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Campus Safety Manual



Autoignition Temp - Minimum temperature required to initiate or cause self-sustained combustion independently of the heating or heated element.

Acute Effect - An adverse effect with severe symptoms developing rapidly and coming quickly to a crisis.

ACGIH - American Conference of Governmental Industrial Hygienists

Asphyxiant - A vapor or gas which can cause unconsciousness or death by suffocation (lack of oxygen).

Boiling Point - The temperature at which a liquid changes to vapor state, at a given pressure; usually expressed in degrees Fahrenheit at seal level pressure (760 mm Hg, or one atmosphere).

Propane -44 degrees F
Anhydrous ammonia -28 degrees F
Gasoline -100 degrees F

"C" or Ceiling - The maximum allowable human exposure limit for any airborne substance; not to be exceeded even momentarily.

Carcinogen - A substance or agent capable of causing producing cancer in mammals.

C.A.S. - Chemical Abstracts Service - A Columbus, Ohio organization which indexes information published in "Chemical Abstracts" by the American Chemical Society and provides index guides by which information about particular substances may be located in the "Abstracts" when needed.  "C.A.S. Numbers" identify specific chemicals.

cc-cubic centimeter - A volume measurement in the metric system, equal in capacity to one milliliter (ml.).  One quarter is about 946 cubic centimeters.

Chemical Family - A group of single elements or compounds with common general name.   Example:  gasoline, kerosene, diesel fuel, etc. are of the "hydrocarbon" family.

CHEMTREC - Chemical Transportation Emergency Center; a national center in Washington, D.C. to relay pertinent emergency information concerning specific chemicals on request.   CHEMTREC has a 24-hour toll free telephone number (800-424-9300).

Chronic Effect - An adverse effect on a human or animal body with symptoms that develop slowly over a long period of time or which recur frequently.

COC - Cleveland Open Cup; a flash point test method.

Combustible - A description of flammability of a liquid based on flash point; generally those with a flash point of 100 degrees Fahrenheit or higher.

Concentration - The relative amount of a substance when combined or mixed with other substances.  Examples:  2 ppm hydrogen sulfide in air, or a 50 percent caustic solution.

Corrosive - As defined by DOT, a corrosive material is a liquid or solid that causes visible destruction or irreversible alterations in human skin tissue at the site of contact.

Decomposition - Breakdown of a material or substance (by heat, chemical reaction, electrolysis, decay or other processes) into parts or elements or simpler compounds.

Dermal Toxicity - Adverse effects resulting from skin exposure to a substance.

Epidemiology - The science that deals with the study of disease in a general population.  Determination of the incidence (rate of occurrence) and distribution of a particular disease (as by age, sex or occupation) may provide information about the cause of the disease.

Evaporation Rate - The rate at which a particular material will vaporize (evaporate) when compared to the rate of vaporization of a known material.  The evaporation rate can be useful in evaluating the health and fire hazards of a material.  The known material is usually normal butyl acetate (NBUAC or n-BuAC), with a vaporization rate designated as 1.0.  Vaporization rates of other solvents or materials are classified as:

  • FAST evaporating if greater than 3.0
  • MEDIUM evaporating if .8 to 3.0
  • SLOW evaporting if less than .8

Flash point - The temperature at which a liquid will give off enough flammable vapor to ignite.  There are several flash point test methods, and flash points may vary for the same material depending on the method used, so the test method indicated when the flash point is given (200 degree TCC, etc.)

Flammable - A "flammable liquid" is defined by NFPA and DOT as liquid with a flash point below 100 degrees Fahrenheit (37.8 degrees Celsius).

Formula - The conventional scientific designation for a material (water is H2O, sulfuric acid is H2SO4, sulfur dioxide is SO2, etc.)

General Exhaust - A system for exhausting air conditioning contaminants for a general work area.

g - Gram; a metric unit of weight.

g/kg - Grams per kilogram.

Hazardous Material - In a broad sense, a hazardous material is any substance or mixture of substances having properties capable of producing adverse effects on health or safety of a human being.

Incompatible - Materials which could cause dangerous reactions from direct contact with one another are described as incompatible.

Ingestion - The taking in of a substance through the mouth.

Inhalation - The breathing in of a substance in the form of a gas, vapor, fume, mist, or dust.

Inhibitor - A chemical which is added to another substance to prevent an unwanted chemical change from occurring.

