R1001.5

Section R1001.5 is titled 'Firebox walls' and covers requirements for masonry fireplaces. The allowed type of material that fireboxes may be constructed with, the thickness of the material dependent on whether or not firebrick is used in the assembly, and where firebrick is used, mortar joint maximum thickness, firebrick standards, mortar type, and a mortar standard is established. The purpose of this section is to prevent the building from catching on fire.

The model shows a partial section of a masonry chimney and fireplace with the firebox highlighted.