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Glossary: Blasting Terms

General Definitions

Source: ISEE Blaster's Handbook


The definitions provided herein are solely for the purpose of general information. These definitions are not necessarily intended to conform to those set forth in any governmental regulations or guidelines, nor are they intended to describe any manufacturer's particular product configuration.

Acceptor - A charge of explosives or blasting agent receiving an impulse from an exploding donor charge

Air Blast - The airborne shock wave or acoustic transient generated by an explosion

American Table of Distances - The quantity-distance table, prepared and approved by IME, for storage of explosive materials to determine safe distances from inhabited buildings, public highways, passenger railways, and other stored explosive materials

Ammonium Nitrate - The ammonium salt of nitric acid represented by the NH4NO3

Ampere - A unit of electrical current produced by 1 volt acting through a resistance of I ohm

ANFO - An explosive material consisting of ammonium nitrate and fuel oil

Approved, Approval, or Authorized - Terms that mean Approved, Approval, or Authorized by the authority having jurisdiction

Artificial Barricade - An artificial mound or revetted wall of earth of a minimum thickness of 3 ft

Authorized Person - An individual approved or assigned by management to perform a specific duty or duties or to be at a specific location or locations

Authority Having Jurisdiction - The governmental agency, office, or individual responsible for approving equipment, an installation, or a procedure

Available Energy - The energy from an explosive material that is capable of performing useful work

Barricaded - The effective screening of a building containing explosives from a magazine or other building, railway, or highway by a natural or an artificial barrier. A straight line from the top of any sidewall of the building containing explosives to the eave line of any magazine or other building or to a point 12 ft above the center of a railway or highway shall pass through such barrier.

Barrier - A material object or objects that separates, keeps apart, or demarcates in a conspicuous manner such as cones, a warning sign, or tape.

Base Charge - The main explosive charge in the base of a detonator

Blast Area - The area of a blast within the influence of flying rock missiles, gases, and concussion

Blast Site - The area where explosive materials is handled during loading prior to shot. (At the mine the blast site this would be the tunnel not the entire mine site.)

Blaster - That qualified person in charge of, and responsible for. the loading and firing of a blast (same as Shot Firer)

Blasting Accessories - Nonexplosive devices and materials used in blasting, such as, but not limited to, cap crimpers, tamping bags, blasting machines, blasting galvanometers, and cartridge punches

Blasting Agent - An explosive material that meets prescribed criteria for insensitivity to initiation. For storage, Title 27, Code of Federal Regulations, Section 55.11 defines a blasting agent as any material or mixture, consisting of fuel and oxidizer intended for blasting, not otherwise defined as an explosive, provided that the finished product, as mixed for use or shipment, cannot be detonated by means of a No. 8 test blasting cap when unconfined (Bureau of Alcohol. Tobacco and Firearms Regulation). For transportation, Title 49, Code of Federal Regulations defines a blasting agent as a material designed for blasting that has been tested in accordance with Section 173.114a and found to be so insensitive that there is very little probability of accidental initiation to explosion or transition from deflagration to detonation (U.S. Department of Transportation Regulation).

Blasting Cap - A detonator that is initiated by a safety fuse (see Fuse Cap)

Blasting Crew - A group of persons who assist the blaster in loading, tying in, and firing a blast

Blasting Galvanometer - An electrical resistance instrument designed specifically for testing electric detonators and circuits containing them. Along with blasting ohmmeters and blaster's multimeters, it is used to measure resistance or to check electrical continuity.

Blasting Log - A written record of information about a specific blast as may be required by law or regulation

Blasting Machine - An electrical or electromechanical device that provides electrical energy for the purpose of energizing detonators in an electric blasting circuit

Blasting Machine-CD Type - See Capacitor-Discharge Blasting Machine

Blasting Machine-Generator Type - A hand-operated electromechanical device that provides an output current to energize electric detonators

Blasting Machine Rheostat - A graduated electrical resistance device used to simulate electric detonator resistances in the testing of blasting machines

Blasting Vibrations - The energy from a blast that manifests itself in earthborne vibrations that are transmitted through the earth away from the immediate blast area

Blend - A mixture consisting of (a) A water-based explosive material matrix and ammonium nitrate or ANFO; or (b) A water-based oxidizer matrix and ammonium nitrate or ANFO.

