Thanks for the link, kengar.
What strikes me is that the HPs assigned to an item is rather arbitrary. The numbers on table 8-12 (PHB p. 136) makes sense for barriers, but not objects.
For example, rope has hardness 0 and 2 hit points per inch thickness. Suppose I have a 1" thick rope. 2 points to cut through seems reasonable.
But wait... what if I apply 2 points of fire damage to a 50' coil of rope? Is the rope completely "destroyed"? Is it burned through in one place? Maybe it is slightly damaged in two places?
Consider, the example of the Cloak of Resistance in the above link. How do you determine that 4 points destroys the cloak? Maybe it makes a few holes that can be repaired?
I guess my point is that assuming that an object is the same as barrier you are attempting to breach seems inconsistent with the HP system.