Why Butane and not Propane?

[Surfer]

We are looking at buying a Radiant Portable Gas Heater and using the gas bottle currently in the caravan which is Propane. The idea is to run a hose from the gas outlet on the side of the caravan to feed the gas heater Just to clarify the caravan is on a seasonal site and the idea is to have a 47kg bottle hooked up which supplies the caravan and the heater.

Now the issue. We are told that you can only use the heaters with Butane gas and not Propane gas. I fail to understand why as the caravan gas appliances can be used with Butane or Propane. Surely it does not make any difference if you use Butane or Propane? My friend has his heater running off Propane no problem. Can any one eplain the issue regarding using Propane instead of Butane?

 

[Mark_5040952]

Hi Ian,

I've just done a search and came up with a result where the opposite is true.

http://www.landmann.co.uk/support.htm
They say that theirs use propane but will use butane with reduced performance.

Have a read and if it's true then look around for one that uses propane.

Hope this helps

Mark

 

[RogerL]

Recent caravan appliances work on a range of pressures but free-standing appliances, like your radiant heater, may only be designed to work on a specific pressure.

A freestanding Butane cylinder is regulated to 28mbar, propane to 37mbar. Older caravans, up to 2002 or 2003, used a cylinder mounted regulator of the correct type. Current caravans, from 2003 or 2004 onwards, use a fixed regulator set to 30mbar for both butane and propane.

If your radiant heater is set for 28mbar butane, it may simply not be designed for 37mbar propane. It should have a rating plate defining the acceptable pressure(s).

 

[ProfJohnL]

Hello Ian,

Further to RogerL's reply, Its not just a question of gas pressure, Butane and Propane are different - that why thay have differnt names. If you appliance states Butane only then for your safety, then you must use butane.

To allow a gas appliace which you own or are responsible for to be used in manner that is not within the scope of its approval is illegal, and contrary to Health & Safety regulations which is a criminal offence.

 

[Surfer]

Thanks for the replies. As for John I would appreciate it if you could state the regulation that prevents you using Propane instead of Butane. Pressure would not be an issue in this case and as Propane has a lower burn temperature than Butane so I cannot see why it will not be safe.

 

[Surfer]

Thanks for the replies. As for John I would appreciate it if you could state the regulation that prevents you using Propane instead of Butane. Pressure would not be an issue in this case and as Propane has a lower burn temperature than Butane so I cannot see why it will not be safe.

John, apologies on re-reading my question may appear to be one of sarcasm. It is a genuine question.

 

[ProfJohnL]

Hello M

Like other correspondents I am not sure why you think you need so much 12V power. Not to mention the massive extra weight of the battery.

Of course it is down to your own choice, but most caravanners can usually survive a whole week on a 110Ah.

This is usually achieved by carefully selecting what you turn on, and of course not forgetting to turn things off again. It may also be down to limited use of things like Tv's etc.

There should be no problem at al if you use pitches with electric hook ups, as most caravans have a built in charger to keep the battery topped up.

If you were able to post more details we may be able to suggest some viable alternatives.

 

[ProfJohnL]

Hello M

Like other correspondents I am not sure why you think you need so much 12V power. Not to mention the massive extra weight of the battery.

Of course it is down to your own choice, but most caravanners can usually survive a whole week on a 110Ah.

This is usually achieved by carefully selecting what you turn on, and of course not forgetting to turn things off again. It may also be down to limited use of things like Tv's etc.

There should be no problem at al if you use pitches with electric hook ups, as most caravans have a built in charger to keep the battery topped up.

If you were able to post more details we may be able to suggest some viable alternatives.

Sorry wrong posting

 

[ProfJohnL]

Hello Ian.

Technically Butane has a higher calorific value than Propane, thus to achieve the same heat input through the same injector and burner means that propane has to be supplied at a higher pressure than butane. Hence the older UK settings of 37mB Propane and 28mB for Butane. Consequently if you supply a butane burner with propane gas at the lower pressure of butane, you will have a lower heat input into the appliance.

