R303.3

Section R303.3 is titled 'Bathrooms' and covers the requirements for providing light and ventilation in bathrooms, water closet compartments, and similar areas. The type of rooms and the required area of glazed and openable elements is established. The purpose of this section is to assure bathrooms, water closet compartments, and similar rooms get adequate light and ventilation for the health and comfort of the occupants. This section has an exception which allows for artificial light and mechanical ventilation in lieu of natural light and ventilation. A cross-reference to another section of this code for the amount of required mechanical ventilation and the location of exhaust termination is established. The purpose of this exception is to allow for practical design considerations and to allow for such rooms that are not enclosed by an exterior wall.

The model shows a powder room with a window to the exterior. An overlay shows the area which must meet or exceed 3 sq.ft, and the window opens to show that half of this area is openable. The model also converts to having no window, but instead is provided with an exhaust fan and electric lighting. The exhaust duct changes to show a compliant duct terminating to the exterior, and then a non-compliant duct which terminates into the attic.