Rules for low-oxygen environments?

[afroakuma]

Has anyone seen some lying around?

[Flickerdart]

Well, there are rules for no oxygen environments such as underwater...

I'd assume Constitution checks to avoid being dazed every once in a while.

[Biffoniacus_Furiou]

Check out altitude sickness, DMG page 90.

[PollyOliver]

Page 90 of the dungeon master's guide, or just search the SRD for high altitude (it's in the mountain travel section).

There's also a little on it in Frostburn (though for the most part it amounts to "read the DMG"). There's also a spell, "thin air", that mimics altitude sickness, and a psionic power that acclimates you. Also, there's a Frostburn prc, the cloud anchorite, built around the idea of high altitude, though it's fairly meh.

Edit: ninja'd

[Kurald Galain]

Has anyone seen some lying around?

What system are we talking about?

Assuming you're talking about Vampire: the Masquerade (which, come to think of it, you're probably not), remember that vampires don't breathe.

[afroakuma]

*shrug* Could be referring to low blood oxygen environments. :smallbiggrin:

Thanks folks, I'll check that in the DMG.

[Prometheus]

Well, it probably depends on what the Oxygen is replaced with, for example, a predominately Helium environment would probably incur a dramatic penalty to Intimidate checks on account of the high pitched voice.

Here is the RL facts on Oxygen Deficiency HazardsOxygen Deficiency Hazards

An oxygen deficiency hazard (ODH) exists when the concentration of oxygen is equal to 19.5 percent or less (by volume) at a typical barometric pressure of 760 mm Hg.

Without adequate oxygen, one can lose consciousness in a few seconds and die of asphyxiation in a few minutes. (See Tools, Cryogenic and Oxygen Deficiency Hazard Safety: ODH Risk Assessment Procedures, Table 1, for the biological effects of reduced oxygen concentrations.)

Liquefied gases can easily and quickly create an ODH. When expelled to the atmosphere at room temperature, liquefied gases evaporate and expand 700 to 800 times their liquid volume. Consequently, leaks of even small quantities of liquefied gas can displace large amounts of oxygen, and thereby render an atmosphere lethal.

Dense gases (those with densities significantly greater the atmospheric air at STP) will fill pits and other low areas. Examples of dense gases include various freons, sulfur hexafluoride, and certain cold cryogens. The greater the gas density, the greater the oxygen displacement and the longer the time required for the gas to dissipate.

"Air dense" gases (those with densities approximating atmospheric air at STP) may be used at SLAC in sufficient quantities that they could dilute the available oxygen in a room/enclosed work area. Examples of air dense gas include nitrogen and argon. This hazard is especially prevalent where boil-off nitrogen is used as a vacuum system purge in clean room environments. Failure of the HVAC system normally in use in such locations (due to maintenance shutdown or power outage) can result in accumulation of gas sufficient to create a hazard, even without any failure of any part of the gas handling system.

Light gases (those with densities significantly lesser than atmospheric air at STP) can affect the areas above a cryogen spill. Examples of light gases include helium and hydrogen. Spill experiences at the Fermi and Jefferson laboratories reveal that even with a connecting shaft of only a few square inches, an ODH can arise at a factor of ten in the building above compared with an area three feet horizontally from the spill. Another potential hazard from a cryogen spill can arise with poor outdoor venting, which can produce a more localized ODH.

Users of cryogens and gases that can create ODHs should always be aware of the possibility that localized ODH conditions can exist. An example would be where use of a welding purge gas is exhausted in such a way that oxygen is displaced from between the welder's face shield and his or her body, creating an oxygen deficiency in the breathing space.
What you are looking at is dizziness leading to unconsciousness to brain death, the fact that it doesn't take very to get there if you are in a low enough environment, and the fact that you can mitigate the hazard if you climb high or drop low (as appropriate).

[afroakuma]

Well, I'm looking at a very high altitude.

Like mesosphere high.

