A cylinder is under 60 bar of pressure. What that means for heat, car, children and motorhome, which testing obligations apply and what to do about a leaking valve.
In short
- Do not store above 50 °C, so never in a sunny car, on a windowsill or next to the cooker.
- Upright, cool, dry, valve cap on, out of the reach of children.
- In the car, keep it in the boot rather than the passenger compartment, and do not leave the car parked in summer heat.
- Cylinders carry a test date; after ten years they may no longer be filled.
What happens inside the cylinder
At room temperature most of the CO2 in the cylinder is liquid, under about 57 bar. If the temperature rises, the pressure rises: to about 72 bar at 30 °C, to over 80 at 40 °C. That is why cylinders carry a bursting disc, which opens in a controlled way at excessive pressure and lets the gas out instead of the cylinder rupturing. It is loud, cold and harmless as long as nobody is standing right next to it.
Storing
- Upright, cool, dry, below 50 °C. The kitchen cupboard is good; the windowsill and the spot next to the oven are not.
- Put the valve cap on when the cylinder is not in the machine.
- Not near children, not in a cellar with a gas heater and no ventilation, not in small closed rooms with many cylinders (CO2 is heavier than air and collects at floor level).
- Do not throw it, do not use it as a hammer, do not open the valve with tools.
Transport
In the car, put it in the boot, secured lying down or standing in a bag, cap on. In summer, do not leave the car standing in the sun for hours; the inside reaches 60 to 70 °C. For private use the dangerous goods rules are simplified, and one or two cylinders are allowed. CO2 cylinders are banned on aircraft, in hand luggage as well as in suitcases.
Motorhome, camping, boat
Secure the cylinder in a storage compartment in the vehicle, away from the heater. Soda makers are popular in motorhomes because they save on crates. Leaving the cylinder in an unheated vehicle in winter is no problem, as cold lowers the pressure.
Testing requirement
A test date is stamped on every cylinder. Ten years after the test it may no longer be filled, but has to be retested or taken out of service. When you swap in a shop, the manufacturer takes care of this: it sorts out old cylinders without you noticing. If you fill your own, you have to keep an eye on the date.
If a cylinder hisses
A quiet hiss at the valve after screwing it in is usually a poorly seated seal: unscrew it, check the sealing ring, screw it in again. If the cylinder hisses continuously outside the machine, put it outdoors or on the balcony and let it vent, do not touch it (it ices over) and do not screw it into the machine. Then swap it at the retailer. How swapping works is explained in the article Swapping cylinders.
Frequently asked questions
Can a cylinder explode?
Practically not. At excess pressure the bursting disc opens and the gas escapes loudly but in a controlled way. The prerequisite is an undamaged cylinder from a retailer.
Is escaping CO2 poisonous?
Not in small amounts; a cylinder in a normal kitchen is unproblematic. Ventilate and that is it. Emptying many cylinders at once in tiny closed rooms would be dangerous.
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