What action should be taken if a pressurized vessel containing flammable gas is exposed to flames?

• A. Apply a solid stream of water
• B. Apply a fog pattern of water
• C. Use dry chemical powder
• D. Immediately ventilate and evacuate the area

Answer: (A)

Cooling a heated pressurized vessel is the priority when flammable gas is involved in a fire. The heat from the flames can raise the metal to its failure point and cause the vessel to rupture or explode. Applying a solid stream of water delivers a focused, high-energy cooling effect to the vessel’s surface, absorbing heat efficiently and slowing or stopping the pressure increase inside. This cooling helps maintain the vessel’s integrity long enough to control the fire and protect responders.

A solid stream is preferred over a fog pattern because it concentrates cooling on the vessel; a fog disperses water, reduces cooling efficiency, and creates more steam, which can hinder heat transfer and visibility. Dry chemical powder is not effective for cooling a hot, pressurized vessel and is not the right tool for this scenario. While evacuation and area ventilation are important safety measures, they do not address the immediate risk of vessel rupture due to heat, which is why cooling with a solid stream is the best immediate action.