Pouring with rain outside, warm and dry inside, and dinner being served.
A recurrent question on many internet chat groups (including BPL) is “Can I cook in my tent?” Such a question always gets a horde of replies that to do so risks death and disaster, and the tent police. Worse, many comments add that you are forbidden to do so by stove manufacturers. Well, I will invoke Caffin’s Law here: “There is no limit to the stupidity available on the Internet”. What follows is very definitely my own personal biased opinion.
The sources of all these warnings can be divided into three categories: ignorance, stupidity, and company lawyers. Let us deal with the company lawyers first. Their concern is solely to protect their companies from liability claims from customers (it’s called CYA); they have zero concern for the survival of the customers. That is understandable – especially considering how some customers are able to misuse gear to an extreme. In many cases one can only sigh and mutter “Darwin Award”. (That’s a well-known “award” given to people who contribute the most to the evolution of humanity by removing their genes from the gene pool. There is even a web site for it.)
The second category is stupidity. Many people, lacking any decent knowledge of how a stove works, simply parrot what they have heard from other equally ignorant or stupid people. They don’t bother to check their “facts” or their “knowledge”, and apparently don’t want to think. (“Most people would die sooner than think – in fact they do so” – Bertrand Russell) I despair of dealing with stupidity, so we will pass on from here as well.
The third category is ignorance. Here we have some hope of improvement, by taking a decent look at what is involved, and making this (technical) information available to those who would like to know more. That’s what this article is about. And no, the answers are not simple. It all depends…
What are the Hazards?
It is undeniable that there are hazards – but let us look at them objectively. We could even try comparing them against the hazards of being killed while driving a car, or being killed by someone with a firearm, or being injured or killed by industrial pollution. Statistically, using a stove is much safer! Anyhow, the hazards with stoves fall in three main areas: getting burnt, losing gear (which might be vital to survival), and poisoning from the fumes. The last includes the obvious hazard of carbon monoxide (CO), but some fuels can also give off toxic fumes.
A blow torch inside the house? Shock horror, we will all die!
While talking about hazards, let’s have a reality check. Some stove companies ‘ban’ the use of your stove inside any enclosed space, such as a tent or building. See for example the Danger section in the MSR User manual for the XGK-EX. I wonder how those lawyers handle the fact that (say) half of the houses in America are equipped with … gas stoves in their kitchens? Places like Home Depot sell a vast range of kerosene heaters for indoor use. Chefs in restaurants use canister-powered blow-torches to make crème brûlée. Oh Dearie Me – we are all going to die! (Which is true, but that’s another matter.)
But yes, there are some hazards, despite the ridicule. So get to know what those hazards are and how to deal with them. Basically, you need to be careful with the fuel, the flames, and the combustion products. But we do that every day at home.
Many of the hazards can be dealt with by being careful, using some common sense, and by having adequate ventilation. A family died in their family camping tent one night when they left their charcoal BBQ running inside their tent overnight – which they had sealed up to keep the warmth in. CO poisoning all around. Unfortunate, but lacking any common sense. In an incredible experiment, some “researchers” put some volunteers inside a sealed tent in the snow with a running stove, and measured how long it took for the volunteers to go unconscious from CO build-up. The ethics of that one leaves me boggled.
Fine and sunny, or howling bad weather? Only 12 hours apart.
What the lawyers and pseudo-experts ignore in all of this are the hazards from banning the use of a stove inside the tent. If it is a fine quiet sunny afternoon at 200 m altitude, there are no problems to cooking outside. The same might apply at 2,000 m in the snow at 2 pm in bright sunshine: it’s quite nice outside. OK. But what if you are at 2,000 m in the snow at 7 pm and there is a 100 kph snow storm howling past outside the tent? What are your chances of ever getting the stove alight outside, let alone getting some hot food? Worse still, suppose you are at 6,000 m on a narrow ridge in the Himalayas in the evening? Without a stove, you can’t even get any water to drink, and you are definitely dehydrated. I asked staff at a major USA gear manufacturer about this, and they refused to answer the question. They just repeated what their lawyers had told them to say.
Never mind the wind: you must cook outside…or so they tell me.
The above does not cover the risks to the cook of sitting outside in pouring rain, howling snowstorm or -15 C temperatures. You might freeze to death before you have made dinner! Unfortunately you can’t see the horizontal snow in the left hand picture – it is just visible in the full-sized original. In the right hand picture my poncho was flapping like mad: it was a posed photo for amusement during some bad weather. Contrast this with being inside a good tent in warm dry clothing on a nice airmat, watching dinner happen (see the first photo). No argument!
