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Absorption
To take up a substance into or throughout a material or fabric by physical or chemical means. A particular piece of protective clothing may act more like a sponge and absorb certain liquids rather than act as an effective barrier. Important also--- some chemicals may be "absorbed" through human skin. Go to top
Afterflame
Persistence of flaming of material under the specified test conditions, after the ignition source has been removed. Go to top
Afterflame time
The length of time for which a material continues to flame, under the specified test conditions, after the ignition source has been removed. Go to top
Afterglow
Persistence of glowing combustion of a material under specified test conditions, after flaming has ceased or removal of ignition source. Go to top
Afterglow time
The time for which a material continues to afterglow after the flaming has ceased or the removal of the ignition source. Go to top
Air Distribution System
A means of injecting and circulating air into and throughout a fully encapsulating garment. Generally, compressed air enters a suit via a "pass thru" (bulkhead) to an integral set of hoses attached to the suit interior. The air provides added comfort for the wearer, but is not used as breathing air. A secondary, NIOSH approved, pass thru with an airline connection to a full face mask is recommended for breathing air connection. Go to top
Ambient Temperature
The temperature of the environment (air) around a suit, object or individual. Go to top
ASTM
American Society for Testing and Materials - Guildelines for safety and standardization of manufactured goods. Organized into 140 committees. Committee F23 is made up of individuals representing both producers and users of protective clothing. The group develops test methods and voluntary standards assessing the performance of protective clothing against occupational hazards. Go to top
ASTM F739
Standard test method for resistance of protective clothing materials to permeation. Gives a consistent and repeatable method to determine if material "X" provides sufficient barrier to chemical "Y". Go to top
ASTM F1001
Standard chemical test battery used to compare material resistance across like chemicals. Currently consists of 15 liquids and 6 gases with each chemical representing a different family of chemicals. Go to top
ASTM F1052
Standard practice for pressure testing of Level A totally encapsulating chemical protective suits. Tests if suit has "air leaks" which could possibly allow entry of hazardous substances. Go to top
Bacteriophage
A type of virus which infects bacteria. Go to top
Boiling Point
The temperature at which a liquid turns to gas in standard atmospheric pressure. For example, the boiling point of water at sea level is 100°C, 212ºF. Go to top
Breakthrough Time
The time that elapses between the time the challenge chemical first contacts the test specimen (e.g. suit fabric) and the time at which the chemical is detected on the collection side of the permeation cell. Basically, how long does the suit material "X" hold out challenge chemical "Y"? This is determined by permeation testing. Also referred to as "Chemical Detection Time".
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'Body Box Test'
This is a test to determine how particle shed a garment has. During the body box test, a subject is placed in a Class 10 room and performs a series of activities during a 10 minute test period. The activities include arm extensions for 3 minutes, walking for 3 minutes and doing 5 deep knee bends in 1 minute. These activities are separated by 1 minute intervals of standing still. The data is reported as the average number of particles .5 micron and larger counted per minute during the 10 minute test period. Go to top
Bootie
A sock-like extension of the suit leg, designed to protect the wearer's feet. Allows the wearer to use his own boots while ensuring the chemical protection provided by the primary suit material. Go to top
Bound Seam
A clean-finished binding that encapsulates the raw edges of two plies of fabric. All layers are sewn through with a chain stitch. Go to top
Butyl
Synthetic rubber or man-made rubber. Invented during the 1950's for use in everything from car tires to chemical warfare suits. Considered a durable fabric, it has good barrier to a limited number of chemicals. Go to top
Challenge Agent
The chemical or mixture to which a material is exposed. Also called "attacking chemical".
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Chemical Detection Time - See Breakthrough Time
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Chemical Flash Fire
The ignition of flammable vapor or gas that produces an outward expanding flame front as those vapors or gases burn. Go to top
Composite (Films/Materials)
Refers to materials constructed with two or more layers of dissimilar (different) materials. Generally exhibit broad chemical resistance. Adding more layers increases the barrier protection of chemical protective clothing. Go to top
cm²
Square centimeter. Measure of area about equal to the size of a standard shirt button. Go to top
Cracking Pressure
Pressure at which a suit's exhaust valve begins to crack open, releasing inner air to the atmosphere outside the suit. Important for determining how much a fully encapsulating suit will "balloon" before releasing air. Go to top
Cryogenic (agents)
Extremely low temperature chemicals that are capable of causing acute or long-term freeze burn damage to the body. Example - ammonia used to deep freeze products in the food packaging industry. Important because suit materials act differently in cold environments. They lose flexibility, often become brittle and show signs of stress cracking. Go to top
Decontamination
To rid a piece of protective clothing of any chemical contaminants. Currently, acid contaminants are washed with base solutions and vice-versa. Solvents are washed with detergents. Exotic methods include freon chambers and thermal decontamination. Generally, these procedures are expensive with no guarantee that all contaminates have been removed. Chemicals may later 'wick' or leach back out of the suit's inner fabric layers. Go to top
Degradation
Refers to the loss of integrity of a material when attacked by a chemical. When a glove is dipped into a chemical, does it change color, wrinkle, fall apart, or show other signs of attack? Tests are usually based on weight gain over a period of time, in other words, has material absorbed chemical? Does not indicate if gases passed through material (permeation). Go to top
Doffing
Taking off a protective suit. Go to top
Donning
Putting on a protective suit. Go to top
Elastomeric
"Rubber" based materials; e.g. Butyl, Neoprene, and Viton. Typically durable but have limited chemical resistance. Go to top
Elongation
Stretching without breaking. One of the physical properties used to compare fabrics. Go to top
EMT
Emergency Medical Technician. Go to top
Evaporation
The changing of a liquid to a gaseous state. See also: Boiling Point, Sublimation, andVapor Pressure. Go to top
Exhaust Valve
Valve devices that allow one way air flow in order to prevent protective suits from over-pressurizing. Conversely, they also prevent outside chemicals from entering the suit. Go to top
Exothermal (Reactions)
A process or chemical reaction which is accompanied by evolution of heat, for example, combustion reactions. Go to top
F.E.P.