Irritant - A substance which, by contact, in sufficient concentration for a sufficient period of time, will cause an inflammatory response or reaction of the eye, skin or respiratory system.  The contact may be a single exposure or multiple exposures.

kg - Kilogram (about 2.2 U.S. pounds)

L - Liter, a metric unit of capacity.  A U.S. quarter is about 9/10 of a liter.

LC50 - Lethal concentration50; the concentration of a material in air which on the basis of laboratory tests is expected to kill 50% of a group of test animals when administered as a single exposure (usually 1 or 4 hours).

LD50 - Lethal dosage50; a single dosage of a material which on the basis of laboratory tests is expected to kill 50% of a group of test animals.  The LD50 dose is usually expressed as milligrams or grams of material per kilogram of animal body weight (mg/kg or g/kg)

LEL or LFL - Lower explosive limit or lower flammable limit of a vapor of gas; the lowest concentration (lowest percentage of the substance in the air) that will produce a flash of fire when an ignition source (heat, arc or flame) is present.

m3 - cubic meter

Melting Point - The temperature at which a solid substance changes into a liquid state.

mg/m3 - milligrams per cubic meter

ml. - Milliliter; 1000 milliliters in one liter.

mmHg - millimeters (mm) of mercury (Hg); a unit of measurement for low pressure or partial vacuums.

mmpcf - million particles per cubic foot; a unit for measuring particles of a substance suspended in air.

Mutagen - A substance or agent capable of altering the genetic material in a living cell.

NRC - National Response Center; a notification center with a toll free telephone number (1-800-424-8002) which must be called when significant oil or chemical spills or other environmentally-related accidents occur.

NFPA - National Fire Protection Association
Classification of Hazardous Materials (NFPA):

Fire Hazard (Red)
0-Will not burn
1-Will ignite if preheated
2-Will ignite if moderately heated
3-Will ignite at most ambient conditions
4-Burns readily at ambient conditions

Health Hazard (Blue) Reactivity Yellow
0-Ordinary combustible hazards of fire 0-Stable and not reactive with water
1-Slightly hazardous 1-Unstable if heated
2-Hazardous 2-Violent chemical change
3-Extreme Danger 3-Shock and heat may detonate
4-Deadly 4-May detonate

Specific Hazard
OXY   Oxidizer
ACID  Acid
ALK   Alkali
COR   Corrosive

NIOSH - National Institute for Occupational Safety and Health.  A federal agency which - among other activities - tests and certifies respiratory protective devices and air sampling detector tubes recommends occupational exposure limits for various substances.

Nox - oxides of nitrogen; undesirable air pollution

Olfactory -relating to the sense of smell

Oral - used in or taken into the body through the mouth

Oral toxicity - Adverse effects resulting from taking substances into the body via the mouth.

OSHA - Occupational Safety and Health Administration

Oxidizer - DOT defines an oxidizer or oxidizing material as a substance that yields oxygen readily to stimulate the combustion (oxidation) of organic matter. Chlorate (CIO3), permanganate (MnO4), and nitrate (NO3) compounds are examples of oxidizers; note that all contain oxygen (O).

Oxidizing Agent - A chemical or substance which brings about an oxidation reaction.   The agent may (1) provide the oxygen to the substance being oxidized (thus the agent has to be oxygen or contain oxygen), or (2) it may receive electrons being transferred from the substance being oxidized (chlorine is a good oxidizing agent for electron-transfer purposes, even though it contains no oxygen.

PEL - Permissible exposure limit; an exposure limit established by OSHA regulatory authority.  May be a time weighted average (TWA) limit or a maximum concentration exposure limit.  Also see skin.

%volatile - Percent volatile by volume; the percentage of a liquid or solid (by volume) that will evaporate at an ambient temperature of 70 degrees Fahrenheit (unless some other temperature is stated).

PMCC - Pensky-Martens Closed Cup; a flash point tested method

Poison, Class A - A DOT term for extremely dangerous poisons, that is poisonous gases or liquids of such nature that a very small amount of the gas, or vapor of the liquid, mixed with air is dangerous to life.  Some examples: phosgene, cyanogen, hydrocyanic acid, nitrogen peroxide.

Poison, Class B - A DOT term for liquid, solid past or semisolid substance - other than Class A poisons or irritating materials - which are known (or presumed on the basis of animal tests ) to be so toxic to man as to afford a hazard to health during transportation.

