Combustible Dust Fires

[watermon]

Hi, I'm new to the forum and was curious if firefighters are aware prior to arriving on the scene of a commercial structural fire if combustible dusts have been generated at the work site during the manufacturing process.

A scenario I'm trying to envision would be suppose combustilbe dusts have covered 5% of the structure on the overhead beams and ledges. This would constitute a potentially explosive atmosphere according to NFPA 654. Potentially explosive could equate to fighting a fire that has flammable liquids and potentially explosive vapors.

[dday05]

I don't know if this is sort of what you are looking for but we have been called to a shop in our area I think 3 times now for a metal dust fire in a big collecter they have. It is rather big and has 6 big filters that catch fire. Usually the fire is contained into the unit. We usually pull the filters out with a pike pole and take them outside. Luckily the machine is close to a door. This is a very dirty job as well and the smoke is pretty bad. It takes about 1 hour to get the smoke out of the building. Now the machine that has been catching fire this company has a few other shops but not in our areas. They have also had fires in the machines to like 5 times I think the guy said. They don't know why the machine catches fire. O would like to talk to them further to see if they figured anything out yet. The guy also said when the unit catches on fire it cost about 40 k to get it back in service...

[watermon]

dday,
Thanks...yes that is exactly the information I'm looking for concerning the complex subject of combustible particuale solids and the combustible dusts that are generated. From your description I'm not sure if the dust collector is outside or inside.

Some excellent resources would be NFPA 484 (http://www.nfpa.org/freecodes/free_access_agreement.asp?id=4 8406)Combustible Metals and NFPA 654 (http://www.nfpa.org/freecodes/free_access_agreement.asp?id=6 5406)Standard for the Prevention of Fire and Dust Explosions from the Manufacturing, Processing, and Handling of Combustible Particulate Solids.

There are several prevention and mitigation measures that can be utilized such as detection, isolation, venting , and suppression of future potential combustible dust fires. Here is a link for more info concerning equipment that is available (http://www.fike.com/explosion_protection_products. html)

I sure would like to talk to the fellow and find out what he is using in his process layout. This is the sort of info that needs to get out in the open in the prevention of future incidents that causes possible personal injury and negative economic impact.

Additionally, I'd like to add this incident to the Google Map (http://dustexplosions.blogspot.com/). of Combustible Dust Fires.

Thanks for you valuable feedback

[rfdmn09]

DD,

I recommend you contact the manufacturer of the collector unit. The business you respond to may have the wrong type of collector for the application. For over 5 years, I worked for a company which sold and serviced dust collectors. When one caught fire, it was either due to wrong application or the business was trying to be cheap and not clean the filters.

Good luck!!

[watermon]

rfdmn09,

Thats an excellent point you bring up concerning proper applications.

John

[chadbutler]

Combustible dusts can sure take you by surprise. Hopefully pre-incident planning can help you identify these problems in your district before they become a problem. Even in the event that pre-incident planning hasn't identified these hazards a sharp eye can often tune you in once you arrive on scene. Just like always, look up, look down, look all around. Combustible dust igniting is more of an explosion that you'll be defending yourself from rather than a fire that you'll be fighting. This is the one time that I've switched from a straight stream to full fog purely for self defence.

[dday05]

DD,

I recommend you contact the manufacturer of the collector unit. The business you respond to may have the wrong type of collector for the application. For over 5 years, I worked for a company which sold and serviced dust collectors. When one caught fire, it was either due to wrong application or the business was trying to be cheap and not clean the filters.

Good luck!!

I will be checking this out and see. This is sort of interesting though... Thanks for the info.

[Geinandputitout]

We respond to 10 to 12 per year. We have two large grain milling facilities in our city, and they regularly catch fire. We've had explosions, dust collector fires, and everything in between.

As some one pointed out earlier they are generally caused by lack of maintenance. They have decreased in recent years due to a reconfiguration and redesign of one of the facilities three years ago.

They are "generally" not that big of a deal, just a ton of work. The dust collectors in both facilities traverse 5 to 7 floors. Someone has to realize that it is actually on fire and shut the mill down. Sometimes this happens quickly and there is not a lot of extension. Other times we have flaming dust and grain particles throughout the building and it takes a couple of days to get them back running.

[InsuranceLCRep]

Combustible dust is a very real danger, look at the poor souls in Ga a few weeks ago at the sugar plant. If you have enough dust to write your name in it, and it is a combustible dust, look out! A lot stuff has to all happen at the same time such as particle size, humidity, source of ignition, BUT when it happens it will blow the building apart. The first explosion shakes the building and then the dust high up is suspended, and that what gives you the big event. Roof lifts up, walls fall in, get the pictures? MOST fire inspectors walk by it and never give it a second look, that is what US Chemical Safety Board said in the report linked below.

http://www.csb.gov/completed_investigations/docs/Dust%20Final%20Report%20Websit e%2011-17-06.pdf

To determine the extent of dust explosion hazards in the United States, the CSB investigators researched the history of dust fires and explosions from 1980 to 2005, and identified 281 major combustible dust incidents that killed 119 workers, injured 718 others, and destroyed many of the industrial facilities. Based on this data, the fatal or disabling/disfiguring injuries in the 2003 dust explosions, and the damages caused by those explosions,
the CSB concludes that combustible dust incidents are a significant industrial safety problem.

The three CSB dust investigations (West, CTA, and Hayes) and the four other explosions described in this chapter identified factors common to all or most of the incidents:

Facility management failed to conform to NFPA standards that would have prevented or reduced the effects of the explosions.

• Company personnel, government enforcement officials, insurance underwriters, and health and safety professionals inspecting the facilities failed to identify dust explosion hazards or recommend protective measures.
• The facilities contained unsafe accumulations of combustible dust and housekeeping was inadequate.
• Workers and managers were often unaware of dust explosion hazards.
• Procedures and training to eliminate or control combustible dust hazards were inadequate.
• Previous fires and other warning events were accepted as normal, and their causes were not identified and resolved.
• Dust collectors were inadequately designed or maintained to minimize explosions.
• Process changes were made without adequately reviewing them for potential hazards


Here are some excellent sites on dust explosion hazards:

http://www.osha.gov/dts/shib/shib073105.html

http://www.csb.gov/completed_investigations/docs/CSB_West_English.pdf

http://www.chemsafety.gov/index.cfm?folder=completed_inv estigations&page=info&INV_ID=53

[watermon]

So far there been over two dozen combustible dust related explosions and fires since Imperial Sugar combustible dust explosion.

Here is a link to a Google Map of all the incidents (http://dustexplosions.blogspot.com/)

Time line of events http://bp2.blogger.com/_wkE-CNoZEYY/R-bSXo4EeAI/AAAAAAAAAHs/-1HnpK8IzLU/s1600-h/recent.jpg

Quaker Oats and Georgia Pacific have occurred since Custom Alloy explosion.

If anyone knows of any other incidents please include them on the Google Spreadsheet (http://spreadsheets.google.com/viewform?key=pAZTkw06KrczzbgYw R5p8KA)

[1835Wayne]

There are a sort of spark arrestor that can be installed in line before the dust collector. The filters in these collectors are made of paper or cloth, and once they are filled with the dust (espaecially if the pulsers are not functioning) they are just waiting for a spark. The good thing is, if the fire is in the dust collector, it should stay there(depending on if the air is put back into the plant afterwards or not.), containing the fire to the collector.

DEFINATELY ensure the blowers are shut off before entering the collector to extinguish. I would only open the hatch and fill the bottom with water. Most of these dusts are considered Haz-Mat and should be contained as much as possible. (My background is with steel and iron producing)