ΔE 12.2, fair: the same colour family, but not a straight swap. Fire Red is more muted, cooler than Intense Brown.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 12). Fire Red is more muted, cooler than Intense Brown.
The same difference applies the other way round: Intense Brown is more saturated, warmer.
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 Intense Brown on the colour wheel See Fire Red on the colour wheel
All matches: Intense Brown equivalents · Fire Red equivalents