Handling explosives. (in combat)

I don't know how they work, so.

If you enter a building, and there's a grenade outside(like say, right next to the wall of the building) what would happen to the wall, and if the wall wouldn't be destroyed, what would happen to a window that was like 5 feet away from that grenade? What about the fire(can't think of a better term off the top of my head) from the explosion? Where does it go? Will the fire suddenly start filling the inside of the building, or would it not?

How hot is it near a typical grenade's explosion (but far away enough to not touch the fire from it?)

Is it possible for a human to survive one? If so, is there equipment to increase the chances of doing so?

What if a grenade is inside a tank's barrel, and it detonates with whatever is supposed to keep things out from the tank left open? (there's a crew inside it)

Explosions essentially have the same effect as a certain area being filled with really fast fire, right?

What can a large artillery shell do? Can it tear through several buildings like they were made of balsa wood? Can the explosion wipe out stone walls?

What if it's going against a modern battleship? How much damage would it cause?

Same questions for other explosives, like missiles and whatnot.

Well, first of all, there are different types of grenades. The most common one is the anti-personnel fragmentation grenade. It functions by sending fragments of its metallic casing into all directions at high speeds, hence the name. They are called anti-personnel because they are designed to tear biological tissue to shreds. As such, they are hardly effective against armored targets (unless you get one inside, which is guaranteed to kill the pilots).

To address your questions, I'll assume we are talking about the modern standard issue American M67.

• A brick wall offers a very good defense against a frag grenade, and the fragments will not penetrate it. Moreover, the fact that the grenade lies at the base of the wall means that all fragments will likely ricochet of it into the opposite direction.
• I don't think that anything will happen to the window unless it is hit by the fragments, in which case it will probably shatter or at least crack. Glass is hard.
• I am not sure about the incendiary potential of an M67, but I do not think it is very high. The purpose of a frag grenade is to flush out the defenders, not to start a fire (it's what incendiary grenades are for). The fire can start if the overheated fragments hit a flammable substance like petroleum.
• The fire "dies" as soon as all explosive substances in the grenade burn up, which is in the first milliseconds after the explosion.
• The fire cannot even enter the building if the grenade lies outside. If a grenade explodes indoors, the fire won't be a problem either (see above on incendiary potential) but the fragments that ricochet off walls will.
• Again, it's not fire that kills you but the fragments. If you are standing within 5 m of a grenade, the heat will be the least of your problems.
• The M67s are designed to be lethal within 5 meters and wounding within 15 m. So if you are standing right next to a grenade without any cover, you are pretty much dead. Of course, if you are wearing some kevlar and you have exceptional luck and medical treatment immediately afterwards, you may survive despite hideous injuries, but your chances aren't high. On a side note, Jumping on a Grenade before it explodes will cause it to discharge most fragments into your body, significantly reducing the injuries of other bystanders.
• The bombsuits are designed to reduce the risks of bomb disposal, so I guess they help against grenades, as well. But your best defense is to run like hell and take cover behind something heavy and solid, like a wall.
• If a grenade explodes inside a tank barrel, it will probably mess up the barrel and yes, some fragments will travel inside the tank and possibly kill whoever is loading the gun at the moment. But that will depend largely on the model and construction of the tank. A much better idea would be to throw a grenade into the tank's open hatch to kill all of the crew at once, or to aim for the tracks to stop the tank for good, or to use a specialized anti-tank grenade.
• Not the frag grenade explosions. You are probably thinking of high power explosives like the C4 or dynamite. These ones indeed explode in a large fireball of superheated plasma. However, their main threat lies in the impact wave, which travels by air at supersonic speeds and can shatter glass and even walls when it hits. The size of the fireball and impact wave of a frag grenade is much smaller.
• A large artillery shell, if it doesn't carry explosions is just a heavy chunk of metal. However, since it travels at very high speeds, it impacts with force equivalent of explosion. And yes, artillery shells can punch through walls, though specially reinforced bunkers are designed to withstand it. It is also notable that large cannons like the Big Bertha went out of style with the advent of modern aviation.
• A significantly large shell will penetrate the battleship's hull or cause considerable damage to its facilities. However, the ship is likely to stay afloat due to its construction until it takes a few more hits. Again, however: the battleships also went out of style with the advent of modern aviation and aircraft carriers because a bomber aircraft has all the advantages over a long range artillery gun, including ones mounted on battleships.
• As for other explosives, I have already described the high explosives, commonly known as "bombs": they hit with the shockwave and the heat and they will shatter walls and kill everyone inside, starting a few fires along the way. This includes bombs deployed manually, aircraft bombs, explosive artillery shells, etc.
• Missiles are basically bombs with additional guiding mechanism. They home in on the target, hit it and explode. Some missiles, especially anti-tank ones additionally have a mechanism that burns through the armor before exploding, ensuring the death of the crew inside.
• The idea with the fire spreading inside is possible with incendiary grenandes/bombs, which don't explode that much but burn very hot. You may know of Molotov's cocktails, which is basically a bottle of incendiary liquid that shatters on impact and makes everything around it burn.

There are multiple, connected threads of questions here.

