What indicates that a propane cylinder may need cooling during a fire?

A propane cylinder may require cooling during a fire primarily if there are any signs of damage present. When a propane cylinder is damaged, it can be at risk of rupturing or leaking gas due to the increased pressures and temperatures associated with fire conditions. This situation can lead to a catastrophic failure, potentially resulting in an explosion or a large fireball. Therefore, identifying physical signs of damage—such as dents, rust, or leaks—indicates that the cylinder may need immediate cooling to prevent these dangerous outcomes.

Other factors, such as proximity to a water source, the absence of visible fire, or whether the cylinder is under pressure, do not directly indicate a need for cooling in the same critical way. While being near a water source may aid in cooling efforts, it does not inherently signal the need for such action. The absence of visible fire may lead to a misconception that no action is necessary, and while a pressurized cylinder can present risks, it doesn't equate to an immediate cooling need unless there's visible damage. Therefore, the presence of damage is the most critical indicator for taking immediate action to cool the cylinder.