Loss of Air

In a situation where air is scarce, the characters may attempt to preserve air, breathe more shallowly, hold their breath, or stay calm to avoid using up more air than necessary. This situation runs on percentages - how many people are present, how much air they use, and how much air is present. Air pressure is also a factor.

Average breath is based on height. A 6’ tall person who breathes air takes in approximately .5 qt per breath at a rate of 12 breaths per minute. This goes down by .1 qt per foot per breath until they are below 1’, at which point it goes down by .025 per 3” per breath. It goes up accordingly - .5 qt per foot per breath. A cubic foot has approximately 30 qts in it. A room that is 10x10x10 will have 30,000 qts of air. A single 6’ person in such a room that is sealed off and can get no new air will use up all of the air in approximately 5,000 minutes. Two people of that size will use it up in half the time. Ten 6’ tall people would use it up in 500 minutes. And so on.

If someone tries to hold their breath, they can roll STR vs. how long they try to hold their breath to see if they succeed in extending the air supply. Holding breath is a difficulty of 4 for 30 seconds, going up by 2 for every further 30 seconds. If someone holds their breath for more than three minutes successfully, they roll stun/wound vs. the scale below for suffocation. If there is air present, anything less than an exceptional wound will recover instantly as they begin to breathe again.

If someone begins to breathe more rapidly - hyperventilation from panic, for example - double the rate of consumption.

If the situation includes other factors that would limit or reduce the air, this can be calculated by the rate the other factors reduce the air. While there are a ton of factors that could go into it - air pressure being primary, but temperature, the direction the air is being circulated, and a bunch of aerodynamic physics, we’ll pretend all things are equal and go with “the size of the hole” and “amount of added material” as our determining factor unless the GM is more mathematical, scientific, and ambitious. A 6” hole for a leak would lose about 20 qts per second from a room if releasing into a vacuum. Anything added - dirt to a grave, for example - would displace air equal to how much dirt was added. A leak in an oxygen tank for a diver would rapidly deplete from a significant leak, scaling the hole-to-loss ratio to a 5% loss per second per eighth-inch per hole.

Air pressure can increase or decrease the rate of the flow in any of these situations. If the pressure is greater outside, it will decrease the rate of loss by the percentage it is greater. If it is greater inside, the opposite is true. This probably doesn’t track with physics precisely, but this is all fun game mechanics.

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Suffocation

Lack of air is a fast killer, but there are those in real life who have survived extended periods without it. In all of those cases, external factors such as temperature, pressure, etc. affected their bodies to give them a better chance. If a GM is expert in such things, they may feel free to factor them in, but this mechanic assumes all-things-being-equal, how long until someone is killed or incapacitated for lack of air.

Different methods or sources of suffocation may have an impact on the damage rolls. Drowning and the vacuum of space are considered different forms of suffocation and damage; see below for more information.

The first method of suffocation is running out of air in a space where no new air is able to get in. In a sealed cave or chamber, for example, with no intentionally poisonous gases being added from anything other than your own breath. This scale starts the moment breathing stops or air runs out:

Time	Stun	Wound
1 minute	4	0
2 minutes	6	2
3 seconds	1	0
3 minutes	9	5
4 minutes	12	8
5 minutes	15	11
6 minutes	18	14
7 minutes	21	17
8 minutes	24	20
9 minutes	27	23
10 minutes	30	26
30 seconds	2	0

And so on. Any wound from suffocation causes brain damage, but it is usually recoverable if air is returned. However, wounds can stack in this instance. Critical wounding means fatal brain damage. Exceptional wounding means permanent brain damage (-1 to AWA per exceptional). For suffocation, a critical wound is three exceptional wounds. An exceptional wound is three special, a special is three normal, a normal wound is three ties. All of these add up as the process goes on. If the victim gets 81 ties, 27 normal wounds, nine special, three exceptional, or one critical wound, they die, even if they get no stun. Combined wound and stun still applies - i.e., double and triple exceptional/critical rules still apply as far as death goes.

