The maximum acceptable surface temperatures for electrically operated toys shall be as follows: ------------------------------------------------------------------------
Thermal Temperatures
Surface type (as described--in Sec. inertia ---------------------
1505.6 (g)(2)) type \1\ [deg]C. [deg]F.------------------------------------------------------------------------A...................................... 1 50 122A...................................... 2 55 131A...................................... 3 60 140B...................................... 1 55 131B...................................... 2 65 149B...................................... 3 75 167C (unmarked)........................... 1 65 149C (unmarked)........................... 2 75 167C (unmarked)........................... 3 85 185C (unmarked)........................... 4 95 203C marked............................... 1 70 158C marked............................... 2 90 194C marked............................... 3 110 230C marked............................... 4 130 266D (unmarked)........................... 1 55 131D (unmarked)........................... 2 70 158D (unmarked)........................... 3 80 176D (unmarked)........................... 4 90 194D marked............................... 1 60 140D marked............................... 2 75 167D marked............................... 3 100 212D marked............................... 4 125 257E...................................... (\2\) (\3\) (\3\)------------------------------------------------------------------------\1\ Thermal inertia types are defined in terms of lambda as follows:Type 1: Greater than 0.0045 (e.g., most metals).Type 2: More than 0.0005 but not more than 0.0045 (e.g., glass).Type 3: More than 0.0001 but not more than 0.0005 (e.g., most plastics).Type 4: 0.0001 or less (e.g., future polymeric materials).
The thermal inertia of a material can be obtained by multiplying the
thermal conductivity (cal./cm./sec./degrees C.) by the density (gm./
cm.\3\) by the specific heat (cal./gm./degrees C.).\2\ All types.\3\ No limit.