Minimum clearances to combustible floor in front of fireplace.
Minimum hearth dimensions of fireplace.

VFSV-18C Model Gas Log Minimum Clearance Requirements

Careful selection of a gas log appliance must include attention to the clearances that are available in your specific installation. Review these minimum requirements as listed in the installation instructions provided with these gas logs.

Minimum mantel height requirement for indicated projection. Note heat resistant material ( not wood )
Minimum  required clearance to adjacent wall and ceiling.