Formula for glassing a planet

[tbontob]

In one of the threads, a formula was given as to the amount of damage a planet must sustain in order to be "killed"

Also there is a formula which gives the probability of a facility being destroyed as a function of population size.

I have researched the data base but cannot seem to find these formulas.

Does anyone know where they are? Or in the alternative, tell me what they are.