MCRP 12-10B.1, page 303

Appendix F Obstacles, Mines, and Demolitions Obstacles are used extensively in combat in built-up areas to allow the defender to canalize the enemy, impede his/her movement, and disrupt his/her attack. Section I Obstacles 1. Introduction. Obstacles are designed to prevent movement by personnel, to separate infantry from tanks, and to slow or stop vehicles. (See MCRP 3-17A, MAGTF Breaching Operations.) 2. Types. Antipersonnel mines, barbed wire, boobytraps, and exploding flame devices are used to construct antipersonnel obstacles (Figure F-1). (See FMFRP 13-5/FM 5-34, Engineer Field Data; FM 5-250, Explosives and Demolitions; and FM 3-11, Flame, Riot Control Agent, and Herbicide Operations, for more detailed information.) These obstacles are used to block the following infantry approaches: Streets Buildings Roofs Open spaces Dead space Underground systems. a. The approval authority to boobytrap buildings is normally the GCE commander. This authority may be delegated to subordinate commanders. b. The three types of wire obstacles used in defensive operations are protective, tactical, and supplementary. Wire obstacles should be integrated with other obstacles and covered by fire and observation. (1) Protective wire is usually located beyond hand-grenade range (40 to 100 meters) from the defensive position. (2) Tactical wire is positioned to increase the effectiveness of friendly weapons fire. Tactical wire is usually positioned on the friendly side of machine gun FPLs.