RECENT TRANSPORTATION INCIDENTS HAVE SHED light on an emerging challenge facing fire departments across the country. Ethanol (ethyl alcohol) and ethanol blends are becoming more prevalent in our economy. Firefighters must understand the unique atmospheric and burn characteristics of this product so they can effectively and safely handle spills or fire scenarios involving these flammable liquids. In addition, firefighters should be aware of the shortcomings of employing common traditional response tactics at incidents involving this product. The ethanol component of blended gasolines, such as E10 and E85, has dramatically changed the chemistry of “new fuel” fires and, consequently, their response methods.
Knowledge is the firefighter’s main tool. This article defines the unique characteristics of ethanol and explains divergent methods for responding to what is fast becoming the foremost challenge for municipal fire responders in public spaces such as highways; gas stations; industrial loading terminals; and other areas where blended ethanol gasolines are transported, stored, and used.
Ethanol is a feisty product when burning because of its water solubility (miscible in all proportions). It is blended with gasoline as an oxygen-enriching agent, creating cleaner burning fuels. Current blends range from 10 percent ethanol up to 95 percent ethanol (basically pure). The challenge for firefighters-as in any flammable liquid incident-is to first identify the suspect product. Once identified, you can execute the proper course of action for mitigating the incident. Departments should contact their foam concentrate supplier to confirm the proper application rates and percentages required for handling gasoline/ethanol blends.
NFPA 11 AND ETHANOL
Let’s first look at the physical characteristics of ethanol or ethyl alcohol. As defined by National Fire Protection Association 11, Standard for Low-, Medium-, and High-Expansion Foam (2005 ed.), ethanol is a Class 1B flammable liquid. Its flash point is -5°F. It has an autoignition temperature of 793°F. Its flammable limits are 3.3 percent lower explosive limit (LEL)-19 percent upper explosive limit (UEL). It has a specific gravity of 0.789 at 68°F and a vapor pressure of 44 (mm Hg) at 68°F.
SPILL FIRES
Studying the NFPA 11 calculations for flammable liquid incidents (low- and medium-expansion foams), we know that for skim and spill fires (defined as up to one inch in depth) the formula should be as follows:
- Surface area is determined by length × width = ft2.
- Ft2 × application rate = gallons per minute (gpm) of water foam solution required; application rates will vary dependng on the alcohol-resistant film-forming AFFF (AR/AFFF) foam manufacturer’s Underwriters Laboratories (UL) listing.
- Gpm of water foam solution required × percent of foam = gpm of concentrate per minute.
- Gpm of concentrate per minute × 15-minute time duration (per NFPA 11) = total amount of foam concentrate needed for firefighting operations.
For this application, we will use an application rate for AR/AFFF foam that has a listing of 13 gpm ft2.
Example:
A 6,000-gallon tanker, assuming the entire contents are spilled, will result in an area 1/2-inch in depth.
- The surface area would be 100 ft × 100 ft = 10,000 ft2.
- 10,000 ft2 × 0.13 gpm per ft2 = 1,300 gpm of water/foam solution required.
- 1,300 gpm of solution × 0.03 percent of concentrate = 39 gpm of concentrate per minute.
- 39 gpm of concentrate per minute × 15-minute time duration = 585 gallons of concentrate required to extinguish the fire.
DIKE FIRES
NFPA 11 tells us that for dike fires (defined as an area that can contain more than one inch in depth of product), the formula should be as follows:
- Surface area is determined by length × width = ft2.
- ft2 × application rate (0.13 gpm minimum per ft2 for in-depth fires greater than six inches) = gpm of water foam solution required.
- Gpm of water foam solution required × percent of foam = gpm of concentrate per minute.
- Gpm of concentrate per minute × 30-minute time duration (per NFPA 11 for a Class I flammable liquid) = total amount of foam concentrate needed for firefighting operations.
Example:
- 100 ft × 100 ft = 10,000 ft2.
- 10,000 ft2 × 0.13 gpm per ft2 = 1,300 gpm of water/foam solution required.
