HOT TANKS
In order to have a fire you must complete the fire triangle. You must have an ignition source + fuel + O2. If we eliminate any one of the three, there cannot be a fire.
You were given a homework assignment to draw a set of tanks which we will monitor for combustibles and O2. How do we acheive this? You only needed to make a crude drawing. Here is my crude drawing and the actual drawing and some actual pics.