Heatilator NA36 Installation & Operating Instructions Manual page 20

NA SERIES INSTALLATION INSTRUCTIONS
18. Hearth Extension
A hearth extension must be installed with all fireplaces to protect the combustible floor in front of the fireplace from
both radiant heat and sparks.
The construction of, and materials used for a hearth extension are shown in Figures 17 and 18. A hearth extension of
this construction may be covered with any noncombustible decorative material and may have a maximum thickness
as per the illustration. Seal gaps between the hearth extension and the front of the fireplace with a bead of
noncombustible sealant.
Field constructed hearth extensions should be constructed in accordance with the instructions in Figure 18. The field
constructed hearth extension must be constructed from ½” MICORE CV230, or a material with an equivalent insulation
value.
WARNING!
20 17789 Rev H 07/03