magnesium fires

[Darren E.R.TEAM]

as you all know to put a magnesium fire out you need to use sand.
as i work at a magnesium recycling plant and have to deal with fires on a large scale.
for example the ponds we have are 4m by 30m and as you can picture its not posable to cover these using a spade.
as anybody got any ideas on what equipment to use?
also if the fire brigade was called in how would they put it out and with what?

[Lee999]

Hi darren,

Are you saying that, on occations within your work place, you have large quantities(4x30) of magnesium on fire, and you dont call the Fire Service?

[Darren E.R.TEAM]

The company that I work for, recycles magnesium castings and then alloys it back in to the customers spec, at this point it is cast back in to ingot or billet, the leftover magnesium mixed with flux is sent to the digestion ponds that we have on site.
These have magnesium swarf added to it, and then flooded with water until it breaks down naturally this will then go to land fill.

From time to time these set on fire as hydrogen gas is released, so we have to cover it with sand.
the last two major fires we have had the fire service sat on site and let our E.R.TEAM deal with the fire, as they have weekly  training sessions  related to industrial fire fighting etc  and are also B.A trained, rescue from height, and on and on.


The main problem we have on the ponds is the volume of sand that needs to be hand balled.
So I have been looking at muck spreaders etc as a fire fighting aids?
so im looking for tride and tested ideas?

When we talk to the fire service to question how they would deal with the situation they seem to have little knowledge on dealing with magnesium fires?
thanks please reply

[Lee999]

Depends which part of the country you are in, but I think your local FRS would deal with this incident in one of the following ways;

1. soda ash
2  DRY sand
3  leave to burn

The perfect answer would be to have some form of fixed firefighting system using metal extinguishing powders.

Your employers should consider this during their premises risk assessment.

What type of container is the magnesium held in?

What type of structure is it contained within?

[fireftrm]

And to add to Lee's questions:

What happens to the products of combustion?

What do the Environment agency have to say about your processes?

[Paul]

I would Guess this site would be under the COMAH umbrella and ISO 14001, so mush of this is essential in complying with both.

Under COMAH, you are required to provide worst case scenarios, modeling and ensure that you have an emergency plan to deal with such.

To be honest I am shocked that your inspectors have not served a notice upon you to have fixed instalations to deal with such.  I understand that Mg can burn with Tempretures above 4000 Deg C.  Surely if you have any sizable fire then fixed installations are essential to prevent injury and damage to surounding plant and more critical other hazards.

If you would like any specific advice I would be happy to help via my email.

Thanks

Paul

[fireftrm]

Shocked is a polite term Paul; I had something rather stronger in mind.

[Paul]

Polite.............me.................that because I'm shocked!"!

[P GUTHARD]

when I was a fireman in the raf we used to use dry powder on magnesium wrapped in a fire blanket or using a water fog on low pressure - if that helps

[AnthonyB]

i'm suprised you don't have approved Class D Powder extinguishers using Sodium Chloride or Graphite - these are equipped with a special applicator to lower the velocity that also, due to it's length, keeps the user a distance away from the metal - not a lot granted, but far further than if applying dry sand sacks.

The common Class D extinguishers are 9 or 12 kilo, normally capable fo extinguishing up to 1 kilo of shavings, but for the larger risks 150lb wheeled or stationary/skid mount models are available.

However, where economy is more important a sack of fine sand is far far cheaper than purpose made Class D agents so it's the first corner to get cut.

One fire service way of dealing with magnesium is to aim a jet off a 2.5" delivery line onto it until eventually after a large fireworks display the metal is cooled and goes out........I kid you not, thats what we were shown at the FS College (with half a 55 gall drums worth of shavings) - their budget obviously didn't stretch to Class D agent training either!

[Ken Taylor]

Didn't it used to be a large container of asbestos dust once? That no longer being realistic, a fixed installation does seem to be needed from your description.