Water and Other Extinguishing Agents

Water and Other Extinguishing Agents by Stefan Särdqvist was originally published (in Swedish) in 2001 by the Swedish Rescue Services Agency (now the Swedish Civil Contingencies Agency) and is used for training in practical firefighting operations. The English translation released in 2002 is an excellent resource for any firefighter or fire officer.

Särdqvist  has a PhD in Fire Protection Engineering, and his passion for this aspect of our profession is readily apparent in this text (and I mean this in the most positive way). Like Fire Ventilation by Stefan Svensson, Water and Other Extinguishing Agents effectively integrates science with the practical aspects of firefighting. Topics addressed in this text include:

  1. Overview of Firefighting Operations
  2. Water
  3. Foam
  4. Powder [Dry Chemical Agents]
  5. Gaseous Extinguishing Agents
  6. Extinguishing Theory

In the opening chapter, Särdqvist  states:

The fire triangle is sometimes used to describe the components needed to start a fire. The fire triangle has three sides: fuel, oxygen, and heat. In some cases an uninhibited chain reaction is added to the triangle to turn it into a four-sided tetrahedron. However, this approach is far too simple to explain why fires go out. It describes the ingredients needed for combustion, but not the mechanisms which cause fires to occur or to be extinguished. For this reason, the fire triangle cannot be used in discussions about extinguishing fires.

Sacrilege! For most of us the concept of the fire triangle and the fire tetrahedron are fundamental concepts applied to both occurrence of fire and fire control. Ah, but things are not as simple as we originally thought. The dominant method involved in fire extinguishment is cooling (with a few minor exceptions). Right at the start, this text challenges some commonly held (but scientifically incorrect) assumptions. 

In the chapter addressing water as an extinguishing agent, Särdqvist addresses water application methods including surface and smoke (gas) cooling. This chapter provides a sound explanation of why steam produced by water changing phase in the hot gas layer does simply add volume and lower the level of the hot gas layer. This is supported by a mathematical explanation of the expansion of steam and contraction of the hot gases as they are cooled. My colleague, Lieutenant Felepe Bazea Lehnert of the Valdivia Fire Department observed that “it is easier to explain this if you understand calculus”. However, Särdqvist does an excellent job of making these concepts accessible to a diverse fire service audience.

Water and Other Extinguishing Agents is available for on-line purchase from the Swedish Civil Contingencies Agency for 335 SEK (around $45.00) plus shipping. The agency will invoice for payment Swedish Kroner after your purchase (which necessitates using a bank that can produce a check in foreign currency).

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