[HR] Variant Heat and Cold rules.

[Trachmyr]

I'm looking at rebooting one of my favorite campaign settings, Clovis-Culture Nomadic Hunter/Gatherers. One of the things that has always bothered me about the setting is the low diversity of equipment for characters.

I've been working on custom design rules for TL0 weapons and clothing, with a lot of emphasis on character-created (rather than player created) items. While creating a custom Leather Clothing/Armor Creation system, it donned on me that I might get a lot more variation by changing how Clothing protects from the elements... rules-wise that is.

My idea is first to narrow the Comfort Zone of humans considerably, as it seems that this comfort zone assumes (it must assume) access to appropriate clothing. Second, is to streamline the Cold & Heat rules so that they assume a naked human. Then finally, to give each garment or outfit, an effective temperature modifier range. Basically, you can add a number within that range to actual temperature, to find if you make it to your comfort zone, and if not, what HT penalty you take to your rolls.

For instance, a normal human will have a range of 65 to 80 degrees for their comfort zone, although they can shift this slightly (by 5 degrees) and modify it with Temperature Tolerance (now 2/level, but available in half levels).

Lets take an example character "Tatanka", he has 1/2 level of Temperature Tolerance (Cold), giving him a comfort zone of 60 to 80 degrees. He wears Light clothing (Moccasins, Breechcloth, Leggins), but also has a heavier long bison-skin cloak. The Light Clothing offers a Temperature range of 0 to 5 degrees, the cloak when worn open offers a range of 5 to 10 degrees, and doubles that when pulled around him.

The day starts out at a pleasant 75, as Tatanka is wearing all regalia, his effective temperature is 80, within his comfort zone. By mid-day the temperature rises to 87. At this point Tatanka needs an HT roll if he is active, at a penalty equal to any encumbrance level. If he is still wearing his cloak, then his effective temperature becomes 92... now he needs a roll every 30 minutes regardless of activity, loses and extra point of fatigue from exertion or dehydration, and makes HT rolls at an additional -1 if active. By Nightfall, the temperature has dropped to a cool 58 degrees, but given his outfit, he stays quite comfortable. However, a coldfront moves in over the night, an he wakes to a chilly 40 degrees. His clothing and cloak can only bring him to 55, which would require an HT roll every 30, so he opts to pull his cloak around him and bump his effective temperature back up to 65, cool, but within his tolerance. A sound startles Tatanks from outside the dwelling, he grabs his spear and goes to investigate. The wind outside is a strong 30mph, making the temperature after the chill factor a brisk 28 degrees. Tatanka is outside some time scarring off raccons that have gotten into the food stores. He requires an HT roll after 15 minutes, if Tatanka had kept his cloak draped around him, his effective temperature would be 53 degrees, requiring an unmodified roll. But not wanting his arms and spear hindered, the cloak only offers partial protection, giving an effective Temperature of 43 degrees, requiring an HT-1 roll.

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So what are your thoughts on this, obviously this man vs. nature detail will be a focus for the setting, thus the detail warrented. Any suggestions, spot any issues?

Thanks in advance...

[Flyndaran]

Interesting. I find to add something is that people adapt a little over time. Such that, for me, in the winter I prefer it a good 5-10 degrees colder than in summer.
In the recent heat wave from hell, I've been able to walk the mile to the grocery store in 90+ degrees that literally gave me heat exhaustion a number of years ago during a sudden heat snap.

[Trachmyr]

The 5 degree variance I allow, plus any bonus from Temp. Tolerance, I will allow it to shift by 1 degree per month in a direction that suits the climate.

[Trachmyr]

This is the full write-up, minus the actual ranges for clothing... still working on that.

Hazardous Temperatures

	The following rules completely replace the default GURPS Basic rules on exposure to cold and heat, and incorporate rules for immersion hypothermia. The original rules provide a large comfort zone, but assume wearing appropriate clothing for the climate. These rules introduce a smaller "naked" comfort zone, and allow clothing to affect this through modifications to effective temperature. These rules remain internally consistent, and compatible with existing material, but allow for greater focus on climate conditions when appropriate for the specific campaign.

	Comfort Zone: A human's naked comfort zone is a sixteen degree band, from 65ºF to 80ºF, inclusive. Within this temperature range, humans need not make any HT rolls to avoid FP or HP loss, and are assumed to be generally comfortable, although perhaps not perfectly so. A Human can vary this range by up to 5º (plus increases from Temperature Tolerance) based on their particular climitization, and this range can shift by 1 degree per month as appropriate for their current climate.

