Any nonconforming use, building or structure which shall sustain partial destruction by any means or cause may be restored or repaired to its condition prior to the destruction. For the purpose of determining what constitutes partial destruction 50% of replacement value of the affected improvement may be used as a nonbinding guideline subject to the facts of each case. Any decision of the zoning officer denying the permits required to restore or repair a partially destroyed nonconforming use, building or structure may be reviewed by the planning board pursuant to an application for a variance under either N.J.S.A. 40:55D-70(c) or (d) as appropriate.