[Mr.Bookworm]

Well, I'm looking at a very high altitude.

Like mesosphere high.

Mesosphere?

Temperatures are in the -100s Fahrenheit up there, and it's the main area where meteors burn up.

There's also so little oxygen, that you would literally pass out, and eventually, die.

[Mystral]

Apropiate Damage for the cold/round.

Appropiate Damage for Vacuum or near-vacuum

Same rules as suffocating, there is so little air up there it hardly matters. If you want to have a difference, double the time it takes to suffocate.

[bosssmiley]

Well, I'm looking at a very high altitude.

Like mesosphere high.

You're best off adapting suffocation/drowning rules in those situations. There's simply not enough oxygen to sustain human life at that altitude. Let go of your lungful of air, you start asphyxiating.

As a species we're pretty much screwed above about 20,000 feet above sea level. Above 25,000ft you're in the so-called Death Zone. More than 5 miles up? Forget it!

IIRC Paizo's "Pathfinder #6" had a whole article on high altitude survival.

[hamishspence]

Nailed to the Sky- epic spell- 2d6 heat damage, 2d6 cold damge, d4 Vacuum damage, + suffocation rules. is the closest thing I've seen in 3rd ed to "You are in space. You start dying."

[Bonecrusher Doc]

Nitrogen narcosis. (http://www.healthatoz.com/healthatoz/Atoz/common/standard/transform.jsp?requestURI=/healthatoz/Atoz/ency/nitrogen_narcosis.jsp) Just thought somebody would find it interesting.

[Optimystik]

Nailed to the Sky- epic spell- 2d6 heat damage, 2d6 cold damge, d4 Vacuum damage, + suffocation rules. is the closest thing I've seen in 3rd ed to "You are in space. You start dying."

Link provided. (http://www.d20srd.org/srd/epic/spells/nailedToTheSky.htm)

Hmm, I just noticed that's a will save... ouch.

[golentan]

The MSRD future section has this; (http://www.dominion-x.net/d20-msrd/FutureEnvironments.html) for mesosphere just town down the vacuum rules a little bit.

[hamishspence]

4th ed Forgotton Realms has a ritual which my be relevant Raise Land. At full power, Lift a 10 mile radius circle of ground, extending to a depth of 5 miles, to a height of 10 miles. Once ritual complete, the land begins to rise.

if these atmosphere rules are used, guaranteed death to an entire small country.

[afroakuma]

Exposure to the mesophere's gonna be 40d6 cold damage every round. Best to stay inside, where there's only extreme cold and altitude sickness with double penalties in addition to a daily Con penalty.

Reasonable?

[Mr.Bookworm]

Exposure to the mesophere's gonna be 40d6 cold damage every round. Best to stay inside, where there's only extreme cold and altitude sickness with double penalties in addition to a daily Con penalty.

Reasonable?

40d6?!?! Not really, more like, say, 2d6, plus suffocation, plus all of the nasty side effects of cold statted out in Frostburn.

[afroakuma]

...2d6?

for -100 degrees Celsius?

With the wind produced by motion, exposed flesh would freeze in under one minute.

[hamishspence]

in Frostburn, -50 degrees Fahrenheit does d6 lethal cold, d4 non-lethal, per minute.

The coldest plane (Auril's area of Fury's Heart, for example, does 3d12 damage per round) beating Caina's 3d10.

2d6 per round is pretty cold.

[ChaosDefender24]

As far as vacuums goes, I know that outer space in Baator does 1d10+6 damage per round.... (FCII 62)

[hamishspence]

not too far off NTTS's d4 damage, though I would say it did need upping. I'm guessing the 2d6 fire damage assumes you are in sunlight with nothing protecting you from the UV.

[Mr.Bookworm]

...2d6?

for -100 degrees Celsius?

With the wind produced by motion, exposed flesh would freeze in under one minute.

2d6 will kill a level 1 Commoner in one round most of the time, 2 rounds if he's extremely lucky. 12 seconds.

