Detonating cord
Encyclopedia
Detonating cord is a thin, flexible plastic tube filled with PETN (Pentaerythritol tetranitrate). With the PETN exploding at a rate of approximately 4 miles per second, any common length of det cord appears to explode instantaneously. It is a high-speed fuse
which explodes, rather than burns, and is suitable for detonating high explosives, usually pentaerythritol tetranitrate
(PETN, Pentrite). The velocity of detonation is sufficient to use it for synchronising multiple charges to detonate almost simultaneously even if the charges are placed at different distances from the point of initiation. It is used to reliably and inexpensively chain together multiple explosive charges. Typical uses include mining
, drill
ing, and demolition
s.
"Cordtex
" and "Primacord
" are two of many trademark
s which have slipped into use as a generic
term for this material.
at a very reliable rate (about 7,000–8,000
m/s
), enabling engineers to control the pattern in which charges are detonated. This is particularly useful for demolitions, when structural elements need to be destroyed in a specific order to control the collapse of a building.
While it looks like nylon cord, the core is a compressed powdered explosive
, usually PETN
(Pentrite), and it is initiated by the use of a blasting cap
. Detonation cord will initiate most commercial high explosives (dynamite
, gelignite
, sensitised gels, etc.) but will not initiate less sensitive blasting agents like ANFO
on its own. 25 to 50 grain/foot (5.3 to 10.6 g/m) det cord has approximately the same initiation power as a blasting cap, but along its entire length. A small charge of PETN, TNT, or other explosive booster
is required to bridge between the cord and a charge of insensitive blasting agent like ANFO
or most water gels
.
s per foot in the United States, or in grams per metre elsewhere. A "grams per metre" rating will be roughly one fifth the "grains per foot" rating. For example, "50 grain det. cord" refers to detonating cord which has 50 grains of explosive per foot of length—or approximately 10 g/m. This is a typical "default" rating for connecting charges for blasting; lighter detonating cords may be used for "low noise blasting" and movie special effect
s, while heavier cords, used where the cord is employed to have some direct explosive effect—such as for precision rock carving work—may use 50 to 250 grain/foot (10 to 50 g/m) detonating cord.
for detonation cord is anopin pyykkinaru (mother-in-law's clothesline), as it resembles ordinary clothesline.
In Filipino
, the corresponding word mitsa has come to be used in a phrase “mitsa ng buhay” which translates to "detonating cord of [one’s] life", a metaphor for something that is very likely to cause one’s death via direct jeopardization (e.g. extreme sports, versus smoking).
Fuse (explosives)
In an explosive, pyrotechnic device or military munition, a fuse is the part of the device that initiates function. In common usage, the word fuse is used indiscriminately...
which explodes, rather than burns, and is suitable for detonating high explosives, usually pentaerythritol tetranitrate
PETN
Pentaerythritol tetranitrate , also known as PENT, PENTA, TEN, corpent, penthrite , is the nitrate ester of pentaerythritol. Penta refers to the five carbon atoms of the neopentane skeleton.PETN is most well known as an explosive...
(PETN, Pentrite). The velocity of detonation is sufficient to use it for synchronising multiple charges to detonate almost simultaneously even if the charges are placed at different distances from the point of initiation. It is used to reliably and inexpensively chain together multiple explosive charges. Typical uses include mining
Mining
Mining is the extraction of valuable minerals or other geological materials from the earth, from an ore body, vein or seam. The term also includes the removal of soil. Materials recovered by mining include base metals, precious metals, iron, uranium, coal, diamonds, limestone, oil shale, rock...
, drill
Drill
A drill or drill motor is a tool fitted with a cutting tool attachment or driving tool attachment, usually a drill bit or driver bit, used for drilling holes in various materials or fastening various materials together with the use of fasteners. The attachment is gripped by a chuck at one end of...
ing, and demolition
Demolition
Demolition is the tearing-down of buildings and other structures, the opposite of construction. Demolition contrasts with deconstruction, which involves taking a building apart while carefully preserving valuable elements for re-use....
s.
"Cordtex
Cordtex
Cordtex is a type of detonating cord generally used in mining. It uses an explosive core of pentaerythritol tetranitrate which is inside its plastic coating.It is commonly the thickness of electrical extension cord and "burns" at 2 km per second...
" and "Primacord
Primacord
Primacord is a registered trademark of detonating cord used in blasting, originally manufactured by the Ensign-Bickford Company. Ensign Bickford sold the trademark to Dyno Nobel Inc in 2003 and it is now manufactured in Graham, Kentucky...
" are two of many trademark
Trademark
A trademark, trade mark, or trade-mark is a distinctive sign or indicator used by an individual, business organization, or other legal entity to identify that the products or services to consumers with which the trademark appears originate from a unique source, and to distinguish its products or...
s which have slipped into use as a generic
Trademark
A trademark, trade mark, or trade-mark is a distinctive sign or indicator used by an individual, business organization, or other legal entity to identify that the products or services to consumers with which the trademark appears originate from a unique source, and to distinguish its products or...
term for this material.
Effects
As a transmission medium, it can act as a downline between the initiator (usually a trigger) and the blast area, and as a trunkline connecting several different explosive charges. As a timing mechanism, detonation cord detonatesDetonation
Detonation involves a supersonic exothermic front accelerating through a medium that eventually drives a shock front propagating directly in front of it. Detonations are observed in both conventional solid and liquid explosives, as well as in reactive gases...
at a very reliable rate (about 7,000–8,000
Orders of magnitude (speed)
To help compare different orders of magnitude, the following list describes various speed levels between approximately 1 m/s and 3 m/s. Values in bold are exact.- List of orders of magnitude for speed :-See also:...
m/s
Second
The second is a unit of measurement of time, and is the International System of Units base unit of time. It may be measured using a clock....
