Martin VENT-FREE FIREPLACE SYSTEMS 33ISDG Installation And Operating Instructions Manual page 13

The gas log heater must be installed at least 5" above any combustible flooring material, such as carpeting or tile, which is
closer than 14" to the base of the fireplace. See Figure 10.
23D8036
Non-combustible
Material
Figure 10 - Minimum Clearance above Combustible Flooring
CLEARANCES and HEIGHT REQUIREMENTS
5"
1"
Combustible
Material
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