All rooms in which food is prepared or served or utensils are washed, dressing or locker rooms, toilet rooms and garbage and rubbish storage areas shall be well ventilated. Ventilation hoods and devices shall be designed to prevent grease or condensate from dripping into food or onto food preparation surfaces. Filters, where used, shall be readily removable for cleaning or replacement. Ventilation systems shall comply with applicable state and local fire prevention requirements and shall, when vented to the outside air, discharge in such manner as not to create a nuisance. (1961 code § 6.06.160.)