Fluorinated ethylenepropylene - type of material commonly known as Teflon® - used in clear form as an overlay for chemical suit visors, to provide extra chemical protection. (Also known as Fluoroethylene Polymer) Go to top
Film (products/fabrics)
Usually refers to materials composed of multiple layers. Such products generally are less durable, but present a wider range of chemical holdout than elastomeric fabrics. Go to top
Flaming Debris
Material separating from the specimen during the test procedure and falling below the lower edge of the test specimen continuing to flame as it falls. Go to top
Flame Resistant
Material that inherently resists ignition (burning), melting or other degradation when exposed to heat or flame. Go to top
Flame Retardant
Material that is typically treated to extinguish itself upon ignition from a flame source. Go to top
Flash Fire
A chemical 'flash fire' is the combustion or burning of flammable vapors or gases; typically occuring in enclosed or confined spaces. A flash fire is the ignition of a gas in the air generating radiant heat energy. Flash fires generate extreme temperatures, of approximately 1200 - 1500Fº (649-816º C) for a short period of time (5-10 seconds). Go to top
Flexural Fatigue Test
Physical test used to measure the durability of a suit material. NFPA test consists of twisting a fabric many times. Go to top
Flow Rate
The rate at which air passes through the exhaust valve in a chemical protective suit; expressed as volume per area, over time (cm³/cm²/min). Go to top
Gas
One of the three physical states (gas/solid/liquid) in which a chemical or substance can appear. This state is characterized by very low density. The gas phase of a substance is dependent on temperature and pressure. Many chemicals appear commercially in liquid and gas state, and require different levels of protection accordingly. Go to top
Gas Tight Suit
Generally considered same as "Level A" suit or "vapor protective suit". Term may be misleading in that no suit is 100% gas tight, there is a 20% pressure drop allowed by the ASTM F1052 pressure test standard. Go to top
Glove Assembly
The set of rings and clamps employed for the mechanical joining of gloves to a protective garment. Can also refer to "glove in glove" assemblies. Usually designed to make replacement easy. Go to top
Hazardous Chemical
Any substance that can cause physical harm. Go to top
Helmke Drum Test
A test for measuring particle shedding of a suit used for cleanroom applications. The suit is tumbled for 10 minutes at 10 revolutions per minute in a stainless steel drum having an enclosed volume of 1 cubic foot to determine the average rate of release of particles 0.3 microns and larger. An automatic particle counter is used to sample the air at the rate of one cubic foot per minute at each minute during the ten minute test period. The particle counts are then summarized. Go to top
Hook and Loop
Fastening technique for storm flap closures. Common trade name is Velcro. Go to top
Inches of Water (or cm of Water)
A measure of pressure. For suit pressure testing, a magnehelic gauge is used. Go to top
Level A Suit
The highest available level of respiratory, skin, and eye protection. Requires a fully encapsulating vapor protective suit with supplied breathing air. A chemical designated level A has a high vapor pressure, is toxic through skin absorption or is carcinogenic. Go to top
Level B Suit
The same level of respiratory protection as level A but less skin protection required. Suits are usually fully encapsulating but not gas tight. Level B chemicals are not vapors or gases with skin toxicity or carcinogenic. Go to top
Liquid
A substance that, unlike a solid, flows readily, but unlike a gas, does not tend to expand indefinitely. Important to know state of chemicals - gas, liquid, or solid - when determining type of protective clothing necessary. Go to top
MDL
Minimum Detection Limit. See System Detection Limit. Go to top
MIL
Unit of length or thickness. 1/1000 (.001) of an inch. Go to top
Molten Debris
Molten material separating from the specimen during the test procedure and falling below the lower edge of the test specimen without flaming. Go to top
Mullen Burst
A physical property test for material strength. Represents the force that would be applied when a bending elbow bursts through a shirt sleeve. Go to top
Neoprene
Natural rubber, non-synthetic. A durable elastomeric material with moderate chemical resistance. Go to top
NIOSH
(National Institute for Occupational Safety & Health) - A regulatory agency for respiratory protection; technical advisement for OSHA. Go to top
Non-Conductive
A property of an object, substance or material which restricts or prevents the flow of electricity. Go to top
NFPA
National Fire Protection Association. Has an active technical subcommittee working on standards for Level A & B HazMat response suits. Go to top
NFPA 1991
Performance standard for vapor protective clothing. Go to top
NPFA 1992
Performance standard for splash protective garments. Go to top
NFPA 1993
Performance standard for disposable protective garments used in decontamination procedures. Go to top
NFPA 1994
