Inferno Orange vs Fire Flame

How close are they?

ΔE 17.1, loose: different enough that you should pick on purpose. Fire Flame is more saturated, cooler than Inferno Orange.

Can I use Fire Flame instead of Inferno Orange?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 17). Fire Flame is more saturated, cooler than Inferno Orange.

Can I use Inferno Orange instead of Fire Flame?

The same difference applies the other way round: Inferno Orange is more muted, 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.