We discovered a leak in a SF6 gas HV circuit breaker. Since we don't know when the leak occurred due to temperature changes I assume there is only air left in the tank. Here is my question. Suppose I have a tank with a fixed volume filled with air at the same pressure as the atmospheric pressure. When we add SF6 gas up to 0.2bar over pressure, what would then be the percentage of each gas (air and SF6) in the tank?