2d6 does 6 damage on average. A level 20 Barbarian, one of the toughest men alive, has 126 HP (max at first level, 6 at every level thereafter). It will take 2 1/10 minutes to kill him, cold alone, if he doesn't suffocate by then. Seems about right.

[afroakuma]

Again, I'm talking about cold so mind-numbing (and direct immersion in thereof) that it can freeze your skin in 20 seconds flat.

Per RAW magma deals 20d6 fire damage for complete immersion.

I'll go glance at Frostburn's info, but it seems a bit off. Nobody should be able to survive 2 1/2 minutes exposed in the mesosphere.

[hamishspence]

I think there are descriptions of direct exposure to hard vacuum that say while you pass out fast, you take a while to expire. I suspect that the same applies to cold. Antarctic has both low temperatures (-89 C) and wind chill- i'd be surprised if people die instantly on exposure.

Magma is much, much hotter, than high atmosphere is cold- +1500 C and higher. And people have survived exposure to very high temperatures for very short periods (probably not that high though).

[hamishspence]

and it's not frostburn's info. That deals with normal atmosphere and very cold weather.

if you've gone straight up, in the day, you're actually taking 2d6 Cold + 2d6 Fire + d4 Vacuum. Very rapid death.

and for extraplanar Coldness, 3d12 per round is a lot.

[memnarch]

Human Body in a Vacuum (http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/970603.html).

[hamishspence]

again- if its just the vacuum (not too cold space, no direct sunburn) you'll last a reasonable amount of time (if you're reasonably high level)

In a sense, with NTTS, its actually more damaging than you might expect.

[PollyOliver]

From the NASA Q&A posted above:


If you don't try to hold your breath, exposure to space for half a minute or so is unlikely to produce permanent injury. (snip)

Various minor problems (sunburn, possibly "the bends", certainly some [mild, reversible, painless] swelling of skin and underlying tissue) start after ten seconds or so. At some point you lose consciousness from lack of oxygen. Injuries accumulate. After perhaps one or two minutes, you're dying.

Note that this is just a normal person; i.e. a commoner in the case of the first part of the explanation and an expert in the example presented later in the link. I don't have any trouble believing that, if a commoner should be able to withstand hard vacuum for 30 seconds, a 20th level barbarian would be able to hold on for a couple of minutes. If anything, the effects of pinned to the sky are too strong, because they'd kill a low-level commoner in a round or two (6 or 12 seconds), rather than the 30 seconds you should be able to recover from or the minute or two it takes to start dying.

[afroakuma]

It's the wind chill that causes the rapid freezing of flesh. I'm talking the mesosphere (not a complete vacuum) with severely fast winds to magnify the wind chill factor.

That said, I'll bring it down to the lowest current level of freezing. 3d12, right? Any word on what temperature that might be?

[Mr.Bookworm]

Again, I'm talking about cold so mind-numbing (and direct immersion in thereof) that it can freeze your skin in 20 seconds flat.

Per RAW magma deals 20d6 fire damage for complete immersion.

I'll go glance at Frostburn's info, but it seems a bit off. Nobody should be able to survive 2 1/2 minutes exposed in the mesosphere.

I understand fully what the temperatures involved. 100ºC is the coldest the mesosphere gets, in the mesopause, the edge of the mesosphere.

Magma is a completely different thing. Magma is basically pressing molten metal and rock against every single part of your body, and quite probably, fully submerged, your insides.

EDIT:


It's the wind chill that causes the rapid freezing of flesh. I'm talking the mesosphere (not a complete vacuum) with severely fast winds to magnify the wind chill factor.

That said, I'll bring it down to the lowest current level of freezing. 3d12, right? Any word on what temperature that might be?

And, like I said, 2d6 will literally knock a level 1 Commoner out in six seconds almost all of the time, death following really quickly. That's pretty rapid.

