Point of no return. I have been a volunteer fire fighter for many years. When I was in training my instructor told us about the point of no return. Sounds very scary and it is very scary. I will give you an example. Think of a large building in your community or an industrial complex with many people working inside. The air bottles that some have are pressurized to 2250 psi and called thirty minute bottles. When filling these bottle air is compressed and if the rate of flow is too fast the air heats up rapidly. When the air cools you lose pressure and what you thought being a full capacity bottle has now been decrease to say 92 percent. So now think of less than 30 minutes. Now take a large fire. You are toned out to an industrial complex with heavy fire. Wouldn’t your heart start beating faster and your breathing become greater. Yes, and you still haven’t even signed off at the fire. You are now in your bunker gear and air pack. Maybe 50 pounds of equipment and you drag a fire hose to the structure. The commanding officer tells you ok it is time to enter the structure. Go on air! he instructs you, and your now crawling on your hands and knee’s because the smoke and heat is tremendous. You have now been on air for 15 minutes and your are breathing very fast trying to get a much air as possible because you are excited. Now think of the math here. You have crawled in the building and it has been 15 minutes. You haven’t even started working the fire or searching for occupants and the 30 minute bottle might last you 22 minutes because you didn’t have full capacity when you started. The low air alarm has just sounded which gives you 5 minutes to get out of the structure. It has taking 15 minutes to get into the structure. This is the point of no return. It is a very scary scenario and something I don’t ever want to put myself in . I hope any firefighters out there are listening to this story because it is a fact Jack, you better be prepared and do the math before you enter that building.