GAS MATTERS

General Issues

Butane or Propane ?
For many newcomers this is normally the first question to arise. Caravan gas appliances are designed to burn either fuel without modification so which one should you use? Well butane is a cleaner fuel than propane (less smelly when burned) and it has a higher calorific value. This means you can get more heat from a given volume of liquefied butane than propane. Butane is also easier to ignite you'll have fewer problems with piezo ignition systems. As the two fuels cost about the same price there would appear to be no contest. Apart from one thing. Butane freezes at 3 degrees Celsius. When you consider that the simple act of using gas from the cylinder also cools it you can begin to see that butane is going to be problematical in cold weather. Propane, on the other hand, can be used in temperatures down to minus 43 degrees Celsius so even severe UK winters present no problems.

		Because butane and propane operate at different pressures they require different regulators so if you change from one to the other you need to bear this in mind. The regulators are not interchangeable so there's no danger of fitting the wrong one. From the 2004 model year new European regulations required all caravans to be fitted with a bulkhead mounted regulator. The gas cylinder is connected to it by means of specially reinforced high pressure hose (right). More details can be found here

Butane is normally supplied in blue cylinders and propane in red so it's easy to tell them apart. Because of the different densities of the two liquids gas cylinders of the same size hold different weights when full. For example a 7kg butane cylinder is the same size as a 6kg propane one.

How Much Left?
You know that a cylinder is part used but you don't know how much is left. So how do you tell? Well the most reliable way is to weigh it. Bathroom scales can prove very handy for this but first you'll need to know the empty (tare) weight of the cylinder. With Calor cylinders this is easy. You will find an aluminium collar which is stamped with figures and letters. These indicate the empty weight in pounds and ounces and also a code indicating when the cylinder was last pressure tested. If you wish to convert from pounds to kilograms then all you need to remember is that there are 2.2 pounds to each kilogram.

Gas Supplier
Calor has dominated the UK scene for many years but more recently Flo Gas has been giving them a run for their money. Flo Gas has been buying up many of the smaller (and some not so small) independent dealers and consolidating them into its own countrywide network. There are still quite a few small independents left and these are often cheaper because of lower overheads, but they're not so convenient when you're away from base.

If you can, take enough LPG to last the whole trip. If you're planning a longer holiday, one tip is to carry a Camping Gaz adapter, which should be available from your local dealer. These come in two types. The first is unregulated (left) and suitable for caravans with a bulkhead regulator. The second (right) has a built in regulator and is therefore suitable for pre 2004 caravans and motorhomes.

Camping Gaz 2.7 kg cylinders are available in over 100 countries. Both propane and butane can be found in larger cylinders in most European countries, but cylinder sizes, connectors and regulators are rarely compatible with UK ones.

You may be able to hire a cylinder and regulator whilst abroad but if you do you need to check that the outlet pressure is in the range 28 –37 mb. Pressures outside this range may be unsuitable for your caravan’s appliances and could be dangerous.

Beware if someone offers to refill your UK cylinders. As the practice is prohibited by UK operators it will normally be the less well regulated outfits that do this. They may not operate to appropriate safety standards and cases have been known of the wrong type of gas being used as well as under and over-filling. It is also unlikely that the normal valve and cylinder safety checks will be carried out.

If travelling to Austria you may come across sites which have low pressure LPG piped to a meter at each pitch. The advent of bulkhead regulators requiring a high pressure feed is likely to mean that this idea will not catch on.

An alternative to all this is to invest in consumer refillable cylinders (see below under Cylinder Innovations).

 

Maintenance Issues

Checking your appliances
Before gas is burned in an appliance it is first mixed with air. This is achieved by passing the gas through a small jet adjacent to an air vent in the feed pipe. The arrangement ensures that the gas burns cleanly with a blue flame and produces plenty of heat. If insufficient air is mixed in then the flame will tend towards a yellow colour and will not be so hot. As the flame burns it consumes not just the air that was mixed in with the gas but also the surrounding air. If there is inadequate surrounding air then the combustion will be incomplete and significant quantities of carbon monoxide will be produced. That is why it is so important for flues to be kept clean and free from obstruction.