	Cold: When in temperatures below your comfort zone, you must make an HT roll every 30 minutes, at -1 per full 10º below your comfort zone, and at an additional -5 if you are wet. Failure costs 1 FP. As usual, once you go below 0 FP, you will start to lose 1 HP per FP. Recovery of FP or HP lost to cold requires adequate shelter and a heat source (flame, electric heat, body warmth, etc.).

	Wind Chill: In light winds (10+ mph), roll every 15 minutes to resist FP loss due to cold. In stong winds (30+ mph), roll every ten minutes. While in gale-force winds (50+ mph) roll every five minutes. In addition, wind speed can make the effective temperature lower, as shown below.

[CHART]

	Frostbite: The table above also shows threat levels for frostbite, which is acute somatic damage to exposed flesh caused by freezing. It’s distinct from FP and HP losses to hypothermia, which represent metabolic damage. The two effects can and often do occur simultaneously! Those exposed to freezing conditions lose 1 HP on any exposed or wet hit location per FP lost to cold. This can cripple extremities or even limbs, and is cumulative with injury due to hypothermia. 
	The lightest blue band represents temperatures which do not normally pose this hazard, but can occur if the extemity is both exposed and wet, or in contact with wet surfaces (Walking barefoot on ice or snow), in which case Make a second HT whenever FP is lost from cold, with the same modifiers, but no penalty for being wet. On a success, no damage is taken, on a failure, 1 HP is lost from the exposed extremity from frostbite. The darker blue band presents this threat to any exposed or wet body part, roll as above, but any exposed body part that is also wet takes damage automaticlly, regardless of the roll. The purple band shows the largest threat, at these temperatures, no HT roll is allowed, all exposed or wet locations take damage.

	Heat: At temperatures up to 9º over your comfort zone, you must make an HT roll every 30 minutes if you are active, apply your encumbrance level as a penalty to this roll. Failure costs 1 FP. On a critical failure, you suffer heat stroke: lose 1d FP. As usual, if you go below 0 FP, you start to lose 1 HP per FP. You cannot recover FP or HP lost to heat until you move into cooler surroundings. 
	At temperatures 10º over your comfort zone or more (90º for most humans), you must make an HT roll every 30 minutes regardless of activity, at -1 per full 10º over your comfort zone, or suffer the same consequences as above. Remaining inactive during this time cuts penalties to the HT roll in half, round in your favor. In addition you lose an extra 1 FP whenever you lose FP to exertion or dehydration. At temperatures 40° over your comfort zone (120° for most humans), this becomes an extra 2 FP, and at 80° over (160° for most humans), this becomes an extra 3 FP.

Humidity can greatly increase the effective temperature, as shown here.
[CHART on this page]

	Intense Heat: Human skin starts to burn at 160° of actual (not effective) temperature; see Flame (p. 433) for damage. Even if no damage penetrates your DR, you will rapidly overheat if the ambient temperature is 400° or more. Temperature Tolerance has no effect on this for humans. After 3 x DR seconds, make a HT roll every second. On a failure, you lose 1 FP. Your DR provides its usual protection against burning damage, but it has no effect on FP loss.

	Sunburn: After a day of full sun on unprotected skin, an albino will be near death and a light-skinned Caucasian will be very uncomfortable (1d-3 damage), sun intenisty can vary this by -2 to +2. Tanned and darker-skinned individuals will take from one to four less damage, and may itch, but aren’t in much danger. Having darker skin than typical for your region or ethnicity can be treated as a 1-point perk, while lighter skin would be a 1-point quirk. Albinism should be treated as a disadvantage, combining Weakness (Sunlight), Distintive Features and penalties in bright light.

	Immersion: Aquatic or amphibious creatures have a comfort zone identical to their normal range, but others, like humans, have comfort zone of only six degrees, for humans this is normally 75° to 80°, but can be shifted by up to five degrees, but must be within your normal comfort zone.
	When in water colder than your comfort zone, roll as for Cold once per minute, but do not apply a penalty for being wet. Sudden immersion in waters 20 or more below your comfort zone without a drysuit causes Thermal Shock. Roll as above, but success on the HT roll still causes the loss of one FP, and failure causes a loss equal to the margin of failure.
	Water hotter than your comfort also requires a roll for Heat once per minute to avoid losing FP, but if less than 10° over your comfort zone, you only roll if active. At 40° above your comfort zone, also take 1d-4 burn damage per minute; at 50°, take 1d-4 burn damage per second. 

