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# DF2012:Temperature

(Redirected from DF2012:Ignition point)

For temperature as it relates to choosing an embarkation site, see Climate.

 This feature has one or more outstanding bugs in the current release version. Please view the Bugs section.

## Temperature scale

Dwarf Fortress uses its own temperature scale in most cases, often called "Degrees Urist" on this wiki. So if you see something like [HOMEOTHERM:10067], don't be amazed.

Magma's temperature is 12000 °U .

The highest possible temperature in Dwarf Fortress is 60000 °U — the temperature 60001 °U is used internally for temperatures which have been set to "NONE".

### Conversion

[DF scale] = [FAHRENHEIT] + 9968

[DF scale] = [CELSIUS] * 9/5 + 10000

[DF scale] = [KELVIN] * 9/5 + 9508.33

[DF scale] = [RANKINE] + 9508.33

(Note: Mod-makers may find this Temperature Conversion Utility handy if they find themselves having to convert a lot of temperatures to and/or from Degrees Urist.)

### Reference Chart

Significance DF Scale Fahrenheit Celsius Kelvin Rankine
Boiling Point of Water 10180 212 100 373.15 671.67
Human Body Temperature 10066.62 98.6 37.0 310.15 558.27
Freezing Point of Water 10000 32 0 273.15 491.67
Absolute Zero 9508.332 -459.67 −273.15 0 0
DF Scale's Zero1 0 -9968 -5555.555... -5282.40555... -9508.33

1. Yes, temperatures in Dwarf Fortress can go far, far below absolute zero, which is physically impossible. Considering Dwarf Fortress also allows perpetual motion, it's best not to ask questions.
2. Technically, fractional/decimal temperatures are not possible in Dwarf Fortress, as they are stored as unsigned 16-bit integers. For instance, body temp for humans in the raws is rounded to 10067 °U .

Examples of some temperatures encountered in DF, the most important ones in bold.

Event / location Temperature
Alcohol freezes 09850 °U
Outside, freezing climate (varies) 09960 °U
Underground, glacier ice 09990 °U
Water freezes 10000 °U
Nether-cap1 10000 °U
Underground 10015 °U
Dwarf/human homeotherm 10067 °U
Outside, scorching climate (varies) 10080 °U
Tiles next to magma (warm stone) 10075 °U
Fat melts 10078 °U
Water boils 10180 °U
Material is fire-safe 11000 °U
Common stone melts (varies) 11500 °U
Items on fire (max) 11640 °U
Magma 12000 °U
Material is magma-safe 12000 °U
Creatures made of flame/fire 14000 °U
Dragonfire2 50000 °U

1. Nethercaps have a fixed temperature of 10000 °U regardless of their environment.
2. Yes, dragonfire is roughly four times hotter than the surface of the sun. Nether-cap is the only usable dragonfire-safe material, due to its fixed temperature.

## Melting point

This is the temperature at which a liquid material will freeze, or a solid material will melt. In Dwarf Fortress, the melting point and freezing point coincide exactly — this is contrary to many real-life materials, which can be supercooled.

## Boiling point

This is the temperature at which the material will boil or condense. Water boils at 10180 °U .

## Ignition point

This is the temperature at which the material will catch fire.

## Heat damage point

This is the temperature above which the material will begin to take heat damage. Burning items without a heat damage point (or with an exceptionally high one) will take damage very slowly, causing them to burn for a very long time (9 months and 16.8 days) before disappearing.

## Cold damage point

This is the temperature below which the material will begin to take frost damage.

## Specific heat

This determines how long it takes the material to heat up or cool down. A material with a high specific heat capacity will hold more heat and affect its surroundings more before cooling down or heating up to equilibrium.

## Fixed temperature

A material's temperature can be forced to always be a certain value via the MAT_FIXED_TEMP material definition token. The only standard material which uses this is nether-cap wood, whose temperature is always at the melting point of water. If a material's temperature is fixed to between its cold damage point and its heat damage point, then items made from that material will never suffer cold/heat damage. This makes nether-caps fire-safe and magma-safe despite being a type of wood.

Due to the way fixed temperature is handled, giving a material a fixed temperature will not cause its actual temperature to change accordingly — instead, its temperature will simply be permanently locked at whatever it was previously. Removing a material's fixed temperature, however, will cause all items made of it to heat or cool until reaching equilibrium with their surroundings.

The fixed temperature of a container does affect its contents, but you can't freeze water by putting it into a bucket made from nether-cap because water will not freeze until it cools below 10000 °U .

The fixed temperature of an inorganic material has no effect on unmined walls made from that material, though boulders will take on that temperature as they are produced via mining.

## Bugs

• A calculation error causes objects in containers to maintain a 1 degree difference from the container, resulting in constant recalculation.Bug:6012 DFhack provides a tweak to stabilize the temperature of such objects.
• Temperature calculations have a significant impact on game performance. (Temperature calculations can be disabled in the D init.txt file.)
• When temperature calculations are disabled, dwarves will refuse to set foot in a cast obsidian tile (or other tiles previously occupied by magma).Bug:6033