Explosives safety

Last updated September 06, 2024

A video on safety when using explosives in the workplace

Explosives safety refers to the practices taken during the use of explosives to prevent injury or death. Explosives include chemicals such as TNT or dynamite.

Hazards

Toxicity

A number of explosives contain chemical compounds which can be toxic, either released as products or contained within the explosive itself.^[1]

Quantity-Distance (QD)

Quantity-Distance (QD) is the foundation of DOD explosives safety standards. It defines levels of protection from blast based on relationships between the quantity of explosive material (NEW) and distance. The relationships are based on levels of risk considered acceptable for specific exposures but they do not provide absolute safety or protection. Exposures are expressed by a “K-factor” (K6, K18, etc.) which represents the degree of protection provided; higher is better. K328 equates to a blast overpressure of 0.0655 psi (452 Pa) which will not harm people in the open.

Blast Wave Phenomena

A Blast Wave Phenomenon is an incident involving the violent release of energy created by detonation of an explosive device. The sudden and intense pressure disturbance is termed the “blast wave.” The blast wave is characterized by an almost instantaneous rise from ambient pressure to a peak incident pressure (Pi). This pressure increase or “shock front,” travels radially outward from the detonation point, with a diminishing velocity that is always in excess of the speed of sound in that medium. Gas molecules making up the front move at lower velocities. This velocity, which is called the “particle velocity,” is associated with the “dynamic pressure,” or the pressure formed by the winds produced by the shock front. As the shock front expands into increasingly larger volumes of the medium, the incident pressure decreases and, generally, the duration of the pressure-pulse increase. If the shock wave strikes a rigid surface (e.g., a building) at an angle to the direction of the wave's propagation, a reflected pressure is instantly developed on the surface and this pressure rises to a value that exceeds the incident pressure. This reflected pressure is a function of the incident wave's pressure and the angle formed between the rigid surface and the plane of the shock front.

Fragments

An important consideration in the analysis of the hazards associated with an explosion is the effect of any fragments produced. Although fragmentation most commonly occurs in high explosives events, fragmentation may occur in any incident involving ammunition and explosives (A&E). Depending on their origin, fragments are referred to as “primary” or “secondary” fragments.

Primary fragments result from the shattering of a container (e.g., shell casings, kettles, hoppers, and other containers used in the manufacture of explosives and rocket engine housings) in direct contact with the explosive. These fragments usually are small, initially travel at thousands of feet per second, and may be lethal at long distances from an explosion.

Secondary fragments are debris from structures and other items in close proximity to the explosion. These fragments, which are somewhat larger in size than primary fragments and initially travel at hundreds of feet per second, do not normally travel as far as primary fragments.

Thermal Hazards

Generally, thermal hazards from explosives events are of less concern than blast and fragment hazards. With the release of energy from an explosion is heat. The amount of heat varies with the energetic compound (explosive). All explosives compound molecules are potentially unstable held together with weak bonds in their outer shell. When this weak bond is broken heat and energy is violently released. It normally takes longer for the thermal blast to incur. Injury from thermal effects follows the blast and fragmentation effects which happen almost instantaneously. This does not imply that there is a time lapse between blast and fragmentation effects of explosives; in fact it happens so fast that humans cannot notice the delay without specialized equipment. The time available to react to a thermal event does increases survivability by rapid equipment designed to react in a fragment of a second. The primary effect of the thermal effect from an explosive detonation on structures, material, and ammunition and explosives (A&E) is their partial or total destruction by fire. The primary concern for explosives safety with a fire involving A&E is that it may transition to a more severe reaction, causing detonations of additional or more hazardous explosives devises and placing more people or property at a greater degree of risk of damage, destruction, injury, or death.

Susan Test

Following the 1966 Palomares B-52 crash and the 1968 Thule Air Base B-52 crash, accident investigators concluded that the conventional explosives used at the time in nuclear weapons were not stable enough to withstand the forces involved in an aircraft accident. The finding triggered research by scientists in the United States into safer conventional explosives that could be used in nuclear weapons.^[2] The Lawrence Livermore National Laboratory developed the "Susan Test"^{[ further explanation needed ]} — a standard test that uses a special projectile whose design simulates an aircraft accident by squeezing and nipping explosive material between metal surfaces. The test projectile is fired under controlled conditions at a hard surface to measure the reactions and thresholds of different explosives to an impact.

Explosives Safety Specialist

This is a highly trained and skilled civilian professional usually a QASAS or a Safety Specialist that has been trained to evaluate risk and hazards involved with conventional, guided missiles and toxic chemical ammunition operations. Department of Defense Standards requires that only trained and certified personnel are permitted to participate in operations involving ammunition, explosives, and/or explosive components, guided missiles, and toxic chemicals. They are responsible for providing protection from the effects of ammunition and explosives by evaluation of a set of standards developed by the Department of Defense and reinforced by additional regulations by the branch of military service responsible for the explosives item. They develop safety programs to minimize losses due to injuries and property damage. They try to eliminate unsafe practices and conditions on sites where ammunition and explosives (A&E) are used or stored. Military explosives safety specialist are deployed along with U.S. Military forces to maintain safe storage and use of A&E. They are responsible to recommend to military command ways to store A&E that reduce the risk of injury or death to service men and women in case of an accidental detonation or if the A&E supply is hit by enemy attack.

