Va. Code § 36-103
Any building or structure, for which a building permit has been issued or on which construction has commenced, or for which working drawings have been prepared in the year prior to the effective date of the Building Code, shall remain subject to the building regulations in effect at the time of such issuance or commencement of construction. However, the Board may adopt and promulgate as part of the Building Code, building regulations that facilitate the maintenance, rehabilitation, development and reuse of existing buildings at the least possible cost to ensure the protection of the public health, safety and welfare. Subsequent reconstruction, renovation, repair or demolition of such buildings or structures shall be subject to the pertinent construction and rehabilitation provisions of the Building Code. The provisions of this section shall be applicable to equipment. However, building owners may elect to install partial or full fire alarms or other safety equipment that was not required by the Building Code in effect at the time a building was constructed without meeting current Building Code requirements, provided the installation does not create a hazardous condition. Permits for installation shall be obtained in accordance with the Uniform Statewide Building Code.
Va. Code § 36-103