Remember if your gas appliance is burning with a yellowish flame or producing soot deposits then there is almost certainly something wrong. Get it checked out by a qualified gas engineer. The most critical time for checking is after any extended period without use. Insects, particularly spiders, have a habit of getting to the bits that are difficult to reach. They block jets and flue pipes and can seriously affect the combustion performance of gas appliances.

Regular servicing is essential if gas appliances are to be maintained in a safe condition. My advice is to ask your workshop to carry out a full check as part of the annual service.

Gas Hoses
Since 2004 new regulations have required caravan and motorhome manufacturers to fit a regulator on the bulkhead of the gas locker. This means that gas cylinders have to be connected using a special high pressure hose. These hoses are naturally manufactured to a much higher specification than low pressure types and may last longer before needing replacement - time will tell. In any event no such hose should continue in use beyond 5 years.

In older systems a short length of hose is used to connect the output of the regulator to the permanent pipework on the caravan. These hoses deteriorate in use because LPG tends to leech out the plasticiser causing the hose to become brittle and prone to fracture. This means hoses should be changed after an absolute maximum of 3 years of use. As a guide hoses are date stamped with the date of manufacture. Correctly stored (cool place away from sunlight) hoses deteriorate only slowly, so do not despair if your dealer sell you hose which is more than a year old.

Bulkhead regulator failures
The 2004 model year saw the introduction of European regulations requiring manufacturers to fit bulkhead regulators to all new caravans. These regulators work at a pressure of 30Mb and are suitable for butane and propane. They connect to the gas cylinder by means of a special high pressure hose. The exact hose depends on whether it has to connect to a butane or propane cylinder as the connections are different. The recommended length for these hoses is just 0.45m (about 18 inches) meaning that all high pressure connections have to be undertaken in the confines of the gas locker. Longer hoses are available if you shop around. The service life of these 'rubber' hoses is 5 years. After that they should be changed.

A few months after introduction these regulators began to fail. Examination revealed them to be contaminated with an oily substance. It was eventually decided that this substance was plasticiser that had been leeched out of the high pressure hoses by the effects of the gas. Since most regulators were below the off-take of the cylinders, this substance drained down the hose and into the regulator.

The solution was to mount the regulators as high as possible on the bulkhead so that the oily substance would drain back towards the cylinder. Depending on the design of the gas locker it may not always be possible to have the regulator higher than the gas bottle valve without switching to smaller bottles. One way round this is to use longer hoses and loop them such that the hose has a low point below that of the regulator to act as a trap for the oily gue. The best solution though is use stainless steel hoses. They are expensive but have a 20 year service life so can be cheaper in the long run. They are available from companies such as Gaslow.

DIY? The basic advice is don’t! Gas is safe in the hands of an expert but in unqualified hands the results can be disastrous. Although caravans and motorhomes in private use are not covered by the same regulations as buildings it still makes sense for any work to be carried out by someone who is registered to do so.
For touring caravans and motorhomes not hired out for use the Caravan Industry Training Organisation (CITO) has a special ACoP (Approved Code of Practice) course and qualification. This qualification should be seen as the minimum standard for anyone working on gas appliances where CORGI registration is not required. It is now required for membership of the Approved Workshop Scheme. This is just another good reason why it makes sense to use such a workshop for all servicing and repairs.
Note: On 1st April 2009 Corgi was replaced by a new official body called the Gas Safe Register. The new brand name is be owned by the HSE. All gas installers are now required to be registered with the Gas Safe scheme.

Safety Issues

Ventilation
Whenever gas burns carbon monoxide can be given off. If the appliance is faulty or the flue is blocked then copious amounts may be produced. Carbon monoxide is an invisible, odourless gas which, if inhaled, can produce drowsiness, giddiness and other symptoms. If immediate action is not taken it can kill. That is why the ventilation grilles in your caravan are so important. Never be tempted to block them up to reduce draughts.