- 1,300 gpm of solution × .03 percent of concentrate = 39 gpm of concentrate per minute.
- 39 gpm of concentrate per minute × 30-minute time duration = 1,170 gallons of concentrate required to extinguish the fire.
TANK FIRES
Compare this to a fire in a storage tank or a situation where the product is greater than six inches in depth. The formula changes to the following:
- 1/2 the diameter × 1/2 the diameter × 3.1416 = ft2.
- ft2 × application rate (0.16 gpm minimum per ft2 for in-depth fires greater than six inches) = gpm of water foam solution required.
- Gpm of water foam solution required × percent of foam = gpm of concentrate per minute.
- Gpm of concentrate per minute × 65-minute time duration (per NFPA 11) = total amount of foam concentrate required for firefighting operations.
Example:
100-foot storage tank:
- 502 × 502 × 3.1416 = 7,854 ft2.
- 7,854 ft2 × 0.16 gpm per sq f2 = 1,257 gpm of water/foam solution required.
- 1,257 gpm of solution × .03 percent of concentrate = 38 gpm of concentrate per minute.
- 38 gpm of concentrate per minute × 65-minute time duration = 2,470 gallons of concentrate required to extinguish the fire.
INDUSTRY ADDRESSES AN EMERGING THREAT
The Ethanol Emergency Response Coalition (EERC) recently sponsored testing under the guidance and participation of the International Association of Fire Chiefs (IAFC) and the Independent Liquid Terminals Association (ILTA) with the intent of finding out what foam agents would work most effectively on incidents involving ethanol fires in bulk storage and transportation scenarios. The testing was conducted over a two-week period, starting in February 2007, at ANSUL’s Fire Technology Center in Marinette, Wisconsin. Using the Underwriters Laboratories 162 (UL 162) Standard for Safety, this test was performed as a blind test; the foam concentrates were put into sterile containers labeled “A,” “B,” “C,” “D,” “E,” and “F” foam equipment and liquid concentrates. Forty-three individual tests were conducted on denatured ethanol (or E95) and E10 (gasohol) using Type II, Type III, and sprinkler applications. The following types of foam concentrate were tested in the blind test:
- AR/AFFF
- Class A foam
- AFFF
- Emulsifying/wetting agent
- Regular Flouroprotein
- AR/FFFP
(Specific manufacturers and products remained anonymous.)
AR-AFFF was the only foam agent that successfully passed the UL 162 tests against both E10 and E85/95. Although some of the other foams may have some degree of effectiveness, depending on the situation and their application rate, the tests confirmed that AR-AFFF will be the most effective foam for fires or spills involving ethanol-blended fuels.
HOW AR-AFFF WORKS
The performance of AR-AFFF foams is identical to that of straight AFFF on hydrocarbons. They form an aqueous film atop the surface to extinguish the flame to eliminate vapor release (hydrocarbons will not pass through a water barrier). However, additional chemicals are added in AR-AFFF foams (particularly xanthum gum) to form a polymeric barrier. This barrier is produced from the foam blanket and develops a membrane, which is nonsoluble in alcohols, thus preventing the water-bearing foam blanket from mixing with the alcohol. This additional chemistry protects the integrity of the foam blanket-a key component when applying foam to a polar solvent-because the polymeric barrier is not self-healing.
AR/AFFF APPLICATION RATES
When assessing your department’s foam needs, another key bit of information is to carefully consider the manufacturer’s UL 162 listing for polar solvents. These listings vary widely from manufacturer to manufacturer. I have seen a range in listings from as low as 0.13 gpm per square foot to as high as 0.20 gpm per square foot. This characteristic greatly affects how much foam is required in staging before operations can begin. A lower UL 162 listing is a direct logistical savings in the field-lower gpm per square foot means less foam your team has to manage on a response.
APPLICATION TYPES
Type II Application
This application is an indirect application most commonly associated with a fixed-foam system such as a sprinkler system on a truck loading rack or a foam chamber on a storage tank.
Type III Application
This type of application is a direct attack using portable equipment such as portable monitors and handline nozzles.
