To limit the probability that the continuity of the insulation will be broken, which could lead to excessive thermal transfer through the building envelope, which could lead to excessive use of energy for heating and cooling, which could lead to an unacceptable effect on the environment.
To limit the probability that the effective thermal resistance will be decreased at the projected area of major structural members that partly penetrate the building envelope, which could lead to excessive thermal transfer through the building envelope, which could lead to excessive use of energy for heating and cooling, which could lead to an unacceptable effect on the environment.