Slightly Unrelated Explosives Question

[Alrik Vas]

So i know we've got some former military in the community as well as some folks who love equations (i mean...you're smarter than me...) so I've got a challenge if anyone feels up to it.

20 pounds of C-4 vs a reinforced stone corridor under 30ft of hard earth. The hallway is twelve feet wide and ten feet high, lots of steel doors (they appear every twenty feet). It would be considered an SDC structure. Walls of the hall are about 18 inches thick, reinforced with three inch iron beams. The charge is inside the hallway, against one of the walls.

Obviously, what happens?

Next, how much MDC (if any) would 20 lbs of C-4 do?

Lastly, what's the equivalent in TNT?

I tried a little research of my own, but I don't understand the equivalency chart and my google-fu is not best.

[ShadowLogan]

Rifts Mercenaries pg100-1, at least for in terms of game mechanics.

How much damage would 20lbs of C4 Plasique do depends on the type of C4 used:
-SDC type would be 40d4x10+20(or is that 20*20 added and not just 20), that could be simplified down to 1d4x100+400 (or +20), or in terms of MDC 1d4+4?
-NG-2 type: 16*20=320MD
-NG-4 type: 20d4x10 or 2d4x100MD
-NG-6 type would be 40d4x10+20 (or is that 20*20 added and not just 20), that could be simplified down to 4d4x100+400 (or +20)MD

How C4 and TNT compare in game terms could be worked out from the Rifts Mercenaries title, if one knows the weight of a stick of dynamite.

[say652]

A centralized crater ie shapecharge would cause maybe a ten to fifteen foot "tunnel" in the rock. Its Not an unfocused explosion like dynamite. In which case the doors become projectiles cause of the rapid change in atmospheric pressure.

Explosions work by rapidly increasing the gravitional pull of objects around them creating shrapnel.

I watched future weapons. Mack is the man.
I'm sure I forgot about air pressure and rapid particle acceleration but, close eniugh for gov'ment work.

I know a trick or two

[Alrik Vas]

Would this much explosive likely cause a collapse of the tunnel? How much of an area?

[say652]

No. It would shake n rattle but not collapse. C4 focuses the explosion. I mean yea have them suffer from deafness penalties. Eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee is never fun but. I mean I'm sure thats what being caught in an explosion sounds like. O look frost....

[flatline]

Explosions work by rapidly increasing the gravitional pull of objects around them creating shrapnel.

Gravity has nothing to do with it. Shrapnel is simply debris that is accelerated by the force of the explosion.

--flatline

[Alrik Vas]

C-4 is used to blow holes in things because it can be molded, though. I mean, is it a fricken melta charge from WH40k? I doubt that. It's going to explode out. 20 lbs of C-4 is a crap ton of boom. 5lbs can shred a truck.

[say652]

My pops used to run a jackhammer for a granite cimpany. I saw 50lbs of plastique sqare off a forty ton chunk of mountain. Thats how I learned about explosives. By observing and fetching stuff.

If they used four five pound charges. Set, boom one. Set, boom two. Set, boom three. Set, boom four. Freedom. But that falls into mining knowledge. Your average eod guy isn't gonna know that.

[Thinyser]

I'm not an expert but 20 Lbs of C4 is a big boom. Considering its detonation velocity is 26,000 Feet/sec it has the ability to SHATTER concrete that it's place up against (even more so if its set into a hole in the concrete but surface mount will still cause massive damage to the concrete). That shattering effect combined with the massive overpressure in a very confined space (all those doors will limit the gas expansion, though several sets on either side of the detonation will likely blow off hinges and become lethal projectiles) means that the now fractured concrete could be pushed back significantly. The final effect is a partial vacuum caused as the gasses rush outward so fast and rapidly cool, they then rush back toward the center of the explosion.

All told I would say that one section between the 2 sets of doors would have a good likelihood of collapse (75% or more) with a very limited possibility of collapse (5%) in the two adjoining section of hall. SDC beings without fully sealed EBA would die for at least 20m on either side of the explosion from simple concussive trauma from the massive over pressure.

[say652]

Fire laser pistol into desired area. Form a circle. Place charges in holes. Boom. Rinse and repeat until your free.

Have the players roll on demolitions skill. Assign penalty. If mechanical engineering and Math advanced are possessed assign no penalty.

[Alrik Vas]

Thanks for the answers, guys.

[dragonfett]

Fire laser pistol into desired area. Form a circle. Place charges in holes. Boom. Rinse and repeat until your free.

Have the players roll on demolitions skill. Assign penalty. If mechanical engineering and Math advanced are possessed assign no penalty.

I would still assign a penalty for the use of improper tools (the laser guns). If Mechanical Engineering and/or Math: Advanced are not possessed, then increase the penalty.

[say652]

Technically a md weapon could just vaporize enough material to tunnel out but, given the realistic element in Alrics game style I figured making them waste e-clips and the explosives seemed more along his lines.

[wyrmraker]

So i know we've got some former military in the community as well as some folks who love equations (i mean...you're smarter than me...) so I've got a challenge if anyone feels up to it.

20 pounds of C-4 vs a reinforced stone corridor under 30ft of hard earth. The hallway is twelve feet wide and ten feet high, lots of steel doors (they appear every twenty feet). It would be considered an SDC structure. Walls of the hall are about 18 inches thick, reinforced with three inch iron beams. The charge is inside the hallway, against one of the walls.

Obviously, what happens?

Next, how much MDC (if any) would 20 lbs of C-4 do?

Lastly, what's the equivalent in TNT?

I tried a little research of my own, but I don't understand the equivalency chart and my google-fu is not best.

In that tunnel, that much C-4, if not properly prepared for either a cutting or breaching charge, would do very little to the tunnel, if it's not prone to collapse. Any sealed doors would be blown out, but that's about it.

As for Mega-Damage of 20 lbs of C-4? No clue. It'd be better to use the Northern Gun explosives from Rifts: Mercenaries.

[Alrik Vas]

Yeah, MD explosives would be better, but that isn't what I had to work with. Was in the hallway under fire with about ten guys coming at us. Popped smoke, I tossed the charge into the hall and booked it.

Thing is, I know people aren't safe from a grenade unless they're about 30 meters away because of frag. Was figuring the concrete shards would deal out some pain and must of the tunnel section would be collapsed.

GM gave me a break and said it brought the house down.

Anyway, again, thanks for the thoughtful replies.

[say652]

I thought you were being attacked from both ends of the tunnel and were trying to escape.

[wyrmraker]

Yeah, MD explosives would be better, but that isn't what I had to work with. Was in the hallway under fire with about ten guys coming at us. Popped smoke, I tossed the charge into the hall and booked it.

Thing is, I know people aren't safe from a grenade unless they're about 30 meters away because of frag. Was figuring the concrete shards would deal out some pain and must of the tunnel section would be collapsed.

GM gave me a break and said it brought the house down.

Anyway, again, thanks for the thoughtful replies.

Sadly, Palladium doesn't really go into hydrostatic shock when dealing with explosives. 20 pounds of C-4 within such a confined space would be enough to gelatinize bone. Megadamage armor rules aren't meant to deal with that sort of thing.

[say652]

20lbs of dynamite would jellyfy a people. C4 is a more focused localized explosion.

[wyrmraker]

20lbs of dynamite would jellyfy a people. C4 is a more focused localized explosion.

C-4 is more focussed and localized when shaped into a purposed charge, such as a cutting or shaped charge. A lump of it just sitting there will explode just like any other explosive.