GOOD TACTICS-WRONG FUEL
To date, it has been a common tactic to deploy airport aircraft firefighting (ARFF) vehicles in response to tanker fires in metropolitan areas, because these apparatus carry their entire agent (foam and water) to the scene. This has truly been a stop-gap measure to attempt to deal with tanker rollovers. However, when we apply the NFPA 11 formula previously discussed to this tactic, we find that at the application rate required-even with hydrocarbons-the ARFF trucks carry only 1,500; 2,500; 3,000; or 4,500 gallons of water. Consider an application at 1,000 gpm in the best-case scenario. This resource would give the firefighter only enough water/foam solution for a 4½-minute application-not nearly enough to meet the 15-minute timeline required by NFPA 11. When we consider the higher application rate required by NFPA 11 for ethanol and E85, it quickly becomes clear that this response method starts off on the wrong foot.
Another common practice is to pull two 1 1/2- or 1 3/4-inch handlines from the first-due or initial attack engine. This will not meet the NFPA 11 fire flow requirements. Remember, applying the correct amount of finished foam “gallons per minute” is what puts out the fire!
TACTICAL EVOLUTION
Establishing a water supply is almost always a serious challenge for this type of incident. Prefire planning can be difficult for cargo tank trucks. However, most jurisdictions are able to identify the potential problem areas that could encounter an incident involving a tanker, such as a freeway cloverleaf interchange. Current means of transporting pure ethanol include cargo tank truck, rail cars, and barge. It is extremely unlikely that responders would encounter ethanol in a pipeline scenario because of compatibility issues between the product and the pipeline, valving, and associated equipment. Prefire planning for storage tanks should be done prior to the incident. We will look at storage tanks later.
Establishing a good water source must be the first priority. The next priority needs to be a good AR-AFFF foam supply with adequate quantities to meet the timeline established by NFPA 11.
The Charlotte (NC) Fire Department is one example of a department making such water supply and foam storage preparations. Its approach to Class B foam operations has been to equip five tankers with 300 gallons of 3 percent × 3 percent AR-AFFF for over-the-road and bulk storage emergencies, with an additional backup supply of eight 265-gallon totes deployed to the scene by designated vehicles.
Another resource consideration is potassium bicarbonate dry chemical agent (Purple K) or other Class B dry chemical agents. Purple K dry chemical is highly recommended where three-dimensional or running fuel fires are encountered. These types of fires cannot be extinguished by foam alone. They must be “blocked in” or “shot out” by interrupting the chemical chain reaction with dry chemical. My experience has shown a hydro-chem application to be most effective in any number of scenarios and conditions. The hydro-chem system very effectively injects the dry chemical inside the water/foam stream for direct application of the dry chemical to the fire without interrupting the nozzle flow.
A method of proportioning large quantities of foam is necessary, since the application-quantities and method-needed for these incidents will necessitate the use of master streams. In most cases, the proportioning on ethanol will be 3 percent. There are several means of providing this proportioning correctly:
- Self-educting Hydro-Foam nozzle. An internal venturi creates a natural vacuum inside this nozzle, drawing in and proportioning the foam additive with the water flowing through the nozzle.
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Portable or built-in “around-the-pump” proportioner. You can vary the flow rates of these devices from low flows (one or two handlines) to master streams by adjusting a metering valve that matches up with the gpm required for the incident. You can also pick up foam with these systems using a “pickup” tube that connects to the pump panel, allowing foam resources to be drawn from totes or drums once the onboard foam tank runs out.
- -Another look at the Charlotte Fire Department reveals all its apparatus (more than 70 units) have built-in “around-the-pump” foam systems (photos 1, 2).
1. Photos by author.
2.
- Dedicated foam pumper with a balanced-pressure foam-proportioning system. This system uses the onboard foam pump-to-pump foam concentrate to the discharge through a metering valve dedicated to that discharge. The foam goes only to that discharge. This system can also use pickup tubes for additional foam resources.
- Direct injection system. This system uses a concentrate injection pump that puts the concentrate into a designated foam manifold. However, most of these types of systems on apparatus today are sized for structural firefighting and Class A operations. They can operate with Class B foam operations but only in limited quantities-for example, two handlines at 3 percent. Also, most direct injection systems do not have external pickup tubes.
