Water, firefighting agents

Because combustible metal powders, flakes, or shavings can ignite, shovels full of the firefighting agents must be dumped onto the smoldering fire. Water must never be used. These firefighting agents should be as close to the source of combustion as possible. 

Foams for firefighting appHcations are typically made from a concentrated foaming agent diluted with water and then mixed with air. Rather than consider the volume fraction of air in the foam, firefighting foams are characterized by their expansion ratio, which is the increase in volume of the Hquid after the foam is formed. Expansion ratios range from 5 1 to over 1000 1 ratios of 5 1 to 20 1 are called low expansion ratios of 21 1 to 200 1, medium expansion and ratios greater than 200 1, high expansion. 

Where water supplies are inadequate for conventional firefighting and foam making, automatically activated fixed clean agent or CO2 systems may be considered for seal fire protection. The agent should be discharged into the seal area below the secondary seal. Fire detection options for these automatic systems include reusable thermal wires and pneumatic tube devices. Thermal wire is typically the more economical choice. 

EXPLOSION and FIRE CONCERNS when heated to decomposition, emits toxic fumes of NOx incompatible or reacts with acids, acid anhydrides, and oxidizing agents forms hazardous decomposition products such as nitrogen oxides, carbon dioxide, carbon monoxide, hydrogen fluoride, nitrogen use dry chemical, water spray or mist, chemical foam, or alcohol-resistant foam for firefighting purposes. 

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