Booster - An explosive charge, usually of high strength and high detonation velocity, used to improve the initiation of less sensitive explosive materials

Box - An outer packaging with complete rectangular or polygonal faces, made of metal, wood, plywood, fiberboard, plastic, or other suitable material and authorized by DOT for packaging and transport of CLASS I materials (explosives).

Bridgewire - A resistance wire connecting the ends of the legwires inside an electric detonator and which is imbedded in the ignition charge of the detonator

Bullet-Resistant - Magazine walls or doors of construction resistant to penetration of a bullet of 150-grain M2 ball ammunition having a nominal muzzle velocity of 2,700 ft/sec fired from a .30-caliber rifle from a distance of 100 ft perpendicular to the wall or door. When a magazine ceiling or roof is required to be bullet-resistant, the ceiling or roof shall be constructed of materials comparable to the sidewalls or of other materials that will withstand penetration of the bullet described above when fired at an angle of 45 degrees from the perpendicular. Tests to determine bullet resistance should be conducted on test panels or empty magazines that will resist penetration of 5 out of 5 shots placed independently of each other in an area at least 3 ft. x 3 ft.

Bullet-Sensitive Explosive Material - Explosive material that can be detonated by 150-grain M2 ball ammunition having a nominal muzzle velocity of 2,700 ft/sec when the bullet is fired from a .30-caliber rifle at a distance of not more than 100 ft and the test material, at a temperature of 70 - 75oF, is placed against a backing material of 1/2-in. steel plate.

Bureau of Alcohol, Tobacco, and Firearms (BAFT) - A bureau of the Department of Treasury having responsibility for the promulgation and enforcement of regulations related to the unlawful use of explosive materials under 18 U.S.C. Chapter 40, Section 847

Bus Wire - Expendable heavy-gauge bare copper wire used to connect detonators or series of detonators in parallel

Cap Crimper - A mechanical device for crimping the metallic shell of a fuse detonator or igniter cord connector securely to a section of inserted safety fuse

Cap Sensitivity - The sensitivity of an explosive to initiation by a detonator. An explosive material is considered to be cap sensitive if it detonates with an IME No. 8 Test Detonator

Capacitor-Discharge Blasting Machine - A blasting machine in which electrical energy, stored on a capacitor, is discharged into a blasting circuit containing electric detonators

Cartridge - An individual closed shell, bag, or tube of circular cross section containing explosive material

Cartridge Count (Stick Count) - The number of cartridges in a standard case. A standard case typically contains about 50 LB of explosive material.

Cartridge Punch - A wooden, plastic, or nonsparking metallic device used to punch an opening in an explosive cartridge to accept a detonator or a section of detonating cord

Case - An outer substantial shipping container meeting DOT specifications for explosive materials

Case Insert - A set of printed, precautionary instructions, including the IME Do's and Don'ts, which is inserted into a case of explosive materials

Case Liner - A plastic or paper barrier used to prevent the escape of explosive materials from a case

Cast, Extrude, or Pressed Booster - A cast, extruded, or pressed solid high explosive used to detonate less sensitive explosive materials

Certified Blaster - A blaster certified by a governmental agency to prepare, execute, and supervise blasting

Circuit - A completed path for conveying electrical current.

Class A Explosives - Explosives, as defined by the U.S. Department of Transportation, that possess detonating or otherwise maximum hazard, such as, but not limited to, dynamite, nitroglycerin, lead azide, blasting caps, and detonating primers

Class B Explosives - Explosives, as defined by the U.S. Department of Transportation, that possess flammable hazard, such as, but not limited to, propellant explosives. photographic flash powders, and some special fireworks

Class C Explosives - Explosives, as defined by the U.S. Department of Transportation, that contain Class A or Class B explosives, or both, as components but in restricted quantities

Code of Federal Regulations - A codification of the general and permanent rules published in the Federal Register by the Executive departments and agencies of the Federal Government. The code is divided into 50 titles which represent broad areas subject to Federal regulation.

