The issue with the flash point

1-3 are all related; 3 is possible. Reference.

It’s all related; it has nothing to do with temperature. The flash point measured in areas with low air pressure is low. But I don’t think the closed-cup flash point has much impact

Is flash ignition caused by the gas concentration reaching a certain level or by temperature?

The flash point is the lowest temperature at which a flash fire can occur on the surface of a liquid under specified test conditions. The flash point depends on the density of the flammable liquid, the air pressure at the liquid surface, as well as whether light components are present in the flammable liquid and their concentration ； The flash point also changes with its concentration ； The flash point is related to the molecular composition of the substance and the pressure at its surface; higher pressure results in a higher flash point. Based on the above principles, it can be seen that: 1. Is the flash point temperature related to the volatility of the liquid? Yes. 2. Is the evaporation of liquids related to air pressure and temperature? Yes. 3. Do the temperature and pressure of the liquid have a significant impact on the flash point? It has an impact. 4. Are there any liquids with a flash point between 61 and 70 whose flash point drops below 60 under high-temperature, low-pressure conditions (in the Xinjiang region in the northwest)? Yes. 5. Is flash ignition caused by a certain gas concentration or by temperature? The lowest temperature at which a mixture of gases evaporated from the surface of a flammable liquid and air can sustain continuous combustion (for a duration of at least 5 seconds) when exposed to an open flame is called the ignition point. The ignition point is higher than the flash point.

When the gas concentration reaches a certain level, it burns when exposed to fire. Spontaneous combustion requires a certain temperature to be reached