What shape is used in the traditional Class D extinguisher symbol?

What shape is used in the traditional Class D extinguisher symbol?

• A. Triangle
• B. Circle
• C. Square
• D. Star

Answer: (D)

Symbol shapes in traditional extinguisher signs are used to identify the fire class at a glance. For metal fires, the symbol is a star, which sets it apart from other classes. This quick cue matters because metal fires require a specific extinguishing approach—typically mineral-based dry powder that can smother the metal and interrupt the reaction. Water, CO2, or ordinary powders can be unsafe or ineffective on metal fires, so recognizing the star design helps ensure the right method is used. Other classes use different shapes (triangle, circle, square), so the star is unique to metal fires.