That is not the whole story, because to archive proper combustion, the pure gas has to mix with entrained air in the venturi tube inside the burner. The propane injected at a lower pressure may not have the velocity and thus momentum to entrain enough air for complete combustion, resulting in high levels of the poisonous gas Carbon Monoxide.

In some appliances where the system employs a pilot flame, the lower heat input rate may affect the size of the flame and its stability. Where the appliance has a user controlled regulator valves (e,g, a cooker) where there is a minimum detent, the flame on propane may be too small and thus prone to blowing out.

I cannot quote regulation numbers as I don't have a copy due to being retired from the industry, but having worked for many years with an LPG Gas appliance manufacturer, I am conversant with the way the regulations are applied.

The appliance manufacturer must apply for CE approval before a new gas product can be sold in the UK. The CE approval for gas appliances unlike CE for many other items cannot be self certified, it has to be tested and ratified by an independent Namas approved test house.

Part of that process involves checking the safety of combustion on the range of gasses and pressures stipulated by the manufacture and any relevant construction regulations of which there are many.

Most manufactures would try to make an LPG fuelled appliance compliant on both Butane and Propane, but some devices may not provide safe combustion on both gasses.

Under these circumstances the appliance will only be CE approved for use on one type of gas with a specified pressure regime.

The Gas (Installation and Use) regulations, govern the application to which any gas appliance can be used. They require that the appliance must be CE approved and may only be installed and used in accordance with the manufactures installation instructions and the Accepted Codes of Practice. (ACOPS) for gas installations. Installations, service and removal must be carried out by a competent person. A person connecting a butane only appliance to a propane supply would be deemed incompetent, and that would be a breach of the regulations.

Health and safety regulations identify that the person responsible for any gas appliance must ensure it is in a safe condition. Using Propane on an appliance only approved for butane would be deemed as unsafe, and thus in breach of the H&S regs. Prosecutions under H&S regs are conducted under criminal law.

 

[JeremyClarksson]

John L

What is your view on external BBQ points and what can be connected to them.

I would like to connect a 3 way fridge to mine and am aware that the maufacturer advises only BBQs.

I realise that a fridge can be left unattended when a BBQ should not be, but what about small gas fires which again should not be left unattended.

Is there some kind of BS or approval rating for the BBQ point which indicates what should be connected.

Realisically the only extra risk area is the physical connection at the BBQ point, the other parts of the operation are common i.e. gas bottle, regulater, pipe and equipment connection.

Risks such as the pipe getting punctured are the same as using a seperate bottle in the same location.

I am veering towards using a seperate small bottle as this could be a useful back up in the event the caravan bottle runs out, but surely there should be smething more concrete than a line in the handbook from the manufacturer - they will always cover themselves.

 

[Surfer]

Hello Ian.

Technically Butane has a higher calorific value than Propane, thus to achieve the same heat input through the same injector and burner means that propane has to be supplied at a higher pressure than butane. Hence the older UK settings of 37mB Propane and 28mB for Butane. Consequently if you supply a butane burner with propane gas at the lower pressure of butane, you will have a lower heat input into the appliance.

That is not the whole story, because to archive proper combustion, the pure gas has to mix with entrained air in the venturi tube inside the burner. The propane injected at a lower pressure may not have the velocity and thus momentum to entrain enough air for complete combustion, resulting in high levels of the poisonous gas Carbon Monoxide.

In some appliances where the system employs a pilot flame, the lower heat input rate may affect the size of the flame and its stability. Where the appliance has a user controlled regulator valves (e,g, a cooker) where there is a minimum detent, the flame on propane may be too small and thus prone to blowing out.

I cannot quote regulation numbers as I don't have a copy due to being retired from the industry, but having worked for many years with an LPG Gas appliance manufacturer, I am conversant with the way the regulations are applied.

The appliance manufacturer must apply for CE approval before a new gas product can be sold in the UK. The CE approval for gas appliances unlike CE for many other items cannot be self certified, it has to be tested and ratified by an independent Namas approved test house.

Part of that process involves checking the safety of combustion on the range of gasses and pressures stipulated by the manufacture and any relevant construction regulations of which there are many.

Most manufactures would try to make an LPG fuelled appliance compliant on both Butane and Propane, but some devices may not provide safe combustion on both gasses.

