defined method to determine the performance of an installation or an element thereof.
thermal desorption (TD)
See desorption, thermal.
thermal extraction
See desorption, thermal.
thermal generator
See aerosol generator, thermal.
thermally generated aerosol
See aerosol, thermally generated.
thermoanemometer (also hot-wire anemometer)
An instrument for measuring air velocity that contains an element heated by a regulated electric source and cooled by the airflow. A thermoanemometer converts the cooling effect on the element to a velocity reading.
thermophoresis
The movement of particles in a thermal gradient. Note: Thermophoresis can induce significant differences between airflow and particle velocity
thickness, filter medium
The dimension perpendicular to the plane of the filter medium.
through bolt
A bolt or other fastener that passes through the sorbent bed.
time domain
Equivalent representations of a physical motion, wherein motion is quantified as a set of amplitudes as a function of time.
TML
See total mass loss.
topcoat
The final layer of paint, applied to a substrate as a decorative or protective coating, or both, in the form of a color coat (or basecoat) or a clearcoat, or both.
topical antistat
A chemical agent that, when applied to surfaces of insulative materials, reduces the ability of those surfaces to accumulate electrostatic charge; usually acts by increasing the surface lubricity of the material. NOTE: A secondary effect of one type of topical antistat, an ionic hygroscopic antistat, is usually to increase surface conductivity, thereby delocalizing any triboelectric charge produced and allowing a slow bleed-off of charge, if the surface of the material is properly grounded.
total mass loss (TML)
Mass that outgases from a material, as specified in ASTM E595, expressed as a percentage of the initial mass of the specimen.
toxic
Poisonous, causing an adverse reaction.
transient vibration
Vibration characterized by temporary sustained motion with amplitudes that nominally start and end at zero.
transmittance, τ
The ratio of the transmitted radiant or luminous flux to the incident flux.
triboelectric charging
(a) The generation of electrostatic charges that results when two objects in intimate contact are separated. Substantial charge can be caused by contact and separation of two materials or by rubbing two objects together. (b) Electrostatic charging following the mechanical separation of solids or the separation of solids from fluids.
triboelectric test
Test of the charge transfer between items. Triboelectric tests are frequently employed to determine the propensity for electrostatic discharge (ESD) damage due to triboelectric charging.
true mean penetration
See penetration, true mean.
Tukon hardness test
A test of hardness or cure of a paint film.
tumble dryer
A drying system that tumbles a bulk quantity of damp garments in a rotating drum that is fed by filtered, heated air.
tunnel dryer
A drying system in which garments are hung separately on a continuous conveyor that moves them through a tunnel supplied with heated, filtered air moving at a speed sufficient to dry the garments before they emerge into the cleanroom.
turbidity
The cloudiness of a liquid resulting from the presence of finely divided suspended material.
two-tone
Painted with two different colors (versus monotone).
U
U descriptor
The measured or specified concentration, in particles per cubic meter of air, including the ultrafine particles. NOTE: The U descriptor may be regarded as an upper limit for the averages at the sampling locations (or as an upper confidence limit, depending on the number of sampling locations used to characterize the cleanroom or clean zone). U descriptors cannot be used to define airborne particulate cleanliness classes, but they may be quoted independently or in conjunction with airborne particulate cleanliness classes.
UCL penetration
See penetration, upper confidence limit.
ULPA filter
See filter, ultralow-penetration air.
ultrafine particle
A particle in the size range from approximately 0.02 µm to the upper limit of detectability of the discrete-particle counter.
unidirectional airflow
See airflow, unidirectional.
unidirectional-airflow cleanroom
See cleanroom, unidirectional-airflow.
uniform airflow
See airflow, uniform.
user
A production or operational organization whose primary function is to produce a product or achieve defined objectives from a facility. (See also owner.)
user (as the term applies to cleanrooms)
A production or operational organization whose primary function is to produce a product or achieve defined objectives from a facility. (See also owner.)
V
validation
Establishment, by means of a specified testing program, that a system or facility under test is capable of performing as intended. (See also certification and verification.)