High explosives create a shockwave at approximately 8 kilometres per second. They don't "burn" per se, but the high pressures created by the shockwave raise temperatures high enough to set fire to combustables that are close enough to the explosion. A typical hand grenade will contain 180 grams of high explosive. If you toss one on a dirt road, it will kick up a bunch of dust. If you toss one in a bucket of gasoline, it will create a fireball. High explosives "detonate", which is a chemical decomposition converting solids to gasses. Low explosives "deflagrate" which is, effectively, a fire burning really fast.

There are basically three types of "artillery" shells. Artillery proper tend to use high explosive fragmentation rounds which amount to being hand grenades on steroids. Although not designed to take out armoured vehicles, a direct hit will cave in the hull of a lightly armoured vehicle like an APC. Anti-tank cannons use either chemical (ie explosive) penetrators or kinetic penetrators. Chemical penetrators use a shaped charge that looks like an inside out cone. The shape causes most of the blast to be directed forward against a layer of metal that is vapourized by the blast forming a plasma jet that melts through the armour. While effective against metal armour, shaped charges are less so against brick or ceramics which don't melt the same way metal does. Plus there are other measures that can be used to disrupt the plasma jet such as layered, composite armour like Chobham (which also uses ceramic plates). A kinetic penetrator is like a giant, high density bullet or dart that rips through the armour at high speed. While there are no high explosives, you will get something akin to an exposion when 20 pounds of tungsten and depleted uranium crashes into something at more than twice the speed of sound.

A grenade placed right against a brick was would cause some damage, but probably wouldn't blow a hole through it, unless you "tamped" it (pack dirt or other material on top of it to direct more of the blast against the wall rather than dissipating into thin air. Nearby windows can be shatter by the air pressure of the blast, particularly if they are sealed shut. This becomes even more so if the grenade goes off inside a sealed room as the pressure has no where else to vent.

On open ground an M67 is considered effective out to 18 metres, although the fatality radius is smaller and the shrapnel can cause injuries out to 100 metres. If you are under cover, you can suffer ear damage out to a metre or two. In an enclosed space, even if under cover, the pressure from the blast will rupture your ears and probably several internal organs.

Kevlar and such will stop the shrapnel but it would take specially designed armour to protect against the blast, such as that used by bomb disposal units like in The Hurt Locker . Even then, you still would need a few metres between you and the grenade.

Not sure about the grenade in the gun barrel. Rule of thumb is that you need a 500 gram block of C-4 to cleanly cut an inch of steel plating. Of course, since the barrel would enclose the blast it would do a lot more damage than in the grenade was on the outside.

Modern anti-tank cannons are able to penetrate 650 mm or more of steel armour. Infantry missiles max out at about a metre of armour (which is not enough to take out and M 1 A 1 on its front armour because the Chobham effectively doubles the protection against missiles and other chemical penetrators).

Iowa class battleships are listed as having 200mm to 500mm of armour so anti-tank weapons could penetrate the armour, but they would only punch a small hole, relative to the size of a battleship. The plasma jets created by the shaped charges are only a few inches in diameter.

edited 26th Dec '10 2:04:38 PM by 66Scorpio

^Didn't know exactly how much high explosives a handgrenade contains, thanks. Yeah, with 180g, the shockwave should be considered, too.

One thing I would like to add to what has already been said:

Real explosions, unlike movie explosions, rarely have fireballs. Real life explosions are usually just a lot of black smoke and a shockwave, while Hollywood adds a lot of petroleum to make them both more impressive and safer to work with.

Mythbusters did some work on that https://www.youtube.com/watch?v=grSa1pMZ21A

edited 27th Dec '10 3:01:57 PM by Sidewinder

I don't know about safer, as C-4 is safer than most petroleum products other than vasoline. And the smoke will typically be white, if any, usually caused by the casing disintigrating or kicking up dust or debris.

I did battle simulations for the army and the centre piece was a nuke sim. You build a six foot high tripod out of 2x4s and dangle a garbage bag full of gasoline and fuel oil about 2' off of the ground. Inside the bag is a bursting charge, on the ground directly underneath is a lifting charge, and near the tripod legs we created a ring-main of smaller charges. The whole thing is blown simultaneously.

The bursting charge ingites the gas and oil into a fireball with black smoke, the lifting charge pushes the fireball straight up, and the ringmain pushes the fireball in on itself with the net effect of a pillar of fire capped by a fireball creating the signature mushroom cloud. In our case, the musroom cloud rose to a couple hundred feet high compared to the one at Hiroshima which was over 40,000', but it looked awesome from close up.

Explosions do damage by two ways, as mentioned. Shock wave and fragments. Either one might do you in - no fragments from a nearby shell detonation get you, but the overpressure wave ends up rupturing your internals and smashing the air out of your lungs or something.

For something as small as a hand grenade, it'll usually be the fragments that will kill or injure you.

A concussion grenade only has a casualty radius of 2 metres in the open, but it will completely ruin your day indoors.

http://www.fas.org/man/dod-101/sys/land/mk3a2.htm

And I stumbled on to this website on explosives, and in particular one page deals with Explosives-Injuries

edited 28th Dec '10 1:09:32 PM by 66Scorpio

@ 66 Scorpio

I didn't mean safer as in safer to handle, but as in "not having to evacuate everyone within 1 Km because the shrapnet that will be produced is deadly." In other words: safer to film near.

Yes, although it depends on the size of the charge and the material you are blowing up. The safety radius for steel cutting is a kilometre while it is 500 and 300 for rock and wood blasting respectively. Of course, low explosives can't be used for steel cutting per se.