Oh, I thought we had already talked about this here: Constant fear of transmitting the virus - #11 by ThomasTu. In the same paper they show the virus is fairly stable at 4 degrees for 6 months and then degrades (100-fold decrease in infection after 9 months). This is probably one of the best case scenarios for Hep B survivability.
To my knowledge, there has not been any similar experiment for room temperature surface survivability with such long periods.
Thomas