Under these circumstances the appliance will only be CE approved for use on one type of gas with a specified pressure regime.

The Gas (Installation and Use) regulations, govern the application to which any gas appliance can be used. They require that the appliance must be CE approved and may only be installed and used in accordance with the manufactures installation instructions and the Accepted Codes of Practice. (ACOPS) for gas installations. Installations, service and removal must be carried out by a competent person. A person connecting a butane only appliance to a propane supply would be deemed incompetent, and that would be a breach of the regulations.

Health and safety regulations identify that the person responsible for any gas appliance must ensure it is in a safe condition. Using Propane on an appliance only approved for butane would be deemed as unsafe, and thus in breach of the H&S regs. Prosecutions under H&S regs are conducted under criminal law.

John thanks very much for going to all the trouble of explaining in depth. It is now quite clear the reasons etc and answers a lot of questions. I will check the plate on the appliance before making uyp my mind.

 

[RogerL]

Garry - you're planning to connect an appliance burning gas, within your awning, and then leave it unattended while you go out?

I think you're mad, please post where you're going so that I can avoid being near you!

 

[JeremyClarksson]

When running on gas do you turn off your water heater and fridge before going out.

From my experience it is very common for 3 way fridges to be run in a well ventilated awning from a bottle, they do have flame failure devices the same as your normal caravan fridge and that normally vents into the awning space.

The issue I have is - is the gas BBQ physical connector a good enough seal for these purposes.

On mine you can not disconnect the pipe without turning the red tap off.

 

[RogerL]

The issue is gas appliances in the awning, not gas appliances venting their combustion products into the atmosphere.

I've always regarded a nearside fridge as being unsafe, often partially blocked by the open door and venting it's flue into the awning.

It would be safer, and cheaper, to use a small domestic compressor fridge but that would require a hook-up, which we always use even on CLs.

 

[JeremyClarksson]

When hookup is available I would turn the 3 way fridge to electric, however for about half of our usage we do not have hookup.

I do not know if you have looked at one of these fridges but the flame is no more accessible than the one on the caravan fridge is from the awning (through the vent), hence is highly unlikely to ignite anything other than stray gas which is my concern with the connector.

As I said earlier my preference now is to use a seperate bottle as that gives us a spare bottle for the van and leaves the BBQ point for the BBQ.

I am however curious about the rules/laws regarding what can be connected to the BBQ gas point. There must be some sort of standard involved.

 

[JeremyClarksson]

Ian

Going back to your original post, are you sure that the instruction re. only using butane is not purely because the heater came with a butane regulater, Calor patio gas cylinders contain propane.

They will also change normal cylinders for patio gas cylinders free and they have level indicaters - I think I got this info from the CC magazine.

I did a calculation a while back that showed that pennies per therm propane is only marginally more expensive than butane - we are only using propane now.

 

[ProfJohnL]

Hello Gary,

I have had no dealings with the design or specification of external BBQ points, thus I cannot offer any advice other than follow the manufactures specifications with regards to what can be connected.

RogerL jumps to the conclusion that you intend to operate a gas appliance within your awning, whilst you don't actually stipulate that, it does seem a realistic assumption. The use of any gas appliance within an awning must be treated with extreme caution for what I hope are obvious dangers.

The dangers from a BBQ or gas fire is that the items are considered portable and thus could be physically unstable or prone to being knocked. Also the amount of heat they produce, and the fact that their external surfaces can become too hot to touch, and could initiate combustion of materials coming into contact with them.

The secondary danger is that they will both have the potential to produce significant amounts exhaust product including Carbon Monoxide (CO). Though it is probably unlikely to be a severe consideration due to the unavoidable amount of ventilation in an awning, there is the potential for the CO to build up and affect the occupants.

On the other hand, a gas powered absorption fridge will norlammy be placed on the ground, and its shape and size make it inherently more stable than a free stnding BBQ or fire. They use a relatively small flame (typ 100 > 200W) and it is contained very effectively within the body of the appliance. With the exception of the exhaust port, none of the other surfaces are likely to exceed the flash point of any of the materials in an awning. Even the exhaust port operates at much lower temperatures than some of the exposed surfaces of a BBQ or fire, so the danger of fire is significantly less than with a fire or BBQ.

