Overview of “Class D” Agents

Portable Extinguishers: Overview of “Class D” Agents

Today’s manufacturing materials and processes are vastly different from those used in the past. Special metals like titanium, magnesium, sodium, and lithium have become a part of our daily lives. These materials and manufacturing techniques present special challenges for today’s firefighters.

The burning characteristics of most combustible metals have both similarities and differences when compared to more common “Class A” materials like wood or paper. Like “Class A” materials, the energy required to ignite a metal depends on the configuration of the fuel; large solid blocks will require much more heat to ignite than will finely divided dust or chips from a lathe. However, unlike common combustibles, burning metals react violently when water is applied. Therefore, it is crucial that the fire protection expert understand the material being protected, its configuration, and its burning characteristics.

Because of the violent reaction to moisture, the use of any water-based fire protection is not permissible. Even the smallest amounts of moisture associated with carbon dioxide, halogenated agents, or other clean agents may cause an unacceptable reaction that will intensify the fire. Standard dry chemicals are not effective on these fuels either as the high heat generation will simply consume the agent.

In the videos linked below, watch as the LAFD responds first to a structure fire located in South Central LA on Slauson Ave. The fire contained large amounts of scrap titanium which eventually exploded like a bomb.

A few weeks later, a similar fire that started in a jeans mfg co. and burned through the wall into another scrap titanium storage facility located across the street resulted in 3 major explosions that destroyed a huge warehouse the size of a city block as burning, melting titanium debris rained down on firefighters and damaged fire apparatus.

LAFD Combats Lithium Fire
LAFD Lithium Warehouse Fire Part 1
LAFD Lithium Warehouse Fire Part 2
LAFD Lithium Warehouse Fire Part 3