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LPG heater- fumes

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mick H28/11/2019 08:51:08
719 forum posts
21 photos

I recently bought new, an LPG heater for the workshop for the coming cold season. My workshop is only fairly small (10ft x 8ft) and when the heater is in use the door is always cracked open and an up and over window is opened. Additionally I usually switch on a small extractor fan. I also have a carbon monoxide detector. I usually only have one radiant burning.

Despite this aeration , I find that the products of combustion are quite obnoxious and I have noticed a slight headache after a while. Theoretically, the products of combustion are water and carbon dioxide. The burner burns a clear blue flame on the surface of the radiant. The fuel I am using is Calor butane. I know that LPG does usually have an odoriser .....could this be the problem?


Journeyman28/11/2019 08:56:34
783 forum posts
134 photos

Not only will you get fumes you will also get a lot of water vapour to rust all your machinery. LPG heaters are definitely not recommended for workshop use. Better with a small electric fan heater with a thermostat. The fumes are probably from the added odour unless you have incomplete combustion in which case you may get some carbon monoxide at a very low level but definitely not good for you. Ditch the LPG and go electric.


Edit: Typo

Edited By Journeyman on 28/11/2019 09:06:46

Ian McVickers28/11/2019 08:58:07
174 forum posts
84 photos

Not sure that the odoriser would be the issue. I did have a space heater in the shop at one time before I got my multifuel stove and I hated it. Got same sore heads sometimes as well and have no idea what caused them. We have bigger space heaters at work but in hugely larger buildings and I don't get any issues working next to them. Maybe they just suck up all the oxy in smaller spaces.

Ian McVickers28/11/2019 09:00:12
174 forum posts
84 photos

On a side note we have odoriser in our oxygen tank supplies and it affects the quality of the cut on our plasma machines. Run the machine off a HP bottle bank and the cut quality is lovely.

Pete Rimmer28/11/2019 09:41:10
685 forum posts
49 photos

A headache probably means that the LPG is not all getting burned. Years ago we had a machine fitted with LPG (propane) conversion designed for indoor use (large spaces). The fuelling was not properly set up initially and it laid three of us low with the worst headaches imaginable after a couple of hours.

I had a butane heater in my 5m x 4m workshop for a long time with no ill-effects. It was an older type but well built. Now I use ceiling-mounted infra-red heaters.

Mike Poole28/11/2019 10:00:16
2546 forum posts
60 photos

They definitely do produce a smell even when working properly, our motorcycle club met in a pub club room and was heated by mobile LPG heaters and walking in from the fresh air it was noticeable. In the factory the ride on floor sweepers were LPG powered and had a distinctive smell when they passed and it was the same with forklifts.


Henry Brown28/11/2019 10:12:07
195 forum posts
48 photos

I nearly killed my self with a SuperSer years back, luckily a neighbour knocked on the door and the knocking eventually roused me. In a workshop the water vapour can also be a problem. They are to be used with care!

SillyOldDuffer28/11/2019 10:24:18
5642 forum posts
1159 photos
Posted by mick H on 28/11/2019 08:51:08:


Despite this aeration , I find that the products of combustion are quite obnoxious and I have noticed a slight headache after a while. Theoretically, the products of combustion are water and carbon dioxide. ...


Water and Carbon Dioxide in a confined space are both bad for humans! As a combustion product, water raises the humidity. High humidity confuses the bodies temperature control system, making your workshop feel hotter than it actually is. Carbon Dioxide reduces the amount Oxygen available, and interferes with the mechanism by which the body decides how hard it's necessary to breath. Although it's not poisonous, 10% Carbon Dioxide in the air will knock you out completely.

In a confined space, elevated humidity and CO2 will make you ill. Although the effects are temporary, the body complains rather quickly. First, we think the room is stuffy, then feel unwell, then a mild headache, dizziness and in extreme cases - death. A breath of fresh air fixes it. Or a chimney!

Even if they don't upset the human, combustion heaters are best avoided in workshops because they promote rusting. An electric heater is better all round.



Edited By SillyOldDuffer on 28/11/2019 10:24:40

Derek Lane28/11/2019 10:41:40
318 forum posts
73 photos

Even though you have cracked open a window and have a small extractor working in such a small space if there is not enough oxygen in the workshop the heater will use this faster than what is coming into the space.

For example, if a gas heater is left in a room with all the windows and doors are closed it will go out as it uses up all of the oxygen and extinguish itself and the safety valve should cut off the gas once no flame is present.

Personally I would never go for a gas type heater in the workshop. not only because of the size of the workshop which is about the same size as yours also because I produce fine wood dust in there.

For heating, I have a greenhouse heater(electric) on all the time this keeps it just above freezing to protect my machines and also an oil filled electric heater which I can turn on just to bring it up to working temperature, this is quite often turned off after 1/2hour as once I have machines running there is enough heat to keep it comfortable for the rest of the day

mechman4828/11/2019 10:58:26
2638 forum posts
408 photos

Ditch the gas Mick; for all the reasons posted above. I have a single garage utilised as my man cave, 17ft x 8 ft, fully insulated walls & roof space. I use 2 small oil filled rads at either end, switched on for 1/2 hr at a time, it soon gets up to a comfy 16*C.


Rockingdodge28/11/2019 11:43:32
208 forum posts
35 photos

I have a Chinese night heater which runs off diesel or paraffin/kerosene, this works really well on kerosene, is cheap and the combustibles are kept in a chamber which exhausts outside and a heat exchanger blows dry warm air.

Works well in my 7 X 5 metre workshop.

BOB BLACKSHAW28/11/2019 12:40:31
292 forum posts
63 photos

As above comments don't use the open flame, look at a green house when using paraffin ln the morning full of condensation on the glass. When buying a electric fan heater check that the thermostat shuts off between a few degrees. usually the cheap fan heaters don't. I use a fan heater which clicks on and off set at a low temperature all night and no problems with condensation.

