ASTM D 4808
ASTM D 4804Â test method describes a small scale laboratory test for determining the comparative burning characteristics of solid plastic materials that due to specimen thickness and non-rigidity distort or shrink when tested under ASTM D 3801.
Specimen:Â Four sets of 5 specimens with nominal dimensions 200mm x 50mm and in minimum and maximum thickness.
Specimen conditioning:Â Two sets of 5 specimens per sample were conditioned as follows:
i. First set at 230C and relative humidity 50% for minimum of 48 hours.
ii. Second set in an air circulating oven for 168 hours at 700C and then cooled in a desiccator for minimum of 4 hours.
Gas flow:Â Set the methane gas flow to 105 ml/min. Adjust the flow and air intakes of the burner to get a clean blue flame 20mm high.
Flame application:Â 20mm Bunsen burner flame
Flame application time:Â 2 x 3 seconds application. The second flame application time begins as soon as the ignited specimen is extinguished or immediately if the specimen does not ignite.
Measurements:
A – Duration of flaming after first flame application (seconds).
B – Duration of flaming after second flame application (seconds).
C – Duration of glowing after second flame application (seconds).
D – Whether or not specimens burn up to the 125mm mark.
E – Whether or not specimens drip flaming particles which ignite cotton swatch.
Based on the measured values using the following table to classify the material as VTM-0, VTM-1 or VTM-2.
Test setup:Â The Bunsen Burner and the test specimen is set up as shown in the test schematic.
