Taking Cover: Dumpsters

[Tallor]

Alternate Title: Crouching Dumpster, Hidden Garbage

You can't always choose your battles, and in an urban environment, you have to make due with a variety of artificial emplacements. Walls of concrete, cinderblocks, or bricks are almost always a good bet for damage resistance, but sometimes all you have between you and your firearm-wielding foe is the thin, cheap sides of the humble-but-ubiquitous dumpster.

...So how much DR does a dumpster have?

Let's start with the math. Cheap steel gives about DR 55 per inch[1], and the walls of a dumpster are 0.1046" thick.[2] Rounded down, this gives an average of DR 5, or DR 10 since a projectile has to penetrate both the near and far walls.

However... this assumes that the dumpster is empty, which is rarely ever the case[3]! I believe that additional "garbage shielding" is in order:

Low-Density Rubbish[4] ----- DR 2-4
Ordinary Trash[5] ------------ DR 5-6
Brush and Bulky[6] ------- DR 8-20
Architectural Debris[7] ---- DR 30-60+

What do you think?
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[1] GURPS Campaigns p.559
[2] How Many? A Dictionary of Units of Measurement
[3] Personal experience of the author.
[4] Shredded paper from offices, recyclable cardboard, plastic bags, etc.
[5] Found behind every TL5+ restaurant, depending on when they invent the dumpster proper.
[6] Somewhat packed branches and/or chunks of tree forts. Can also stand for lighter architectural debris.
[7] Loose bricks, timbers, drywall, the works. Not as tough as a solid wall of material, but still extremely difficult to penetrate. A character with Serendipity may opt to have their dumpster full of bricks and girders, making overpenetration nearly impossible!

[Myrion]

Awesome! In the last campaign I ran, I could actually have used this info at one point. :)

[The Colonel]

If we had the DR for hard plastic (IDHMBWM) we could also do something very similar for the ubiquitous four wheeled 1100L gash bin that inhabits most British and European cities these days... (I'd guess at DR2-3 per side).

[spacemonkey]

I'd imagine dumpsters are made from decent steel, given they have to hold up to some pretty heavy loads and being slung around by robot arms. There's also probably an issue with shooting through 2 steel plates a yard or more apart. I think hiding behind the dumpster would be pretty safe even against .223 rifles and the like, and hiding in it would probably be completely safe against typical handguns. AP ammo would change things.

[The Colonel]

Originally Posted by spacemonkey

I'd imagine dumpsters are made from decent steel, given they have to hold up to some pretty heavy loads and being slung around by robot arms. There's also probably an issue with shooting through 2 steel plates a yard or more apart. I think hiding behind the dumpster would be pretty safe even against .223 rifles and the like, and hiding in it would probably be completely safe against typical handguns. AP ammo would change things.

They're really not. As the OP implies a steel dumpster is generally 1-2mm of mild steel and a coat of paint on each side. Construction waste skips might be heavier built, as may hazmat bins, but those used for light recycling or mixed gash might as well be made from bean tins.
Also, as noted, you get a lot of cast plastic bins about these days, or at least you do in the UK and Europe.

[Tomsdad]

Originally Posted by The Colonel

They're really not. As the OP implies a steel dumpster is generally 1-2mm of mild steel and a coat of paint on each side. Construction waste skips might be heavier built, as may hazmat bins, but those used for light recycling or mixed gash might as well be made from bean tins.
Also, as noted, you get a lot of cast plastic bins about these days, or at least you do in the UK and Europe.

Yep quite.

A lot of the overall strength for supporting the load will come from support bars, rails etc, rather than having thick walls, floors etc.

I couldn't find any good specs for dumpsters, but here's a good one on 20' shipping containers with a payload rated up to 62,130 lbs.

Which is considerably more than the largest 40 yard dumpsters.

The steel used is SS400. Which I think* at a HB of 160 is between mild steel and RHA in terms of hardness (although there's more to DR/bullet resistance than just that I know)

The side panels vary from 1.6mm - 2.0mm thickness


So yeah I think what's in it will matter more than the actual construction of it.

*and could well be wrong!

[robkelk]

Originally Posted by Tallor

...
Let's start with the math. Cheap steel gives about DR 55 per inch[1], and the walls of a dumpster are 0.1046" thick.[2] Rounded down, this gives an average of DR 5, or DR 10 since a projectile has to penetrate both the near and far walls.
...

Wouldn't the round need to penetrate DR 5 twice, rather than penetrating DR 10? There's quite a bit of space (empty or filled with refuse) between the two sheets of mild steel.

I'm not sure whether this makes a difference with most types of rounds, mind you.

[David Johnston2]

Originally Posted by robkelk

Wouldn't the round need to penetrate DR 5 twice, rather than penetrating DR 10? There's quite a bit of space (empty or filled with refuse) between the two sheets of mild steel.

I'm not sure whether this makes a difference with most types of rounds, mind you.

In truth going through the first barrier would probably sent most bullets off at a tumbling tangent anyway.

[Ulzgoroth]

Originally Posted by robkelk

Wouldn't the round need to penetrate DR 5 twice, rather than penetrating DR 10? There's quite a bit of space (empty or filled with refuse) between the two sheets of mild steel.

I'm not sure whether this makes a difference with most types of rounds, mind you.

It would, and it would make a difference, but I can't think of any GURPS rules covering that difference.

[The Colonel]

Originally Posted by Ulzgoroth

It would, and it would make a difference, but I can't think of any GURPS rules covering that difference.

How about fragmenting rounds? I'm guessing that anything from JHP downwards is going to spread on the first one and be substantially less effective against the second, but I don't recall the rules for that off the top of my head...