Once you have all these preparations in place, you must apply proper foam application techniques for the extinguishment of polar solvents such as ethanol.
APPLICATION METHOD
The best method for Type III applications would be an indirect method or “banking.” This method directs the foam stream toward any structure or object adjacent to the burning fuel to create a “splash” or cascading foam application that introduces the foam to the burning surface more gently than directly plunging the foam. The banking method better protects the polymeric barrier of the foam blanket. Most important is that plunging or direct applications are not recommended for Type III applications on a tanker or rail car fire. Plunging will disturb the polymeric barrier of the foam, which prevents the foam’s water content from mixing with the polar solvent. Note: Any finished foam that plunges below the fuel surface will be consumed by the fuel.
When dealing with storage tanks, the operation becomes more complex. Outage-or space inside the tank-of approximately seven to eight feet allows Type III application of the finished foam using portable monitors and nozzles by hitting the back wall of the tank or by using the inner wall to deflect the foam stream, creating a swirling motion to gently apply the foam. If foam expansion tubes (that will not reduce the reach of the foam stream) are available, I would recommend attaching them to the nozzles for ethanol fires and for nonfire situations, for additional foam expansion.
LESSONS LEARNED
Because of the testing done by the IAFC and the EERC, we now have hard-and-fast data that AR-AFFF foam concentrate is the best choice for dealing with ethanol emergencies. As stated earlier, the best formula for success, in addition to a good AR-AFFF, is first doing your homework by prefire planning as much as possible and by educating yourself and your fellow firefighters on how to calculate the water and foam needs per NFPA 11 for tanker, rail, marine, and storage tanks.
Remember that without the correct gpm flow, you are setting yourself up for certain failure and possible injury to personnel. Make sure you establish a good water supply with large-diameter hose (LDH), preferably five inch or larger. Make sure to have some type of large-flow foam-proportioning equipment up to the capacity of your engine or ladder companies at 3 percent. Forward or reverse lays and relay pumping should be part of your standard operating guidelines (SOGs). Always consider the need for a secondary water supply source should the primary water supply fail.
When it comes to bulk storage facilities, you need to have enough foam on-site for at least one extinguishment and for one or preferably two more extinguishments en route to your location. Why? Because, believe it or not, more foam will be consumed following extinguishment than during the firefight, especially on bulk storage incidents. Once extinguished, you still have a hazard. It’s just that the hazard is no longer burning. ARFF trucks and handlines are not adequate for this firefighting operation. Establish mutual-aid agreements with fellow departments, along with operational SOGs.
In remote rural operations, water resources may have to be shuttled in to drop tanks. Responders should always “think outside the box.” A fire department in Pearland, Texas, when responding to a bulk storage lube oil company fire used the loading dock as its water resource. It sealed off the drains, then shuttled water in until the dock filled up to the point that it could begin drafting operations for the fire flow requirements.
. . . Ethanol is truly unique as a fuel fire. However, understanding its nature and proper response tactics can ensure a successful response. Find the water, establish proper foam and dry chemical stores, understand and apply high-volume foam-proportioning methods, and apply the foam so that the foam blanket is protected.
Trends in industrial and municipal emergency response environments will have municipal firefighters responding to incidents involving industrial assets more and more. These duties will obviously stretch the knowledge and experience of the municipal departments that may have industrial facilities in their response areas. Many industrial companies have their own fire brigades with industrial-trained firefighters, but sometimes the local municipal department is the only firefighting agency available to deal with these incidents.
Ethanol’s presence in public commerce and public spaces brings a “foreign” industrial type hazard into the municipal firefighters’ realm; firefighters must be familiar with it and train for incidents involving ethanol. Flammable liquids have been dealt with for decades in the industrial sector, but they are presenting new challenges to municipal firefighters who rarely, if ever, have seen a flammable liquid fire in their career.