I have a Carcoon for my MGB but I don't use it, its covered over with a cover and a fan blowing underneath with two carpets on the concrete floor and no condensation.and in my opinion as good as a Carcoon. So air circulation and insulation is all I have found needed over winter.


not done it yet28/11/2019 12:49:08
4509 forum posts
16 photos

As much as I dislike any cheap chinese heater, the kero/gas oil type, with heat exchanger must be the better idea. Lorry drivers and caravaners/boaters have used them for years - but not the cheap chinese knock-offs!

John MC28/11/2019 13:07:09
274 forum posts
38 photos

Many years ago if I fancied a winter evening in the workshop (insulated wood 4m x 2.5m) after work, as soon as I got home I would light up an LPG heater. An hour or so later the workshop was warm and I turned off the heater. Problem was the humidity, everything swimming in water., rust became a problem.

I very soon stopped using the LPG heater. The reason for using it was cost, I mistakenly thought it would be cheaper than electricity. I acquired a couple of oil filled radiators. Just as effective. A little cheaper to run and easier to control. Above all was the safety aspect, no evil exhaust emissions!

That was a long time ago, my present workshop was built as part of a home extension, double, now triple glazed and on the central heating heating circuit.


Rockingdodge28/11/2019 13:07:49
208 forum posts
35 photos
Posted by not done it yet on 28/11/2019 12:49:08:

As much as I dislike any cheap chinese heater, the kero/gas oil type, with heat exchanger must be the better idea. Lorry drivers and caravaners/boaters have used them for years - but not the cheap chinese knock-offs!

Maybe not the Professional drivers but certainly many motorhomers, caravanners and boaters do use them without any issues. Granted the quality/longevity can be questionable but there are british importers that give aftermarket support and there are plenty of forums out there doing the same.

I got a 100 litre drum and purchased 80 litres of Kerosene, I'm into my second winter now and have used maybe 15/20 litres so certainly the most cost effective way of having a warm dry workshop to spend my hours mking swarf.

Vic28/11/2019 13:22:41
2497 forum posts
14 photos

I use a fan heater in my workshop, it soon heats up. I’m fortunate in that the floor is wood covered in painted ply so it’s a lot more comfortable than my past workshops with concrete floors.

Martin Hamilton 128/11/2019 13:56:52
169 forum posts

I only ever used a Calor gas fire once in my 10 x 8 insulated shed which got it toasty warm, never again after the condensation that had formed on every single machine surface in the workshop. I could not believe the amount of water that had formed on every cold metal surface when i went into the workshop the next day, didn't realise at first where all this water had come from. It then dawned on me the moisture from the Calor gas burning, it looked as though everything had been sprayed with water from one of those plant vapour spray bottles. I now use those low wattage tubular electric heaters left on all the time during winter months.

peak428/11/2019 16:15:58
1080 forum posts
124 photos
Posted by Rockingdodge on 28/11/2019 13:07:49:......................................

Maybe not the Professional drivers but certainly many motorhomers, caravanners and boaters do use them without any issues. Granted the quality/longevity can be questionable but there are british importers that give aftermarket support and there are plenty of forums out there doing the same.............................

I've actually got a Propex propane heater in my Landrover, from when I was sitting for prolonged periods on cold rally stages.

Yes, they are propane, but have a flue and a heat exchanger, such that the exhaust products and the hot air don't mix. I that regard, they are similar to a balanced flue gas wall heater, but with a 12v fan assist.
When Propane was cheaper, I'd considered running a 12v Propex one to heat my small, well insulated, workshop. Water vapour wouldn't have been a problem, as it would have gone out of the flue, along with any combustion by-products.
My new workshops are unfortunately too big to easily heat, at 6.6m² with a double pitched roof, which is why I'm sitting indoors typing, rather than playing on the lathe.

The red 12v Propex ones certainly used to be fitted to some BT (jointers) vans, later being replaced by a different make; They may well use diesel ones now.

N.B. BT/GPO also used to issue propane radiant heaters for use in external jointers' tents. They must not be used in a closed space.
I was reading last week about someone reminiscing on an ex-BT Facebook group. Either he or one of his mates had passed a van they recognised at the side of the road, and stopped to say hello to their colleague. This proved fortunate, as when he opened the back door, they were both out cold with carbon monoxide poisoning, and didn't have long to live; yes they'd used the radiant heater in the van for some reason.

One option for a workshop, other than a Propex or similar, might be a diesel Eberspacher running off a 12v or 24v supply. Just make sure you plumb in the flue correctly and follow the same regulations as a gas balanced flue heater or boiler , with respect to siting in the vicinity of opening windows.


Brian Baker 128/11/2019 18:00:09
114 forum posts
24 photos

Greetings, on top of all that has been said above, LPG does contain sulphur, and other impurities, which when burnt, will produce toxic products, which will affect you.



John Paton 128/11/2019 18:20:36
268 forum posts
17 photos

I can add that I had experience (professionally) of excessively high Aldehyde concentrations with a gas 'direct fired' space heater in a large public swimming pool. When investigating this I discovered that carbon monoxide is produced under the same conditions that create aldehydes, indeed this is an algorithm used when testing natural gas fired cookers.

Aldehydes cause watering eyes and headaches so are a better warning than you get with carbon monoxide. If you are sensitive to them you will find them in the outlet of most gas burning devices.

As others have said the primary cause is lack of sufficient oxygen but this can also be due to poor set up of the burner (which was the cause of the swimming pool problem) but we also found that (in the humidity and chemically charged) atmosphere of an indoor swimming pool there appeared to be some 'ponding' of combustion gases in certain parts of the room.

Be aware!

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