This appendix describes general techniques for the employment of breaching materials. FMs 5-25, Explosives and Demolitions, and 5-34, Engineer Field Data, provide detailed information.
Frequently, infantrymen will be required to employ explosives and demolitions without engineer assistance. The most common demolition requirement for assaulting infantry is the breaching of walls, ceilings, and floors. Complicated destruction/denial missions should only be attempted by skilled combat engineers.
BREACHING EXTERIOR WALLS
One of the most difficult demolition operations is the breaching of masonry and reinforced concrete walls. When faced with a requirement of this nature, C-4 is the ideal explosive for the infantry soldier. Normally, buildings have walls 61cm (2 feet) or less in thickness. Assuming that all outer walls are constructed of reinforced concrete, a good rule of thumb for breaching is to tie or tape 4.5 kg of C-4 on a pole, place it against the target between waist and chest height, and detonate. This will normally blow a hole large enough for a man to get through. If his charge is not elevated at least one wall thickness above the base of the wall, the charge will not create the desired effect.
Figure E-1. Breaching Wall With C-4
Metal reinforcing bars will not be cut by this charge. Once exposed, they can easily be removed by using the following rule of thumb for cutting reinforcing bar:
NOTE: Before attempting to cut reinforcing bar, handgrenades should be thrown into the opening created by the breaching charge.
BREACHING INTERIOR WALLS
Holes can be readily blown in interior walls by using C-4 or Flex-X. Although Flex-X explosives have adhesive backing, additional means must be taken to secure charges to the walls. When using C-4, one block should be cut into three equal parts. They should be placed on the wall at an equal distance, from neck to knee height. The charges should be primed with detonating cord or three electric blasting caps to obtain simultaneous detonation.
With Flex-X there are four sheets per package. Use two sheets placed against the wall at midchest and midthigh height. Prime in the same manner as with C-4. When emplaced as described, these charges will effectively blow a hole in an interior wall (not concrete) large enough for a man to get through.
NOTE: When using time fuse, care must be taken by the members of the search team to insure that enough time is available to get out of the room and take cover. The overpressure caused by the explosion in a room can cause casualties.
Figure E-2a Breaching With C-4
The claymore mine contains .67kg of C-4 explosive. It can knock doors down, breach thin walls, and destroy minor obstacles in a building.
When using claymore mines to breach interior walls, tamping material such as sandbags should be used to increase their effectiveness and reduce the amount of explosive force directed to the rear.
Figure E-2b Breaching with Claymore (C-4)
The greatest danger to personnel from demolitions is the debris and fragments thrown by the explosion. Leaders must insure that measures are taken to protect personnel and equipment from injury or damage. The distances listed below indicate the minimum safe distances from bare charges for persons in the open.
EXPLOSIVE IN SAFE DISTANCE KILOGRAMS POUNDS IN METERS
1-12 1-27 300
13.5 30 311
18 40 342
22.5 50 369
45.0 100 465
NOTE: These distances will be modified in combat when troops are in other buildings, around corners, or protected by intervening walls.
DO NOT: Take chances.
Handle explosives carelessly. Divide responsibility for explosive work. Mix explosives and detonators. Carry explosives or caps in pockets.
DO: Keep the blasting machine under the control of a NCO.
Wear helmets at all times while firing explosives.
Handle misfires with extreme care.
Clear the room and get people protected when blowing interior walls.
Prepare some charges, minus detonators, beforehand to save time.
Carry enough demolitions for your needs.
Use C-4 to breach hard targets (masonry construction).