A thermoresponsive gel extinguishes fires by transforming from a thin, water-based liquid into a thick, adhesive gel when it contacts heat. This phase change keeps the cooling agent precisely where it is needed most, locked onto the burning surface rather than running off. The result is faster heat extraction, flame suppression, and a significantly reduced risk of re-ignition compared with water alone. The sections below unpack the chemistry behind this process, its specific advantages against lithium-ion battery fires, and its practical compatibility with existing fire suppression infrastructure.
How does temperature trigger the gel-forming reaction?
When a thermoresponsive gel contacts a hot surface, rising temperature causes the suspended particles within the fluid to cross-link and swell, converting the low-viscosity liquid into a dense, viscous gel. This phase transition is automatic and requires no activator other than heat itself. The higher the surface temperature, the more rapidly and completely the gel structure forms.
In Anogas Hydrogel, the thermoresponsive behaviour is driven by modified natural clay particles dispersed in water. At ambient temperature, the mixture flows freely and can be pumped, sprayed, or discharged through standard nozzle configurations. When the fluid reaches a hot fire source, the clay particles respond to the thermal gradient by thickening the surrounding water matrix. The gel does not simply coat the surface, according to Anogas, it can also expand during application, improving contact with irregular or porous surfaces and increasing the total area over which heat is extracted.
This self-regulating mechanism is one of the key reasons thermoresponsive gel outperforms plain water in sustained cooling applications. Water runs off a hot surface almost immediately, carrying heat away in a single brief exchange. The gel, by contrast, remains in place and continues drawing heat out of the material beneath it for as long as the thermal gradient persists.
Why does gel cling to surfaces better than water?
Thermoresponsive gel adheres to hot surfaces more effectively than water because its increased viscosity under heat creates physical resistance to runoff. Where water flows away within seconds of contact, the gel matrix grips vertical surfaces, curved structures, and internal cavities, maintaining a persistent cooling layer that water simply cannot sustain.
The clay component in Hydrogel plays a dual role here. It provides the structural backbone that gives the gel its adhesive properties, and it acts as a natural barrier that limits oxygen access to the burning material beneath. This oxygen restriction contributes to flame suppression independently of the cooling effect, meaning the gel is working through two mechanisms simultaneously.
The practical consequence for fire suppression is significant: because the gel stays in place, less extinguishing agent is needed to achieve the same cooling outcome. Runoff is reduced, which lowers the volume of contaminated liquid that must be managed after a fire incident. For industrial operators and building managers, this translates directly into lower clean-up costs and reduced environmental impact from discharge.
How does thermoresponsive gel suppress lithium-ion battery fires?
Thermoresponsive gel suppresses lithium-ion battery fires through four simultaneous mechanisms: rapid and sustained cooling, physical isolation of heat, neutralisation of hazardous gases, and chemical stabilisation of reactive lithium components. No single conventional extinguishing agent addresses all four of these challenges at once, which is why lithium-ion battery fires have proven so resistant to standard suppression approaches.
Understanding why these fires are so difficult to control requires a brief look at thermal runaway. When a lithium-ion cell overheats, through mechanical damage, overcharging, or manufacturing defect, it enters a self-reinforcing cycle in which rising temperature accelerates chemical reactions that generate more heat. Adjacent cells can be drawn into the same cycle, causing the fire to spread through an entire battery pack even after visible flames appear to be extinguished. The thermal runaway blocker function of Hydrogel is specifically designed to interrupt this chain reaction.
Cooling and physical containment
Hydrogel’s high water content absorbs heat rapidly, lowering battery surface temperature within seconds of application. The gel then adheres to the battery casing and, where possible, penetrates internal structures to deliver localised cooling directly to affected cells. The resulting thermal barrier limits heat transfer to adjacent cells, slowing or stopping propagation through the battery pack.
Gas neutralisation and chemical stabilisation
Lithium-ion battery fires release hazardous gases including hydrogen fluoride, flammable hydrocarbons, and methane. Hydrogel reduces the concentration of these flammable gases, restricts oxygen availability, and, according to Anogas, interacts with hydrogen fluoride to convert it into less harmful ionic components. Separately, modified clay particles within the gel are described as penetrating damaged battery structures and binding reactive lithium ions, reducing the chemical reactivity that drives re-ignition long after visible flames have been suppressed. A full breakdown of how Hydrogel works at the molecular level is available from Anogas directly.
