16 CFR 1615.3 - General requirements.
(a) Summary of test method. Five conditioned specimens, 8.9 × 25.4 cm. (3.5 × 10 in.), are suspended one at a time vertically in holders in a prescribed cabinet and subjected to a standard flame along their bottom edge for a specified time under controlled conditions. The char length is measured.
(b) Test criteria. The test criteria when the testing is done in accordance with § 1615.4 Test procedure are:
(1) Average char length. The average char length of five specimens shall not exceed 17.8 cm. (7.0 in.).
(2) Full specimen burn. No individual specimen shall have a char length of 25.4 cm. (10 in.).