Central Processing Unit (CPU)
The portion of a computer's or microprocessor's logic which executes the program.
Centroid Height
Mass-weighted mean height of plume.
Certificate of Insurance
A document verifying that a company maintains insurance at a specific coverage level.
Certification
Completion of the formal training and qualification requirements specified by applicable codes and standards.
Character
Element of a finite set of different elements, called the character set, defined for representation of information, and usually represented by a letter, number of symbol.
Character Set
A defined set of representations, called, characters, from which selections are made to denote and distinguish data. Each character differs from all others, and the total number of characters in a give set is fixed (e.g., letter A to Z, punctuation marks, and blank (space) character).
Characteristic velocity
The typical wind speed in the obstacle array. Chemical reactions Removal of pollutants from the air by reactions with other chemicals. However, although one pollutant may be removed by the chemical reaction, another pollutant may be generated. Recent research has expanded this concern to heterogeneous reactions involving both gases and particles.
Charge (Q).
An excess or deficit of electrons expressed in Coulombs. An electron carries an electric charge of -1.6x10-19 Coulombs.
Charge Density
The quantity of charge divided by the total volume that contains this charge, expressed in Coulombs per cubic meter.
Charge Neutralizer
A device that increases the conductivity of air so that charge drains away to ground.
Charge Relaxation
The process by which separated charges recombine or excess charge is lost from a system.
Charge-to-Mass Ratio (Q/m).
Charge density expressed per unit mass of condensed phase material. Also known as specific charge.
Charging Current (Ic).
The rate of flow of charge into a given system per unit time, expressed in Amperes.
Checklist
A list of items requiring verification of completion; typically, a procedure format in which each critical step is marked off (or otherwise acknowledged/verified) as it is performed. Checklists are often appended to procedures that provide a more detailed description of each step, including information regarding hazards, and a more complete description of the controls associated with the hazards. Checklists are also used in conjunction with formal hazard evaluation techniques to ensure thoroughness.
Checklist Analysis
A hazard evaluation procedure using one or more pre-prepared lists of process safety considerations to prompt team discussions of whether the existing safeguards are adequate.
Checksum
In a computer, a summation of digits or bits summed according to an arbitrary set of rules and primarily used for checking purposes. Typically used as an error detection technique in communication and data storage.
Chemical
Any element, chemical compound or mixture of elements and/or compounds. (OSHA 1994)
Chemical Barrier
See Suppressant Barrier
Chemical Family
A group of single elements or compounds with a common general name. Example: acetone, methyl ethyl ketone, and methyl isobutyl ketone are of the "ketone" family; acrolein, furfural, and acetaldehyde are of the "aldehyde" family. Importance: Elements or compounds within a chemical family generally have similar physical and chemical characteristics.
Chemical Isolation
The stopping of a flame by means of a chemical suppressant.
Chemical Process Industry
The phrase is used loosely to include facilities which manufacture, handle and use chemicals.
Chemical Reactions
Removal of pollutants from the air by reactions with other chemicals. However, although one pollutant may be removed by the chemical reaction, another pollutant may be generated. Recent research has expanded this concern to heterogeneous reactions involving both gases and particles
Chemical Reactivity
The tendency of substances to undergo chemical change. (NOAA 2002)
Chemical Reactivity Hazard
A situation with the potential for an uncontrolled chemical reaction that can result directly or indirectly in serious harm to people, property or the environment. The uncontrolled chemical reaction might be accompanied by a temperature increase, pressure increase, gas evolution or other form of energy release.
Chemtrec
Chemical Transportation Emergency Center; a national center established by the Chemical Manufacturers Association in Washington, D.C in 1970, to relay pertinent information concerning specific chemicals. Importance: Chemtrec has an emergency 24-hour toll free telephone number (800-424-9300).
Chronic
Long-term, usually multiple exposures
Chronic Effect
An adverse effect on a human or animal body, with symptoms which develop slowly over a long period of time. Also, see "Acute". Importance: The length of time that a worker is exposed is the critical factor. Long periods of time pass, with repeated exposure to a chemical, before any ill effects are detected in a worker.