Older caravans were lit by gas and had vents to suit. This ventilation standard was maintained until the mid 1990's despite the fact that caravans had not had gas lights for many years. I am sometimes asked if any vents can be covered to reduce draughts. The answer is NO definitely not!! The caravan would then be in breach of the standard to which it was produced and certified and you may even find yourself uninsured. What's more unless you know exactly how to calculate these things you would have no way of knowing the effect of any modification.

Liquefied petroleum gas (LPG) is heavier than air. If you have a gas leak then the gas will tend to fall and so that's why the gas lockers have ventilation holes their floors. It's also why there's a ventilation grill in the floor beneath your cooker. Needless to say it is essential that these floor vents are never obstructed as they can help to prevent dangerous build ups of any leaking gas.

Storage and carriage
When liquid gas becomes a vapour it increases in volume some 200 times. Given that it's not unusual for the valve on top of a gas cylinder to leak slightly you can see why it's much safer for cylinders to be used and stored upright. Caravan and motorhome gas lockers are designed with this in mind and have an anchoring system to keep the cylinders upright and in place. If you are using a larger cylinder than will fit into your gas locker then wedge it firmly upright in the boot of your car before travelling. Do not do as some I have seen who lay it horizontally on the caravan floor with just a cushion to wedge it tight. I did see one chap who had built a special cradle to hold the cylinder firmly upright over the axle inside the van - a good idea if executed properly.

Leaks Even on the best maintained systems leaks can occur from time to time. LPG is not poisonous as such but it can make you ill if you breathe it in. If you suspect you have a leak then turn off the gas at the cylinder, open windows and doors and investigate. In modern caravans appliances each tend to have their own isolating tap on a central manifold (often on the floor near the kitchen sink) so these can be used to narrow down the area of search. If you have a pressure gauge on your cylinder you can use it to determine the extent of any leak. With all appliances switched off simply turn the cylinder on and then off and see how long the indicated pressure is maintained for. If the answer is a minimum of 15 minutes then there shouldn't be too much to worry about. Remember no system is going to be 100% gas tight so do not expect the indicated pressure to be maintained for hours on end. A good way to test a joint for leaks is to use soapsuds applied with a soft paintbrush. Washing up liquid contains salt, so is not ideal. Purpose made liquid can be bought from your plumbers merchant .

General Precautions

• Store and use cylinders in the upright position

• Ensure that our gas is turned off at the cylinder(s) before travelling

• Change cylinders in the open air so that any escaping gas can quickly disperse

• Never try to refill a gas cylinder or cartridge yourself - the results could be disastrous!

• Never subject a cylinder or cartridge to heat - even if empty

• Protect cylinder valves from damage—they are your primary means of controlling the flow of gas

• If you smell fumes switch off the gas and open windows and doors to disperse them

Cylinder Innovations

Over the last few years consumer refillable cylinders have made an appearance. Basically they fall into two types. The first type is permanently installed in your RV and connected to an external filling point. The idea is that, when the gas gets low, you take your RV along to the nearest autogas filling station and top it up just as you would a car running on autogas. The concept is really aimed at motorhomes where weight and visits to filling stations are not really issues but I do know of one or two who have had their caravans fitted with the system. Autogas is propane so it's perfect for caravan or motorhome use. Apart from the convenience it works out much cheaper than conventional bottled gas and, with suitable adapters, it's possible to fill up on the continent too.

Consumer Refillable - Portable
MTH Autogas supplied cylinders The cylinders on the right here were available in the UK via a company called MTH Autogas from 2004 to 2007. The company has since disappeared without trace amid concerns over the safety and reliability of the cylinders. They are made of lightweight translucent plastic (see picture on the right) and are significantly lighter than their standard metal counterparts. Their main advantage over the fixed type is that you can take the cylinder to the autogas station, you do not have to take your caravan or motorhome. However safety concerns are such that most filling station operators have banned the filling of these cylinders and indeed any other cylinders where the filling connection is made directly and does not go through a one way safety valve.. The most recent of these is Countrywide following an incident in 2009 in which the side of a motorhome was badly scorched.
		These cylinders are potentially unsafe in use

One of the safety concerns is that it is also imperative that the cylinder valve is shut tight before disconnecting the filling nozzle. Failure to do so will result the release of gas at very high pressure. Needless to say this is potentially very dangerous.

