Area to height
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What type size means here
The regulation defines it as "the actual height of the printed image of each upper case or capital letter as it appears on the label". A measured result, not a nominal font size.
Which is why this property gives no point sizes
A point size and a cap height are different measurements and the relationship varies with the typeface. Converting would introduce a rounding we have no business making.
The signal word, by panel area
3/64 inch for 0 to 2 square inches, 1/16 for over 2 to 5, 3/32 for over 5 to 10, 7/64 for over 10 to 15, 1/8 for over 15 to 30, and 5/32 for over 30.
The statement of hazard, by the same panel area
3/64 inch up to 5 square inches, 1/16 for over 5 to 10, 3/32 for over 10 to 30, and 7/64 for over 30.
So the signal word is always at least as large
And usually larger. The word that says how serious this is outranks the sentence that says what it is, which is a deliberate hierarchy.
The bands are absolute, not proportional
A panel of 31 square inches and one of 300 are in the same band. The table sets a floor by size class rather than scaling continuously.
Which produces step changes at the boundaries
A panel just over 5 square inches needs a larger signal word than one just under. Designing a label close to a boundary is designing close to a step.
And the small end is not generous
3/64 of an inch is small, and a tiny panel still has to carry a signal word, a statement of hazard and everything else the Act requires. A very small bottle is a hard label.
Which is the same shape as problems elsewhere in this library
The hair care property has a Drug Facts panel that triggers on occupying 60 percent of available label space, and the miniature painting property has a statute that refuses to shrink a label for a 30 mL bottle.
The order to work in
Decide the classification, typeset the required text at the height the table demands, measure it, then choose the container. Not the reverse.