Conventional Breaching

Question 1

Critical factors to success:

Answer 1

Size, shape, placement and tamping

Question 2

Breaching charges will not cut ____

Answer 2

Rebar

Question 3

Use ____ formula on rebar

Answer 3

P=D

Question 4

Charge thicknesses

Answer 4

0 to less than 5lb = 1”
5 to 40lb = 2”
40 to 300lb = 4”
300lb or more = 8”

Question 5

Breaching charge formula

Answer 5

P = (R^3)KC
P = pounds TNT
R = breaching radius
K = constant for material factor
C = tamping factor

Question 6

Breaching radius

Answer 6

Thickness of the material that needs to be destroyed in feet

Question 7

K

Answer 7

Strength and hardness of the target material

Question 8

C

Answer 8

Tamping factor, depends on charge location and material

Question 9

Tamp to ____ than the breaching radius

Answer 9

Equal or greater

Question 10

External breaching radius rounding

Answer 10

Thickness of target, round breaching radius up to the nearest 1/2 foot

Question 11

Internal breaching radius rounding

Answer 11

1/2 the thickness of placed in the center, remaining thickness if not in the center.
Round internal radius up to nearest 1/4 foot

Question 12

Determining material type

Answer 12

Assume target consists of strongest material in each group if material cannot be positively identified. Always assume concrete is reinforced if unknown and masonry is first class.

Question 13

Tamping factors

Answer 13

Do not consider a charge fully tamped unless it is covered at a depth equal to or greater than breaching radius.

Question 14

Number of charges formula

Answer 14

N = W/(2R)

If N is less than 1.25, use 1 charge
If N is 1.25 to less than 2.5, use 2 charges
If N is 2.5 or greater, round off to nearest whole number

Question 15

Counterforce charge effective against masonry or concrete columns ____ thick or less.

Answer 15

4 feet

Question 16

Counterforce charge. Obstacle must have at least ____ free faces

Answer 16

3

Question 17

Counterforce charge relies on

Answer 17

Shockwave collision

Question 18

Counterforce rounding

Answer 18

Round up to nearest 1/2 foot. External charge

Question 19

Counterforce charge only works on ____

Answer 19

non reinforced concrete

Question 20

Counterforce charge formula

Answer 20

P = 1.5 x Br

P = pounds of plastic explosive 
Br = breaching radius, 1.5 times thickness of the target

Question 21

Counterforce charge priming

Answer 21

Rear center of charges with blasting cap or m151/m152. Detonate simultaneously.