Infinite Burn Tag?

Hi all, I'm probably missing something simple here, but I just want to make a block type that can support fire infinitely like netherrack, but just in one dimension. 
I have the path currently of minecraft/tags/block/infiniburn_dimname.json but this does not work. I wanted to know if there's a step in the process that I may be missing.
The code below is for both blocks that I tested, and both fail.
  "replace": false,
  "values": [
    "red_sand",
    "obsidian"
  ]
}```