So let’s look at the different sorts of stoves or cooking arrangements we might consider using in a tent in some detail. Many of them are in fact quite unsuitable.
Wood Fires of all sorts
The hazard with wood fires is that they are somewhat uncontrolled. They can, and do, shoot sparks into the air above the stove, and they can make lots of eye-stinging smoke. Yes, I am including both open fires and “tin can wood stoves” here. Without any further ado, I suggest you do not use any wood fires near a tent – inside or outside.
Think you will ever get any hot water from these in a storm?
There are several forms of solid fuel available, in the hexamine and candle wax classes. They can make a fair bit of smoke at times, and they certainly can give off toxic fumes under many conditions. The fumes are often due to incomplete combustion, so that intermediate combustion by-products are released. Small candles may be “safe”, but have you ever tried boiling water over one? Can you image even getting hot water from such a flame (let alone melting much snow) when outside in bad weather?
If you must use such fuels in bad weather, you may be in for a long wait for food or water even if you are inside a tent, and you will need to have a lot of ventilation. Personally, I would try very hard to avoid being in this situation.
Methyl alcohol is basically toxic to humans, so unburnt vapors won’t do you any good. Propyl alcohol gives off toxic by-products at times which won’t do you any good either. Used outside in an ‘alky’ stove, you can usually stay upwind and get away with it fairly safely. Ethyl alcohol is what you find in wine and spirits, and is (relatively) safe for humans – although drinking an excess can kill.
The problem with ethyl alcohol is that one cannot normally buy pure ethyl alcohol: one buys something vaguely called “methylated spirits” or other terms such as HEET [actually methyl alcohol]. The name [‘metho’] means that other substances have been added to the ethyl alcohol to make it undrinkable, thereby avoiding the revenuers. Unfortunately, there are no regulations in America covering just what can be added – and some very toxic chemicals have been and still are used by some companies. The vendors have not allowed for the use of the alcohol as a fuel, so breathing the fumes in can be dangerous. (In Australia regulations very severely limit what can be added, so that all methylated spirits is safe for burning.)
Invisible flames on alcohol stoves – except where dangerous.
Apart from the fumes, there are some other hazards with alcohol stoves. The flame can be almost invisible, meaning you may or may not know when the stove is still burning. There are horrible stories of people trying to refill an alky before the flames went out completely. The left and middle photos here both have lit stoves in them: can you see the flames? (Sketti, by MiniBull Designs and White Box by White Box)
The fuel is easy to spill but hard to see, and will catch alight fairly easily. Spilt fuel is a fairly well-known risk with alky stoves in fact. You may find your stove sitting in a spreading ring of fire if you are not careful. For obvious reasons the stove in the right hand photo was not alight: I am not (too) stupid. One might say that spilt fuel could be the most dangerous aspect of alky stoves when used in a tent – or on a wood bench in a hut – to both you and to your gear.
Yes, you can use an alky inside your tent – but there are risks and you need to be aware of them. Given the slow rate of heating from most alky stoves, you may have to wait a bit for your dinner, and use a good windshield. But, it is possible.
Old white gas stoves: Handy Camper, Optimus 8R, and MSR Whisperlite.
This is an old favorite – and I do mean old. There is a myth that white gas stoves are more powerful than canister stoves, but this myth derives from comparisons against the old “Bleuet” canister stove. For very good technical reasons to do with the large amount of oxygen needed for complete combustion, white gas stoves are now generally lower in power than modern screw-thread canister stoves. However, white gas stoves have been very popular for decades, the fuel is quite cheap, and they still have a loyal following despite their high weight and high cost – and their hassles. (Sorry, I don’t have a good photo of a Svea.)
MSR XGK being primed, photo by Kevin Babione.
The problems or hazards with white gas stoves include priming, CO emission, fuel weight and controllability (or lack of). The latter two are not relevant here, but priming is. Typically, users prime their white gas stoves using the MSR “fireball” technique. That is, you slosh fuel around the stove and light it, creating a small to large fireball engulfing the stove for a while. To quote the MSR instructions for their XGK stove: “A brief soccer ball size flame is normal”. Priming fireballs are not the only hazard with white gas: if the stove splutters at all you can also have a column of flame above your stove, as shown here. It is not hard for that to reach to the tent fabric above. You do not want that inside your tent! And, of course, some stoves generate a lot of CO, but to me that seems a smaller hazard than flames.
