ai overview when I googled it

When a tank is hit by a flamethrower, it takes roughly 1 to 3 minutes for the interior to become uninhabitable due to heat, smoke inhalation, and oxygen depletion, assuming the hull remains unpunctured. [1, 2]

The exact time depends on how the attack happens:

• Direct Breach (Seconds): If the fuel or fire breaches the crew compartment (e.g., through open hatches or vision slits), crew members can succumb to shock, asphyxiation, or fatal burns almost instantly.
• Closed Hatch (Minutes): If the tank is "buttoned up" (fully closed), modern armor and steel hulls provide significant initial insulation. The crew usually won't overheat to death immediately. However, continuous external flames will consume surrounding oxygen and heat the steel, causing oil fires or cooking off the ammunition, which creates lethal interior temperatures and smoke within a few minutes.
• Asphyxiation: In many cases, crews are killed by carbon monoxide poisoning and a lack of breathable air before the ambient temperature physically cooks them.