Commercial Explosives - Explosives designed, produced, and used for commercial or industrial applications rather than for military purposes

Compatibility Letter - A letter assigned by DOT which follows an explosive's division number to specify the controls for the transportation, and storage related therto, of explosives to prevent an increase in hazard that might result if certain types of explosives were transported together.

Connecting Wire - Wire used to extend the firing line or legwires in an electric blasting circuit

Continuity Check (Circuit Continuity Check) - A determination made by instrumentation where possible, and visually in all cases, show that an initiation system in continuous and contains no breaks or improper connections that could cause stoppage or failure of the initiation process.

Core Load - The explosive core of detonating cord, expressed as the number of grains of explosive per foot

Crimp - The folded ends of paper explosive cartridges, the circumferential depression at the open end of a fuse cap or igniter cord connector that serves to secure the fuse; or the circumferential depression in the blasting cap shell that secures a sealing plug or sleeve into electric or nonelectric detonators

Crimping - The act of securing a fusecap or igniter cord connector to a section of a safety fuse by compressing the metal shell of the cap against the fuse by means of a cap crimper

Current Leakage - Portion of the firing current bypassing part of the blasting circuit through unintended paths

Current-Limiting Device - An electric or electromechanical device that limits:
1) current amplitude,
2) duration of current flow. or
3) total energy of the current delivered to an electric blasting circuit

Cutoff - A break in a path of detonation or initiation caused by extraneous interference, such as flyrock or shifting ground

Date-Shift Code - A code applied by manufacturers to the outside shipping containers, and, in many instances, to the immediate containers of explosive materials to aid in their identification and tracing

DC - Direct current

Decibel - A unit of air overpressure commonly used to measure air blast

Deflagration - An explosive reaction such as a rapid combustion that moves through an explosive material at a velocity less than the speed of sound in the material

Delay - A distinct pause of predetermined time between detonation or initiation impulses, to permit the firing of explosive charges separately.

Delay Blasting - The practice of initiating individual explosive decks, boreholes, or rows of boreholes at predetermined time intervals using delay detonators, as compared to instantaneous blasting where all holes are fired essentially simultaneously

Delay Detonator - An electric or nonelectric detonator used to introduce a predetermined lapse of time between the application of a firing signal and the detonation of the base charge

Delay Element - The device in a delay detonator that produces the predetermined time lapse between the application of a firing signal and detonation

Delay Interval - The nominal time between the detonations of delay detonators of adjacent periods in a delay series; the nominal time between successive detonations in a blast

Delay Period - A designation given to a delay detonator to show its relative or absolute delay time in a given series

Delay Series - A series of delay detonators designed to satisfy specific blasting requirements. There are basically two types of delay series: millisecond (MS ) with delay intervals on the order of milliseconds, and long period (LP) with delay times on the order of seconds.

Delay Tag - A tag, band, or marker on a delay detonator that denotes the delay series, delay period, and/or delay time of the detonator

Delay Time - The lapse of time between the application of a firing signal and the detonation of the base charge of a delay detonator

Density - The mass of an explosive per unit of volume, usually expressed in grams per cubic centimeter or pounds per cubic foot

D.E.P. - Commonwealth of Pennsylvania-Department of Environmental Protection

Department of Transportation (DOT) - A cabinet-level agency of the federal government. It has the responsibility for the comprehensive regulation of transportation safety and issues regulations governing interstate shipments of explosives and other hazardous materials.

