Motorhome advice: Gas tanks or refillable cylinders?

Until about 15 years ago, your options for gas were limited to using exchangeable gas cylinders stored in a purpose-made locker. Now it’s possible to have a direct replacement of your exchangeable bottles with similar-sized refillable cylinders or install a bulk tank fixed to the underneath of your motorhome or campervan.

Calor cylinders

For the majority of users of exchange cylinders, the choice is Calor. Other companies supply exchange cylinders, but Calor’s the only company with a truly comprehensive national network of outlets. Calor cylinders are also available on just about every large campsite in the UK.

The only rival for coverage is Campingaz cylinders but, with the largest (907) cylinder containing 2.75kg of butane gas, it has only limited appeal for motorhomers. Also, butane performs poorly in low temperatures compared to propane. Therefore, the Calor option is an excellent one for motorhomers who tour in the UK, but the cost of refills does cause concern.

Cost aside, the other disadvantage of Calor cylinders is the lack of availability abroad. If you’ve room in your gas locker for an extra Campingaz cylinder, this could help as Campingaz operates a Europe-wide exchange service, but a 907 refill costs about £28. Exchangeable cylinders are seen as expensive, but this has to be viewed in the context of the large costs associated with filling and distribution. Plus, gas companies are responsible for inspection and refurbishment of cylinders.

Refillable cylinders

For many years, refillable cylinders were frowned upon, often for good safety reasons. Now there are several manufacturers that have refillable cylinders with excellent safety features, making them a viable option. This option enables users to refill cylinders at service stations with autogas for less than the equivalent exchangeable refill. Autogas is LPG (liquified petroleum gas) sold for vehicles converted to run on LPG and in the UK this is largely propane gas.

There is still reticence among some fuel stations regarding refilling such cylinders, which stems from guidance issued by UKLPG, the British trade association for the LPG industry. The current advice from UKLPG is, “free-standing LPG cylinders should not be filled at LPG refuelling facilities by customers or untrained personnel.” Because of this, most refillable cylinder suppliers offer the option of a remote external filling point for fitting in the external bodywork of the motorhome. Generally, filling stations accept refilling when it is undertaken in exactly the same way as refilling a LPG-powered vehicle.

LPG is widely available throughout Europe and listings of LPG stations at home and abroad are available. As you travel south in Europe you may find auto LPG contains a greater proportion of butane but, providing you’ve a 30mb regulator system, your appliances should function normally.

Gaslow was one of the early pioneers in safe refillable gas systems. As well as its systems filled remotely, it also offers a direct fill cylinder, whereby the gas dispensing nozzle is affixed directly to the cylinder. As many filling stations will deny use of their forecourt for this style of filling, Gaslow publishes a list of filling stations that permit such refilling on their forecourts.

 

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Fixed tanks

In recent years, more and more gas tanks for motorhomes have been fixed underneath the vehicle. Some early examples of gas tanks fitted to motorhomes left much to be desired from the safety aspect. The supply and fitting of tanks is governed by a variety of regulations and standards, but so often not legally or easily enforceable.

The National Caravan Council (NCC) produced a Code of Practice (CoP) in 2011. This CoP 306 is now an industry standard and refers to 14 regulations, standards and codes of practice. Gas It, which supplies 95% of the fixed tanks used in the UK motorhome industry, helped prepare the standard and offers training to the industry on CoP installation. However, there are still a number of installers and manufacturers who do not work in accordance with the CoP.

Safety issues 

The main concern with refillable gas containers is overfilling. LPG tanks and containers for motorhomes are intended to supply gas vapour to appliances rather than liquid LPG used to power a vehicle. If a container is filled to full there’s a possibility liquid will be channelled to your appliances. Since LPG in its vapour form has a volume around 270 times greater than the liquid form, any liquid reaching, say, a gas hob will, when released to the atmosphere, expand dangerously.

Hence, all containers should be constructed to automatically limit the amount of liquid gas that can be filled to 80% of the gross capacity of the tank or cylinder. The 20% empty space at the top of the cylinder, where the offtake pipe is located, enables the liquid to boil off and convert to gas vapour before leaving the cylinder.

Exchange cylinders, such as Calor bottles, are refilled at a regulated station where the filling of liquid gas is carefully controlled by weight to achieve the 80% capacity. It should be noted that refilling of Calor or other exchangeable bottles is illegal by any party other than by the gas supplier. It is also very dangerous to do so. Similarly, refillable cylinders that don’t contain an 80% automatic shut-off valve should never be used.

Fixed tank installations provide additional challenges to manufacturers due to their horizontal alignment and location, which means they’re subject to spray, flying stones, road humps and the possibility of being involved in a crash. Hence, fixed tanks must be constructed and fitted to European Standard R67, which also requires the standard 80% shut-off valve, plus an excess flow valve in case of rupture of the off-take hose as well as much more. There are other overlapping regulations and standards that apply, which is why the NCC’s comprehensive CoP is so important for manufacturers and installers.

In general, portable gas cylinders like Calor are manufactured to the less demanding TPED (Transportable Pressure Equipment Directive). Gaslow decided several years ago to upgrade its portable cylinders to R67 standards and this is where looking at standards becomes complicated and you find conflicting opinions. Finally, there’s the issue of the service life of cylinders and tanks.

Industry recommendations are for an annual inspection followed by a final 10-year inspection for steel cylinders and tanks and a similar annual regime for five years for composite cylinders. At the end of the 10-year life, steel cylinders and tanks must be inspected internally and externally for corrosion and for any damage or age-related degradation and the valves must also be scrapped. For exchangeable cylinders, this work and the associated costs are borne by the supplier. For refillable cylinders and fixed tanks, the owner is liable for the checking and costs.

The danger with fixed tanks is they are ‘out of sight, out of mind’ and there’s no statutory regime for safety inspections and they’re not included in vehicle MoTs. Therefore, owners should get qualified personnel to undertake an annual inspection. Lacking any other service availability, at least ask for the tank and fixings to be inspected at the base vehicle’s annual service.

Restrictions

There is no discrimination between fixed tanks and refillable and exchange cylinder systems by ferry companies or Eurotunnel. The amount of gas permitted on board varies with operator, but even Eurotunnel, which denies access for LPG-powered cars, is happy to take motorhomes with fixed tanks as long as the amount of gas does not exceed 47kg and the system is shut off.

Choosing the best option

Given the simplest scenario, a 6kg refillable cylinder provides the most economical solution, but you do need to keep a close eye on how fast your cylinder is being depleted. For a small extra cost – perhaps £20 – you could upgrade to an 11kg cylinder with a capacity of 21 litres, if it fits in your gas locker. Cost is only one element in this choice.

For most motorhomers the overriding factor for refillable is likely to be availability in Europe. If this isn’t a concern, you may well prefer the easy availability of exchangeable cylinders at campsites you stay on within the UK. Fixed tanks are among the most expensive option and it’s worth remembering it’s not practical to transfer them to your next motorhome. Their overwhelming advantage is the releasing of locker space so, for a compact motorhome, a fixed tank is a perfect option.

So, the choice is yours to suit your style of camping. Just ensure, if you go down the refillable route, you look for a reputable company offering containers with 80% overfill shut-off valves. Always ensure a gas-competent technician installs the kit or at least checks your DIY installation. A fixed tank should only be professionally fitted and insist the tank and installation comply with the NCC’s code of practice.

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