Smoke Burns
Paul Grimwood
During the 1980s the two Swedish fire engineers Mats Rosander and Krister Giselsson introduced a new method of applying water to interior room (compartment) fires. In those days this 'new-wave' use of fog tactics was termed 'offensive firefighting'. They taught us to use a 35-60 degree fog pattern in very brief 'pulses' or 'bursts', using the flow control bale or handle to open, close and sometimes simply 'crack' the nozzle in a series of controlled applications of water-fog lasting anywhere between half a second (pulse) up to five seconds (burst). 

The length of the water-fog pulses/bursts depended on the size and geometry of the compartment, room or space and the intensity of the fire. The main reason for using small amounts of water was to cool the gases effectively in the overhead without disrupting thermal balance or creating large volumes of scalding steam. With practice the smoke layer stays high, or even rises, and the dangers associated with rapid fire phenomena are greatly reduced.

The Swedish fire service also showed us how ISO steel shipping containers could be used as an economical form of training structure in which to practice these compartment firefighting techniques.

However, the main thrust of the training that took place in containers (Fire Development Simulators) (FDS) was to allow firefighters to observe fire behavior as an enclosed fire developed and grew larger, under a range of different ventilation parameters. For the first time, firefighters could work and train at very close quarters with fire in a controlled and safe environment. The learning curve was immense.

During the late 1970s, I had had not long returned to London Fire Brigade following a two year detachment into the US where I worked areas of the South Bronx during time spent with the FDNY 7th Division, under the watchful eye of then Deputy Chief Bill Bohner. Assignments throughout the South Bronx, between 1975-77, during the busiest period for fires the FDNY had ever seen, taught me a great deal about the strategy & tactics used by US firefighters. It was common to have 3-5 large structures burning in the same street at the same time during this period and every night seemed to bring us new challenges.

In 1984, at the time the 'new-wave' firefighting concepts were being introduced in Sweden, I was introducing new venting tactics to the UK Fire Service through a long series of technical articles in the trade journals. I had promoted a 'middle ground' approach that suggested UK firefighters failed to utilize venting tactics to their advantage whilst the US firefighter's primary reliance on venting practices sometimes led to great disadvantage.

The Swedish use of water-fog, in brief pulses and bursts, was taken on locally in the west-end of London over a ten year period (1984-94) on a trial basis. Our firefighters became very adept in using these tactics and combining them with a controlled approach to venting structures. I further published technical papers and a book describing how these tactics were being combined. I also introduced the concepts of 'Tactical Ventilation' and '3D Firefighting' as a means of labeling the 'combination of tactics' that were aimed at controlling and stabilizing interior fire conditions in a way not common to most fire-grounds. Over the next twenty years these labels were to become well known around the globe.

There has since been a long history of flashover & backdraft tragedies in the UK and London; France & Paris; Germany; Canada and the USA before 3D Firefighting techniques were finally seen as a solution and were harnessed as a viable learning and training tool in the localities involved.

In the 1980s, however, there were initial issues with some of the terminology and theories brought through the translation from Swedish to English. The Swedish engineers had begun to redefine what had already been established by scientists and firefighters in the US and the UK several decades before by using new terms, definitions and explanations for events associated with various rapid fire phenomena.

The original Swedish terminology related to the term 'flashover' has since been altered in its translation to conform with current European and North American accepted scientific definitions as follows:

• 'Lean Flashover' - is ROLLOVER

• 'Rich Flashover' - is BACKDRAFT

• 'Delayed Flashover' - is SMOKE EXPLOSION

• 'Hot Rich Flashover' - is AUTO-IGNITION

• 'Black Fire' - See Article HERE

A 'lean flashover' (accepted scientific terminology is ROLLOVER) is the ignition of the gas layer under the ceiling, leading to total involvement of the compartment. The fuel/air ratio is at the bottom region of the flammability range.

A delayed flashover occurs when the colder gray smoke cloud ignites after congregating outside of its room of origin. The results can be very unpredictable, and if the ignition occurs at the ideal mixture, the result can be a violent smoke gas explosion. The internationally accepted scientific terms for this process are either smoke explosion or fire gas ignition depending on the severity of the combustion process.

A hot rich flashover occurs when the hot smoke with flammable gas ratio above the upper limit of flammability range and temperature higher than the ignition temperature leaves the compartment. Upon dilution with air it spontaneously ignites and the resultant flame can propagate back into the compartment, resulting in an event similar to a rich flashover. The internationally accepted definition of this process is known as auto-ignition which is another form of fire gas ignition.

