TB 145 COMBUSTIBLE METALS Flashcards
TB 145 COMBUSTIBLE METALS
Most combustible metal fires produce extreme temperatures ranging from ____ to ____ degrees Fahrenheit. These temperatures are high enough to separate water into its basic elements: hydrogen and oxygen.
5000 to 9000
TB 145 COMBUSTIBLE METALS
Fires involving combustible metals are designated as a class “___” fire.
D
TB 145 COMBUSTIBLE METALS
The extreme temperatures become a major factor when selecting an extinguishing agent since water (H2O) will dissociate when super heated to its basic elements of hydrogen and oxygen.
Hydrogen becomes a free burning fuel and oxygen acts as an oxidizer that accelerates the burning rate, fire spread, and temperature to the higher end of the range above.
Reference
TB 145 COMBUSTIBLE METALS
Combustible metals can be divided into two categories:
ALKALI METALS
Alkali metals (Lithium, Sodium, and Potassium) are water-reactive under non-fire conditions and should be placarded with the “W” under the NFPA 704 system.
They are usually stored immersed in mineral oil or kerosene (paraffin oil). Applying water to Alkali metal under any circumstances will result in fire and extreme reactions.
ALKALI EARTH METALS, TRANSITIONAL METALS, AND OTHER METALS
Alkali Earth metals (Magnesium), Transitional metals (Titanium, Zirconium), and Other Metals (Aluminum) do not present the same hazards as Alkali metals; however, when burning, they can become extremely dangerous when in contact with water.
Reference
TB 145 COMBUSTIBLE METALS
These metals (titanium, magnesium, zirconium, and aluminum) shall be indicated by an “\_\_” in the fourth space if the quantities or form meet the LAFD criteria for placarding (occupancies that exceed \_\_\_ pounds of combustible metals as per Table 4-A of the Los Angeles Fire Code or that process or store \_\_\_ pounds or less of combustible metals that are in the form of dusts, chips, powders, turnings, or ribbons). If multiple hazards exist, the symbols (no more than two) shall be stacked with the most severe hazard indicated on top and the combustible metal symbol “M” (when applicable) always positioned at the bottom.
M
500
500
TB 145 COMBUSTIBLE METALS
Flames burning with a ‘white hot’ appearance, the presence of flowing or molten metal, and white colored smoke are conditions that exist during a combustible metal fire.
Reference
TB 145 COMBUSTIBLE METALS
There are some additional events that can occur after applying water to burning combustible metals. These events are explosive in nature and may cast or shower molten metals onto firefighters, civilians, and exposures as well as creating a concussive event following the explosion.
Reference
TB 145 COMBUSTIBLE METALS
Members of the LAFD working within ___ feet of a burning metal product are considered to be working in an IDLH
30
TB 145 COMBUSTIBLE METALS
Extinguishment of combustible metal fires is accomplished through smothering of the burning material. If the fire is allowed to burn, this process will occur naturally as an oxide crust develops over and smothers the burning material beneath.
Traditional firefighting methods utilizing water, foam, Purple “K”, or dry chemical extinguishing agents can disrupt this process and actually make the fire worse.
Reference
TB 145 COMBUSTIBLE METALS
Dry powder, under the brand name “______”, is the only approved product provided by the LAFD to extinguish combustible metal fires.
MET-L-X
TB 145 COMBUSTIBLE METALS
Supply and Maintenance maintains approximately ___ pounds of MET-L-X and has the ability to deliver it to the scene of the fire. MET-L-X is applied manually through use of a shovel or by disbursing the product directly from the storage bucket.
The entire stock of MET-L-X maintained at Supply and Maintenance would only extinguish a fifty square foot fire.
LAFD is only capable of using Met-L-X to control small fires in the incipient stage.
500
TB 145 COMBUSTIBLE METALS
Per the manufacture’s recommendations, a one-inch layer of MET-L-X is required to effectively smother a fire. Ten pounds of product is required for every ____ square foot of fire.
1
TB 145 COMBUSTIBLE METALS
“Copious amounts of water in a coarse stream” can be effective on certain types of combustible metals in small
quantities. Magnesium engine blocks, for example, can be eventually extinguished utilizing copious amounts of water. If a fire is burning beyond the incipient stage or is involving a large amount of product, copious amounts of water can be counter productive and can cause increased fire intensity and explosions.
Reference
TB 145 COMBUSTIBLE METALS
First on-scene companies will need to quickly determine the product type that is burning and make a decision as to whether the burning material can be safely
Separated
Isolated
Extinguished.
Reference
TB 145 COMBUSTIBLE METALS
Separate
A small amount of product (approximately the size of a ________) that is in the incipient stage of burning may possibly be manually separated from exposures by a fully encapsulated Firefighter through use of a shovel or similar tool.
wastebasket
