John,
Assuming IBC (not IRC) and 5B for VN, a reduction is permitted with an NFPA 13 (not 13R)
708.3 Fire-resistance rating. Fire partitions shall have a fire resistance rating of not less than 1 hour.
Exceptions:
1. Corridor walls permitted to have a 1/2 hour fire-resistance rating by Table 1018.1.
2. Dwelling unit and sleeping unit separations in buildings of Type IIB, IIIB and VB construction shall have fire-resistance ratings of not less than 1/2 hour in buildings equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1. (NFPA 13)
711.3 Fire-resistance rating.
Exception: Dwelling unit and sleeping unit separations in buildings of Type IIB, IIIB and VB construction shall have fire-resistance ratings of not less than 1/2 hour in buildings equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1.