What does a solid green triangle signify?

A solid green triangle on a fire extinguisher indicates that it is a Class A extinguisher. Class A extinguishers are specifically designed to combat fires involving ordinary combustible materials such as wood, paper, cloth, and some types of plastics. The use of the triangle design, particularly its solid green color, is part of a color-coding system which helps firefighters and the general public quickly identify the suitable extinguishing agent for particular fire classes. This color-coding facilitates quick and effective responses in emergency situations, making it critical for safety in firefighting operations. Other classifications, such as Class B, C, and D, use different symbols and colors to indicate their specific firefighting capabilities and target materials.