Low and high order detonation in tetryl leiper 1996. What is the difference between low and high explosives. Whether the mine is on the surface or is buried underground, the detonation or deflagration of either a high or low explosive in a confined space can be used to liberate a fairly specific subvolume of a brittle material in a much larger volume of the same or similar material. An explosive is classified as a low or high explosive according to its rate of combustion. Erratum page 50 lines 6 and 7 from the bottom should read.
Low velocity detonation lvd in a solid explosive from input shocks below the threshold for high velocity detonation hvd had been previously reported for pbxn109 in two gap tests with sample diameters of 36. For example wood is often used as fuel but trees do not explode unless that are hit in an electrical storm. Before a fire or explosion can occur, three conditions must be met simultaneously. Is fuel classified as a low explosive, or high explosive. Explosives may also be categorized by their sensitivity. The detonation behaviour of tetryl has been investigated by analysing published charge diameter effect data for two mesh sizes of powders, using slightly divergent flow theory. Under normal conditions, low explosives undergo deflagration at rates that vary from a few centimeters per second to approximately 400 metres per second.
High explosives and propellants 0080238335 flexicover. Hazardous materials chemical warfare agents biological index radiological isotopes reference pesticides and herbicides explosives, including atf bombs methamphetamine production precursors it will also inform first responders about. Trace fire and safety trace fire protection and safety. The low nitrogen form of nitrocellulose is soluble in acetone and an etheralcohol mixture. A high explosive burns at a very rapid rate and detonates instantaneously. Why shouldnt high speed mills be used in preparing the sample for moisture determination. Solid propellants are usually made from low explosive materials, but may include high explosive chemical ingredients that are diluted and burned in a controlled way deflagration rather than detonation. However, only the two general classes, high and low, are covered in this chapter. Low explosives are mixtures of chemicals that burn very rapidly, but. What is the difference between high explosives and low. Question 1 what is the difference between a high e.
In a softer or highly jointed rock, a low velocity explosive, for example,anfo with a heaving action may give satisfactory results at a. Explosives are classified as low or high explosives according to their rates of decomposition. What is the difference between a low explosive and a high explosive. What are the differences between low explosive and high. What makes an explosive effective at different jobs. Ahigh explosive may be a pure compound or a mixture of several. They may contain nitrogen and inorganic substances or mixtures of both. Lower and upper explosive limits for flammable gases and vapors. What are the differences between low explosive, explosive. To distinguish between them, the potassium nitrate and sodium nitrate. High explosives high explosives are usually nitration products of organic substances. Loworder detonation in solid high explosives nature.
What is the difference between primary high explosives and and secondary high explosives. What is the difference between high explosives and low explosives. Question 1 what is the difference between a high explosive and a low explosive. Whats the difference between a high explosive and a low explosive. Similar phenomenon has now been observed for the highly insensitive pbxih140, whose critical diameter of 100 mm required an even larger gap test with a sample diameter. Charging and firing of shots clearing of fumes produced during shotfiring.
High explosives, such as c4 and tnt, expand more rapidly, generating much greater. Because high explosives do not require oxygen or any other coreactant, they. Explosions may be supersonic as in the case with detonations using high explosives like pentaerythritol tetranitrate petn or subsonic and initiated by deflagration combusting materials via heat transfer of low explosives like gun powder, as seen in fireworks or. Whats the difference between an explosive, a propellant. High and low explosives may be further classified by their reaction, composition, or service use. Lower and upper explosive limits for flammable gases and. Trace fire and safety consultants, ltd is a consulting firm that provides investigative and consultative services in the areas of fire, arson and explosion investigation, safety auditing and managment, industrial accident investigation and osha. For the reports conclusions and recommendations, see here. Storage regulations do not apply to binary explosives until mixed. The simple answer is the amount of energy put out by each in equal quantities or even better, the velocity of explosion voe as that is what differentiates between. A low explosive has combustible materials that burn at a slower rate compared to high explosives, producing a large volume of gas. High explosives, upon initiation, function by detonation, a rapid decomposition explosion of the material caused by a shock wave moving through the.
It will inform people of what the peacwmd software is and what it can do. Propellants are generally low explosives because their combustion is much easier to control. For high explosives the velocity, or time of reaction, is high usually in feet per second, as opposed to low explosives, where the velocity is low usually in seconds per foot. Strength was changed in the different grades by varying the amount of explosives used.
The explosive, high nitrogen form is soluble in acetone, but not in etheralcohol mixtures. Primary high explosives are extremely sensitive to mechanical shock, friction, and heat, to which they will respond by burning rapidly or detonating. In low explosives, such as the propellant in a bullet cartridge, the reaction occurs relatively slowly and the pressure isnt as damaging. Facebooktweetlinkedinpinemail this is a section of aoavs report, material harm. Generally, explosives with a lower vod tend to release gas over a longer period and consequently have more heave. For convenience, low and high explosives may be differentiated in the following manner. In general, high explosives are or are based on metastable compounds that function by decomposing into simpler substances. Therefore the difference in gravitational weight between military and improvised explosive devices can result in up to 45% reduction in explosive weight. What is the difference between high and low explosive. With cartridge explosives, the confined velocity is seldom attained because complete confinement is usually impossible.
