Foam fire extinguishing agents will be widely applied in urban fire protection in the future. Covering flammable liquid surfaces with foam of certain thickness stops flammable vapor from spreading to fire zones. It isolates liquid surfaces from air and blocks heat transfer to combustibles. Foam breaks down rapidly under high temperature due to thermal expansion, so it cannot work in high-heat environments. Below are the functions and classification methods shared by foam agent manufacturers.

Classification Methods of Foam Fire Extinguishing Agents
1. By mixing ratio
Classified into 3% type, 6% type and other specifications based on the proportion of foam concentrate and water.

2. By foam expansion ratio
Divided into low-expansion, medium-expansion and high-expansion foam agents.

3. By application property
Categorized into Class A and Class B foam fire extinguishing agents according to service purposes and characteristics.

4. By base material
Separated into protein-based foam agents and synthetic foam agents.

Foam is a cluster of membranous bubbles mechanically mixed by foam concentrate, water and air. Its relative density ranges from 0.11 to 0.16, with air as internal gas. The foam liquid is hydrolyzed from animal and plant protein substances.

Functions of Foam Fire Extinguishing Agents
Fire Extinguishing Principle
Mass carbon dioxide and foam are ejected to adhere to combustibles and cut off air contact, thereby putting out fires.

Foam extinguishers are divided into portable type, trolley type and air foam type. They shall be stored in dry, cool and well-ventilated areas, away from high temperature and direct exposure to avoid deterioration. Anti-freezing measures are required in winter to prevent freezing. Regular dust cleaning and nozzle dredging are necessary to keep smooth discharge.

Water-based fire extinguishing agents take water as the basic solvent, including enhanced water agent, wet water agent and colloidal agent. Common water has limited fire suppression efficiency and easily causes water damage. Water-based agents feature eco-friendliness and reliable fire fighting capacity, possessing both cooling and chemical inhibition effects. They can be filled into portable and wheeled extinguishers to put out initial Class A solid fires, Class B liquid fires and ordinary Class E electrical fires.

Foam fire extinguishing agents consist of thickener, stabilizer, flame retardant and foaming agent. When sprayed onto burning surfaces, water foam cools combustibles and forms a sealed water film and foam layer. Liquid evaporation absorbs heat and reduces oxygen concentration to smother fires. Meanwhile, chemical reactions produce polymers that restrain free radicals and break combustion chain reactions.

Mixing 3% to 6% foam concentrate with water can greatly boost fire suppression efficiency. It can extinguish solid fires of wood, paper and fabric, as well as liquid fires such as gasoline. Equipped with fine mist nozzles, it is also applicable to electrical fires. This product is suitable for factories, hotels, cinemas, entertainment venues, schools, hospitals and commercial buildings.