	Temperature Tolerance (2/level): As comfort zones have been greatly reduced, a reexamintaion of the Temperature Tolerance advanatge is needed, and it's cost increased to 2 points per level. This advantage now gives an increased range to comfort zones equal to average racial HT, this is 10 for normal humans. Each additional level doubles the increase, to 2 x racial HT at level 2, 4 x racial HT at level 3, 8 x racial HT at level 4, etc., and can be purchased in half levels. For instance, level 1.5 would give a race with HT 13 an increased comfort zone range of up to 19°, and would cost 3 points. 
	Amphibious and aquatic races gain the full increase to their immersion comfort zones, while others gain only half. Other races may by Temperature Tolerance for immersion zones only as a seperate advantage with a -50% limitation. For races with Temperature Tolerance as part of their racial package, this will also increase the ambient temperature threshold for intense heat, at up to 5° x the increase to comfort zone. 
	Humans may purchase up to one and a half level of Temperature Tolerance in a realistic campaign, and an additional one and a half levels of Temperature Tolerance with the Immersion Only limitation. Overall, Temperature Tolerance is more expensive through low levels, but becomes increasingly more powerful at levels 5 and higher.

	Clothing: The most significant change in these rules is how clothing affects your effective temperature. This is given as a range, for clothing that gives an increase to effective temperature, you must apply at least the lower value, and may apply any amount up to the higher value. This range represents altering the way clothing can be worn (opening a jacket, rolling up sleeves, etc.) as well as quality garments that grant you in effect a wider comfort zone. For clothing with a decrease to effective temperature, you may choose to apply any value withing the given range.
	High-Tech gear can offer climate control systems that can grant a huge range to choose from, or if sealed, grant a specific effective temperature. Ambient temerature might affect such systems directly, reducing their effiency, details are left to the GM.
	Other gear can reduce effective wind speed when calculating wind chill, while wickening garments can reduce effective Humidity. Most clothing offers no benefit what-so-ever when immersed, although specialy made Wetsuits and Drysuits avoid this limitation. Other clothing can be waterproofed, so the penalty for being wet only applies if the interior of the outfit is wet.
	Finally, many heavy forms of clothing are in fact layers of lighter garments. It is perfectly reasonable to stow some heavier items away, and treat the clothing as a lighter version. Cold weather gear is very dependant on having all accessories (Boots, Mittens, Scarf, Headgear), and the GM is free to apply large range reductions if some of these items are omitted or missing. Lastly, you can always strip down to minimal or no clothing at all if the heat gets too unbearable, although the social consequences of such actions will vary by setting and situation.

Clothing list...  In progress

[Trachmyr]

Here is a rough draft version of basic clothing values:

Summer Clothes: Typical range is +0 to +5. Status -2 outfits are just +0. Higher quality gear (Status 1+) can give +0 to +10.  Heavier 	outfits raise min. & max. by +5. Hot Weather clothes can also give +0 to -5, and high quality versions can offer +0 to -10. 	This assumes lightweight footwear, if heavier add +5 to both numbers.
Ordinary Clothes: Typical range is +5 to +15. Status -2 reduces range by 5, high quality increases range by 5. Heavier versions are 	available that increase upper and lower range values by 5 or 10. No footwear or very light footwear (sandals) can lower 	upper and lower numbers by 5, while heavy footwear can increase it by another 5. A light windbreaker (+0.5CF) can be 	added that reduces effecftive Wind Speed by 10mph.
Formal Wear: Typical range is +10 to +20. Status -1 reduces range by 5, high quality increases range by 5. Heavier 	versions are 	available that increase upper and lower range values by 5 or 10. No footwear or very light footwear (sandals) can lower 	upper and lower numbers by 5, while heavy footwear can increase it by another 5. A wind-resistant jacket (+0.5CF) can be 	added that reduces effecftive Wind Speed by 10mph.
Winter Clothes: Typical range is +20 to +50. Status -2 reduces range by 20%, high quality increases range by 10. Heavier and lighter 	versions are available that change the upper number by 10 or 20, and the lower number by half that. No footwear or very 	light footwear (sandals) will reduce lower number by 5 and upper number by 20. Normally includes some wind resitance 	that reduces wind speed by 10 mph, but a better version is available for +0.5CF that doubles this.
Artic Clothes: Typical range is +50 to +100. Status -2 reduces range by 20%, high quality increases range by 10. Heavier and lighter 	versions are available that change the upper number by 10 to 30, and the lower number by half that. No footwear or very 	light footwear (sandals) will reduce lower number by 5 and upper number by 40. Normally includes some wind resitance 	that reduces wind speed by 15 mph, but a better version is available for +0.5CF that doubles this.

[JCurwen3]

I think these rules are really good. Have you considered submitting them as an article for Pyramid (perhaps / probably in a future Alternate GURPS)?

One thing: did you consider, instead of absolute range modifiers for clothing, assigning clothing a Temperature Tolerance range (fractions being permitted)? That way clothing would confer some degree of that advantage (as it can confer DR and others). It might also help with scaling these for use by characters of different races. So arctic clothes would have, instead of base range of +50 to +100, base TT of ~3.322 to ~4.322 (calculated via LOG((degrees / 10),2)+1, the 10 being there as human racial average).

