From what I can tell after my read-through of the rules, items no longer have HP. In lieu of HP, taking damage over their hardness will cause them to gain a dent, and taking more than twice their hardness in damage causes them to instead gain two dents. For most items, this causes them to be "broken" meaning that, with the exception of armor, they stop providing any benefits until repaired. If a broken item gains any additional dents, it is instead destroyed.