By Collyn Rivers (updated November 2012)
This article discusses the very real risks if LPG is misused in a caravan or motor home, or any type of RV, tent or annexe. In particular it emphasises the major risk of brain damage at very low levels of carbon monoxide produced. It also advises that the previous AS 5601 Gas Standard has been replaced by the joint AS/NZS two-part Standard AS 5601.2010. That relevant for the RV field is Part 2 (Gas Installations in caravans and boats for non-propulsive purposes). Note that, legally, 'caravans' includes all RVs.
In the Beginning...
Around 1850, when the first domestically available gas was produced by burning coal (usually as carbon) in the virtual absence of air, (about 10% carbon monoxide content), few people knew why it was so lethal. But the only too real danger became quickly known and respected. Following the general acceptance of propane in the 1930s and the later usage of LPG in RVs, and natural gas in homes, much of that respect appeared to become lost.
The reality is not that that LPG is safe, but that because its carbon monoxide concentration is lower, it takes longer to kill than it did before. Nevertheless approximately 30% of people with severe carbon monoxide poisoning are likely to result in death. 
It is still, in some countries, that most used for deliberate poisoning. During 2001-2002, carbon monoxide poisoning was responsible for 43.9% of deaths by poisoning in New Zealand. That same NZ report also noted that imported LPG portable appliances, certified only for outdoor use, were nevertheless being claimed by their manufacturers and distributors as suitable for indoor use.
It warned that the misuse of such appliances in an indoor environment, including caravans and tents, could be unsafe and potentially fatal. In 2010 an independent report (for NZ Energy Safety) found that there was not a sufficient safety problem to ban their use, but because of fire risk and concerns about ongoing chronic health hazards, additional health and safety warnings were placed on these units at their point of sale.
The Cause of Risk
The major risk with LPG (and fossil fuels generally) is that they require a lot of air to burn safely. Burning LPG in an enclosed space decreases the oxygen content and increases the carbon dioxide concentration. Further, the amount of air required varies with the nature of that gas. Most RV equipment is designed to run from propane, but if used as some do (illegally as well as dangerously) with Autogas, that gas might well contain a fair amount of butane and thus produces a lot of carbon monoxide through incomplete combustion. A total giveaway is any yellow content in the flame.
As 100% total burning cannot be guaranteed, space heating in Australia, and many other countries, requires the burning process to be external to the space heated.
The above is made totally clear in AS/NZS AS5601. As with its earlier version, and its predecessor, (AG 601-1995), the appropriate wording states:
‘The following appliances shall not be installed in a caravan *:
(c) a space heater, other than a room-sealed type.
* (A caravan is defined in AS 5601 as being – ‘a structure that is or was designed or intended to move from one place to another, whether towed or transported, which is intended for human habitation... and includes a self-propelled recreational vehicle.’)
Item 6.9.4 of the new Code calls for a permanently legible label with a minimum character height of 4.0 mm to be affixed 'in a conspicuous position on or adjacent to, the '[gas cooking]' appliance and shall provide at least the following information:
Ensure ventilation when the cooker is in use.
Do not use for space heating.’
Inhaling even relatively small amounts of the gas can lead to hypoxic injury, neurological damage and even death’ 
Carbon monoxide exposure might lead to a significantly shorter life span due to heart damage, . Exposures at 100 ppm (part per million) can be dangerous to human health.  Carbon monoxide poisoning is the most common cause of injury and death due to poisoning, worldwide. 
This matter came to a head in early 2012, when three men died in a matter related to carbon monoxide poisoning, in a caravan in Tasmania. Despite the Coroner’s report not yet having been published and ongoing media reports based almost totally on speculation, this was initially met on some Internet forums by a wall of denial from people with no possible knowledge of what had occurred.
