Search Past Articles
Explore Past Articles
Haz Mat "Specialist Course"

Foam 107.2 Application Techniques

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.

Bouncing Off

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.

Rain Down

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



Foam 106.2 Discharge Devices and Nozzles

Air aspiration is paramount in the formation of a proper “Bubble.” It is this structure that affords the firefighter, when properly constructed, to suppress fires, eliminated hazardous vaporization, and eliminated the immediate need for large scale evacuation of “affected” persons. An “Affected” person is terminology that directly refers to civilians in the nearby area of the spill that are untrained residents or business workers that can quickly be negatively affected by these hazards. For Fire Departments and Haz Mat Teams, the ability to quickly evacuate these persons has multiple difficulties for obvious reasons. Manpower, transport vehicles, and evacuee destination location medical needs, are some that top the list. All these complicate your resources and lengthen the time to mitigate an incident.

Low to medium aspiration nozzles or devices are usually sufficient for flammable liquid fires but not for hazardous material vaporization control. For this tactic medium to high aspiration nozzle devices must be used. This is critical for your choice to eliminate the need of immediate evacuation. Choosing the correct device will allow you to “shelter-in-place” “affected” persons reducing your manpower needs and decreasing the incident mitigation time overall. Because you can now concentrate on spill mitigation as opposed to civilian evacuation concerns.

Low aspiration nozzles construct a smaller, wetter, bubble. This bubble absorbs more ambient heat from a flammable liquid fire while still able to hold its structure affording vaporization control over the remaining flammable liquid preventing re-ignition and subsequent “burn-back” resulting in a continued flammable liquid fire. Medium aspirated devices produce a larger “dryer” bubble. This bubble is better for vaporization control as it floats longer, and holds its structure as long as not subjected to flame. Here, the vaporization control time is longer without replenishment and affords confident hazardous material mitigation techniques and longer time frames that are associated with this discipline. 

The choice and or adaptability of your air aspiration nozzle device can yield you desirable or undesirable results depending on which is chosen. Expansion rates (Foam 106) are critical understanding for making this choice. They reflect the mathematics of “how” the air aspirating nozzle or device is functioning. Always refer to these Foam standards under the NFPA 11 section dealing with air aspiration for the appropriate choice.

The number 1 concept to understand is; for proper extinguishment, vapor control, smothering, and elimination of off-site evacuation, Finished Foam MUST be ASPIRATED in order to perform. Without aspiration, large quantities of Foam concentrate shall be wasted without success in extinguishment or vaporization mitigation. Choose wisely, your incident will depend upon it.

   Haz Mat Mike



Foam 105.2 - Foam Proportining

            The key to delivering the finished Foam to its target is the proper proportioning within the hose-line in the form of Foam solution. This occurs “after” the Foam concentrate has been “educted” from its container into the delivery hose-line or standpipe system. The percentage becomes critical in obtaining maximum results to best deploy the finished Foam allowing its particular characteristics to shine. By having the correct “eduction” percentage drawn into the Foam solution maximum suppression and vapor suppression is achieved. When the incorrect setting is used, Foam wastage occurs and your resources are drained at a faster rate thus limiting a positive outcome. This feature in the “system” operation is a critical one balancing resources, cost, successful outcome of your incident all at the same time.

          As NFPA 11 dictates the need for correct proportioning, it does not mention any reference other than to refer to the Foam manufacturer recommendations. This is purposeful as the manufacturer “designs” the Foam Concentrate to be “educted” at specific percentages for its exact purpose. This is critical to the Foams performance and needs to be included into the SOP documents of your Department. When changing from Foam concentrates this feature may be overlooked and cause poor performance. Always be sure that eduction is set for the correct percentage or your attack results may be rendered useless.

          While line eductors are the first choice for suppression operations due to their portability and ability to be used from “Engine-to-Engine” one device for large scale fires should be more closely looked at. These are the “around-the-pump-proportioners”.

