ΔE 11.6, fair: the same colour family, but not a straight swap. Grunge Brown is noticeably lighter than Red Brick.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 12). Grunge Brown is noticeably lighter than Red Brick.
The same difference applies the other way round: Red Brick is noticeably darker.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Red Brick on the colour wheel See Grunge Brown on the colour wheel
All matches: Red Brick equivalents · Grunge Brown equivalents