fire in a cave

3 tips for a safe fire in a cave

Is a fire in a cave safe? ‘Fire in a cave’ sounds like something you could consider a pretty bad idea. Fire sucks the oxygen out of the room, which is something you probably would have enjoyed breathing in. Also: doesn’t a fire generate an enormous amount of smoke? No, fire in a cave is a bad idea: you’re much better off building a fire at the entrance of a cave. Right? That’s what we thought. We tried this during our adventure in the Peak District. Turns out, it’s the other way around, and here’s where you will read why.

Fire in a cave

If you build a fire outside the cave, close to the entrance, you not only expose that fire to the elements, the smoke will also be blown inside. And assuming you’re looking forward to sleeping in that same cave, then smoke in your face is the last thing you want.

Vuur in grot

Build the fire at the back of the cave

Fire attracts oxygen, uses in during the combustion process, and sends all kinds of other gasses into the atmosphere. Those gasses are warm, and therefore ascend to the roof of the chamber of the cave. The oxygen is sucked in over the floor, and the hot residual gasses leave following the roof. This way, you keep enough oxygen in your cave to breathe, it stays nice and warm, you’re less visible from the outside, you’re keeping animals out and you’re protected from the elements.

Don’t make your fire too big

Imagine for a second that you know what type of rock is surrounding your cave. Then imagine that you know how sensitive that rock is to sudden changes in temperature. In that case, you could make a solid, informed assumption on how big your fire can be, and whether you’re causing a potential cave-in risk when the fire heats the rock.
But you don’t know any of these things, do you? So it’s smart to keep your fire nice and small, keeping a safe distance between the flames and the roof and walls of the cave. Also: you don’t need a lot of fire to warm up the cave to comfortable levels.
Extra free protip:Position yourself between the fire and a wall of the cave. The heat of the fire will reflect of the wall, warming up your back as well as your front. It will also make sure you keep enough distance between the flames and the rock, so you’re minimising a cave-in risk.

Use very dry wood

And I mean really dry. wet or damp wood generates smoke. Or steam. So much so that changes of you smoking yourself out of your cave are high. With dry wood, you minimise that riskm and (captain obvious alert) it burns a lot better than wet wood.

Another smart thing to do (if I may say so myself): build your pyre with the larger pieces close together at the bottom, and the smaller pieces of wood at the top. This will sound unnatural to some people, as we’ve all been taught to build a little piramid of tinder to start a fire. But when you light the tinder on top of a pyre as described above, the hot ambers will trickle down to the layer below as they burn, heating and lighting up that layer. This technique results in a much hotter, cleaner and maintenance-proof fire. And results in a lot less smoke.

Comments 5

  1. Rupert Wolfe Murray

    I’m writing a fairy tale and had my hero making a fire by the entrance of his cave, but my brother Gavin found this article and pointed out my error…so thanks for sharing your experience.

  2. Bob

    My Dungeons and Dragons campaign had a wooden barricade at the opening of a cave catch fire, and I wanted to know what kind of safety concerns the party should have.

    If the flaming barricade were producing significant amounts of smoke, would the smoke go in or out of the cave? The barricade was erected at the entrance with no intention of being set alight (stray Scorching Ray spell set off the fire). I’m not entirely sure. The party needs to push into the cave anyway, but I don’t know how much to rush them. I would assume the oxygen in the cave would begin dwindling since the main source is mostly blocked.

  3. Paul

    This is incredibly useful, thanks – I’m in the middle of planning a novel where this would be an issue. This is probably obvious but if the cave had a high ceiling but only a very low opening – high enough for a person to squeeze themselves through on their belly (and possibly quite wide lengthways) but not much more – I assume the smoke/oxygen situation would be dramatically different and you’d probably smoke yourself out or suffocate (even with really dry wood) as it wouldn’t be able to vent the gases/smoke or pull in enough oxygen? What do you think, could someone get through a night like this? Thanks.

    1. Paul

      Also, would a fire built outside a cave like I describe be enough to fill it with smoke or do you think I could get away with that? I guess it might depend on wind direction and strength?

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