Performance standard for domestic preparedness protective garments. Go to top
Pass Through
A bulkhead. A coupling system that allows supplied air to enter a suit without being contaminated, the airline is attached outside the suit to the pass through and the face piece respirator is attached by a short airline to the pass through inside the suit. Go to top
Penetration
Visible physical entry of a chemical in liquid form through an opening such as a seam, zipper, or similar area. Not on a molecular level as with permeation. Go to top
Permeation
Refers to the passage of a chemical through a protective clothing material on a molecular level. Gases may be passing through the material leaving no detectable physical signs of damage to the clothing. Unlike degradation, testing for permeation involves elaborate gas detection instruments. It is the highest level of testing available for protective clothing fabrics. Go to top
Permeation Rate
The rate at which permeation occurs. Commonly expressed a micrograms per square centimeter per minute (µg/m²/min). Go to top
Polymer
A general term used to define chemical compounds such as polyethylene or polypropylene. Technically they are long chains of molecular bonded repeating structural units of the original molecules. Go to top
PPM
Parts Per Million. A typical example of part per million is one second in 11 days. Go to top
Pressure Testing
Standard test used is ASTM Method F1052. Tests for leaks that would compromise the vapor protection of a chemical suit. Go to top
Primary Suit Material
The material that is used for the main body parts of a garment. Go to top
PVC
Poly Vinyl Chloride. A durable thermoplastic material with a variety of uses from floor tiles to protective clothing fabric and face shields (visors). Good durability but has limited range of chemical protection. Typically used for protection against acids. Go to top
Radiant Heat
The energy given off (for example from a flash fire) in the form of infrared radiation, like that from a heat lamp. Go to top
Reagent Grade
The highest concentration of a chemical commercially available. Typically greater than95% concentration. Go to top
SCBA
Self-Contained Breathing Apparatus. Typically 1-2 air tanks worn on the back and connected to a full face mask respirator. Go to top
SDL
System Detection Limit. Describes the sensitivity of the instruments used for detecting gases during permeation testing. This limit is determined prior to each permeation test by exposing the detection device to a minimum known quantity of the challenge chemical which will produce a measurable signal. SDL is expressed in parts per million. Go to top
Seam
Where two sections of a garment are joined. There are several types available, examples include serged, bound, taped, and NSR®. Go to top
Serged Seam
A seam where three threads are interlocked around the raw edges of two plies of material.
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Splash Protection
Protection from physical contact with a liquid. Go to top
Static Electricity
Electrical charges generated by friction. Go to top
Steady State
Refers to flow rate in permeation testing. The point at which the challenge chemical has began to permeate the fabric, and the rate of permeation flow is neither increasing, nor decreasing.
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Storm Flap
Splash guards constructed from the primary suit material which help keep liquids off the zipper, valves, boots or other components. Go to top
Taped Seam
A very strong seam produced when a sewn seam is covered with a strip of compatible material. The strip is attached by heat sealing as with film laminated materials. Go to top
TES
Totally Encapsulating Suit - A full coverage suit where the head, arms, torso, and legs are fully protected. Not necessarily gas tight. Can be level A or level B. Go to top
Thermal Heat
Direct heat transfer from a source, non-radiant, as in a burning liquid splashed onto a chemical suit. Go to top
Thermoplastics
Heat welded or heat laminated fabrics such as PVC or CPE. Go to top
Third Party Testing
Testing not performed by any parties who might financially profit by test outcome. Ensures objective, fair test results. Go to top
Tongue Tear
A physical test which determines the force (non-shear) required to tear a fabric. Go to top
Toxicity
Level of poisonous effects from a chemical. Go to top
Vapor Pressure
The pressure created by a gas at any given temperature in equilibrium with its liquid state. The pressure build up (particularly in warm weather) in a car fuel tank is an example of vapor pressure. Go to top
Vapor Protective Suit
Level A, Totally encapsulating suit. Go to top
Visor
The area of a totally encapsulating gas tight suits that allows the wearer to view his surroundings. Typically made of clear PVC; may have a Teflon overlay for added chemical protection. Go to top
Viton
Trademark name for a series of flouroelastomers based on the copolymer of vinylidene fluoride and hexaflouropropylene. A common elastomeric with fair to good chemical holdout. Go to top
Zipper
Suit opening. Either air tight or non-air tight. Main components are slide, chain, and pull.
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