Also, I think you're failing to fully understand just how much punishment the human body can take. It's pretty reasonable for a human to survive twenty seconds in -100ºC weather.

[hamishspence]

Wind chill is, I supect, dependant on dense enough air for conduction to be a problem. I'm not sure if Frostburn has rules for wind chill factors.

even 3d10 is, oddly, capable of harming the ice Devils that live in it (Resistance 10 cold) So, they might be in shelter some of the time.

Antarctica combines -130 F temperatures with strong winds, and people don't freeze instantly in that (quickly though)

I think the "insta-freeze downdrafts from mesosphere" in Day after Tomorrow might be exaggerations.

[Mr.Bookworm]

I think the "insta-freeze downdrafts from mesosphere" in Day after Tomorrow might be exaggerations.

After I gained more science, I quickly learned that DAT is about as accurate a source on things as that crazy homeless drunk guy shouting about the Alpha Confederation of aliens eating our brains.

It's a fun movie, though perhaps only for pointing out the two science mistakes they make every second.

[hamishspence]

the question I'm wondering is- is direct exposure to the high winds, low temperature, and low pressure, all togethr, going to almost instantaneously Popiscleize you?

There have been balloon flights (wearing suits) that high up- I'm guessing the answer to that, is no.

[afroakuma]

Not coming from that film. Drawing from this (http://www2.fhs.usyd.edu.au/ESS/smith/EXSS%203004%20Ergonomics/Lectures/Work%20Environment%20II.pdf), among other sources.

If I need to put things higher up, I will. I want the most deadly cold imaginable. I want to yank the average commoner's lungs out in one second. I am talking about a raging, profane cold derived from 100 km/h winds and nearly space-cold temperatures.

[hamishspence]

Problem is- low density winds don't actually do much. A raging storm on Mars will barely buffet the heavy object caught in it- I suspect wind chill can't be much of a factor either.

[PollyOliver]

It's the wind chill that causes the rapid freezing of flesh. I'm talking the mesosphere (not a complete vacuum) with severely fast winds to magnify the wind chill factor.

That said, I'll bring it down to the lowest current level of freezing. 3d12, right? Any word on what temperature that might be?

That's still quite a lot of damage, but in any case, this is how I would figure the temperature out: (note that I'm not a earth, atmospheric, or planetary scientist, and this is just estimation)

Let's take the mesosphere temperature as being approximately -100 C (low, for the most part, but an easy number). A quick google turned up a few measurements of air currents in the mesosphere as between 50 and 150 m/s; again, I'll use 100 as an easy number. Putting this into a wind chill calculator from the national weather service (just google "wind chill calculator"), I got that it feels like approximately -180 C, or -290 F. Lower in the mesosphere you'd probably get something that's more like "feels like" 100-150 C.

Edit: this is assuming, of course, that wind chill remains a factor. I don't know enough about low pressure effects to really speculate on that.

[Mephit]

I'm with Bookworm on this one. 2d6 per round plus suffocation seems right.
I mean, a 20th level barbarian dieing from the environment in 2 1/2 minutes. We're talking about a 20th level barbarian here. For comparison, think 20th level wizard and what he can do. That guy has superhuman endurance.

[hamishspence]

Does the wind chill factor continue to apply as density drops?

3d12/3d10 per round were the coldest of extraplanar cold zones- way beyond Unearthly. Even the Elemental Plane of Cold is only Severe (Fort save DC15 +1 per subsequent check, every 10 min, d6 nonlethal)

[afroakuma]

Then tell me how to ratchet it up.

This is for epic-level characters. They'll snicker at such low damage. I need a threat dangerous enough to keep them inside except when they have no alternative.

[hamishspence]

Radiation, and, of course, meteorites. While normal rule requires object a minimum of a pound in weight to do falling damage, you could stat small (sling bullet sized) meteors that, because they are moving at relative speed of 20 miles per second, will do much damage.

UV/IR is accounted for in the 2d6 fire damage. Then you can add in cosmic rays- stat out your own slow, unpleasant CON disease with very very high saves.