Detonating Cord - A flexible cord containing a center core of high explosive and used to initiate other explosives

Detonating Cord MS Connectors - Nonelectric, short-interval (millisecond) delay devices for use in delaying blasts that are initiated by detonating cord

Detonating Cord Trunkline - The line of detonating cord that is used to connect and initiate other lines of detonating cord

Detonating Primer - A name applied for transportation purposes to a device consisting of a detonator and an additional charge of explosives, assembled as a unit

Detonation - An explosive reaction that moves through an explosive material at a velocity greater than the speed of sound in the material

Detonation Pressure - The pressure produced in the reaction/zone of a detonating explosive

Detonation Velocity - The velocity at which a detonation progresses through an explosive

Detonator - Any device containing any initiating or primary explosive that is used for initiating detonation. A detonator may not contain more than 10 g of total explosives by weight, excluding ignition or delay charges. The term includes, but Is not limited to, electric blasting caps of instantaneous and delay types, blasting caps for use with safety fuses, detonating cord delay connectors, and nonelectric instantaneous and delay blasting caps that use detonating cord, shock tube, or any other replacement for electric legwires.

Donor - An exploding charge producing an impulse that impinges upon an explosive "acceptor" charge

Do's and Don'ts - A list of precautions (IME Safety Library Publication No. 4) printed by the Institute of Makers of Explosives pertaining to the transportation, storage, handling, and use of explosive materials and inserted in cases of explosive materials and cartons of detonators

Electric Blasting Circuit - An electric circuit containing electric detonators and associated wiring

Electric Detonator - A detonator designed for, and capable of, initiation by means of an electric current

Emulsion - An explosive material containing substantial amounts of oxidizers dissolved in water droplets, surrounded by an immiscible fuel

Energy - A measure of the potential for the explosive to do work

Explode - To react chemically in a rapid manner to produce heat and pressure. The term encompasses both deflagration and detonation.

Explosion - A chemical reaction involving an extremely rapid expansion of gases, usually associated with the liberation of heat

Explosive - Any chemical compound, mixture, or device, the primary or common purpose of which is to function by explosion

Explosive Materials - These include explosives, blasting agents, and detonators. The term includes, but is not limited to, dynamite and other high explosives; slurries, emulsions, and water gels; black powder and pellet powder; initiating explosives; detonators (blasting caps); safety fuse; squibs; detonating cord; igniter cord; and igniters. A list of explosive materials determined to be within the coverage of 18 USC Chapter 40, "Importation, Manufacture, Distribution, and Storage of Explosive Materials" is issued at least annually by the Director of the Bureau of Alcohol, Tobacco, and Firearms of the Department of the Treasury. The U.S. Department of Transportation classifications of explosive materials used in commercial blasting operations are not identical with the statutory definitions of the Organized Crime Control Act of 1970, Title 18 USC, Section 84 1. To achieve uniformity in transportation, the U.S. Department of Transportation in Title 49, Code of Federal Regulation. Parts 1-999 subdivides these materials into:

Class A Explosives - detonating or otherwise maximum hazard
Class B Explosives - flammable hazard
Class C Explosives - minimum hazard
Blasting Agents - see definition of Blasting Agent

Explosive Strength - The amount of energy released by an explosive upon detonation that is an indication of the capacity of the explosive to do work

Extraneous Electricity - Electrical energy, other than actual firing current or the test current from a blasting galvanometer, that is present at a blast site and that could enter an electric blasting circuit. It includes stray current, static electricity, RF (electro-magnetic) waves, and time-varying electric and magnetic fields.