Much of the work of military explosives safety specialist is identical to their civilian counterparts. They have offices where they analyze data and write reports to upper commands on the storage of A&E. Much of their time is spent reviewing or preparing explosives safety site plans. An explosives site plan (ESS) is the composite risk management (CRM) process associated with explosives/toxic chemical activities to ensure the minimum risk to personnel, equipment, and assets, while meeting mission requirements. The damage or injury potential of explosions is determined by the separation distance between potential explosion sites (PES) and exposed sites (ES); the ability of the PES to suppress blast overpressure, primary and secondary fragments; and the ability of the ES to resist explosion effects. Planning for the proper location and construction of A&E facilities and surrounding facilities exposed to A&E facilities is a key element of the explosives/toxic chemical site planning process. This management process also ensures that risks above those normally accepted for A&E activities are identified and approved at the proper level of command.

Explosives Safety Specialist must often travel to different storage sites to verify that the military installation is meeting the service explosives safety regulations.

Explosives Safety Specialist often works with other safety professionals. They are required to know OSHA, EPA, NFPA and other consensus standards when looking at safety and if these regulations are stricter than their service regulation they must apply these standards and regulations. They must also know Alcohol, Tobacco, and Firearms (ATF) regulations dealing with A&E and apply those standards if it is required. They must be able to convince people the need for following prescribes explosives safety standards/regulations. They must also work with ammunition cleanup sites insuring that safety laws and regulations as well as industry standards are followed. They should be good at solving problems.

The military is not the only industry to use explosives safety specialist but are by far the largest employer. Mining and construction also use explosives safety specialist to evaluate hazard and risk from explosives and blasting operations. Ammunition and explosives manufactures also use these professionals. Outside the military explosives safety specialist must apply and be knowledgeable of ATF, OSHA, EPA, NFPA, as well as state and local regulations dealing with safety of A&E.

Related Research Articles

An explosive is a reactive substance that contains a great amount of potential energy that can produce an explosion if released suddenly, usually accompanied by the production of light, heat, sound, and pressure. An explosive charge is a measured quantity of explosive material, which may either be composed solely of one ingredient or be a mixture containing at least two substances.

<span class="mw-page-title-main">Nitroglycerin</span> Chemical compound

Nitroglycerin (NG), also known as trinitroglycerol (TNG), nitro, glyceryl trinitrate (GTN), or 1,2,3-trinitroxypropane, is a dense, colorless or pale yellow, oily, explosive liquid most commonly produced by nitrating glycerol with white fuming nitric acid under conditions appropriate to the formation of the nitric acid ester. Chemically, the substance is an organic nitrate compound rather than a nitro compound, but the traditional name is retained. Discovered in 1846 by Ascanio Sobrero, nitroglycerin has been used as an active ingredient in the manufacture of explosives, namely dynamite, and as such it is employed in the construction, demolition, and mining industries. It is combined with nitrocellulose to form double-based smokeless powder, used as a propellant in artillery and firearms since the 1880s.

A warhead is the section of a device that contains the explosive agent or toxic material that is delivered by a missile, rocket, torpedo, or bomb.

A bomb is an explosive weapon that uses the exothermic reaction of an explosive material to provide an extremely sudden and violent release of energy. Detonations inflict damage principally through ground- and atmosphere-transmitted mechanical stress, the impact and penetration of pressure-driven projectiles, pressure damage, and explosion-generated effects. Bombs have been utilized since the 11th century starting in East Asia.

<span class="mw-page-title-main">Tetryl</span> Chemical compound

2,4,6-Trinitrophenylmethylnitramine or tetryl (C₇H₅N₅O₈) is an explosive compound used to make detonators and explosive booster charges.

<span class="mw-page-title-main">Detonator</span> Small explosive device used to trigger a larger explosion

A detonator is a device used to make an explosive or explosive device explode. Detonators come in a variety of types, depending on how they are initiated and details of their inner working, which often involve several stages. Types of detonators include non-electric and electric. Non-electric detonators are typically stab or pyrotechnic while electric are typically "hot wire", exploding bridge wire or explosive foil.

<span class="mw-page-title-main">Ammonium nitrate</span> Chemical compound with formula NH4NO3

Ammonium nitrate is a chemical compound with the formula NH₄NO₃. It is a white crystalline salt consisting of ions of ammonium and nitrate. It is highly soluble in water and hygroscopic as a solid, although it does not form hydrates. It is predominantly used in agriculture as a high-nitrogen fertilizer.

C-4 or Composition C-4 is a common variety of the plastic explosive family known as Composition C, which uses RDX as its explosive agent. C-4 is composed of explosives, plastic binder, plasticizer to make it malleable, and usually a marker or odorizing taggant chemical. C-4 has a texture similar to modelling clay and can be molded into any desired shape. C-4 is relatively insensitive and can be detonated only by the shock wave from a detonator or blasting cap.

