The gas appliances industry is always coming up with new products. One of these innovations are the so-called (mobile) gas cylinders or. fuel tanks that, according to the manufacturer, any user can refill independently at liquid gas stations.
Sounds like a good idea at first, but a closer look shows that there are some critical points to be noted here. This is how the german liquefied petroleum gas association e.V. (DVFG) has taken a clear position on this matter and last year pointed out very clearly that such filling is not permissible.
As a specialist dealer in gas products or. operators of a stationary gas filling plant and autogas station in bonn, we would like to pass on this important information – also against the background of increased customer demand – with this article (see z.B. See also our article on the subject of safety in gas appliances).
The DVFG on filling gas and tank cylinders at public filling stations
The filling of portable compressed gas containers such as propane gas and/or tank cylinders is prohibited at autogas filling stations in germany! And with good reason. Although the manufacturers advertise the integrated 80% fill stop of these containers, this is prohibited by the DVFG rules.
Removable gas cylinders may only be filled by specialist personnel in filling plants. The simple reasoning: the customer could simply hold the bottle at an angle and thus bypass the 80% fill stop in order to fill the bottle to the brim. Especially when heated, there is a great danger due to increased cylinder pressure.
Why are gas cylinders only allowed to be filled to 80%??
Explanation: propane is stored in gas pressure vessels in the liquid aggregate state. Hence the designation liquid gases. If a gas cylinder is exposed to high temperatures or great heat, the liquid gas also expands. Accordingly, all commercially available gas cylinders are also designed for significantly higher pressure conditions than they occur in reality.
This is also due to the fact that the pressure of liquid gas increases very quickly by 7 bar per 1° C and gas cylinders must therefore have a sufficient expansion volume. For clarification, a short example calculation for propane gas:
- At an outside temperature of 15° C, the pressure in a cylinder filled to 80% with propane gas is approx. 7bar.
- Under the above-mentioned conditions, the liquid filling reaches the complete cylinder volume only at an external temperature of approx. 70° C, which leads to a pressure of 25bar.
- If the temperature continues to rise, the pressure inside the cylinder increases at a rate of 7 bar per degree-celsius and can, in the worst case, lead to a critical pressure.
The last point is of course purely theoretical, but it illustrates the problem very clearly. In addition – and this is crucial here – the gas cylinders are equipped with a safety valve that regulates the pressure inside the cylinder.
When is it permissible to fill gas cylinders independently??
Here, too, the specifications are clear. Only permanently installed gas cylinders that have a filling connection on the vehicle may be filled independently by the customer.
Against this background, the problem also arises. As a rule, the above-mentioned products contain a reference to this regulation in the small print, which in turn means that the bottle may not be used by the user when filled.
Conclusion: it is forbidden to fill pressurized gas cylinders at autogas filling stations!
As an operator of a gas filling station we have to pay attention to the compliance with these regulations and must not allow such a filling. This may not be easy for some customers to understand, but in the interest of safety, we are taking a clear stand here. A corresponding notice can also be found on the fuel tank system.
Andre gensmann – logistics& hazardous goods officer
the filling of portable compressed gas containers (propane gas cylinders/tank bottles) at autogas filling stations is prohibited in germany! This also applies to the recently frequently advertised tank bottles. Even if it is advertised that you can fill them yourself because of the integrated 80% fill stop.
Here is a link to the latest information from the DVFG in PDF format, which once again explicitly sets out the legal requirements.