TM 9-1375-213-12
firing a single charge or set of charges. If two or more
cord leading to charge detonates but charge fails to ex-
charges are to be fired simultaneously, two detonating
plode, delay investigation until it is certain that charge is
cord ring mains are laid out, and a branch line from each
not burning.
charge is tied into each ring main. Figure 2-17 shows the
(2) If charge is intact, insert new priming.
layout for a nonelectric dual tiring system.
(3) If charge is scattered by detonation of original
NOTE
detonating cord, reassemble as much of original charge as
possible, place new charge if necessary, and reprime.
obtained from dual-detonating cord-primed fir-
Make every attempt possible to recover all explosives
ing systems by extending the cap ends of the
scattered by misfire, particularly those used in training ex-
lead-in detonating cords and tying them together
ercises.
in a square knot or a girth hitch with one extra
2-13. Dual Firing
Systems
turn. For a nonelectric firing set-up the time fuse
There is always a certain amount of danger to personnel
for each cap is sequentially initiated. Assure
investigating misfires. Since duel priming increases greatly
sufficient time fuse is allowed for personnel
the probability of successful firing, it should be used
safety.
whenever possible. Duel priming consists of two complete
2-15. Electric Dual Firing
System
systems independent of each other, and each capable of
This dual tiring system consists of two independent
firing the same charge(s). It can be two electric systems,
electric circuits, each with an electric blasting cap in each
two nonelectric systems, or an electric and nonelectric
charge, so that firing of either circuit will detonate all
system. The main reason for duel priming is reliability
(i.e., prevention of misfires). Rigging a dual priming
wires of the two circuits should be kept separated so that
system for just a few separated charges is usually not
both will not be cut by a single bullet or a single shell frag-
worth the effort. Simple circuits are inherently more relia-
ment. Firing points also should be at two separate loca-
ble than complex ones so dual priming is much more ad-
tions.
vantageous (even necessary) in complex demolition cir-
cuits. Circumstances will of course affect the user's deci-
2-16. Combination Dual Firing
System
sion on whether or not to make the extra effort. In a criti-
The combination dual firing system uses an electric and
cal situation it may well be worth the extra effort to dual
prime even a single charge in order to gain the extra small
primed electrically and nonelectrically. Both the electric
and nonelectric systems must be entirely independent of
each other. The nonelectric system must be fired first.
2-14. Nonelectric Dual Firing System
This consists of two independent nonelectric systems for
Change 4