Brisance is the shattering capability of a high explosive, determined mainly by its detonation pressure.

ANFO ( AN-foh) (or AN/FO, for ammonium nitrate/fuel oil) is a widely used bulk industrial high explosive. It consists of 94% porous prilled ammonium nitrate (NH₄NO₃) (AN), which acts as the oxidizing agent and absorbent for the fuel, and 6% number 2 fuel oil (FO). The use of ANFO originated in the 1950s.

<span class="mw-page-title-main">Effects of nuclear explosions</span> Type and severity of damage caused by nuclear weapons

The effects of a nuclear explosion on its immediate vicinity are typically much more destructive and multifaceted than those caused by conventional explosives. In most cases, the energy released from a nuclear weapon detonated within the lower atmosphere can be approximately divided into four basic categories:

"Duck and cover" is a method of personal protection against the effects of a nuclear explosion. Ducking and covering is useful in offering a degree of protection to personnel located outside the radius of the nuclear fireball but still within sufficient range of the nuclear explosion that standing upright and uncovered is likely to cause serious injury or death. In the most literal interpretation, the focus of the maneuver is primarily on protective actions one can take during the first few crucial seconds-to-minutes after the event, while the film of the same name and a full encompassing of the advice also cater to providing protection up to weeks after the event.

<span class="mw-page-title-main">Blast injury</span> Type of physical trauma

A blast injury is a complex type of physical trauma resulting from direct or indirect exposure to an explosion. Blast injuries occur with the detonation of high-order explosives as well as the deflagration of low order explosives. These injuries are compounded when the explosion occurs in a confined space.

The Explosive Shipping Classification System exists as part of the United Nations Recommendations on the Transport of Dangerous Good: Model Regulations. The system describes the classification of explosives, divisions within that class that describe the type of hazard they present and compatibility groups that identify the specific type of explosive substance, and what articles are compatible for transport and storage.

<span class="mw-page-title-main">Anti-personnel mine</span> Form of land mine designed for use against humans

An anti-personnel mine or anti-personnel landmine (APL) is a form of mine designed for use against humans, as opposed to an anti-tank mine, which target vehicles. APLs are classified into: blast mines and fragmentation mines; the latter may or may not be a bounding mine.

A bomb suit, Explosive Ordnance Disposal (EOD) suit or a blast suit is a heavy suit of body armor designed to withstand the pressure generated by a bomb and any fragments the bomb may produce. It is usually worn by trained personnel attempting bomb disposal. In contrast to ballistic body armors, which usually focus on protecting the torso and head, a bomb suit must protect all parts of the body, since the dangers posed by a bomb's explosion affect the entire body.

Process safety is an interdisciplinary engineering domain focusing on the study, prevention, and management of large-scale fires, explosions and chemical accidents in process plants or other facilities dealing with hazardous materials, such as refineries and oil and gas production installations. Thus, process safety is generally concerned with the prevention of, control of, mitigation of and recovery from unintentional hazardous materials releases that can have a serious effect to people, plant and/or the environment.

An explosion is a rapid expansion in volume of a given amount of matter associated with an extreme outward release of energy, usually with the generation of high temperatures and release of high-pressure gases. Explosions may also be generated by a slower expansion that would normally not be forceful, but is not allowed to expand, so that when whatever is containing the expansion is broken by the pressure that builds as the matter inside tries to expand, the matter expands forcefully. An example of this is a volcanic eruption created by the expansion of magma in a magma chamber as it rises to the surface. Supersonic explosions created by high explosives are known as detonations and travel through shock waves. Subsonic explosions are created by low explosives through a slower combustion process known as deflagration.

A sympathetic detonation, also called flash over or secondary/secondaries (explosion), is a detonation, usually unintended, of an explosive charge by a nearby explosion.

Blast-related ocular trauma comprises a specialized subgroup blast injuries which cause penetrating and blunt force injuries to the eye and its structure. The incidence of ocular trauma due to blast forces has increased dramatically with the introduction of new explosives technology into modern warfare. The availability of these volatile materials, coupled with the tactics of contemporary terrorism, has caused a rise in the number of homemade bombs capable of extreme physical harm.

References

↑ Hoek, Bart (2004). "Military Explosives and Health: Organic Energetic Compound Syndrome?". Medicine, Conflict and Survival. 20 (4): 326–333. doi:10.1080/1362369042000285955. ISSN 1362-3699. JSTOR 27017607. PMID 15688883.
↑ Jonas A. Zukas, William P. Walters (2002). Explosive Effects and Applications. Springer. pp. 305–307. ISBN 0-387-95558-5.

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[1] Hoek, Bart (2004). "Military Explosives and Health: Organic Energetic Compound Syndrome?". Medicine, Conflict and Survival. 20 (4): 326–333. doi:10.1080/1362369042000285955. ISSN 1362-3699. JSTOR 27017607. PMID 15688883.

[2] Jonas A. Zukas, William P. Walters (2002). Explosive Effects and Applications. Springer. pp. 305–307. ISBN 0-387-95558-5.

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