R304.3

Section R304.3 is titled 'Height effect on room area' and covers the requirements for the determination of habitable room area in correlation to the ceiling height. The allowed contributing habitable room area where ceilings are sloped or furred is established. The purpose of this section is to provide for general health and well being, as well as to provide space for smoke to dissipate in the event of a fire, which allows occupants time to escape before being overcome by smoke.

The model shows a section view of 2 rooms - one with a sloped ceiling, the other with a furred ceiling. The floors of each room are highlighted to show the areas that are and are not allowed to be included in the habitable room area calculation, which is less than 5' with a sloped ceiling and less than 7' with a furred ceiling.