Consequent to those deaths, a formal government-related initiative, the ‘Gas Appliances (Carbon Monoxide) Safety Strategy’ was established with the intent of making people (particularly RV users) aware of the risks. I was asked to assist in preparing the formal submission for the 60,000-plus membership of the Caravan and Motorhome Club of Australia (CMCA). That submission included: ‘Our view is not so much that the existing regulations relating to gas installation in RVs necessarily need changing, but that RV owners do not take the known risks sufficiently seriously. This is shown often, not only on our own (now shut down) website forum, but on other similar RV forums.’
It then noted that: ‘The major risk identified (in our opinion) is that of gas appliances being used in an inappropriate manner, e.g. LPG gas ovens left on with the door open to provide heat, steel plates and ceramic pots placed over LPG gas rings for the same purpose. It also alluded to the ongoing illegal use of LPG catalytic heaters ‘in poorly ventilated annexes and within the RV itself.’
The submission also noted: ‘A further issue is the lack of quantitative data on reported incidents of carbon monoxide poisoning in RVs. This has created a concern because the warnings of the dangers are frequently met by denial on the basis that no hard data is available.'
Quantifying the Risk
About 35 ppm (parts per million) causes headache and dizziness within six to eight hours; 200 ppm (about 0.02%) causes a slight headache within two to three hours, plus loss of judgment; at 800 ppm (0.08%) there is dizziness, nausea, and convulsions within 45 min, insensibility within two hours and death within three hours. At 1600 ppm (still a mere 0.16%), there is ‘headache, tachycardia, dizziness, and nausea within 20 min. Death occurs in less than two hours. Even at 6400 ppm (0.64%) death occurs inside 20 minutes; and at the far from high 12,800 ppm (1.28%) you become unconscious after 2-3 breaths and will be dead in less than three minutes. 
To gain some concept of the above levels, the natural atmospheric level is about 0.1 ppm. The exhaust from a warm car’s exhaust (that lacks a catalytic converter) is 7000 ppm. 
The above is reflected in the USA’s relevant (OHSA) regulations that limit long-term workplace exposure levels to less than 50 ppm (0.005%) averaged over an 8-hour period. In addition, employees are to be removed from any confined space if an upper limit (‘ceiling’) of 100 ppm is reached.’ 
The build-up of carbon monoxide is often exacerbated by blocked ventilation, so the risk of brain damage at lower levels of exposure, particularly where ventilation is poor, is only too real. The elderly, children, and people with heart and respiratory problems are likely to suffer from the effects sooner and more severely, as may heavy smokers.
The advice that ‘it is only dangerous if you do not stay awake’ shows an astonishing naïve lack of understanding of the early symptoms. It is in itself dangerous, but to advise others accordingly is naive almost beyond credibility.
For anyone still doing this, and some still are, it is advisable to bear in mind that, were someone to die as a result of following such advice, the consequent charge may extend to manslaughter. Further, those inciting others to perform an illegal act may be committing a criminal offense.
Appliances - Defined
It is thus for very good reasons that the use of any gas for the purpose of direct space heating in a caravan is illegal in every state of Australia and that any cooking appliance used for space heating, by any form of burning gas is defined as a ‘gas appliance’.
Many argue that a ceramic pot or whatever is ‘not an appliance’, but overlook that devices are legally definable in terms of intent - not necessarily of content.
A screwdriver may thus be defined as a device for dealing with screws, or in dangerous areas at night, may be defined as an offensive weapon. The same reasoning extends to a gas cylinder; or a can of petrol that, if carried onto a plane, will almost certainly be designated as a bomb.
A ceramic device placed over a lighted gas stove for the purpose of space heating is thus liable to held to be an ‘appliance’ that is intended to be a space heating device for that usage - and therefore prohibited.
The reason why it is so dangerous to do this with (say) a ceramic flower pot or steel or cast iron plate, is that the flame is trapped within an area where air may not flow freely, and thus the gas is not fully burned. Then, that seemingly innocent setup is a carbon monoxide generator – and in some cases exhibits that by burning with that tell-tale yellowish flame, or forming and depositing soot.