Polymerization - A chemical reaction in which one or more small molecules combine to form larger molecules.  A hazardous polymerization is such a reaction which takes place at a rate which releases large amounts of energy.  if hazardous polymerization can occur with a given material, the MSDS usually will list conditions which could start the reaction and - since the material usually contains a polymerization inhibitor - the expected period before the inhibitor is used up.

ppm - parts per million; a unit for measuring the concentration of gas or vapor in air - parts (by volume) of the gas or vapor in a million parts of air.  Also used to indicate the concentration of a particular substance in a liquid or solid.

ppb - parts per billion.

psi - pounds per square inch.

Reaction - A chemical transformation or change; the interaction of two or more substances to form new substances.

Reactivity - The tendency of a substance to undergo chemical reaction with the release of energy.  Undesirable effects - such as pressure buildup, temperature increase, formation of noxious, toxic or corrosive by-products - may occur because of the reactivity of a substance to heating, burning, direct contact with other materials or other conditions in use or in storage.

Reducing agent - In a reduction reaction (which always occurs simultaneously with an oxidation reaction) the reducing agent is the chemical or substance which (1) combines with oxygen or (2) loses electrons to the reaction.  See "oxidation."

Respiratory system - The breathing system; includes the lungs and the air passages (trachea or "windpipe", larynx, mouth, and nose) to the air outside the body, plus the associated nervous and circulatory supply.

Sensitizer - A substance which on the first exposure causes little or no reaction in humans or test animals, but which on repeated exposure may cause a marked response not necessarily limited to the contact site.

Specific gravity - The weight of a material compared to the weight or an equal volume of water; an expression of the density (or heaviness) of the material.

Insoluble materials with specific gravity of less than 1.0 will float in (or on) water.
Insoluble materials with specific gravity greater than 1.0 will sink (or go to the bottom) in water.  Most (but not all) flammable liquids have specific gravity less than 1.0 and, if not soluble, will float on water - an important consideration for fire suppression.

Stability - an expression of the ability of a material to remain unchanged.  For MSDS purposes, a material is stable if it remains the same form under expected and reasonable conditions of storage or use.  Conditions which may cause instability (dangerous change) are stated - examples, temperatures about 150 degrees Fahrenheit, shock from dropping.

STEL - Short term exposure limit, ACGIH terminology.

TCC - Tag (Tagliabue) Closed Cup; a flash point test method.

Terratogen - A substance or agent to which exposure of a pregnant female can result in malformation in the fetus.

TLV - Threshold Limit Value; a term used by ACGIH to express the airborne concentration of a material to which nearly all persons can be exposed day after day, without adverse effects.

TLV-TWA - The allowable Time Weighted Average concentration for a normal 8-hour workday or 40-hour week.

TLV-STEL - The Short Term Exposure Limit, or maximum concentration for a continuous 15-minute exposure period (maximum of four such periods per days, with at least 60 minutes between exposure periods, and providing that the daily TLV-TWA is not exceeded).

TLV-C - The Ceiling exposure limit - the concentration that should not be exceeded even instantaneously.

TOC - Tag Open Cup; a flash point test method

Toxicity - The sum of adverse effects resulting from exposure to a material, generally by the mouth, skin or respiratory tract.

TWA - Time Weighted Average exposure; the airborne concentration of a material to which a person is exposed, averaged over the total exposure time - generally the total workday (8 to 12 hours).  Also "TLV."

UEL or UFL -0 Upper explosive limit or upper flammable limit of a vapor or gas; the highest concentration (highest percentage of the substance in air) that will produce a flash of fire when an ignition source (heat, arc or flame) is present.  At higher concentrations, the mixture is too "rich" to burn.

Unstable - Tending toward decomposition or other unwanted chemical change during normal handling or storage.

Vapor density - The weight of a vapor or gas compared to the weight of an equal volume of air; an expression of the density of the vapor or gas.  Materials lighter than air have vapor densities less than 1.0 (examples: acetylene, methane, hydrogen).   Materials heavier than air (examples: propane, hydrogen sulfide, ethane, butane, chlorine, sulfur dioxide) have vapor densities greater than 1.0)

Vapor pressure - The pressure exerted by a saturated vapor above its own liquid in a closed container, in millimeters of mercury (mmHG) at 68 degrees Fahrenheit (20 degrees Celsius), unless stated otherwise.  Three facts are important to remember:

  1. Vapor pressure of a substance at 100 degrees Fahrenheit will always be higher than the vapor pressure of the substance at 68 degrees Fahrenheit (20 degrees Celsius).
  2. Vapor pressures reported on MSDS's in mmHg are usually very low pressures; 760 mmHg is equivalent to 14.7 pounds per square inch.
  3. The lower the boiling point of a substance, the higher its vapor pressure.

Safety Manual: Table of Contents