Since water can be either hot or cold, does its temperature affect its ability to extinguish fires?


A fire needs 3 things as shown in the image:
fire triangle
Water reduces the heat as it turns into steam; and hot water turns into steam faster. But the most important thing water does, is to prevent oxygen getting to the fuel. So as long as there is liquid water, it does a great job.

  • $\begingroup$ This really depends on the fuel, don't you think? Water may not be the most efficient retardant for a grease fire. $\endgroup$ – ringo Jun 11 '15 at 5:17
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    $\begingroup$ @ringo The OP wants to know about water, so I limited my answer to that. $\endgroup$ – LDC3 Jun 11 '15 at 5:19
  • $\begingroup$ To turn to steam, you need to (1) raise the liquid to the boiling point, and (2) add the enthalpy of the phase transition. So, yes, boiling water will be less effective than cold water, but the enthalpy is still a big term (vague memory, about half as effective). Coupled with the smothering noted by @LDC3, use whatever water is available and don't wait for the tap to cool down. (and don't pour water on a grease fire). $\endgroup$ – Jon Custer Jun 11 '15 at 13:38

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