This was confirmed to me unequivocally by a Gas Regulator in mid June 2009: when asked specifically if placing a ceramic pot or steel plate over a gas ring, or leaving the door open on a lighted oven, with the intent to heat an interior space, it becomes, by definition a space heater, he responded ‘my bloody oath’!
References to local usage are in Australian Standard AS/NZS 5601.2.2010. A summary called Guide to Gas Installations in Caravans & Mobile Homes (and containing all of the above references) is available free from The Office of Gas Safety (or its equivalent in each state) but relates primarily to the previous Standard. It is also available on the Internet (Google the above title).
Until 2010 the Gas Standard (AS 5601) related only to Australia - primarily because Australia’s LPG is either propane or mostly propane with a small proportion of butane, whilst NZ uses propane and up to 50% butane. Appliances built to burn one form of LPG can be hazardous when used to burn another. The Gas Regulators’ view was that (as with using Autogas illegally to replace LPG) that this posed an unacceptable safety risk respectively to New Zealand and Australian consumers.
This issue has now been resolved: including by 'Australian RV appliances increasingly being certified for use with Universal LPG Gas to accommodate the NZ market': written advice from the NZ Office of Energy Safety, 18/09/2012. This 'Universal LPG gas' issue affects only Australian gas appliances made for the NZ market).
Safe RV Heating
Germany's Webasto and Eberspächer companies produce very similar diesel-powered space and space-plus-hot-water power heaters. Truma now has a generally similar LPG powered equivalent. Both draw fresh air in from outside and exhaust to the outside too. These are the only form of heating that can be recommended for RVs. They are fully covered in the author's The Campervan and Motorhome Book, and also the second Edition of the author's The Camper Trailer Book published in August 2012. The Eberspächer product in some countries is marketed under the Dometic name and sold by Dometic.
I normally research topics thoroughly prior to writing anything technical - but rarely include such references in material intended for general reading. I include references (from referred papers from major journals etc) here however in an attempt to stave off 'that’s just your opinion’ responses.
Gas Installation Code AG 601 - 1995
Published by (Australia’s) The Gas Installation Code Committee.
AS/NZS 5601.2: 2010
Published by Standards Association of Australia.
Report of the (SA) Technical Regulator 2005-2006
Annual Report (p.7).
Office of Gas Safety (Vic) – Guide to Gas Installations in Caravans & Motor homes.
Similar guides are available from all state gas regulatory bodies.
New Zealand (facts and data)
Permanent Exemption of LPG appliances from the Trans-Tasman Mutual Recognition Arrangements. (Regulation Impact Statement for Consulation - 2008.)
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4. Henry CR, Satran D, Lindgren B, Adkinson C, Nicholson CI, Henry TD (January 2006). “Myocardial Injury and Long-term Mortality Following Moderate to Severe Carbon Monoxide Poisoning”
5. Prockop LD, Chichkova RI (Nov 2007). “Carbon monoxide intoxication: an updated review”. Journal of the Neurological Sciences 262 (1-2): 122–130.
6. Thom SR (October 2002). “Hyperbaric-oxygen therapy for acute carbon monoxide poisoning”. The New England Journal of Medicine 347 (14): 1105–1106
8. Struttmann T, Scheerer A, Prince TS, Goldstein LA (Nov 1998). “Unintentional carbon monoxide poisoning from an unlikely source”. The Journal of the American Board of Family Practice 11 (6): 481–484.
9. “OSHA Fact Sheet: Carbon Monoxide”. United States National Institute for Occupational Safety and Health. http://www.osha.gov/OshDoc/data_General_Facts/carbonmonoxide-factsheet.pdf.
Collyn Rivers (© Caravan & Motorhome Books (2012) Church Point, NSW Australia.)
Caravan & Motorhome Books, and Successful Solar Books, PO Box 356 Church Point, NSW 2105 (Australia) Tel: 02 9997 1052. Websites: www.caravanandmotorhomebooks.com and www.successfulsolarbooks.com email: firstname.lastname@example.org