We must be very careful how we relate to events and use terminology associated with various forms of rapid fire phenomena. We must use a standard language.

For more information go HERE and HERE and HERE

Pierre Louise Lamballais writes -

Here is the terminology I use at the Jurbise Fire School in Belgium. It's the same as in your article on FGI;

First family: flashover

- Flashover. Transition event to a fully involved fire. It's in the "fire room". We have a smoke layer, radiative feed-back and so on. Signs are rollover, ghosting-flames, dancing angel ... The tirigger is heat. In reality, seem to be hard to imagine firefighter facing such an event because if vent is large enough, it happen very quickly, before we're on scene.

- Ventilation induced flashover. Same as previous, but we change the vent by breaking a glass, entering the room.... The firefighter is the "trigger"!

Second family: backdraught
- Self ignition backdraught. The smoke is over its ignition temp. The air intake blend smoke, and when air touch the hot area, we see an orange flame then the explosion. In this case the explosion start at ceilling level (we can see that on the Australian doll's house ont the 3D FF CD.)

- Flames are back to ember! The smoke is not hot enough. The air intake blow on ember. When flame goes back on ember, it ignites the gazes. The explosion came from the ground. The delay can be very long, depending on the ember (still hot or not, directly in the air intake or not...)

For backdraft, the missing parameter is air.

Third family: FGI
- An area with smoke and air. EG a hole in the fire-room, by which smoke goes out to another room. It can be also pyrolyse, and as pyrolyse dont use air, the room is filled with fuel (smoke) and air. When we introduce energy, we have a flame. If the result is an explosion, it's a smoke explosion. If it's not explosive, it's a flash-fire.

We can say flashover and backdraft occurs in the room where the fire is located. Flash-fire and smoke explosion occurs in room where there is no fire (so not the main fire room), or in the "fire-room" but when the fire is extinguished.

www.flashover.fr 

Join the 3D Firefighting Mailing List

Enter your name and email address below for important 3D Firefighting Safety Alerts:

Name:
Email:
Subscribe  Unsubscribe 

Crew Deployment Training
Paul Grimwood
January 2007
'Fire-ground commanders and company officers should adopt a greater appreciation of the when; how; why; and where to deploy into; attack; ventilate or isolate fires and gain a more in-depth and practical understanding of what 'coordinating' fire attack with ventilation actually means' ...

Over the years we have clearly identified needs and promoted training programs for structural firefighters in the practical aspects of fire behavior; rapid fire phenomena; flashover; backdraft; fire gas ignition; how 'smoke burns'; smoke explosion; tactical ventilation; and interior fire attack operations. We have developed techniques associated with '3D Firefighting' which utilize methods of asserting control over an enclosed fire in a way that creates a safer working environment for firefighters. We apply these principles in a phased training approach, using purpose built CFBT training facilities based around the ISO modular steel shipping container design.

Since the mid 1980s we have compared strategies and tactics employed by firefighters around the world and introduced and developed a global strategy termed 'Tactical Ventilation' that harnesses both venting and fire isolation (anti-ventilation) tactics, depending on conditions, key fire behavior indicators and ventilation profile. We have analyzed and compared firefighting flow-rates and developed easy to use fire-ground formulas to assist on-scene commanders to anticipate water and resource requirements.

We have advanced risk assessment and risk control measures to encompass fire department SOPs in areas where resources and staffing may be restricted and have developed strategies that optimize critical tasking of the resource limited response. We have further developed on high-rise firefighting procedures in both commercial and residential buildings and developed a model approach and training program based on lessons learned from past experiences.

We are now seeing that there is a critical failing of many incident & crew commanders to make effective tactical decisions and deploy their crews safely and effectively during the vital first few minutes following fire service arrival. We see this as a key area related to LODD (firefighter fatalities) and we are now developing and presenting our program further.

See the article SMOKE BURNS by Battalion Chief Ed Hartin

Learning and Leadership
Mike DeGrosky
Wildfire, Nov 1, 2005

There has to be a clear responsibility on fire authorities to train their staff effectively. There also has to be an inbuilt desire to advance one's personal knowledge base to 'seek out new information, gain new knowledge and use that new knowledge to challenge assumptions and conventional wisdom, and stimulate new ideas. Adopt a culture of continuous learning. Organizations succeed because people at all levels share information and learn from experience'....... HERE