When foam is discussed at fire conferences worldwide talk about tighter regulations owing to environmental concern dominates. At least as much attention should be given to performance, said fire foam executive Javier Castro Bigotes.
“I’m not saying that the environment is not important, but so is performance,” Castro said. “This business is not only about making foam. It’s about extinguishing fires.”
Javier Castro, general manager of Auxquimia Fire Fighting Products, addressed attendees at one such firefighting conference – the U.S. Fire Pump “Big Water” Symposium in November in Baton Rouge, LA. While introducing Castro, leading innovator in industrial firefighting Dwight Williams announced that he would be teaming with Auxquimia to produce a “signature” fire foam that will bear his name.
“We got together and talked,” Williams said. “We have a product that is extremely close to everything I wanted.
The new product is scheduled to hit the market in January, he said.
Javier Castro, a chemical engineer, has spent the last 15 years working on foam products. His company, based in Spain, is the main supplier of firefighting foam to the petrochemical industry south of Europe, he said.
The presentation by Castro centered on improving existing fluorinated foam for better performance and to meet tighter environmental regulations rather than switching to newer fluorine free firefighting foams
Fire foam has seen continual improvement in performance since it achieved wide use in the 1940s. That progress plateaued in the mid to late 2000s with the arrival of fluorine free foam products, Castro said.
“In terms of general performance, fluorine free products are at the level reached by the traditional fluoroprotein products and still far below that of AFFF” Castro said. “However, the new fluorine free foams meet most of the international standards and could do a great job in some circumstances.”
Regulators take issue with fluorinated firefighting foam based on the environmental persistence of PFOS (perfluoroctyl sulphonate), a raw material in foam, and PFOA (Ac. Perfluoroctanoic), a subproduct generated in the making of foam, he said.
However, alternatives exist to adapting these fluorinated foams to meet the new regulations reducing PFOA levels, Castro said. By decreasing the molecular chain length of the fluorinated materials used from eight carbon atoms (C8) to only six (C6), manufacturers can effectively reduce precursors of PFOA.
“Fluorinated products with eight carbons atoms can degrade into PFOS or PFOA which does not happens with six carbons one” Castro said.
Fluorinated compounds remain critical to performance, he said. Note that restrictions are only on the presence of PFOS and PFOA and not to the full fluorosurfactant range of products, he said.
Auxquimia has traditionally based its formulation on C6 fluorocompounds, always with the aim of achieving top-performing products. The C6 technology is not new and there have been several C6 fluorochemicals available in the market for more than 20 years.
It is true that old C6 products were not as pure as they are now and could contain some minor C8 components, Castro said. Those impurities have been resolved with the new grade of raw material available.
“The key decision for final users now to be made is should we hang on to AFFF foam using high purity C6 raw materials or should we go with fluorine-free foam?” Castro said.
AFFF foams are traditionally proportioned at three and six percent. New developments have reduced the proportioning rate to one and half percent.
“A reduction in the proportioning rate does not mean a reduction in performance and advantages in manufacturing and logistics are clear” he said.
New fluorine free foams are proportioned at not less than three percent, he said.
Viscosity remains the key physical chemical property to consider when buying foam, as in how easily does the product flow, Castro said.
“To proportion our products with water we need to move it,” he said. “Viscosity is the property that makes a difference in doing that.”
In changing foam brands, make sure the equipment in place can handle the new product at the rate it flows. Be aware that different methods of testing viscosity are used by regulators in North America and Europe.
One means of increasing viscosity is the addition of polymers, Castro said. It also increases the stability of the foam, making it alcohol resistant and strong enough to deal with polar solvents. On the downside, it can cause problems with compatibility, proportioning and stability of the concentrate.
New technology in low viscosity AR-AFFF has made it easier to move at low temperatures and has the advantage of low proportioning rates – 1 x 1, 0.5 x 1 and 0.5 x 0.5, Castro said.
Expansion index and drainage time depend on the concentrate, equipment such as the nozzle or generator used and ambient conditions. Castro said.
Theoretically, AFFF has been defined by physical and chemical properties such as fuel surface tension, foam solution surface tension and interfacial tension solution with the fuel. The advantages of AFFF includes direct application over hydrocarbons, no foam contamination of the fuel, short extinguishing time, long burn back, low application rates, heat resistance and not requiring an aspirating device.
Understanding the difference between what national or international standard is being applied is also important, he said. Each standard mimics a specific real condition. Final users should select the right one based on their risk.
“When someone says, their foam is better, you have to ask under which standard and for what purpose,” Castro said.
UL-162 (foam equipment and liquid concentrates) is a widely recognized standard for testing firefighting foam concentrates. However, it varies from other international standards in that, as well as using fire performance standard test methods, the product is checked at every stage from manufacturing to final use (proportioning, packing compatibility, etc.).
Under UL-162, the application density for FFF (fluorine-free foam) is 0.06 (gpm/ft2). In the case of AFFF (film forming agents) application rate is 0.04 (gpm/ft2) for the same test. “You may have two products that are both UL listed but the conditions for using them are not the same” he said.
In a six-month study conducted by Auxquimia, five AFFF foam products were tested against five fluorine free foams. The results were presented at the SAA-IAFPA FireFighting Foam Seminar in Singapore. These results were based on an average rather than a single test result.
Results varied based on the fuel used for testing, Castro said. For example, using heptane, an international standard fuel in foam testing, Auxquimia found that fluorine free foam took nearly six percent longer to control a fire.
“When we used Diesel, AFFF was six percent quicker” Castro said. “But when we went to gasoline and kerosene the differences were as much as 50 or 60 percent.”
People often call Auxquimia asking for a quote on firefighting foam, yet they are not able to give the specifics needed to determine which foam is best for their situation. It is important to have a proper specification for the foam needed.
“Foam is a product that sits in tanks for a long time unchecked,” Castro said. “Many of the final users are not able to see if the foam really works or not.”
Fortunately, it may never be used, he said. “But if it does not work the day it is needed there will be a lot of responsibility involved,” Castro said.