Types of cylinders Butane and propane are supplied in high-quality steel cylinders. They must be able to withstand the treatment they are subjected to: transport, storage and use. The butane gas cylinders of Seminck Gas are purple and contain 12,5 kg of butane gas. The propane gas cylinders of Seminck Gas are grey and are available in 10.5 kg, 18 kg, 33 kg and 46,5 kg. Seminck Gas also has 18 kg green propane gas cylinders, for example for fork-lift trucks. These are fitted with a cylinder valve with a dip tube. Never use these cylinders for domestic purposes. Storage and use Propane vaporises at an ambient temperature of -40°C. The cylinders of propane gas that stand outside can therefore be used at any time. Liquid butane only vaporises when the ambient temperature is higher than 0°C. For this reason butane gas cylinders can only be used where the ambient temperature is at least 5oC. The handy gas cylinders have many applications: for both domestic (cooking, heating water, etc.) and professional use (frying, chicken roasted on the spit, etc.). Always be careful with gas in cylinders!! If propane or butane escapes from the cylinder into the surrounding air, the vapour will not rise, but will collect at ground level. If there is the slightest draught, the gas will be diluted very quickly. If, however, a gas cylinder is placed in a basementer where there are no draughts, and there is a leak, however minor, it is very likely that over a long period of time an extremely dangerous gas mixture will form in this confined space. The slightest spark can have disastrous consequences! ! So never place gas cylinders in a basement or in a confined space and always make sure that the flexible tubes are in good condition. Use ring clamps to connect the flexible tube and close the gas cylinder properly when it is not in use. Do not forget to fit a pressure regulator.