Failure continued storage conditions

Storage chambers should be validated with respect to their ability to maintain the desired conditions, and, if so equipped, the ability to sound an alarm if a mechanical or electrical failure causes the temperature to deviate from preestabilished limits. They should also be equipped with recording devices, which will provide a continuous and permanent history of their operation. Logbooks should be maintained and frequent readings or mercury-in-glass, National Institute of Science and Technology traceable thermometers recorded. 

Let us consider a non-continuous processing system with n upstream and m downstream units (usually n m) with an intermediate storage. We assume that the processing units are operated periodically, and stochastic failures of the units under general conditions may occur. Furthermore, we suppose that the filling and removal rates may vary in time arbitrarily, i.e. they are described by general functions exhibiting at most finite number of jump discontinuities. 

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