          This device functions by using the discharge of a fire pump to create the venture affect, drawing Foam Concentrate into your Fire Service Pump. The benefit of this technique is that “ANY” discharge device on your vehicle or relayed to another device can produce Finished Foam. This has wide reaching capabilities. Finished Foam can be delivered to your target through any large scale master stream device you wish. This is especially useful on large scale tanker truck fires. Facilities that store or contain are volume of Flammables or toxics can also be suppressed using this device. The downside is Foam solution is now contained inside the entire pumping circuit system. This means that EXTENSIVE flushing of ALL intake and discharge pathways will need to be completed before Fire Service Apparatus is returned to normal emergency service. This is sometimes ignored due to exhausted crews after the fire, and disastrous results have occurred. When Foam solution or concentrate is not properly flushed out of your system it can crystalize and block discharges, drain valves, block nozzles, and generally cause future fire suppression pumping actions to fail. Always flush your systems pump and discharge after using this tool to avoid these problems.

          The versatility of the around-the-pump proportioner far exceeds the tedious exercise in proper flushing. One technique that is successful is to drain the pumper after flushing. This will eliminate any crusty issues from forming preventing future operations. Follow this procedure at a minimum;

1] Flow water through all discharges and intake until clear of Foam solution

2] Fill all intakes, discharges, and tanks with clear water

3] Drain the above until empty and no longer dripping (this takes time)

          You may want to add to this procedure to enhance your safety, this is fine, just allow enough time for all the above operations to be done properly to prevent any future clogging issue.

                                 Haz Mat Mike


Winter 2016 "Technician" AAR

The AAR (After Action Report) or presentation for the "Post-Incident Critique" was submitted by the winter 2016 Madonna University Students as an outline for their final "Crtique" after last weeks scenario in the field.

Their was a number of positive leadership concepts that they naturally seemed to have no issue with as is seen in many first-time response students to a hazardous materials incident. 

As you can see by the log-book "time-line" taken from their SSP (Site Safety Plan) they sized-up the situation and made their initial choices as to level of CPC and initial tasks to be performed in the span of 30 minutes. This was a bold move and demonstrated skill confidence beyond "their first response!" 

This was commended as they followed their guidelines for response;

1] Identification

2] Prioritize

3] Mitigate

4] Environmental Recommendations 

Their analysis using the "Chem-Cat" device dictated their prioritization of the following hazards listed in the table below. In addition towards making prudent and safe decisions with this tool their "lessons-learned" were as follows.

1] Decontamination Plan - 

A more exact plan for actual decontamination procedure needed to be "in-place". The students found that mis-communication led to cross-contamination within the decontamination line. This is accomplished through frequent practical training and Team inter-communication.

2] CPC - Dressout

Some decontamination "dry" techniques were complicated due to a entry-team members confusion over the dress-out order between level "A" and level "B" ensembles'. 

3] Communication - 

The students found that a system of remote communication MUST be in-place. whether it be hand signals or portable radio, communication issues slowed the response coordination and increased personnel hazards.

All three of these items "could" be remedied by practical training, although it is strongly recommended that some sort of remote, portable, communication devices be in place. Given the limited equipment, in-experience, and "first-time-out" scenario, the students were still able to successfully ID, decision make, and mitigate this multiple hazard scenario. They will all be assets to the Emergency Management Field in their future.