[AslanCross]

The FR Underdark book has rules for low-oxygen environments (caves, caves with noxious fumes, etc).

[hamishspence]

Edge of space is more No-oxygen than low oxygen. though the Low oxygen rules could be used for in-between zones. I think Silver Maraches also has rules for oxygen starvation on the tops of high mountains.

[Coidzor]

If they're epic then they should have some way of acquiring some kind of shelter and ability to function for at least short periods of time in such conditions anyway, they'd at least have worked out how to avoid the oxygen problem.

environmental hazards are usually either an insta-death wall for herding (i.e. lava-flows, magma pools) or something that taxes the endurance (extreme cold limiting the amount of time they can travel and necessitating more stopping and either taking shelter from opponents or defending their shelter against opponetns.

What are you doing and why are you doing it?

[afroakuma]

Little of column a), little of column b).

It's an epic-level dungeon suspended in the planetary atmosphere; the main dungeon has oxygen (though much thinner due to altitude) and is merely extremely cold. Outside, gale-force wins blow from the orbital motion and the characters are exposed to the full wrath of space.

In other words, inside you have low-oxygen, altitude threats and endurance-breaking cold. Outside, if you try to do something clever like fly to the next hangar (teleporting doesn't function) you'll quickly find out that that is a bad idea.

[ericgrau]

All mesosphere stuff below is according to Wikipedia, FWIW:
20d6 per round is the cap for immersion in lava. I'd say cold is similar. -100C (-148F) isn't insane enough though IMO. That's just a step below antartica.



Extreme cold (below -20° F) deals 1d6 points of lethal damage per minute (no save). In addition, a character must make a Fortitude save (DC 15, +1 per previous check) or take 1d4 points of nonlethal damage. Those wearing metal armor or coming into contact with very cold metal are affected as if by a chill metal spell.
That's per minute. And below 0 is 1d6 nonlethal every 10 minutes. For the -146F mesophere I'd make it just a few d6's every round, unless protected. Not sure how many. Bear in mind your PCs have far more HP than commoners, whom I can understand dying in a round or so. EDIT: Then again I could see increasing it somewhat for wind chill factor, see below.

I agree that there is too little oxygen in the mesosphere to breath. Just use suffocation rules unless the PCs get a source of air. Not to mention low pressure problems, similar to space.

The mesosphere is where meteors burn up. Millions per day, in fact. 1 million/day is 1 per 200 sq. miles per day, so for "millions" I'd guess 1 per 20 square square miles per day. These range in size from a grain of sand to a boulder, but their extremely high velocity gives them enormous energy: as strong as several nukes. I'd give it at least 20d6 fire damage (if not far more) in a 1/2 mile radius (1 mile diameter), or some variable diameter near or below that. And perhaps vary the damage based on proximity to center of blast. I'd guess a 5% chance of getting hit each day (per 24 hour period), with only an instant to see it coming after that tiny meteor erupts into a gigantic streaking fireball (resembling a column or sphere of white hot, eye burning flame or light, perhaps). Likewise it's over in a flash. Getting caught in the center of the blast is a lot less likely than getting hit by another part, but this always gives you the ultimate "rock falls, everybody dies" option.

But the main feature of the mesosphere, according to Wikipedia, is atmospheric tides. These can result in wavelike air motions of over 100mph (about 1000 feet per round). That's a hurricane force wind (http://www.d20srd.org/srd/weather.htm#hurricaneForceWind). The periods of these waves are measured in hours, so the wind would likely be sideways, up or down (depending where the PCs are in the wave) and then switch directions every couple of hours. Unless the PCs have a way to stop themselves, they would also move at this speed and direction.

So... ocassional nukes and constant hurricanes. Epic enough for you? :smallamused:

[hamishspence]

2d6 cold per round was Nailed to the Sky- sounds like a pretty good compromise number, and fits with existing rules.