Dry Ice Plugs in Pipes and Hoses
Dry ice plugs can be formed inside hoses and piping when liquid carbon dioxide is
decreased below its triple point pressure of 4.18 bar. The dry ice can be compacted into a
plug which can trap gas.
The pressure behind or within a plug may increase as the dry ice sublimes until the plug is
forcibly ejected or the hose or pipe ruptures. A dry ice plug may be ejected from an open
end of hose or pipe with enough force to cause serious injury to personnel, both from the
impact of the dry ice plug and/or the sudden movement of the hose or pipe as the plug
ejects. Liquid carbon dioxide must be purged from the hose or pipe before reducing the
pressure below 5 bar. This can be done by supplying carbon dioxide vapour to one end of
the hose or piping system to maintain the pressure above the triple point while removing
the remaining liquid from the other end.
Cylinder labelling
Cylinders are labelled in accordance with national regulations.
Users of carbon dioxide are advised to carefully read and observe the precautionary
information on the labels. If a cylinder is not clearly marked it should not be used and the
Supplier should be contacted.
NOTE - It is unlawful to remove cylinder labels/marking.
Some cylinders have an additional label on the body or valve guard. This contains
important information on the use of cylinders which should be carefully read and
observed.
Typical Cylinder Label
Comments to the label can be summarised as:
Carbon Dioxide
EEC No. 2046969
UN No. 1013
Compressed Gas
Supplier Details
Green
- Asphyxiant in high concentrations
- Keep container in a well ventilated area
- Do not inhale gas
- Use no oil or grease
- Vapour pressure 57.3 bar (20°C)
DRY ICE/CARBON DIOXIDE CYLINDERS - Safe Use & Storage
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