image
Flashover - What do YOU Know? - Firetactics.com
What is 'flashover'? There are so many different forms of 'flashover' related phenomena it can become confusing for the firefighter. We have grouped the various phenomena under the single heading - Rapid Fire Progress (RFP). These are all events that are known KILLERS of firefighters! It is essential for firefighters to know -
  • What actions might CAUSE an event of RFP?
  • What actions might PREVENT an event of RFP?

Study the following images and test your knowledge of RFP, then click on the link at the bottom of the page to download the answers!

1. THE DOOR ENTRY

Take a close look at the three images on the left. They display a typical scenario where firefighters arrive on-scene and observe 'nothing showing'. However, as they gain entry through the front door, a thick black plume of smoke issues from the upper regions of the doorway. Within seconds this smoke has turned to belching flame! What event has occurred? Is this a 'flashover'? What actions could you take to prevent or reduce the chances of this event occurring?

 
 
image
2. THE WINDOW ENTRY

Sometimes we vent a window from the exterior. Our reasons for doing so may be an attempt to -
  • Assist advancement of an interior hose-line (Vent for 'Fire')
  • Attempt to gain access for Vent-Entry-Search (VES) (Vent for 'Life)
  • Improve interior conditions for trapped occupants

What is happening where the smoke turns to flame? What type of event is this?

 

3. THE SMOKE LAYER

Here is a situation (see the four images, to the left and below) we can experience in a training simulator (and of course real fires), where a smoke layer builds up at the ceiling, some distance from a fire in an enclosed room at the end of the simulator. When the door to the fire compartment is opened, or the fire reaches the ceiling, the smoke layer ignites above our heads in a rolling ball of flame. What type of event is occurring? Where might this occur? What can we do to alleviate, prevent or reduce the likelihood of this event?

 


image
4. THE 'HIDDEN' FIRE

As firefighters turn up they locate the fire a state of smolder. It might be a simple mattress with fire smoldering away underneath (left), or it could be a sofa fire with the fire smoldering deep inside the cushions or structure of it. It could also be a pile of rubbish bags in an under-stairs cupboard that have spontaneously ignited and smoldered!

As we raise the mattress what happens?

Now imagine if that flammable smoke layer (at 3 above) from the smoldering fire has dispersed throughout the room or area you are occupying. What might occur here as you uncover the hidden fire? Lift the mattress? Cut into the sofa?

How should we approach this situation?

4a - A recent (August 2007) quote by a County Fire Marshal investigating the LODD of two California firefighters .... 

"A smoke explosion happens when a large buildup of smoke becomes very hot inside a room, and the whole cloud ignites all at one time," said the County Fire Marshal. "A flashover is pretty much the same thing without smoke."

But is this statement true? 

5. UNPLANNED VENTILATION 

Firefighters arrive to see smoke issuing from the upper floor bedroom window. They attempt to advance a hose-line into the structure from this vantage point using ladder access, but fail to notice the heavily stained black windows on the first (ground) floor level. 

Suddenly, the windows on the first (ground) floor break through the heat and smoke turns instantly into flame .... what occurred? How can we prevent this?

 

6.  LARGE VOLUME STRUCTURES

Firefighters arrive on-scene to a commercial or large volume industrial or storage building showing fire in the rear. They make entry through the front but the fire has access to an abundance of fuel and air, and the fire continues to develop in size so rapidly that it escalates beyond the flow-rate available at the nozzle/s and chases them out of the structure just a few short minutes after gaining entry.

What might cause this sudden development of fire? Can flashover occur in such a large volume area? 

7.  BACKDRAFT OR SMOKE EXPLOSION?

Again, using images from a 3D Firefighting CFBT simulator (below), what event occurs here when the fire is allowed to smolder for several minutes inside the simulator, before opening a window hatch to allow air to enter and smoke to escape. Is this a backdraft? A smoke explosion? What is the difference between this and the door entry at 1 above?

How can we prevent or reduce the chances of such an event from occurring?

8.  WHAT EVENT DO YOU SEE HERE (Above)?

9.  THE OSCEOLA 'FLASHOVER'

A window venting action (below) of a room demonstrating high levels of heat and near zero visibility .... What event of RFP is taking place?

10. 'SEA OF FLAMES'

It moves lazily as if in slow motion .... hanging just a few feet above your head .... what is it? What are the dangers here?

Download the answers HERE

More FREE PDF Downloads & Links on Rapid Fire Phenomena

  • Flashover Information HERE
  • 'Black Fire' HERE
  • Flashover - A Firefighter's Nightmare HERE
  • Fire Gas Ignitions HERE
  • Forced Draft (Draught) Fires HERE
  • Flashover 'Pathways' HERE
  • Smoke Explosions HERE
  • Backdraft HERE
  • Rapid Fire Progress HERE
  • Tactical Objectives HERE
  • Exterior/Interior Temperature Differences HERE
  • 'Confusing' Definitions of Flashover HERE
  • Flashover - Kennedy (Excellent Review) HERE
      Paul Grimwood
      training@fire2000.com
image