Heat an explosive reaction of a high explosive is always accompanied by the rapid liberation of heat. Primary unstable and ultrasensative to heat, secondary stable and insensitive to heat, shock, friction. Low explosives are sensitive to heat, friction, and shock and examples of low explosives include. The section exploring homemade explosive materials is here. This newsletter is for aristatek and the peacwmd software. Low explosives like black powder rely on combustion to generate energy. High explosives are usually nitration products of organic substances, such as toluene, phenol, pentaerythritol, arnines, glycerin, and starch, and may be nitrogencontaining inorganic substances or mixtures of both.
High explosives, such as c4 and tnt, expand more rapidly, generating much greater pressure. Whats the difference between an explosion and a detonation. In some cases explosives may be made to fall into either class by the conditions under which they are initiated. A high explosive compound detonates at rates ranging from 1,000 to 9,000 meters per second, and are, conventionally, subdivided into two explosives classes, differentiated by sensitivity. High and low velocity detonation in a highly insensitive. In this video we talk about basics of explosives, constituents of explosives, high explosives, low explosives and difference between them.
A coal miner loading a drill hole with a water gel explosive called tovex. The major difference is that ebws contain no primary explosive. High explosives detonate, and the detonation process is progressive. The following pieces of evidence were found at separate explosion sites. Nxburst safety cartridges for rock breaking geobreak. Low explosives are mixtures of chemicals that burn very rapidly, but subsonically as opposed to supersonically, meaning that they deflagrate. Detonators are used frequently in the laboratorys work.
The properties of the explosive indicate the class into which it falls. Types of chemical explosives explosives and 2 deflagrating, or low, explosives. Hello the difference between an active low and an active high sr flipflop is that with the active low sr flipflop, the system is activated when the inputs to system are zeros while with the. This can happen under higher pressure or temperature, which usually occurs when ignited in a confined space. The popularity of anfo is largely attributable to its low cost and high stability. Tnt developed by alfred nobel in 1860s, first used in a military application in. A bomb blast is an instantaneous chain of events in which an explosive material is rapidly converted into a gas under extremely high temperatures and pressure. The difference in pressures, loads, and speed of forming developed in. Detonation velocity is one of the most important factors in assessing the peak blast pressure and impulses. Created by the primary initiation of a small amount of high explosives using friction. Differences between improvised and military explosive. Diagnostics of production blasts in a deep underground mine.
Often times the word explosive is used interchangeably for propellants and true explosives. Materials that detonate the front of the chemical reaction moves faster through the material than the speed of sound are said to be high explosives and materials that deflagrate are said to be low explosives. Low explosives deflagrate, which means the combustion propagates thermally. High explosives do not have to be contained to produce a violent, shattering effect, while low explosives must be contained to. Two important products were 1 low density ammonia dynamites and 2 semigelatins. Chemical explosives can be classified as low or high explosives. Detonating explosives, such as tnt and dynamite, are characterized by extremely rapid decomposition and development of high pressure, whereas deflagrating explosives, such as black and smokeless powders, involve merely fast burning and produce relatively low pressures. Evidence found within the published data for the existence of high and low order detonation velocities. The vod range in commercial explosives is 25007500 ms. High explosives do not have to be contained to produce a violent, shattering effect, while low explosives must be contained to have the same effect. Based on the speed of the explosion, explosives are categorized as either high order explosives he or low order explosives le. In both detonation and combustion, energy is released when a complex molecule is broken down into simpler constituent parts. The expanding gases only serve to push a small object.
There are many important differences between real explosives high explosives and so called low explosives. No sharp distinction exists between low and high explosives, because of the difficulties inherent in precisely observing and measuring rapid decomposition. Slurry explosive article about slurry explosive by the. In ballistics and pyrotechnics, a propellant is a generic name for chemicals used for propelling projectiles from guns and other firearms. It is perhaps best, then, to differentiate between the terms thermodynamically stable and kinetically stable by referring to the former as inert. A boostersensitive packaged watergel slurry explosive with a density of 1. However, the distinction between these two terms is critical when discussing the pressures formed during a reaction which takes place inside an oxygen bomb. Low explosives black powdere high explosives dynamites and blasting agents ammonium nitrate fuel oil. Contact operations require specific studies of the interactions between the metal, the explosives, and the byproducts. High vod explosives are more suitable in hard rock and low vod in softer rock. In a softer or highly jointed rock, a lowvelocity explosive, for example,anfo. It produces gaseous and solid products as a result.
Uniform mixing of oil and ammonium nitrate is essential to development of full explosive energy. The explosion of low explosives happens within microseconds, while that of high explosives happens within milliseconds. Prior to their development, the density of most dynamites was about the same and was quite high. Explosive, any substance or device that can be made to produce a volume of rapidly. High explosives boosters are sometime spaced along the borehole to assure propagation throughout the column. An explosion is a mechanical process generating a destructive high pressure wave in a fluid. I have obtained similar results in the case of heavily confined cast t. An overview of high order and low order explosives. For blasting in hard rock, a high velocity explosive is preferable. The explosion of low explosives happens within microseconds, while that of high explosives happens within milliseconds no right choice. Do not experiment with explosives the odds are too much against you. Chemical explosives are traditionally divided into two categories. Explosives compositions in general, high explosives are compositions and mixtures of ingredients capable of instantaneously releasing large amounts of energy and doing work of various kinds on.771 462 8 13 1278 1185 912 1393 938 1285 793 760 61 290 869 1524 1043 1108 1112 1423 741 323 853 877 25 176 1263 1245 926 126 242 93 1116 341 442 25 1030 392