For intentional or directed suffocation - a pillow over the mouth, being buried alive, sealed in concrete, a hand or cloth over the mouth - there are modifiers to stun. Pillow is +3, buried alive is +1 (unless there is active force being applied, then it may go up), concrete is +6, cloth is +2, hand is +1. This is at the GM’s discretion; the rule of thumb is that the more force and coverage applied, the higher the bonus.

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Drowning

Drowning is a lot like suffocation, but it has the added factor of water filling the lungs. While someone may drown by not breathing underwater while still preventing water from coming in, this damage would be counted as suffocation for our mechanical purposes. Drowning here is the extra damage caused by the water filling the lungs and preventing breathing.

Assuming no breathing or protective devices are present (which would have their own scores in prevention and support to mitigate damage), it is assumed that a drowning person begins to experience extra damage from water as soon as they breathe in water. If the person is taken by surprise, this may happen immediately upon submersion. If the person is aware and attempting to not breathe in water, they will only begin taking drowning damage once they fail to prevent it, usually when they pass out (exceptional stun).

If someone is submerged and at risk of drowning and awake and aware, they must roll AWA to avoid breathing in water, to successfully hold their breath to avoid drowning until they can gain control of themselves. The difficulty to do this is a 6. On a tie, the person must reroll the next round at -3 to successfully avoid taking in water. On a normal failure, they take in a little water and the drowning damage is equal to suffocation+1. Special failure means suffocation+3. Exceptional means suffocation+6. Critical is suffocation+9.

If they succeed at holding their breath, they roll for suffocation rules because they aren’t breathing. Once they pass out, they begin to drown because their body will start to breathe and take in water. If someone passes out, it is assumed they normalize their breathing and take suffocation damage+3, even if they were previously at a worse rating. However, they will have any wound penalties previously acquired, often exacerbating the issue. Besides brain damage from suffocation, the wounds also apply to the lungs.

If someone is actively holding the character under, this is PRO vs. ATH or PRO to obtain the hold and STR vs. STR to maintain it. If the holder fails the initial PRO roll, the victim is not being drowned. If they succeed, they may add success bonuses to their STR roll to hold the victim down.

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Vacuum

Dying in a vacuum is truly a terrible way to die. Your body can swell up and implode, your tongue can freeze, you expel all the waste in your body, organ and brain damage happens rapidly, and you likely have seizures. This does not include damage from radiation or temperature drops which often occur simultaneously.

This mechanic is only for the vacuum damage. See Cold Damage and Radiation for the other effects. Damage is determined by exposure time to the vacuum.

Exposure time	Stun	Wound
3 seconds	6	4
6 seconds	8	6
9 seconds	10	8
12 seconds	12	10
15 seconds	14	12

And up two points for every three seconds thereafter. Wound damage is also amplified due to the impact on the entire body. Even a normal failure has permanent results:

Wound	Effect
Normal wound	Total of -1 permanent stat loss to STR, ATH, WIL, or AWA (player’s choice)
Special wound	Total of -3 permanent stat loss to STR, ATH, WIL, and/or AWA and -1 to STH or PRS (player’s choice)
Exceptional wound	Total of -6 permanent stat loss to STR, ATH, WIL, and/or AWA and -2 to STH and/or PRS (player’s choice)
Critical wound	Total of -9 permanent stat loss to STR, ATH, WIL, and/or AWA and -3 to STH and/or PRS (player’s choice)

A player may replace -3 to STR with -5 to disease/poison resistance due to organ damage.

Permanent stat losses to STR and ATH may be recovered with extensive physical therapy, diet, exercise, etc. Losses to WIL and AWA may be recovered with mental therapy and better living. Losses to PRS and STH may not be recovered without magic, as these reflect personality changes which have been noted in victims of vacuum damage.