3.0 Flashcards
(37 cards)
Define “Critical Diameter” of an explosive.
Minimum explosive diameter at which the combustion / detonation process, once initiated, will support itself until the exp is fully consumed and detonation is complete.
Define “Detonation Velocity.”
Speed at which the detonation shockwave travels through material.
Describe what happens during the positive phase of an explosion.
The blast pressure wave moves outward from the detonation point. The leading edge delivers a violent force. The phase is short, but destructive.
Describe what happens during the negative phase of an explosion.
Known as suction phase. It lasts 3 times longer in duration, a vacuum is formed at the detonation point, and the vacuum causes displaced air to reverse back to the detonation point.
Which of the two phases of an explosion is longer in duration?
The Negative Phase
Describe what the “shape charge effect” is and what three components of a shape charge are required to produce this effect.
Effect is created when a shape charge is detonated when a cavity of a shape charge is lined with metal or glass. The explosion will produce a narrow, deep hole greater than a shallow crater.
1. Cone Angle, 2. Linear, 3. Standoff.
Why does damage to a structure occur at a lower PSI value compared to injury of humans.
Structures have a larger surface area and are rigid compared to human tissue.
What is the PSI created inside a wood framed structured room with a volume of 10’ x 10’ x 12’ by an explosive charge weighing 4 ounces (TNT)
5.39
What predicted damage (if any) can be expected to this portion of the structure.
Windows will shatter. Frames will fall. Walls and roof rafters will crack. Ceiling tile will collapse. All mirrors, glass, light bulbs will shatter.
List 5 reasons why internal breaching may not be as practical as other methods.
- Fire / Breathing hazard
- Time factor to place charge / position deps.
- Type of barrier
- Vision obscure
- Fragmentation of the charge / barrier.
What is a “K-factor” and which value is used to calculate fragmentation hazard distances?
A constant numerical value for a specific PSI value used in the main equation for calculating safe separation distances and PSI distances to/from detonation.
What hazards could be produced during breaching operations using explosives?
- Blast - over-pressure.
- Fragmentation
- Fire
- Smoke / Fumes
When an explosive charge is selected for a given breach point that doesn’t exceed the required net explosive weight, the hazard to over-pressure is only outside the objective instead of inside. (T or F)
True
What two factors determine the type of configuration of an explosive charge to be utilized?
- Explosives available
2. Intended breach point.
What of the following are NOT one of the basic types of charge configurations?
A) Shape Charge Conical
B) Oval
C) Strips
D) Placement between non compressible mediums
A) Shape charge conical
Why must the net explosive weight of a charge be calculated?
To determine the potential damage of a charge to the surrounding area. It is also used to determine the safe distance from the charge from over-pressure.
Explain what is meant by the “relative effectiveness” of an explosive and what explosive is used to compare the work potential of all other explosives.
The destructive potential of an explosive is compared to the work of TNT. The R.E. is the numerical value comparison.
Aside from SW060-AA-MMA-0110 (Demolition Materials), which is used in this course, there are numerous credible sources for finding the relative effectiveness for an explosive, many which conflict. (T or F)
True
An explosve charge consists of 54 gr/ft det cord, 10 grams of a 20gram booster, 24” of 125gr/ft flexible linear shaped charge, and a 6” x 6” square of C-2 explosive sheet.
A)What is the NEW in TNT?
B) What is the MSD for team personnel?
C) What is the maximum limit of the frag hazard zone?
D) What distance could damage to reinforced concrete walls occur that leave rebar exposed?
E) What distance could complete destruction to a metal (butler type) building occur?
A) 1.0
B) 18 feet
C) 328 feet
D) 10 feet
E) 20 feet
A fracture charge consists of 54 feet of 50gr/ft det cord and 21 squares of C-8, 3” x 3” explosive sheet.
A) What is the NEW in TNT?
B)What is the MSD for team personnel?
C) At what distance could a wood framed structure collapse?
D) What distance could residential windows shatter?
A) 6.17
B) 33 feet
C) 28 feet
D) 138 feet
A charge consists of 2’ of 50gr/ft det cord, 5 grams of a 20 gram booster, and 6’ x 1” strip of C-6 explosive sheet.
A) What is the NEW in TNT?
B)What is the MSD for team personnel?
C) At what distance could asbestos shingles shatter?
D) What distance could residential windows break?
E) What distance will corrugated aluminum paneling buckle?
A) 1.62
B) 22 feet
C) 53 feet
D) 88 feet
E) 88 feet
List three courses of action that can be used to protect the team personnel from fragmentation.
- Breach point clear of debris and loose objects.
- Place charge so fragmentation travels away from team.
- Use natural cover and/or ballistic shields.
What are basic type of charge configurations?
- Strips
- Between non compressible mediums
- Ovals and Squares.
All firing systems should be dual primed. (T or F)
True