Many years ago a pair of climbers in the Himalayas found this out the hard way. They had trouble with wet matches, and did not realize how much white gas they had spilt. When they did get a flame the spilt fuel went “whoomp”, and all they had left were the tent poles. Sorry – I can no longer find the source for this story.
A melted tent from an exploding white gas stove (photo author name withheld).
A further hazard with white gas stoves comes with the use of very large pots. The sheer size of the overhead reflector can mean that too much heat can be reflected down on the pressurized fuel tank. The pressure in the tank can rise to alarming heights. The photo here shows a melted tent after an “incident”. There were two MSR white gas stoves (Whisperlites from memory) running side by side, both with large pots, but well outside the tent. The fuel tanks overheated and exploded, and burning fuel splashed the tent from the outside. Two people nearby suffered severe burns as well, requiring urgent air evac and quite extensive plastic surgery.
If you wish to use a white gas stove in your tent, can I suggest that you first prime it just outside the tent? Stay inside yourself and just stick the stove outside, in the lee of the vestibule. Then bring the stove into the vestibule region, but maybe not too far in. Try to arrange it that there is no tent fabric above the stove. Then use a windshield around the stove to keep the flame under control – out of direct wind. That way you will also have enough ventilation that CO emission should not be a problem. And do not use a pot more than about 1.5 L.
My Coleman Peak Apex II much used kero stove, showing signs of several rebuilds.
Ah, kerosene – the original fuel for ‘portable’ stoves, aka Primus. I used it for many years, first with an MSR Whisperlite, then with a Coleman Peak Apex II, even though it stank. Why use kero? Because it does not go ”whoomp” the way white gas does, and in the early days the screw-thread canister was not yet available. In fact, a common fire brigade demo was (and still is) to pour kero (or diesel) into a metal dish and to throw a lit match onto it. The match goes out. Then they do it with petrol or gasoline – from a distance. But my wife who was normally up the back of the tent severely disliked the whole kero stove thing because of the smell which bottled up at the back of the tent.
Kerosene and so some extent white gas, or petrol car fuel, have the advantage that you can often buy them in strange places like Nepal or the middle of Africa. And you can often arrange to buy a few jerry cans of the stuff too. Trekking in Nepal often sees one unlucky porter carrying the kero drum. It usually leaks – on his clothing.
An early MSR G/K stove: the ‘K’ means it also burns kero.
As a historical side note, the 1979 instructions (in another image I have) for the MSR G/K stove, a predecessor of the XGK, say rather more realistically: “We do recommend against cooking in a tent. But when you have no other choice, use kerosene in a model G/K stove for relative safety because kerosene is far less volatile than gasoline.” That was before the lawyers took over.
The problems with kero are similar to those with white gas: priming is harder, CO emission can be significant, and so on. I was able to prime my kero stoves without fireballs by using a very small amount of methylated spirits as a priming fuel – as suggested in the above photo. It took practice, but I was sufficiently confident after a year or two that I could light my kero stove sort-of inside the vestibule of my tent. But starting the stove safely always took full concentration – which can be difficult if you are really tired.
Personally, I think kero stoves are even more dinosaur than white gas stoves, but if you learn to prime them properly with the right method you can use them in an open tent vestibule. Make sure you have plenty of ventilation – to get oxygen in and CO away. You just have to put up with the smell.
Canister Fuel – Propane and Butane
Greg Child’s tent after the Bleuet accident on Shivling, photo author unknown.
No, I am not going to proclaim that canister stoves are perfectly safe when used inside a tent. You have fuel and a flame, and if you screw up things will go “whoomp”. In this case the climbers were using the old Bleuet canisters. My guess is that in the cold the butane would not come out of the first can, so one climber disconnected the can and attached a new one. Then he lit it. But the discarded can still had gas in it, plus a large hole, and it was venting. Despite the tent being opened to let the gas out, it had filled with butane vapor which predictably went “whoomp”. It is interesting to note however that the tent melted: it did not burn.
Let’s deal with the old Bleuet can first. I strongly recommend you do not use this can or the stove any more. There have been so many accidents with the “seal” that there are now official moves in Europe towards disqualifying the design. To put it bluntly, the Marseilles Regional Trauma Burn Centre is fed up with the number of cases they (and other burn centers) get from this system. The number of accidents is just too high – when they could be replaced with the far safer canister with a Lindal safety valve. I have to agree, after having one of the Bleuet stoves leak inside my pack.
Basic hydrocarbon chain – butane in this case (green = carbon, red = hydrogen, thin rods are bonds).
