13-200-390 Existing mechanical ventilation supply, return and exhaust systems.

   Existing systems which are in compliance with codes in force at the time the building was built or altered may remain:

   (a)   If room sizes are increased or the use of a room is changed, the altered area shall be provided with ventilation, in accordance with the requirements of Chapter 18-28.

   (b)   If existing mechanical systems are altered, those altered systems shall comply with the requirements of Chapter 18-28.

   (c)   Mechanical ventilation shall not be permitted as the sole means of ventilation in any habitable space in a residential occupancy, except as provided in Chapter 18-28. Natural light and ventilation shall be provided in accordance with the code in force when the building was built or altered.

(Prior code § 78.1-38; Amend Coun. J. 11-9-16, p. 36266, § 27)