Brisance
Definition
The shattering power of a detonating explosive, distinct from heave (bulk displacement). Measured by the Trauzl lead block test. High-brisance explosives (RDX, PETN) shatter rock and steel close to the charge; low-brisance materials cause displacement.
- Measured by
- Trauzl lead block test, Hess plate-dent test
- High-brisance examples
- RDX, HMX, PETN
- Driven by
- Rate of pressure rise (dP/dt) in the detonation zone
Common questions
What's the difference between brisance and blast overpressure?+
Brisance is the shattering effect, caused by how fast pressure rises in the detonation zone. Blast overpressure is the bulk push that displaces material. High-brisance explosives shatter rock and steel nearby, while low-brisance materials cause more heave and displacement.
How is brisance measured?+
Brisance is measured using standardized tests like the Trauzl lead block test or the Hess plate-dent test. These measure the crushing and shattering effect of the detonation to classify explosives by their fragmentation power.
Why does brisance matter in forensic investigations?+
Brisance helps identify the type of explosive used. High-brisance secondaries like RDX, PETN, and HMX leave shattered fragments and crush materials in contact with the charge, while low-brisance explosives leave more intact structural displacement. Blast damage patterns at a scene reflect the brisance of what was detonated.
Related terms
- Deflagration
- A subsonic combustion front propagating through an explosive by thermal conduction. Characteristic of low explosives such as black powder and smokeless powder;...
- Detonation
- A supersonic shock wave coupled to a chemical reaction front, propagating through a high explosive at velocities between approximately 4,500 and 9,100...
- Deflagration-to-Detonation Transition (DDT)
- The acceleration of a deflagrating burn front to supersonic detonation velocity, triggered by confinement. Relevant to understanding how improvised devices using low...
- Oxygen Balance
- A percentage expressing the surplus or deficit of oxygen in an explosive molecule relative to stoichiometric complete oxidation of carbon to CO2...
- Primary Explosive
- A high explosive sensitive enough to detonate from friction, spark, percussion, or flame without confinement or a separate booster. Examples: mercury fulminate,...
- Secondary Explosive
- A high explosive insensitive to normal friction, spark, and percussion; requires a primary explosive shock or blasting cap to initiate detonation. Examples:...
- ANFO
- Ammonium nitrate fuel oil: 94% ammonium nitrate prills + 6% diesel fuel oil. Detonation velocity approximately 4,500-4,800 m/s. The most widely used...
- Chapman-Jouguet (CJ) Condition
- The steady-state condition in a detonating explosive at which the coupled shock and reaction zone travel at the same velocity (the detonation...
- Chapman-Jouguet Velocity
- The minimum stable detonation velocity for a given explosive at a specific density, a thermodynamic property of the explosive composition. Used to...
- Detonator
- A small initiating charge of primary explosive (lead azide, lead styphnate, mercury fulminate or DDNP) that converts an electrical, mechanical or pyrotechnic...
- DMDNB Taggant
- Dimethyldinitrobutane, a detection marker incorporated into plastic explosives (including Semtex) under the ICAO 1991 Convention on the Marking of Plastic Explosives; allows...
- Dynamic Pressure
- The pressure component due to mass flow of gas behind the shock front, proportional to gas velocity squared; the blast wind that...
Explained in these topics
- Blast Dynamics: Overpressure, Fragmentation, Deflagration vs DetonationThe shattering power of an explosive, governed by the rate of pressure rise (dP/dt) in the detonation zone rather than total energy; measured by the Hess plate...
- Explosives Classification: Low vs High, Primary vs SecondaryThe shattering power of a detonating explosive, distinct from heave (bulk displacement). Measured by the Trauzl lead block test. High-brisance explosives (RDX,...
- Explosives Classification: Low, High, Primary, Secondary, TertiaryThe shattering or crushing effect of a detonation, distinct from the push or heave effect of blast overpressure. High brisance materials (HMX, PETN, RDX) shatt...
- Explosives: Definition, Types and ClassificationThe shattering effect of an explosive, related to how fast the pressure peak rises. High-brisance secondaries (RDX, HMX, PETN) shatter steel; low-brisance comp...