Remember Halon? How to get rid of it?

[lustyd]

Reminds me of one of my clients who had a "small fire" in the server room due to "human error" (not mine) when no suppression system deployed. Me and customer went to the "operators" to enquire as to why we had not been asphyxiated as normal procedure. Apparently it was too expensive to refill the 20 cylinders every time some fool caused an electrical fire in the server room so during the daytime fire suppression was off until a burning man requested it be reinstated

 

[GrahamHR]

The decomposition product of the halons (CFCs) and their gaseous replacements (HCFCs, HFCs, HFAs etc) in the presence of flames , being HF, HCl. HBr, phosgene etc are indeed very toxic or corrosive ( but not "nerve gases"). Likewise, never touch a burned out car; the residues on the bodywork from the fluorine containing wiring can contain HF. A HF spill was the used as the chemical disaster in the first "Casualty" TV programme; it is very nasty indeed.

The halons/ freons ( and perfluorinated/ perchlorinated hydrocarbons themselves) are rather innocuous, apart from their degreasing effect ( the notable exception being carbon tetrachloride, once a common solvent- we had it at school !- now a confirmed carcinogen).

With regard to refrigeration, many domestic units have foam made with pentane blowing agents; quite flammable !

The legislation to get rid of halons and freons was not well thought out.

 

[penfold]

The danger of these gases is that they actually burn (pyrolise) around the flame completely cutting the supply of oxygen for the fire to continue. CO2 doesn't do this, so requires a far higher concentration to be as effective. But the pyrolised product is a similar compound to the nerve gas Phosgene.

This is why they are such great extinguishers for enclosed spaces like ERs; the heat of the fire causes them to react preferentially with all the oxygen in the compartment, putting the fire out(and asphyxiating you if you are in there). The smarter shipping companies are moving to water-fogging, as it's cheap, cools as well as smothering the fire and is not toxic or otherwise hazardous for firefighters. It also runs for as long as your water supply lasts; they usually run off a tank of fresh water, but the ones I've seen can be supplied with sea water in the event of it running out, although if you haven't managed to put the fire out after 1hr+ of water fogging it's time to get in the lifeboat.

As Colin says, if the extinguisher is in good condition and fully charged keep it; you might be thankful one day.