), enabling engineers to control the pattern in which charges are detonated. This is particularly useful for demolitions, when structural elements need to be destroyed in a specific order to control the collapse of a building.
While it looks like nylon cord, the core is a compressed powdered explosive
Explosive material
An explosive material, also called 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...
, usually PETN
PETN
Pentaerythritol tetranitrate , also known as PENT, PENTA, TEN, corpent, penthrite , is the nitrate ester of pentaerythritol. Penta refers to the five carbon atoms of the neopentane skeleton.PETN is most well known as an explosive...
(Pentrite), and it is initiated by the use of a blasting cap
Blasting cap
A blasting cap is a small sensitive primary explosive device generally used to detonate a larger, more powerful and less sensitive secondary explosive such as TNT, dynamite, or plastic explosive....
. Detonation cord will initiate most commercial high explosives (dynamite
Dynamite
Dynamite is an explosive material based on nitroglycerin, initially using diatomaceous earth , or another absorbent substance such as powdered shells, clay, sawdust, or wood pulp. Dynamites using organic materials such as sawdust are less stable and such use has been generally discontinued...
, gelignite
Gelignite
Gelignite, also known as blasting gelatin or simply jelly, is an explosive material consisting of collodion-cotton dissolved in either nitroglycerine or nitroglycol and mixed with wood pulp and saltpetre .It was invented in 1875 by Alfred Nobel, who had earlier invented dynamite...
, sensitised gels, etc.) but will not initiate less sensitive blasting agents like ANFO
ANFO
ANFO is a widely used bulk industrial explosive mixture. It consists of 94 percent porous prilled ammonium nitrate , that acts as the oxidizing agent and absorbent for the fuel — six percent Number 2 Fuel Oil...
on its own. 25 to 50 grain/foot (5.3 to 10.6 g/m) det cord has approximately the same initiation power as a blasting cap, but along its entire length. A small charge of PETN, TNT, or other explosive booster
Explosive booster
An explosive booster acts as a bridge between a low energy explosive and a low sensitivity explosive such as TNT. It increases the explosive shockwave from an initiating explosive to the degree sufficient to detonate the secondary charge.Unlike C4 plastic explosive, not all explosives can be...
is required to bridge between the cord and a charge of insensitive blasting agent like ANFO
ANFO
ANFO is a widely used bulk industrial explosive mixture. It consists of 94 percent porous prilled ammonium nitrate , that acts as the oxidizing agent and absorbent for the fuel — six percent Number 2 Fuel Oil...
or most water gels
Water gel explosive
A water-gel is a fuel sensitized explosive mixture that consisting of an aqueous ammonium nitrate solution that acts as the oxidizer. Water gels that are cap-insensitive are not strictly explosives and are referred to as blasting agents....
.
Rating
Detonating cord is rated in explosive mass per unit length. This is expressed in grainGrain (measure)
A grain is a unit of measurement of mass that is nominally based upon the mass of a single seed of a cereal. From the Bronze Age into the Renaissance the average masses of wheat and barley grains were part of the legal definition of units of mass. However, there is no evidence of any country ever...
s per foot in the United States, or in grams per metre elsewhere. A "grams per metre" rating will be roughly one fifth the "grains per foot" rating. For example, "50 grain det. cord" refers to detonating cord which has 50 grains of explosive per foot of length—or approximately 10 g/m. This is a typical "default" rating for connecting charges for blasting; lighter detonating cords may be used for "low noise blasting" and movie special effect
Special effect
The illusions used in the film, television, theatre, or entertainment industries to simulate the imagined events in a story are traditionally called special effects ....
s, while heavier cords, used where the cord is employed to have some direct explosive effect—such as for precision rock carving work—may use 50 to 250 grain/foot (10 to 50 g/m) detonating cord.
Direct employment
Low-yield detonating cord can be used as a precision cutting charge to remove cables, pipes, wiring, fiber optics, and other utility bundles by placing one or more complete wraps around the target. Detcord/Primacord is used in commercial boilers to break up clinkers (solidified coal ash slag) adhering to tube structures. Higher-yield detonating cord can be used to cut down small trees, although the process is very uneconomical compared to using bulk explosive, or even a chainsaw. High-yield detonating cord placed by divers has been used to remove old dock pilings and other underwater obstructions. Creating a slipknot from detonating cord yields a field improvised device that can be quickly employed to cut a locked doorknob off a door. Det cord can be taped in several rings, to the outline of a military man-sized target and detonated, breaching a man-sized hole into wooden doors or light interior walls. Detonating cord is also employed directly in building demolition where thin concrete slabs need be broken via channels drilled parallel to the surface, an advantage over dynamite since a lower minimum of explosive force may be used and smaller diameter holes are sufficient to contain the explosive. Anything much more substantial than these uses requires the use of additional explosives.Colloquialisms
The Finnish army colloquialismColloquialism
A colloquialism is a word or phrase that is common in everyday, unconstrained conversation rather than in formal speech, academic writing, or paralinguistics. Dictionaries often display colloquial words and phrases with the abbreviation colloq. as an identifier...
for detonation cord is anopin pyykkinaru (mother-in-law's clothesline), as it resembles ordinary clothesline.
In Filipino
Filipino language
This move has drawn much criticism from other regional groups.In 1987, a new constitution introduced many provisions for the language.Article XIV, Section 6, omits any mention of Tagalog as the basis for Filipino, and states that:...
, the corresponding word mitsa has come to be used in a phrase “mitsa ng buhay” which translates to "detonating cord of [one’s] life", a metaphor for something that is very likely to cause one’s death via direct jeopardization (e.g. extreme sports, versus smoking).