Fertilizer-Grade Ammonium Nitrate - A grade of ammonium nitrate as defined by The Fertilizer Institute

Fire Extinguisher Rating - A rating set forth in the National Fire Code that may be identified on an extinguisher by a number (5, 20, 30, etc.) indicating the extinguisher's relative effectiveness followed by a letter (A, B, C, etc.) indicating the class or classes of fires for which the extinguisher has been found to be effective

Fire-Resistant - Construction designed to offer reasonable protection against fire

Firing Current - An electric current of recommended magnitude and duration to sufficiently energize an electric detonator or a circuit of electric detonators

Firing Line - The wire(s) connecting the electrical power source with the electric blasting circuit

Flags-Danger - Flags, usually red, that may or may not be Imprinted with a warning and used to caution personnel around explosives operations, or displayed on trucks transporting explosives

Flammability - The ease with which an explosive material may be ignited by flame and heat

Flashover - The sympathetic detonation between explosive charges or between charged blastholes

Flash Point - The lowest temperature at which vapors from a volatile combustible substance ignite in air when exposed to flame, as determined in an apparatus specifically designed for such testing

Flyrock - Rocks propelled from the blast area by the force of an explosion

Fuel - A substance that may react with oxygen to produce combustion

Fumes - The gaseous products of an explosion. For the purpose of fume classification, only poisonous or toxic gases, such as carbon monoxide, hydrogen sulfide, and nitrogen oxides are considered.

Fuse - See Safety Fuse

Fuse Cap (Fuse Detonator) - A detonator that is initiated by a safety fuse; also referred to as an ordinary blasting cap

Gauge (Wire) - A series of standard sizes such as the American Wire Gauge (AWG), used to specify the diameter of wire

Galvanometer - See Blasting Galvanometer

Gap Sensitivity - The maximum distance for propagation between standard charge sizes of explosive donor and acceptor. It is used for measuring the likelihood of sympathetic propagation.

Ground Fault - An electrical contact between part of the blasting circuit and earth

Ground Vibration - Shaking of the ground, by elastic waves emanating from a blast, usually measured in inches per second of particle velocity

Hangfire - The detonation of an explosive charge at some nondetermined time after its normally designed firing time

Hanging Wall - The wall or rock on the upperside of an inclined vein. It is called the roof in bedded deposits.

Hardwood - Red oak, white oak, hard maple, ash, or hickory, free from loose knots, wind shakes, or similar defects

Heading - Refers to the driving of openings of the various exploration and development passageways

Hertz (Hz) - A synonym for "cycles per second"

High Explosives - Explosives that are characterized by a very high rate of reaction, high pressure development, and the presence of a detonation wave in the explosive

IME-22 Container (Compartment) - A container (portable), or a compartment (permanently affixed to a vehicle), which is constructed in accordance with IME SLP-22 specifications and is authorized by the Department of Transportation for the transport of certain types of detonators on the same vehicle with other explosives.

Incendivity - The property of an igniting agent (e.g., spark, flame, or hot solid) whereby the agent can cause ignition

Inhabited Building - A building regularly occupied in whole or part as a habitation for human beings. or any church, schoolhouse, railroad station, store, or other structure where people are accustomed to assemble, except any building or structure occupied in connection with the manufacture, transportation, storage, or use of explosive materials

Initiation - The act of causing an explosive material to detonate or deflagrate

Initiator - A detonator or detonating cord used to start detonation in an explosive material

Inner Packaging - A packaging for which an outer packaging is required for transport.

Instantaneous Detonator - A detonator that has a firing time of essentially 0 sec as compared to delay detonators with firing times of from several milliseconds to several seconds

Institute of Makers of Explosives (IME) - A nonprofit safety-oriented trade association representing leading producers of commercial explosive materials in the United States and Canada and dedicated to safety in the manufacture, transportation, storage, handling, and use of explosive materials

Institute of Makers of Explosives No. 8 Test Detonator - IME No. 8 test detonator has 0.40 - 0.45 g of PETN base charge pressed to a specific gravity of 1.4 g/cc and primed with standard weights of primer, depending on manufacturer

Inventory - A listing of all explosive materials stored in a magazine

Leading (Lead) Lines or Wires - The wire(s) connecting the electrical power source with the circuit containing electric detonators

Leakage Resistance - The resistance between the blasting circuit (including lead wires) and the ground

Legwires - The two single wires or one duplex wire extending out from an electric detonator

Liquid Fuels - Fuels in a liquid state. They may be used with oxidizers to form explosive materials.

