R1001.6

Section R1001.6 is titled 'Firebox dimensions' and covers requirements for masonry fireplaces. The minimum firebox depth, height of the throat above the opening, throat depth, and cross-sectional area of the passageway for elements above the firebox leading to the flue is established. The purpose of this section is to prevent the building from catching fire and smoke from entering the interior of the building. This section has an exception which allows for alternative dimensions. The purpose of this exception is to allow for a design which is historically known to function in a safe and effective manner.

The model shows an exploded partial section of a masonry fireplace and chimney, with the minimum dimensions notated, and a translucent overlay at the throat, damper opening, top of the smoke chamber, and near the top of the flue section, which represents the required minimum cross-sectional area of the flue.