As a municipal responder, you need to spend time performing prefire planning and educating yourself about these new hazards and how to safely and effectively deal with them, because it’s only a matter of time before you will encounter one. You also need to effectively evaluate your firefighting equipment and tactics by conducting live drills on-site, if possible. My experience in dealing with industrial companies has been that some will provide training for your department at recognized schools such as the following:
- The annual Advanced Flammable Liquid School conducted by Williams Fire & Hazard Control at the B.E.S.T facility in Beaumont, Texas. It is conducted in May.
- The TEEX annual Industrial/Municipal School in July each year at Texas Engineering Extension Service at College Station, Texas.
- The Fire Science Academy in Elko, Nevada, offers specific schools throughout the year.
If your department isn’t able to send all your personnel out of town to these schools, have a company come to your department to present training tailored to your response scenarios and specific challenges.
The Charlotte Fire Department did that in 2001. We brought in Williams Fire & Hazard Control, which helped us with tactical needs and equipment configurations. We applied for a state grant for hazmat training (which is available through your state Emergency Management Office or state fire marshal’s office). The grant covered the cost of the storage tank emergency school: Williams came to our department and trained all of our personnel on storage tank firefighting. This experience was invaluable, because we got first-hand instruction from industrial people who had extensive direct experience with the very issues for which we needed to prepare.
TROY C. JOHNSON is a captain and 19-year member of the Charlotte (NC) Department, assigned to Fire Station 17/company officer on Blaze 5. He is the department’s ARFF instructor and an adjunct instructor in the Training Division. Previously, he served as a fire protection specialist in the U.S. Air Force. Johnson is also a lead ARFF Instructor for the South Carolina Fire Academy and chairman of the NC State ARFF certification committee. He is a NC-state certified firefighter III, level III fire instructor, fire officer I, and EMT.
Extinguishing Ethanol Fires: Practice Needed for Proficiency
BY DWIGHT WILLIAMS
As ethanol becomes more prevalent in our economy, I believe municipal responders will face some new and specific challenges that need to be addressed according to their unique characteristics. I have always said that every fire is a unique situation-the fuel may be the same, but the environment will always present complex dynamics that affect the way a fire will behave. The same is true for ethanol-related fires.
When ignited, ethanol, in open spaces as well as in transport containers, will burn differently from gasoline and must be extinguished through methods specific to the fuel involved.
For decades we have witnessed the volatility of various flammable liquids and how they respond in different environments-open air, in depth, and under pressure. We have constantly adapted our methods and equipment to create the most effective response when confronting these scenarios.
As ethanol makes its way into public transport, processing, and storage, the municipal tactics, foam, and equipment used to address these fires will have to be adapted to the nature of this fuel. Specific tactics and calculations are important to extinguish these fires. It is difficult to merely overwhelm them. Proper foam must be applied in the appropriate amount using an acceptable method.
And, because of the water miscibility of the fuel, responders must ensure that they are applying AR-AFFF foam to the fire. Independent tests have shown that this is the proper foam blend that has a chance of extinguishing this fuel. When realizing that this is more than a running spill fire-that the fuel is “in depth”-the responder can then apply the correct calculations and application of the foam attack.
In my experience with flammable liquids over the past 38 years, I have seen that different fuels have different personalities and extinguishing them is as much an art as a science. Firefighters must practice on ethanol fires to become proficient.
Over the past several years, more and more industrial and municipal responders have found themselves working together as teams. In the field and at our annual Industrial Fire & Hazard training in Beaumont, we have seen municipal departments adapting many of our industrial response tactics and equipment for their own applications. The recent ethanol proliferation is a perfect example. Methods and foam we have been using in industry for years can provide the effectiveness required for these municipal emergencies.
DWIGHT WILLIAMS, founder of Williams Fire & Hazard Control, lends his experience and observations to the recent dilemma of ethanol-related fires in municipal response scenarios. For the past 27 years, he has led his teams to more than 180 successful extinguishments of large-scale industrial-related fire emergencies involving flammable liquids, hydrocarbons, and pressure fires, including the world’s largest fully involved storage tank fire extinguishment, which exceeded 270 feet.