Another concern is that these cylinders do not have a device to prevent overfilling. Extreme care must therefore be taken when filling them. Because it can be difficult to see and determine exactly how much gas is in one the best advice is only to fill them when they are completely empty and then put no more in than the cylinder label says you should.

A seriously overfilled cylinder is potentially very dangerous. Firstly it could burst if subjected to heat, e.g. hot sunshine, secondly there would be a chance of liquid gas getting into the regulator and rendering it effectively useless. The result would be that any connected gas appliances would be subjected to a pressure several thousand times their rating.

In addition to all the problems mentioned above there is now evidence that some of these Slovakian made cylinders have begun to leak where the gas valve assembly bonds to the plastic cylinder. A number were returned for examination to the manufacturer via the UK importer but no more was ever heard. Now anyone who rings the importer's number is told that the company is no longer there.

Safefill cylinders Launched at the NEC show in February 2011 these cylinders are also made of lightweight plastics and designed to address the safety issues associated with those above. The main change is a filling valve with overfill protection and inbuilt safety valve to stop gas escaping under high pressure in the event that the cylinder is disconnected from the filler without first shutting its control valve. There is also a tamper proof device to stop gas from coming out of the cylinder unless it is connected to an appliance. Despite these safety features the cylinders are still likely to be affected by the blanket ban on filling cylinders that has been imposed by the forecourt operators. The suppliers therefore direct users to the independent autogas retailers most of whom they claim will fill these cylinders for you. There is just one size available, 6kg, at a cost of £150

BP Gas light cylinders In 2006 BP and Truma announced a partnership to supply propane in lightweight plastic cylinders to the caravan and motorhome market.The cylinders come in 5 & 10kg sizes, are made in Norway and are filled by BP. They can be bought through Truma dealers as well as some caravan dealers and hardware stores (including Homebase). The cylinders use a 27mm push on connection so adapters are needed for use with caravans and motorhomes. (This is the same push on connection as Calor use on their patio gas cylinders.) Beware also that these cylinders are wider than conventional ones and may not fit all gas lockers. BP gas light cylinders are available on the continent but sadly the UK is not part of BP's European exchange programme. This means you can't exchange UK sourced cylinders abroad. The reason is that the cylinder connectors are different. The situation is under review by BP and may change.

Calor Lite cylinders

In april 2008 Calor introduced a lightweight steel cylinder specifically for the leisure market. The cylinders are available just in one size and fuel (6kg propane). With a tare weight of half that of a conventional cylinder they complete quite nicely on weight grounds with plastic cylinders. At the NEC launch Calor indicated that all cylinders would be fitted with a level gauge but in practice this has not been the case. It seems a large number were released without the handy device. (See pic right.) Calor say they will rectify this as cylinders are returned for refill. Calor Lite cylinders can be exchanged free of charge for the standard 6kg cylinders but you will pay a premium for the contents (see below).

Typical Costs
(As at March 2011. Local prices may vary.)

COST COMPARISON TABLE	Cylinder charge inc VAT	Refill cost inc VAT	Cost per kg inc VAT
BP Gas Light 5kg	£45.00	£25.00	£5.00
BP Gas Light 10kg	£45.00	£35.00	£3.50
Calor Standard 6kg	£29.99	£19.99	£3.33
Calor Lite 6kg	£29.99	£21.99	£3.67
Calor 13kg	£29.99	£25.49	£1.96
FloGas 6kg	£29.99	£18.99	£3.17
FloGas 11kg	£29.99	£23.95	£2.17
6kg (11.9 litres) gas from autogas station at 76.6 pence per litre	Expensive but you own it	£9.12	£1.47

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