Density of Smoke from the Burning or Decomposition of Plastics
This standard test method tests for the density of smoke produced by the burning
or decomposition of a plastic glazing.
For the 4-minute test, a square plastic glazing specimen (1”x1”x¼”) is exposed to
a flame and the smoke emitted is trapped within this testing unit. The size of the
testing unit is 12”x12”x31” and is sealed completely except for four 1” high vents.
Three specimens shall be used for testing.
Within the testing unit a meter measures a horizontal light beam affected by the
smoke caused from the burning glazing. After the three specimens have been tested
the average readings, taken every 15 seconds, are plotted in a similar way to that
shown in Table 1.0.
Light Absorption vs Time
The highest point on the curve represents the maximum smoke density. The result
of total smoke produced comes from measuring the area under the curve divided by
the total graph size multiplied by 100, thus:
Ordinate: 10% = 10mm; Absicca: 30 seconds = 10mm.
Graph Area = (10 rows x 10mm) x (9 columns x 10mm) = 9000mm²
Area under curve = 6810mm² (taken from sample data)
Smoke Density Rating: 6810 / 9000 x 100 = 75.7