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FIRE SERVICE AND GENERAL FIRE SAFETY TOPICS => Fire Safety => Topic started by: kurnal on October 11, 2006, 07:22:34 AM
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A metal recycling yard handles titanium turnings- they are received, pulverised and bagged. A fire involving these would be both difficult and expensive at about £18k/tonne. They currently have a full range of standard extinguishers of all common types but clearly these will not be suitable for the more reactive metals.
Please can anybody point me in the direction of suitable extinguishers for this type of risk? I understand that bags of salt shovelled onto the fire may be effective but that doesnt sound like first aid firefighting to me.
They did have a fire involving titanium a couple of years ago and the local brigade tried to extinguish it with water!!! before allowing it to burn out.
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'Ternary eutectic chloride' perhaps? See section 11.4.6 of Physics and Chemistry for Firefighters, Vol 1 Fire Service Manual. Also says that some metal fires can be tackled by dry earth or sand, powdered talc or graphite soda ash or limestone, all of which act as a smothering agent.
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TEC powder forms a crust over the metal and allows it to burn without spreading. That how it extinguisher magnesium or if it is in open ground you can put water on it which accelerates the burning with long range jets. (Get back quicker for your tea.) You cannot smother magnesium as it produces its own oxygen but it appears you can smother titanium according to "IFE Hazardous loads"
PROPERTIES Solid: usually in powder or granular form, flammable (even when wet) May be ignited by a spark. When dry burns without flame. When burning reacts explosively with water.
EMERGENCY PROCEDURES. Beware explosive risk from dust in air mixture. Small spillage may be covered with dry salt or dry sand. Do not strike sparks from tools during application.
EXTINGUISHING AGENTS. Dry salt or if not available dry sand may extinguish by smothering then allow cooling. Do not use water, foam, dry powder or gas type extinguishers under no circumstances.
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Thanks to you both for the useful information. I would like to provide some equipment on site for the staff to be able to use on a first aid firefighting basis- do you know if any extinguishers are available? if my memory serves me well I think TEC was extremely toxic so may be unwise in unskilled hands?
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twsutton sorry magnesium does not produce its own oxygen it chemically impossible. What does happen is that burning magnesium is so reactive that it will grab oxygen from other compounds. Hence it will grab the oxygen from carbon dioxide and leave carbon residues. More excitingly it will also grab the oxygen from water leaving free hydrogen.
What happens with the TEC is that it forms a crust over the burning magnesium preventing any oxygen getting to the metal, this puts the fire out but everything needs to cool before the crust can be disturbed.
Here endeth the chemistry lesson.
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I stand corrected Mike. I should have listened more at the chemistry lectures instead of concentrating on the UBB.
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The FS Manual mentions something about the TEC or similar materials being in plastic bags which are laid on the burning metal - the plastic melts and releases the agent to form its crust. So there would not be handling of the TEC directly involved.
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the fire service manual still quotes 40 year old out of date rubbish about PFE agents.
TEC was created by UKAEA decades ago for uranium fires, is highly toxic as it's contents include barium chloride and isn't seen in use much. If you really want some they still make it in India.
Class D Powders extinguishers are readily available and have been for years, and the formulations usually fall into three types - graphite, sodium chloride & copper.
You simply need a typical Class D extinguisher which we supply as does Chubb and any company selling Amerex, Gloria, or Thomas Glover extinguishers which will have low velocity applicator. To see one in use there is a free streaming video on Chubbs site showing the results of using normal extinguishers and then the correct use of their Pyromet Class D unit.
Expect to pay £150 - £500 a unit depending on who you buy them from
Or you could buy the agent bagged to throw on manually of course.
The manufacturers of the well known (in the trade) Cetrimax Powders state that their high grade ABC powder is approved for class d fires if use with a class d extinguisher body (i.e. low velocity applicator) but this is only tested on magnesium
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Try http://www.amerex-fire.com/Literature/classd.pdf#search='class%20d%20fires' you may find it interesting.
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Thanks for the updates.
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Thanks to all for your advice.. If Class D extinguishers are readily available then problem solved. My usual supplier was not aware of this. Anthony- I may well be in touch!!! Client is in your patch!
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No problem! Amazingly some extinguisher companies are out of date in technology, there are still some that don't offer water additives, or Wet Chem with the result that on inspections we still find large fryer risks where the user has been told a AFFF spray or ABC DP & blanket will work or staff are expected to lug around big 9 litre plain waters!
As a rule we are not an extinguishers supplier & service agency (I do hold a FETA cert though!), but we retain the ability to do so to assist clients on one off or short notice/emergency jobs and for specialist requirements, there is no type, finish or size we can't supply! Still can't find a nationwide extinguisher company to recommend as there is always some drawback with them!