                    Haz Mat Mike


SITE PLAN                              12 April 2016

1800 Hours               Alarmed to Macomb Community College East Campus

1830 Hours               Responded to spill

1858 Hours               Technicians Dressed & on air

1900 Hours               Entry team entered hot zone

1902 Hours               Decontamination Technicians on air & stationed 

1910 Hours               Entry team retrieved chemical samples & entered decon                   

1914 Hours               Cross contamination (suits)

1916 Hours               Entry team clear of decon

1922 Hours               Decon team clear

1925 Hours               Debrief

1932 Hours               Chemcat Testing [flame test, pH, Specific Gravity, Iodine, Cyanide]

1942 Hours               Chemcat Testing complete

1945 Hours               Debrief

2051 Hours               Preparation for second entry [entry & decon team]

2057 Hours               Entry team enters hot zone           

2100 Hours               Decon entry

2110 Hours               Decon complete

2115 Hours               Debrief
















Specific Gravity



#1 Yellow




<1 (insol)

Slightly +



#2 Pink

Non Flammable



<1 (insol)




#3 Clear

Non Flammable



=1 (sol)




#4 Baby Blue




<1 (insol)




#5 Yellow

Non Flammable



=1 (sol)





Foam 104.2 - How Foam Works

While past articles have given and listed the various components of Foam functionality, this issue will concentrate on the bottom-line of all Foam workings. Whether the Foam you use is for various materials or liquids, one set of physical concepts are at the base of the Foams successful outcome for your incident. These are best stated in four (4) words. If you grasp the concept of these ideas, your knowledge base will be able to choose the correct product, apply it properly, design a system of application that is best suited for your response, and mitigate a successful outcome to your responses.

The four concepts that sum up Foam workings are; interstitial interface limited solubility.

When we talk about “Interstitial” we are focused on the connective surface that lies between the bottom of your Finished Foam Blanket and the top surface of the hazard you are attempting to cover or suppress vapors from evolving. This space is where fire is extinguished, vapors are halted from escaping to the atmosphere, (to your exposures, environment, affected persons, and in general becoming the hazard source). It is here that the entire incident is either make or break. This surface contact space is “between” where the activating successful components of the finished Foam blanket stops further emanation of the hazard for a limited time period. Therefore, it is this area where “1/4 drain time” needs to be at its maximum length. By creating Foam “systems” for your response that maximizes this feature, reduces re-application times, provides post incident security, extinguishes combustion, halts future vaporization from the products source, and most importantly safe mitigation of your hazard product. When this is understood and completed, the emergency has ended and clean-up can begin safely.

Secondly, the term “Interface” refers to this space as it is directly connected between the bottom of the Foam blanket and the top of your hazard surface. Areas that become “plunged” or “exposed” to the atmosphere violate this area and are no longer protected by the finished Foam blanket. This can cause re-ignition and re-vaporization placing you back to square one while possibly endangering all responders that have moved into offensive forward positions to begin confining techniques towards final mitigation. Only where you have provided a pooled surface without atmosphere exposure and without sub-surface irregularities will this interstitial interface exist, and allow you to accomplish sustained smothering of the spilled hazard.

Thirdly, “limited” refers directly in this case to time length. As previously published in accompanying articles on “Foam” in our series, this can be thought of as ¼ drain time. As the Foam bubble and accompanying liquid content confine and make contact within the interstitial interface, this time length is critical for intact suppression of fire or vapors. Once the Foam bubble begins to degrade back into its normal state of a liquid, vapor suppression decreases and the danger factor increases. Therefore, this limited time is also dependent on its sister physical property of “solubility”.

Lastly, as we know from our basic hazardous materials “Technician” course, “solubility” is the percentage ability of a substance to evenly mix and stay in solution with another liquid. Most commonly in the environmental field “water” is used as the base solution. In finished Foam water plays a major role in Foam solution. This solubility affords the responder application of the suppressant Foam solution onto the top surface of the hazard. It is also the means by which the suppression will occur for this limited time frame before breakdown occurs. These four words/principles give true example to the phrase, “all things in life have balance”. This is the foundation of proper techniques and physics of the application of Finished Foam. It is this “balance” that suppresses fire, stops vaporization, and provides safety for “affected persons” and responders mitigating your incident. Keep these principles in mind when creating a Foam “system” for your Teams’ operations and your incidents will be safe and successful.

                            Haz Mat Mike