Loading - Placing explosive material in a blasthole or against the material to be blasted

Low Explosives - Explosives that are characterized by deflagration or a low rate of reaction and the development of low pressure

Magazine - Any building, structure, or container, other than an explosives manufacturing building, approved for the storage of explosive material

Magazine Keeper - A person responsible for the inventory and safe storage of explosive materials, including the proper maintenance of explosive materials, storage magazines, and areas

Magazine, Surface - A specially designed and constructed structure for the storage of explosive materials on the surface of the ground

Magazine, Underground - A specially designed and constructed structure for the storage of explosive materials underground

Main Explosive Charge - The explosive material that performs the major work of blasting

Manufacturing Codes - Code markings stamped on explosive materials packages, indicating, among other information, the date of manufacture

Mass Detonate (Mass Explode) - Explosive materials mass detonate (mass explode) when a unit or any part of a larger quantity of explosive material explodes and causes all or a substantial part of the remaining material to detonate or explode simultaneously. With respect to detonators, "a substantial part" means 90% or more

Maximum Recommended Firing Current - The highest recommended electric current to ensure safe and effective performance of an electric detonator

Millisecond - One thousandth of a second

Mine Safety and Health Administration (MSHA) - An agency of the Department of Labor concerned with promulgation and enforcement of health and safety regulations in the mining field

Miniaturized Detonating Cord - Detonating cord with a core load of 5 or less grains of explosive per foot

Minimum Recommended Firing Current - The lowest recommended electric current to ensure reliable performance of an electric detonator

Minimum Gap Sensitivity - An air gap, measured in inches, that determines whether the explosive material is within specific tolerances for gap sensitivity

Misfire - A blast that fails to detonate completely after an attempt at initiation; also the explosive material itself that failed to detonate as planned

MS Connectors - Nonelectric, short-interval (millisecond) delay devices for use in delaying blasts that are initiated by detonating cord

Natural Barricade - Natural features of the ground, such as hills, or timber of sufficient density that the surrounding exposures that require protection cannot be seen from the magazine when the tress are bare of leaves

No. 8 Test Cap - See Institute of Makers of Explosives No. 8 Test Detonator

Nonelectric Detonator - A detonator that does not require the use of electric energy or safety fuse to function

Nonsparking Metal - A metal that will not produce a spark when struck with other tools, rock, or hard surfaces

Occupational Safety and Health Administration (OSHA) - An agency of the Department of Labor active in eliminating occupational hazards and promoting employee health and safety

Oxidizer or Oxidizing Material - A substance, such as a nitrate, that readily yields oxygen or other oxidizing substances to stimulate the combustion of organic matter or other fuel

Parallel Blasting Circuit - An electric blasting circuit in which the legwires of each detonator are connected across the firing line directly or through buswires.

Parallel-Series Circuit - See Series in Parallel Blasting Circuit

Particle Velocity - A measure of the intensity of ground vibration. specifically the time rate of change of the amplitude of ground vibration

PETN - An abbreviation for the name of the explosive, pentaerythritoltetranitrate

Placards - Signs placed on vehicles transporting hazardous materials (including explosive materials) indicating the nature of the cargo

Plosophoric Materials - Two or more unmixed, commercially manufactured, prepackaged chemical ingredients (including oxidizers, flammable liquids or solids, or similar ingredients) which are not classified as explosives but which, when mixed or combined, form a blasting explosive.

