Firefighting foam has been critical in combating flammable liquid fires for decades. Among various types, aqueous film-forming foam (AFFF) has been widely used due to its effectiveness in extinguishing. However, per- and poly-fluoroalkyl substances (PFAS), particularly in fluorinated AFFF, have raised significant environmental and health concerns.
In response, there has been a growing demand for fluorine-free alternatives. But are we truly at a stage where these alternatives can replace AFFF without compromising fire suppression efficacy? Let’s delve into the current landscape of fluorine-free firefighting foams.
Contents
The Problem
PFAS are synthetic chemicals used in various applications due to their unique properties, including oil and water repellency and thermal stability. However, their persistence in the environment and potential health risks have led to increasing regulatory scrutiny and public concern.
AFFF containing PFAS has been a major source of environmental contamination, particularly in areas surrounding military bases, airports, and industrial facilities. An ACS Publications study found three major sources of PFAS, one of them being AFFF discharge sites. Most of these were military or major airport sites where PFAS-based aqueous film-forming foam was used to suppress inferno.
Besides environmental contamination, AFFF is also associated with numerous health hazards, including cancers, reproductive issues, developmental problems, etc. According to TruLaw, AFFF exposure can cause bladder, breast, testicular, colon, kidney, and many other forms of cancers. It can also negatively impact cholesterol levels, liver enzymes, and vaccine response.
Due to these health concerns, many exposed individuals have filed an AFFF lawsuit. They have now been consolidated into multidistrict litigation (MDL), with over 8,061 cases pending as of May 2024. These lawsuits allege that aqueous film-forming foam manufacturers should have known and informed consumers about potential hazards. Moreover, the military is scrutinized for carelessly disposing of AFFF in water bodies.
The Quest for Fluorine-Free Alternatives
The search for fluorine-free alternatives to aqueous film-forming foam has been ongoing for years. This quest is driven by the need to address environmental and health concerns while maintaining effective firefighting capabilities.
Several approaches have been explored in this quest, including developing foam formulations based on alternative surfactants, natural polymers, and innovative technologies.
Alternative Surfactants
One approach to developing fluorine-free firefighting foams involves replacing PFAS-based surfactants with alternative compounds with similar fire-suppression properties. Researchers have investigated various classes of surfactants, such as fluorine-free fluorosurfactants (F3), hydrocarbon-based surfactants, and bio-based surfactants derived from renewable sources.
While some of these alternatives have shown promising results in tests, research is needed to assess their performance in the real world. However, the good thing is that their effectiveness is increasing with advancements and passing time. A Springer Journal study mentions that the performance of F3 has significantly increased over the past two decades.
Natural Polymers
Another avenue of research involves leveraging natural polymers, such as proteins and polysaccharides, to create environmentally friendly firefighting foams. These polymers can form stable foams with good fire suppression capabilities and are biodegradable, reducing the risk of long-term environmental contamination.
However, challenges remain in optimizing the foam formulation to achieve the desired balance of performance, stability, and cost-effectiveness. A ScienceDirect study analyzed the performance of AFFF and protein foams (PF). It found that AFFF had a higher expansion ratio than PF, meaning it could spread quickly to suppress larger fire areas. Moreover, it concluded that aqueous film-forming foam could easily form a more dense, stable, and widespread suppressing blanket than PF.
Innovative Technologies
Advances in materials science and nanotechnology have opened up new possibilities for developing fluorine-free firefighting foams with enhanced properties. For example, researchers have explored using nanostructured materials, such as graphene and clay nanoparticles, to improve foam stability and fire suppression efficiency.
Additionally, the incorporation of smart additives, such as heat-activated polymers, holds promise for enhancing the performance and durability of fluorine-free foams.
Challenges and Considerations
Significant progress has been made in developing fluorine-free alternatives to aqueous film-forming foam. However, several challenges and considerations must be addressed before widespread adoption can occur. These include:
- Performance: Fluorine-free foams must demonstrate comparable or superior fire suppression efficacy to AFFF, particularly in high-risk scenarios involving flammable liquids. According to a US Fire Administration article, the Department of Defense (DoD) has recently issued a new performance specification for firefighting foams. The specification mentions the performance expectations of alternative options. It states that the foams must effectively suppress class B hydrocarbon fires without containing PFAS.
- Stability: Foams must keep their integrity and efficacy over time, resisting deterioration caused by temperature changes, UV radiation exposure, and mechanical agitation.
- Compatibility: Fluorine-free foams must be compatible with current firefighting equipment and infrastructure, such as fire trucks, pumps, and storage systems. This will help provide a smooth transition from aqueous film-forming foam into firefighting operations.
- Cost: Fluorine-free firefighting foams must be competitive with AFFF to be affordable to fire departments and industrial establishments. This is especially true given the probable requirement for equipment modification and personnel retraining.
- Environmental impact: Fluorine-free alternatives have the advantage of lowering PFAS pollution. However, their environmental impact must be carefully assessed to ensure they do not bring new ecological concerns or negative impacts.
Frequently Asked Questions
Are Fluorine-Free Firefighting Foams as Effective as AFFF?
Fluorine-free firefighting foams are less effective than their aqueous film-forming foam counterparts. However, even though they are not as effective, they can successfully fight fires. Like AFFF, these foams use alternate chemical components to suppress flames by forming a barrier between the fuel and oxygen.
Are Fluorine-Free Foams Environmentally Friendly?
In terms of environmental effects, fluorine-free foams are typically regarded as more environmentally benign than aqueous film-forming foam. AFFF contains fluorinated chemicals known as PFAS, which have prompted concerns about their environmental persistence and potential health effects. On the other hand, fluorine-free foams are often made from biodegradable and less persistent materials.
Are Fluorine-Free Foams Compatible With Existing Firefighting Equipment?
When migrating to fluorine-free foams, it is critical to consider compatibility with existing firefighting equipment. While certain changes may be required to achieve peak performance, many fluorine-free formulas are intended to work with typical firefighting equipment. Firefighting organizations and equipment manufacturers must work closely to address any compatibility difficulties.
Are Fluorine-Free Foams More Expensive Than AFFF?
When comparing fluorine-free foams to AFFF, the cost might be an important consideration. Fluorine-free foams may have a higher initial cost due to R&D efforts and the usage of alternative constituents. However, the cost differential may narrow when demand rises and manufacturing expands.
To conclude, fluorine-free alternatives to AFFF are promising to address the environmental and health concerns associated with PFAS contamination. While significant progress has been made in developing alternative foam formulations, further research is needed to validate their performance and suitability. By overcoming the challenges, we can pave the way for a safer and more sustainable future in firefighting foam technology.
