Helium has the lowest boiling point of the elements. The slightest change in temp can cause it to vaporize and expand. To prevent pressure explosions, a line from the tank has a "burst disk" in case a of sudden pressure increse. then the diaphragm would rupture and release the gas before pressure was too high. This is an example of which physics law? Charles? Boyle? Ideal? I think possibly Charles because as it warmed up due to the fire, the pressure expanded and it exploded. Temp increase, pressure increase. Does that make sense?

Charles law? Isn't that constant pressure?

I am uncertain which of the events you are looking for a "law". When you say "this is an example" I wonder what "this" refers to. The rupturing of the disk? That has nothing to do with gas laws.

Yes, it does make sense. The phenomenon you described, where a slight change in temperature causes helium gas to expand and potentially lead to a pressure explosion, can indeed be explained by the laws of physics. In this case, the most relevant law is Charles' Law.

Charles' Law, also known as the law of volumes, states that the volume of a gas is directly proportional to its absolute temperature when pressure is held constant. In simpler terms, as the temperature of a gas increases, its volume also increases, assuming the pressure remains the same.

In your example, when the temperature of the helium gas inside the tank increases due to the fire, according to Charles' Law, the volume of the gas will also increase. As the gas volume expands, the pressure inside the tank will rise. If the pressure continues to increase without any release mechanism, such as the burst disk you mentioned, it could potentially lead to an explosion.

Therefore, the burst disk serves as a safety measure in case of a sudden increase in pressure. It functions by allowing the diaphragm to rupture and release the gas before the pressure becomes too high, thus preventing a potentially dangerous or destructive situation.

In summary, the example you provided can be explained by Charles' Law, which describes the direct relationship between the temperature and volume of a gas when pressure is held constant.