Huntsman can correct me on this if I'm wrong (and I possibly am), but having tons of explosives just ready to blow through an existing network of detonators and wiring could be tripped simply by a maintenance worker accidentally sending a charge through the system, or even a power surge from the local hydro utility. Who in his right mind would write an insurance policy for such a building?
The whole idea just seems perposterous to me.
Well, there's electric and non-electric. Electric is wires, and could be set off by somebody, say, accidentally cutting through both an electrical wire and the detonator wire. The blasting caps use volatile explosives, and are sensitive. Speaking of which , they don't survive long (sahort shelf life), something someone should point out to Mr. Loony-concrete-core.
Non-electric uses MDI (Modern Demolition Iniation). This is basically a plastic tubing, lined on the interior, that will transmit a shock wave down the length. Also detonator cord could be used, but that's gone pretty much out of fashion (det cord on your foot would take off your toes...MDI is safer). However, detonator cord is sensitive to heat and fire (one short circuit or one cord too close to an HVAC and boom). MDI, while not likely to explode, IS likely to fail. Like all plastics, it becomes more brittle with age and tends to crack. Also, specific to MDI, the interior coating inside the tubing can fall off with too much handling, making a "break" in the line. Finally, any moisture in the line will stiop the transmission and cause the system to fail.
Anyway, C-4 is what's called a secondary explosive: relatively stable and safe under most conditions. You can burn it, jump on it, chew it, twist it, throw it, and it isn't going to go boom. To make it go boom, you need a detonator, which is a small explosive that produces extreme shock and heat pulse. These primary explosives, however, are likely to be set off by static electricity, a stray spark, heat, flame, and anything else. To give an idea, gunpowder can be used as a primary explosive for a detonator (a round with the bullet removed can be crimped over your initiation system). So, things such as shorts, sparks, excess heat, local fires, etc, could set them off. If they happen to be in that block of C-4 at the time...