CO2 extinguisher feels empty

[Guest petertow]

i checked our extinguishers this morning and the extinguisher feels empty. Nothing sloshing around. How can I find out if the Co2 has been emptied?

[Safelincs]

Hi Peter

As the CO2 extinguisher does not contain liquefied CO2 but highly pressuried CO2 gas, you will not hear any liquid moving in the CO2 extinguisher. Since CO2 extinguishers have no pressure gauges, the only way to check that the extinguisher is still correctly filled is by weighing the total weight and comparing it against the weight at manufacture. The gross weight is stamped on the extinguisher body.

Harry

[Tom Sutton]

CO2 is a solid at absolute zero (-273C) and as the temperature increases the pressure increases until -56.4C / 5.11 bar known as the triple point where it exists as a solid, liquid and gas. As the temperature increases to 31.1C / 73bar (critical point) it exists as a liquid and gas, above that, it becomes a super critical fluid. Check Phase Diagram.

Check CO2 Phase Diagram http://i419.photobuc...ediagramco2.jpg

Because of the very high pressures in the cylinder (55bar) I doubt you will notice any sloping about but as Harry said you check its contents by weighing it and comparing contents with the full weight stamped on the neck of the cylinder and if it has lost more than 10% then it needs recharging.

[Guest Sulaimon]

Thank you for your reply. Though the question did not originate from me but I am also trying to get answer to it.

Can there be any time that the content will seize to be co2 maybe because it has not been use since it was serviced say over a year.?

[Tom Sutton]

Assuming you mean cease and not seize, then no it will always be CO² while it is sealed in the cylinder.

[green-foam]

If it helps, I have some CO2 extinguishers here at home that are old, they never get serviced, and they are still full of CO2. (I know they are full because as Tom points out, its easy to weigh them)

As an aside, if the contents were to cease to be CO2 what would it be? I have also had one that leaked (after being used in a video) it was so bad you could actually hear it hissing / crackling.

[Sulaimon]

I took about 4 extinguishers  for servicing, someone told me the content has changed to pressurized gas. Is this actually possible? 

How? 

[AnthonyB]

CO2 doesn't decay and of all the types of extinguisher they are the type most likely to still work if left sitting in a corner unchecked and unused for years.

They can leak, usually from a cracked neck or defective neck or valve seat O rings, but this is rarer than in once was (it was an issue with early aluminium cylinders in the 60's, 70's and early 80's)