Kerosene, white gas, propane and butane are all long-chain hydrocarbons with similar burning characteristics. However, propane and butane are far more volatile than white gas or kerosene, so they can vaporize at normal ambient temperatures. This means that under non-winter conditions upright canister stoves do not need priming. You screw the stove onto the canister, sit the lot upright, and gently open the valve while holding a flame next to the burner. It is perfectly possible to light up an upright canister stove inside your tent to have a flame no more than 10 mm high. No “whoomps”, no meter-high flames, just a small highly controllable little flame.
A base plate (e.g. 3 ply) makes a stove so much more stable.
Now, let me hasten to add here, that if you are clumsy and tip your stove (plus pot) over, there will be trouble. A flare-up is most likely, and you will lose your dinner too. If you do this right inside your tent, on the groundsheet, you will have wet gear and a hole in the groundsheet. A nice hard base plate is considered by many to be essential for stability: I use a small square of light 3-ply.
In winter things are a bit more complicated, as it is likely you will be using a remote canister stove with a liquid feed. These do take a tiny bit of priming to get the stove hot enough (like >10 C) so the liquid fuel will vaporize. Yes, +10 C is quite enough: a far cry from the red heat needed for white gas and kero stoves. Users of the Coleman Xtreme stove as shown above (or my winter stove) often don’t really bother with a full priming cycle: they just start with the valve turned really low. So just a little more care is required – that’s all.
Cooking INSIDE, from When Things Go Wrong: you really did not want to be outside!
What about field experience? Well, in my experience, most of the hoorah comes from people who do not know much about canister stoves – or maybe bad weather. Experienced winter campers, snow-shoers and XC ski tourers just retire to their tents and cook dinner, ignoring all the waffle. In the photo here the wind outside was clocking around 100 kph: even standing up was tricky. If this stamps all over your biases, my apologies about your hurt feelings, but I see no need to change what I have said. I have far too many years of safely cooking in my tent. But of course you may do as you wish.
But what about Fine Weather?
Well, OK you might say, but that does not mean you should cook in your tent in fine weather when so many vendors warn against doing so. Sigh – we have been through the vendor thing already. Strictly CYA.
But let us look a little more closely at the rest of the idea here. Maybe it is safer to cook inside your tent when the weather is really (really) bad, but not otherwise? That is a bit of an odd idea: isn’t that just when you are most at risk and when you are most stressed? Wouldn’t you be even safer when you are relaxed and not highly stressed? Ah, too many people just follow the mob. Find me some hard published statistics if you want to convince me.
Cooking outside in fine weather.
Oh, OK, sometimes it is fine to sit and cook outside. Yes, I did have a windscreen around the stove here, but I removed it for the photo. It was a nice day, and it was lunch time.
Since one major aspect of the problem is the tent rather than the stove, a few words are in order about the flammability of the fabric. Yes, I have photos of some melted tents above. But notice that in most cases the tent melted in places but did not burn down. That is because most tent fabrics, when arranged as a tent, won’t support continued combustion. Look at the tents in the photos to see. My experiences with silnylon – like performing burn tests according to the Standards, indicate that silnylon at least can barely support a flame without having a candle underneath it. Of course, if it is pouring rain or a howling snow storm outside, the fabric is even less likely to melt.
It is an interesting exercise to search for “melted tent” on Google. None of the picture hits or text hits actually showed a melted tent. But then finding real hits among the Google guano can be difficult. There was one mention of a fire in a tent – but it was clear that the fire was driven by other materials.
Some States in America require that any tent be constructed out of fabric which has been treated with a flame retardant. I have several problems with this. First, the chemicals used are highly toxic to humans. That is well documented. Second the single bit of research done on the retardants has been grossly misused by the manufacturers of the retardant, to the extent that the researcher involved has disavowed the whole matter. Third, the level of retardant commonly used on commercial fabric is but a small fraction of the level which had to be used in the research to get an effect. Finally, the whole thing was driven right from the start by two groups. The first were the manufacturers of the chemicals, who stood to make huge profits. The second was Big Tobacco, who were seeking to divert attention away from the idea of a “fire-safe cigarette” which could be safely dropped on a fabric lounge cover without starting a fire. The whole thing has been well documented by The Chicago Tribune, amongst others. There has been no independent research to justify the use of flame retardants in the real world: it has all been political posturing with pictures of little girls in flannel pajamas in front of open fires and straight out fraudulent testimony. (And yes, I have references for all of this.)
Bottom line here: you may melt a hole in your tent with an ember from a fire or splashes of burning liquid fuel, but you are very unlikely to burn it down with a small carefully managed canister stove.