Chronic Exposure
A frequent or continuous exposure to a toxic agent over an unspecified, but generally lengthy, period of time.
Chronic Hazard
The potential for injury or damage to occur as a result of prolonged exposure to an undesirable condition (e.g., smoking, with the potential for causing lung cancer).
Chronic Risk
A risk arising from a long-term persistent exposure.
Chronic Toxicity
Adverse (chronic) effects resulting from repeated doses of or exposures to a substance over a relatively prolonged period of time. Importance: Ordinarily used to denote effects in experimental animals.
Class
The NFPA system for flammable and combustible liquids is given in NFPA 30. Class I flammable liquids have closed-cup flash points below 100 deg F (37.8 degC) and Reid vapor pressures not exceeding 40 psia (2068.6 mmHg) at 100 degF (37.8 degC). Combustible liquids have closed cup flash points at or above 100 degF (37.8 degC) and are subdivided into Class II and Class III. See also Combustible Liquids and Flammable Liquids.
Cleanroom
A room in which the concentration of airborne particles is controlled, and which is constructed and used in a manner to minimize the introduction, generation, and retention of particles inside the room and in which other relevant parameters (e.g., temperature, humidity, and pressure) are controlled as necessary.
Client
The term used in this text to identify the company issuing the tolling contract to the toller. The toller's client.
Cloud
Any type of pollutant mass moving through the atmosphere.
Cloud Mass-Weighted Mean Height
The concentration mass-weighted mean height of a pollutant cloud.
Coccus (plural cocci)
A spherical bacterium.
Code
Written requirements that affect a facility and/or the process safety requirements that apply to a facility. Codes contain requirements that apply to the design and implementation of management systems, design and operation of process equipment, or similar activities. The difference between a code and a standard is that codes have become part of a law or regulation, and therefore their requirements become mandatory within the jurisdictions that have adopted the code requirements in their laws or regulations. This usually occurs at the state level, but may also occur in local or federal laws or regulations.
Coherent
A coherent fault tree uses only "AND" and "OR" gates to represent the failure logic. Time delay gates, inhibit conditions, or "NOR" gates are not permitted.
Collision
An incident involving two or more moving vessels that collide while meeting, overtaking, or crossing.
Combustible
Capable of burning.
Combustible Concentration
Reduction The technique of maintaining the concentration of combustible material in a closed space below the lower flammable limit. This is also called Air Dilution.
Combustible Concentration Reduction
The technique of maintaining the concentration of combustible material in a closed space below the lower flammable limit.
Combustible Dust
A finely divided combustible particulate solid that presents a flash fire hazard or explosion hazard when suspended in air or the process specific oxidizing medium over a range of concentrations.
Combustible Liquid
A term used to classify certain liquids that will burn on the basis of flash points. The National Fire Protection Association (NFPA) defines a combustible liquid as any liquid that has a closed-cup flash point above 100 degF (37.8 degC) (NFPA 30). There are three subclasses, as follows; Class II liquids have flash points at or above 100 degF (37.8 degC) but below 140 degF (60 degC). Class III liquids are subdivided into two additional subclasses; Class IIIA: Those having flash points at or above 140 degF (60 degC) but below 200 degF (93.4 degC), Class IIIB: Those having flash points at or above 200 degF (93.4 degC). The Department of Transportation (DOT) defines degcombustible liquids deg as those having flash points above 140 degF (60.5 degC) and below 200 degF (93.4 degC).
Combustible Particulate Solid
Any combustible solid material, composed of distinct particles or pieces, regardless of size, shape, or chemical composition.
Combustion
An exothermic reaction between a fuel and an oxidizer (usually but not necessarily oxygen) that results in a significant temperature rise and usually a visible flame or glow.
Commercial Device
A device that is manufactured by a consistent production method and has consistent quality. The device is complete with a part number and documentation (e.g., instructions and customer drawings).
Commodity Data
Information about the hazardous material(s) that is being shipped such as physical properties of the chemical, packaging types (including quantity in transit and storage conditions), annual shipments, time of day the shipment moves across the route or segments of the route, and breakout of loaded versus empty miles.
Common Cause Failure
Concurrent failures of different devices, resulting from a single event, where these failures are not consequences of each other.