I guess they can be flame resistant or flame retardant whatever..Thank You
Low-E reflective insulation paper? Al
Fire extinguishers are under high pressure. You have a canister that is at some higher pressure and you the atmosphere (surroundings) that are at a lower pressure (1atm). Let's say you have a gas at high pressure contained in certain volume. Then you decrease the pressure of the gas by exposing it to the open atmopshere; according to Boyle's law the volume of the gas will increase or the gas will expand. This still doesn't tell you why the gas gets colder. Thermodynamics tells us that at constant temperature when an ideal gas expands, the internal energy remains constant. In other words the heat that enters the gas is equal to the work that the gas does on the surroundings. The quantity of thermal energy flows into the gas as the expansion occurs, and the work is performed. Therefore, the surroundings furnished the energy (through heat flow) necessary to perform the work(Zumdahl 410). This may sound strange because heat entering the gas causes the gas to get colder. This is because it is absorbing heat. This is an endothermic process. Heat is leaving your hand when you touch the the flame retardant, so it feels colder. The gas is in fact colder.
