PM-503.1 Bathrooms and toilet rooms: Every bathroom and toilet room shall be equipped with natural or mechanical ventilation in accordance with Sections PM-503.1.1 or PM-503.1.2.

PM-503.1.1 Natural ventilation: Natural ventilation shall be provided by openable area equal to or greater than 4 percent of the bathroom or toilet room served.
PM-503.1.2 Mechanical ventilation: Air exhausted by a mechanical ventilation system from all bathrooms or toilet rooms shall comply with the mechanical code or shall provide a minimum of 6 air changes per hour to the space and shall be exhausted to the exterior without recirculation to any space, or not more than 85 percent of the exhaust air shall be recirculated where the system is provided with effective absorption and filtering equipment.

PM-503.2 Process Ventilation: Where injurious, toxic, irritating or noxious fumes, gases, dusts or mists are generated, a local exhaust ventilation system shall be provided to remove the contaminating agent at the source. Air shall be exhausted to the exterior in accordance with The Philadelphia Code and not be recirculated to any space.