I have a question that is more theoretical in nature. I know that when you have 14/2 cable and put it in a 1/2 conduit you are above fill (or just at max fill). The NEC cites that this is in part due to heat dissipation.
300.17 Number and Size of Conductors in Raceway. The number and size of conductors in any raceway shall not be more than will permit dissipation of the heat and ready installation or withdrawal of the conductors without damage to the conductors or to their insulation.
Consider a close-celled foam installation:
The cables are usually entirely encased in the stud-bays (even less clearance than in 1/2 conduit), and while foam is a good insulator it is a bad heat-sink; it doesn't allow good heat-dissipation due to there being little to no air.
Since I've seen a few foam installations where the cable is completely covered there must not be a code regarding it, and I was just wondering why? Doesn't the foam pose an issue for heat dissipation?
Please when answering cite official sources if at all possible and don't rely on conjecture.
Additional section of interest:
(3) The rate at which generated heat dissipates into the ambient medium. Thermal insulation that covers or surrounds conductors affects the rate of heat dissipation. (4) Adjacent load-carrying conductors — adjacent conductors have the dual effect of raising the ambient temperature and impeding heat dissipation.