The combustible gas formed in an LTC may
gradually dissipate into the atmosphere if the LTC has a free or desiccant-type breathing system, or the gas
may accumulate and then occasionally vent into the atmosphere through a pressure relief valve in a sealed
tank system. Fortunately, in spite of the variability of gas accumulation even under normal conditions in
non-faulty equipment, it is possible to discern certain patterns which can be used to distinguish between
normal and faulty behavior in many cases.