Demolition Flashcards
What are the types of block demolition charges the Army uses?
TNT M112 block (C4) M118 block M118 sheet Ammonium Nitrate M1 Dynamite H6 Cratering Charges
For charges over 500 lbs what’s the safe distance formula?
Distance in Feet = 300 x cube root (lbs of explosives)
Distance in Meters = 100 x cube root (lbs of explosives)
What’s the minimum safe distance for a 500 lb charge when you’re in a missile-proof shelter?
328 feet
Should you ever divide responsibility when preparing, placing, priming, or firing charges?
No.
When should you be 1,000 meters away from a detonation site?
When detonating explosives on steeling, Bangalore torpedoes, and mines. (100 meters if you’re in a missile proof shelter)
What should you never mix during transport?
Explosives and Detonators.
What does 1 meter equal in feet?
3.28 ft
What does 1 kg equal in pounds?
2.20 lbs
What does 1 foot equal in meters?
0.3048 meters
What does 1 lb equal in kg?
4.536 kg
What are the steps to solving a demo problem?
- Identify and measure critical dimensions
- Calculate for TNT/Rule of Thumb
- Divide by RE factor
- Divide by package weight/volume round up to next whole package
- Calculate number of charges
- Calculate total amount of explosives
How close can you be to power lines with electric detonators?
155 meters
What is the formula to cut timber with a tamped, internal charge?
P = D^2/250
What is the formula for cutting timber Abatis?
P = D^2/50
What is the formula for external charges when cutting timber?
P = D^2/40
Where do you place the charges when cutting timber to produce a fall in a desired direction?
On the side you want the fall to happen on.
What are the rules of thumb when blowing a dead stump?
- For dead stumps, use 1 lb of explosive per foot of diameter. Place charge 1 foot deep for every foot of diameter.
- For green stumps, use 2 lbs of explosive per foot of diameter. Place charge 1 foot deep for every foot of diameter.
- For standing timber, increase charge size by 50%
What’s the formula for cutting steel?
P = 3/8 * cross section in in^2
What’s the formula for cutting high-carbon steel, alloy steel, or slender steel members?
P = D^2
What are the rules of thumb for cutting mild circular sections such as chains, rods, and cables?
- Less than 1 inch in diameter, use 1 lb of TNT
- More than 1 inch but less than 2 inches use 2 lbs of TNT
- Over 2 inches use P = 3/8 x Area
What are the rules of thumb for Special Demolition Techniques?
- For railroads 5 inches or higher, use 1 lb of any explosive.
- For railroads less than 5 inches, use 1/2 lb of any explosive.
- For a ditch that measures a cubic yard of earth, use 1 lb of explosive.