I saw this on a sign in an office-building stairwell.

Problem:
A hyphen is missing.

Explanation:
When a noun plus a noun modify a third noun, the first and second nouns must be joined with a hyphen to form the modifier of the third noun.

So the first noun “FIRE” plus the second noun “FIGHTING” must be joined with a hyphen to form the modifier of the third noun “EQUIPMENT”.

Unfortunately, many sign makers drop hyphens because they believe that hyphens are unnecessary or make signs less attractive.

Although this isn’t the best example, there are many examples where the absence of a required hyphen leads to confusion and double- or triple-pass reading of a sign to understand what the sign writer meant.

Solution:
“FIRE-FIGHTING EQUIPMENT”