When performing the needle flame test in Annex S.1, if the burning material extinguishes before the first 30 seconds, is this an acceptable result?
More specifically you asked: When performing the needle flame test in Annex S.1, the standard states the test flame is applied for 10 seconds and, if the flame does not exceed 30 seconds, the test flame is re-applied. However, if there is no self-sustaining flame for the full 30 seconds, is this an acceptable result (test passed)?
The needle flame test of S.1 is derived from IEC 60695-11-5 with some modifications for 62368-1, such as flame application time and compliance.
The application of the test flame is required to follow the stated sequence (it is one sequence, not separate tests):
-the test flame is applied for 10 s;
-if flaming does not exceed 30 s, the test flame is immediately reapplied for 1 min at the same point;
-if again flaming does not exceed 30 s, the test flame is immediately reapplied for 2 min at the same point.
The compliance criteria require all of the following:
-after every application of the test flame, the test specimen shall not be consumed completely; and
-after any application of the test flame, any self-sustaining flame shall extinguish within 30 s; and
-no burning of the specified layer or wrapping tissue shall occur.
As mentioned in the compliance criteria, each application of flame is required to meet all three dashes.
Specifically to the submitted question, the 2nd and 3rd dashes (of the first set of dashes above) require the test flame to be applied to the same test specimen if no flame remains after the first 30-sec application and there is no burning of wrapping tissue after 1st application. Therefore, it is not an acceptable result alone for the complete test if the test specimen’s sustaining flame extinguishes within the first 30 seconds – that is required to pass part of the test, but then there are two other dashes that also need to be applied and met.
Furthermore, S.1 requests three test specimens – even if the first specimen complies, the remaining two specimens also are required to meet the above tests as well. All three specimens are required to pass the test.