VCM
See volatile condensable material.
vegetative organisms
Microbial cells that are metabolically active.
velocity pressure
See pressure, velocity.
verification
The procedure for determining compliance of air in a cleanroom or clean zone to a specified airborne particulate cleanliness class limit or U descriptor; also, the result of determining such compliance. (See also certification and validation.)
viable particle
A living organism capable of performing biochemical processes and reproducing.
vibration
The alternating transfer of energy between its potential and kinetic forms, expressed as acceleration, velocity, or displacement of a physical object, and of which may be time-varying.
vibration, simple harmonic
Vibration characterized by motion for which the amplitude is a sinusoidal function of time.
vibration threshold
The point at which process tool can withstand vibration but still perform within acceptable limits. The vibration threshold may be expressed as an rms (linear) spectrum, or as single numerical values of displacement, velocity, or acceleration.
viricide
A substance or formulation capable of destroying viruses.
virus
An obligate intracellular parasite, typically in the size range of 0.01 to 0.1 µm, that can infect and cause disease in man, animals, plants, and insects.
viscosity
A measure of the resistance to flow of a liquid paint formulation, as determined with a viscosity meter.
visibly clean
Examination of a surface for the absence of contamination using specified lighting (illuminance and angle), viewing distance, viewing angle, and normal or magnified vision.
VOC
See volatile organic compound.
volatile organic compound (VOC)
(a) A gaseous product released from polymeric or other materials under certain conditions of temperature and pressure. (b) An organic material, such as a solvent, that has a significant vapor pressure at ambient temperature and pressure; i.e., a significant portion of the material is present as a vapor at equilibrium. (c) A term used in reference to the evaporative nature of the solvent component of a paint.
volatile condensable material (VCM)
Gaseous products released from a material under specified conditions of temperature and pressure, which condense at other conditions of temperature or pressure or both.
volume resistivity
An inverse measure of the conductivity of a material, equal to the ratio of the potential gradient to the current density, where the potential gradient is measured in the direction of current flow in the material. Units are expressed in ohm-centimeters (Ω-cm).
W
wall effect
Partial gas stream bypass of the adsorbent that occurs along an unbaffled metal-to-adsorbent interface.
warp
A series of yarn filaments that extend lengthwise in woven fabric
washer crystal
Particles caused by the crystallization of minerals, additives, cleaners, or chemicals found in the water of power washers.
water repellency
The ability of a filter medium to resist wetting.
wavelength, λ
The distance in the direction of propagation of a periodic wave between two successive points at which the phase is the same at the same time.
wavenumber, ν
The number of waves per unit length in units cm-1.
weft (also woof or filling)
series of yarn filaments that are woven crosswise through the warp in woven fabric
weight solids
See percent nonvolatile.
wind tunnel
An apparatus designed to establish near straight-line air velocities of a known magnitude at a defined spatial location with controlled characteristics such as low turbulence intensity. NOTE: General categories of wind tunnels used in the calibration of instruments include subsonic, trans-sonic, and supersonic, depending on the ranges of measured air velocities.
window weighting
Applying a profile or function on the time signal prior to doing the Fourier transform.
wipe-down station
A facility provided in a change room for the cleaning of materials that are going to be brought into the cleanroom.
witness plate (or witness surface)
(a) A test coupon or other designated surface used to collect samples of particulate matter deposited under the influence of gravity, for quantification and microscopical analysis. (b) Surface used to collect contaminants deposited from the environment; typically selected to simulate particular products (examples include silicon wafers, microscope plates, membrane filters, and glass photomask substrates). (c) Surface used to collect contaminants during exposure and then removed and analyzed or measured after exposure.
witness surface
See witness plate.
woof
See weft.
work zone
The volume within the clean-air device or cleanroom that is designated for clean work and for which testing is required. The work zone volume is defined by an entrance plane and an exit plane (normal to the airflow where there is unidirectional airflow).
woven fabric
Cloth made on a loom by interlacing warp (vertical) and weft (horizontal) yarn filaments.
Z
zero count
The maximum particle count indicated by a particle counter, in a specified period of time, that is sampling particle-free air. This value is specified by the manufacturer and is commonly also referred to as false call rate, false count, noise, or noise level.
zero-to-peak value
The difference between zero and the maximum signal level. The case of simple harmonic motion, the zero-to-peak value is equal to the maximum amplitude.
zipper placket
See placket.