It is important to note that while Hydrogel reduces hazardous gas exposure, it does not eliminate it entirely. Operators should maintain a safe distance and use appropriate respiratory protection throughout any intervention involving lithium-ion battery fires.
What fire classes can a thermoresponsive gel extinguish?
Hydrogel is rated for Class A, Class B, and Class F fires, covering solid combustibles, flammable liquids, and cooking oils and fats respectively. This broad fire-class coverage makes it a versatile suppression agent across residential, commercial, and industrial environments, not a specialist tool limited to a single fire type.
Class A coverage includes wood, paper, textiles, and plastics, the most common fire type in buildings and warehouses. Class B coverage extends to flammable and combustible liquids, which are relevant in industrial and maritime settings. Class F coverage addresses high-temperature cooking-fat fires, which conventional water extinguishers can dangerously worsen by causing violent steam explosions.
Beyond these standard classifications, Hydrogel is specifically formulated to address lithium-ion battery fires, which do not fit neatly into traditional fire-class definitions. As electric vehicles, e-bikes, energy storage systems, and consumer electronics become more prevalent across every sector, the ability to handle battery fire incidents with the same agent used for conventional fires represents a meaningful operational simplification for distributors and end users alike. Handheld extinguishers using Hydrogel are available for exactly this multi-risk scenario.
Is thermoresponsive gel safe for people and the environment?
Hydrogel is classified as non-dangerous to humans and the environment under the most stringent European chemical legislation. It contains zero PFAS, independent measurement confirms less than 1 part per billion, and is composed of more than 99% naturally derived components: modified natural clay and water. Aquatic toxicity studies conducted according to OECD guidelines confirmed non-toxic status for both algae and daphnia.
The PFAS-free status is particularly important in 2026, as regulatory pressure on fluorinated extinguishing agents continues to intensify across European and North American markets. Many legacy fire suppression agents, including certain foams and dry powders, contain per- and polyfluoroalkyl substances that persist in soil and water systems. Hydrogel contains none of these compounds, making it compliant with current and anticipated future environmental regulations.
From a lifecycle perspective, Hydrogel has a service life of more than ten years. When replacement is eventually required, the material can be discharged without special disposal procedures because it is ECO-safe. After its service life, Hydrogel is expected to be recyclable into a compost-enrichment supplement, a genuinely circular end-of-life outcome that no conventional extinguishing agent currently matches. The carbon footprint of the product is less than 0.7%, reflecting the low-energy, naturally derived manufacturing process.
For people applying the agent during a fire incident, Hydrogel itself presents no chemical hazard. The risks during a lithium-ion battery fire intervention come from the fire itself and the gases the battery releases, not from the suppression agent.
Can thermoresponsive gel replace water in existing fire suppression systems?
Yes. Hydrogel is fully interchangeable with water and can be used in all water-based fire suppression systems without modification to pipework, nozzles, or pumping equipment. This compatibility removes the most common barrier to adopting a new suppression agent: the cost and complexity of replacing existing infrastructure.
Despite being more than 95% water by composition, Hydrogel can be safely deployed on energised electrical equipment up to 1,000 V when used with suitable nozzle configurations. This electrical safety rating extends its applicability to data centres, EV charging infrastructure, industrial control panels, and other environments where conventional water discharge would create an electrocution risk.
The interchangeability also means that facilities already operating sprinkler systems, deluge systems, or other fixed suppression installations can integrate Hydrogel without engineering a new system from scratch. For distributors advising clients on upgrades, this is a commercially significant advantage: the conversation shifts from infrastructure replacement to agent substitution, which is a far simpler procurement decision. Details on compatible fire suppression systems and integration options are available for operators and specifiers evaluating the transition.
Because the gel adheres to surfaces longer than water, the total volume of agent required to achieve effective suppression is lower. This reduces both the cost per incident and the volume of contaminated runoff that must be managed afterward, two outcomes that matter equally to environmental compliance officers and site managers responsible for post-incident clean-up.