Premature Firing - The detonation of an explosive charge before the intended time

Prilled Ammonium Nitrate - Ammonium nitrate in a pelleted or prilled form

Primary Explosive - A sensitive explosive that nearly always detonates by simple ignition from such means as spark, flame, impact, friction, or other primary heat sources of appropriate magnitude

Primer - A unit. package, or cartridge of explosives used to initiate other explosives or blasting agents, and which contains,

1 ) a detonator, or
2) detonating cord to which is attached a detonator designed to initiate the detonating cord

Propagation - The detonation of explosive charges by an impulse received from adjacent or nearby explosive charges

Quantity-Distance Table - A table listing minimum recommended distances from explosive materials stores of various weights to a specific location

Receptor (Acceptor) - A charge of explosive materials receiving an impulse from an exploding donor charge

Resistance - The measure of opposition to the flow of electrical current, expressed in ohms

Safety Standard - Suggested precautions relative to the safety practices to be employed in the manufacture, transportation, storage, handling, and use of explosive materials

Seismograph - An instrument, useful in monitoring blasting operations, that records ground vibration. Particle velocity, displacement, or acceleration is generally measured and recorded in three mutually perpendicular directions.

Sensitiveness - A measure of an explosive's cartridge-to-cartridge propagating ability under certain test conditions. It is expressed as the distance through air at which a primed half-cartridge (donor) will detonate an unprimed half-cartridge (receptor).

Sensitivity - A physical characteristic of an explosive material classifying its ability to be initiated upon receiving an external impulse such as impact, shock, flame, friction, or other influences that can cause explosive decomposition

Separation Distances - Minimum recommended distances from explosive materials accumulations to certain specific locations

Sequential Blasting Machine - A blasting machine designed to actuate separate series of detonators at accurately timed intervals. Also called Sequential Timer.

Series Blasting Circuit - An electric blasting circuit that provides one continuous path for the current through all caps in the circuit

Series in Parallel Blasting Circuit - An electric blasting circuit in which the ends of two or more series of electric detonators are connected across the firing line directly or through buswire

Shelf Life - The length of time of storage during which an explosive material retains adequate performance characteristics

Shock Wave - A transient pressure pulse that propagates at supersonic velocity

Shot Firer - That qualified person in charge of and responsible for the loading and firing of a blast (same as a Blaster)

Shunt - The shorting together of the free ends of:

1) electric detonator legwires, or
2) the wire ends of an electric blasting circuit or part thereof-, the name of an electrical shorting device applied to the free ends of electric detonators by the manufacturer

Signs-Explosive (Placards) - Signs, called placards, placed on vehicles transporting explosives denoting the character of the cargo, or signs placed near storage areas as a warning to unauthorized personnel

Silver Chloride Cell - A special battery of relatively low current output used in a blasting galvanometer

Specific Gravity - The ratio of the weight of any volume of substance to the weight of an equal volume of pure water

Stability - The ability of an explosive material to retain chemical and physical properties specified by the manufacturer when exposed to specific environmental conditions over a particular period of time

Static Electricity - Electric charge at rest on a person or object. It is most often produced by the contact and separation of dissimilar insulating materials

Storage - The safekeeping of explosive materials, usually in specially designed structures called magazines

Stray Current - A flow of electricity outside an insulated conductor system

Sympathetic Propagation - The detonation of an explosive material as the result of receiving an impulse from another detonation through air, earth, or water

Table of Recommended Separation Distances of Ammonium Nitrate and Blasting Agents from Explosives or Blasting Agents - A quantity-distance table from National Fire Protection Association Standard No. 495

Temporary Storage - Storage of explosives for less than 24 hours.

Test Blasting Cap No. 8 - See Institute of Makers o Explosive No. 8 Test Detonator

Theft-Resistant - Construction designed to deter illegal entry into facilities used for the storage of explosive materials

Trunkline - The line of detonating cord on the ground surface that connects detonating cord downlines

Tunnel - A horizontal or nearly horizontal underground passage that is open to the atmosphere at both ends. The term is loosely applied in many cases to an adit

Unbarricaded - The absence of a natural or artificial barricade around explosive storage areas of facilities

Unconfined Detonation Velocity - The detonation velocity of an explosive material without confinement, for example, a charge fired in the open

Volt - The unit of electromotive force. It is the difference in potential required to make a current of 1amp flow through a resistance of 1 ohm

Warning Signal - A visual or audible signal that is used for warning personnel in the vicinity of the blast area of the impending explosion

Watt - A unit of electrical power equal to 1 joule/sec