The much smaller flame in the fridge will produce some CO, but the rate of production is likely to be much less than the available ventilation in the awning, and thus it is not a significant threat.

It should also be noted that many caravans already vent the internal fridge exhaust into the awning space, and if this were considered a sustainable threat, then the installation regulations would reflect it, and advise fitting so the exhaust was into free air.

Regardless of the above you should follow the manufacture's user instructions.

 

[ProfJohnL]

I forgot to mention that the fridge will definitely have a flame failure device which will cut the gas if the flame goes out - some BBQ, and fires also have this feature.

 

[JeremyClarksson]

I was only talking about operating the 3 way fridge in the awning and with the manufacturers recommended clearance around it and, as you say, there is no chance of it getting knocked over.

I would never dream of using a BBQ anywhere closer than a minimum 1-2M from the awning, which is why I always find the recommended 2M pipe to be only just sufficient.

I have one of those little cartridge type gas heaters but have only used it facing in to an open awning from outside for some extra heat (bonfire night) with all the kids firmly sat on laps.

I have to be extra careful with anything like this anyway having 2 primary age schoolchildren.

 

[Surfer]

Some people argue almost correctly about venting in your awning etc, but if this was an issue why would they allow a gas fire in a confined space like a caravan with the doors closed. Most issues boil down to using common sense. I would imagine that in an awning there would be more than ample ventilation otherwise you would not require heating out there. I really cannot see a problem with using a 3 way fridge on gas in the awning.

Our caravan is a 2004 Lunar using Propane and it has the external BBQ or gas point. It is from this point that I would like to operate the gas fire as at the BBQ point it will have already been regulated. Perhaps Garry can use this external BBQ point for his fridge without any problems.

When refering to regulated, supply, I assume this to be a common denominator where the pressure is the same whether or not you use Butane or Propane. In theory this should then allow the gas heater or fridge to use either Propane or Butane safely.

 

[RogerL]

The gas heater INSIDE a caravan is room sealed, it discharges fumes outside - it's not a gas fire as such, they were outlawed, in new caravans, decades ago.

 

[JeremyClarksson]

Gas room heater,water heater and fridge on my van and most modern vans all vent to the outside with the fridge venting to the awning space.

 

[RogerL]

The room heater will vent through the roof on modern caravans, through the floor on older ones but never into the awning space.

A minority of caravans have fridge and/or water heater on the nearside but MOST have them on the offside, specifically to avoid the awning area.

 

[ProfJohnL]

Some people argue almost correctly about venting in your awning etc, but if this was an issue why would they allow a gas fire in a confined space like a caravan with the doors closed. Most issues boil down to using common sense. I would imagine that in an awning there would be more than ample ventilation otherwise you would not require heating out there. I really cannot see a problem with using a 3 way fridge on gas in the awning.

Our caravan is a 2004 Lunar using Propane and it has the external BBQ or gas point. It is from this point that I would like to operate the gas fire as at the BBQ point it will have already been regulated. Perhaps Garry can use this external BBQ point for his fridge without any problems.

When refering to regulated, supply, I assume this to be a common denominator where the pressure is the same whether or not you use Butane or Propane. In theory this should then allow the gas heater or fridge to use either Propane or Butane safely.

Hello Ian,

Taking your last paragrapgh, You can only legally use the appliance on the gas supplies for which it has been approved. The data plate on the appliance will specify the gas categories it is designed to be used with.

If it only states Butane, then to remain legal and safe you must only use butane supplied at the correct pressure.

Many appliances that were designed for Butane at 28mBar may look identical to the units now supplied for the 30Mbar standard, however the differences may be undetectable to the naked eye, as they may be very small dimensional differences to injectors or venturies, or burner plate patterens.

Do not assume gas compatability always check teh data plate.

 

[ProfJohnL]

The gas heater INSIDE a caravan is room sealed, it discharges fumes outside - it's not a gas fire as such, they were outlawed, in new caravans, decades ago.

And Caravans have a certainamount of fixed ventilation, where as awnings is not defined and is variable.