[Bruno]

On the one hand, insulation just isn't a relative thing. Two inches of fur is two inches of fur whether I'm a jungle elf or a cave troll, watertight clothes keep everyone equally dry (preventing water from wiking away heat) and so forth.

On the other hand, how much heat a body generates, how much surface area there is to radiate it out from, and whether they even sweat like humans at all is likely to be very species specific...

But I'm inclined to say that overall, I would suggest it not be relative. Instead races with unusually weird relationships with insulating clothing have an additional quirk or perk, or it's subsumed into another trait (like Subsceptable to overheating or Cold Blooded)

[Trachmyr]

Originally Posted by JCurwen3

I think these rules are really good. Have you considered submitting them as an article for Pyramid (perhaps / probably in a future Alternate GURPS)?

I have, in conjucntion with my detailed leather/textiles cration rules, I think they might make a good addition to the Prehistoric issue.

I'm still having a bit of difficulty reconciling the rules with Low-Tech, the weights for leather armor ther seem to be based on using 13/15 oz armor-grade leather weight at over DOUBLE the individual's surface area, with absolutely no accounting for fitting.

For example, if I were to make in actualtity a real, but simple leather curiass, from armor-grade Leather (13/15oz per square foot), I would need a 28in x 44 in project piece. This would leave the arms bare at the shoulder down, and would cover the chest and abdomen, but not groin. Total material weight would be 7.5 pounds without removing material for fitting... which with my skill level (Dabbler w/ Decent IQ & Taking extra time), would be a wash with the straps and buckles I would need to add. By Low-Tech, a fitted curiass covering those regions would weigh 11.4 pounds, maybe a bit less if I consider that it doesn't offer full protection to the abdomen, at 3in6 coverage (which is definately less than what my example is) this still would be 10.2 pounds, more than a third heavier!

Here's a simple one, a pair of vambraces, I would start out with two rectangular pieces of 13x10 inches, and 13/15oz weight. Weight would be about 1.6 pounds after removing trimmed material towards the wrist, but adding cords and eyelets. By Low-Tech, the weight would be 2.4 pounds! I'm constantly finding Low-Tech to be about 50% heavier than simple, barely-fitted, amateur efforts in the real world... and that;s not taking into effect that I'd be a ST12 225pound guy by GURPS rules... trying to outfit a 130 pound woman gives you extremely HARSH numbers.

One thing: did you consider, instead of absolute range modifiers for clothing, assigning clothing a Temperature Tolerance range (fractions being permitted)? That way clothing would confer some degree of that advantage (as it can confer DR and others). It might also help with scaling these for use by characters of different races. So arctic clothes would have, instead of base range of +50 to +100, base TT of ~3.322 to ~4.322 (calculated via LOG((degrees / 10),2)+1, the 10 being there as human racial average).

I did, in fact that was my first approach. But there's two issues. The first is that it only accomplishes half of my goal, getting warm clothing to bump you up into your comfort range. The second goal, having overly warm clothing overshoot your range and cause issues, is not satisfied. To do so I would need a second mechanic, either negative levels of Temp Tolerance or simply a boost to effective temperature. So I opted for the Effective Temperature route that handled both goals simultaneously. But, in actuality, when an outfit gives a range, that is the same as Temp Tolerance.

The second issue was fractions (other than halves), while they don't scare me or most on this forum, we are not representative of the population. Better to stay away, and using whole numbers, I can Satisify Pentaphillia for pre-worked examples, and give a lot of customization room for detailed creation.

Originally Posted by Bruno

On the one hand, insulation just isn't a relative thing. Two inches of fur is two inches of fur whether I'm a jungle elf or a cave troll, watertight clothes keep everyone equally dry (preventing water from wiking away heat) and so forth.

On the other hand, how much heat a body generates, how much surface area there is to radiate it out from, and whether they even sweat like humans at all is likely to be very species specific...

But I'm inclined to say that overall, I would suggest it not be relative. Instead races with unusually weird relationships with insulating clothing have an additional quirk or perk, or it's subsumed into another trait (like Subsceptable to overheating or Cold Blooded)

I probably need to go in and make notations on how Cold Blooded is affected, other affects can be handeled by a Variant Temperature Tolerance that affects ranges of clothing only... so if I have Temp Tolerance 1 (Clothing), I would double the upper range... a 50% limitation would double both numbers, and negative levels would reduce both nubers. Will think on it.

[Flyndaran]

The bigger you are, the less ectothermy is an issue. Clothing would be somewhat less effective for them as they produce less heat than a comparably sized endotherm. Intelligent ectotherms can mimic mammals and shiver voluntarily to produce more heat, or jog in place.