We are planning to put in a vinyl plank floor (didn't pick one yet) and also a fireplace in a new construction house in upstate New York. I was just perusing the installation instructions for a fireplace (we didn't decide on one yet) and I see statements that vinyl flooring gets hot, and that the hearth has to be extended, to double the size, of what it would be if floor was not vinyl. Can anyone comment please? Also, how much does this matter re the building code, home insurance, etc? TIA.

See copy/paste below, from the instructions:

Vinyl Flooring is sensitive to heat. A 48 inch minimum depth hearth extension is recommended when using vinyl flooring up to the wall. See Figure 8.8. Notice: Clearances that do not meet the minimum guidelines could result in damage or buckling to the vinyl flooring and is done at the installer’s risk. Hearth and Home Technologies does not recommend adhesive based vinyl flooring due to thermal expansion. Floating-style flooring can be used, but will reach temperatures up to 110°F in a room with ambient temperatures of 70°F. Consult flooring specifications to ensure compatibility.