When we speak of the implementation of application techniques as we did in (see Foam 107 post) what we are really training the firefighter in is the “practical” application of these techniques. This requires actual hands-on suppression of flammable liquid fires using firefighting Foam and the techniques discussed.
If you do not have access to a training facility that is set-up for flammable liquid firefighting, this can be accomplished using a designated area and “pan fires”. Pans are constructed out of heavy gauge steel, welded at the corners to keep flammable liquids and suppression water confined.
To do this in your local area, apply for a Fire Department “Variance” through your local government and employ the talents of your own DPS (Department of Public Services). If these cannot be done, a trusted local welding contractor can fabricate your “pan”. For multiple students repeating a fire extinguishment, a good place to start is with a 4 to 6 inch wall to the pan. This will allow you many extinguishments without having to halt the training session to empty the pan level. Any size or shape can be made, but a good starting place is to make construction of the pan so that it fits inside a standard pick-up truck box. This makes transportation of your “burn pan” easy for multiple vehicles. One idea we added was to incorporate wheel casters into the fabrication design. However, extra sturdy and heat resistant casters must be used for extreme heat and use.
When teaching the three methods of Bounce off, Bank-In, and Rain down, you must key the avoidance of “plunging”. In all three methods, “plunging” of shooting a concentrated stream of firefighting Finished Foam into a flammable liquid pool will do two things;
1] Spray ignited flammable liquid into the air, thereby spreading the fire, ignition of exposures not currently involved in fire. This can also needlessly endanger nearby firefighters involved in your operation.
2] Plunging disturbs the flow of the Foam blanket which is what you are attempting to create. This “blanket” of solid finished Foam is what causes extinguishment by smothering and cooling of surfaces.
When teaching this technique, the most important factor is to use the “object” involved, as a deflector. The object is irrelevant, what is not is the idea and practical theory of breaking the solid stream so that the resulting Foam will “flow” across the pool where the majority of the flammable liquid fuel source is located. This cools and smothers the “feedstock” of the flammable liquid fire, soon to eliminate flame as soon as the fuel source is entirely covered.
When there are no deflectors or objects to “bounce-off” this method can be used by easily striking the ground in front of the flammable liquid pool. This action causes the finished Foam to pile up and form a wave-like roll of finished Foam that continues towards the pool and eventually overlapping the pool edge, continuing to flow across the pooled surface.
This method is primarily used for vertical storage tanks due to the configuration of these high walls. Often it is too hazardous to reach the top of these storage tanks and Foam application must be made from ground devices. Unfortunately, this technique requires larger Foam concentrate resources. Due to the “burn-back” and subsequent loss of Foam from passing through the fire and super-heated gasses, this technique requires longer application with greater volumes of Foam concentrate.
When using this operation, coordinate liquid levels with Tank personnel to be sure your Foam concentrate does not “drain-time” quicker than it extinguishes. If this is not figured in to your over-all attack plan your efforts could overflow the flammable liquid while it is on fire! Great care to watch and monitor tank levels must be made to avoid overflow and protect fire department personnel.
Haz Mat Mike