1、 Principle:

Produce a test flame, burn the test sample according to a certain time, and observe the danger of ignition. The tester consists of the action control part of the test box and the electrical control part:

II. Basis standard

According to gb4706.1 and gb5169.5-1997

Operation steps:

General description of the test:

If possible, the sample should be a complete device or component or element. If necessary, remove part of the shell or cut off the appropriate part for the test, but carefully ensure that the influence of the test conditions on the shape, air circulation, thermal stress effect and possible flame, as well as the impact of burning or hot particles falling near the test sample, is not significantly different from that of normal use.

If the test cannot be carried out on a complete test sample, the appropriate part may be taken as the test sample.

If the test sample is an appropriate part cut from the large machine, care must be taken to ensure that the test flame is applied correctly in this special case, for example, do not apply the test flame to the edge caused by cutting.

Operation method:

1. A layer of silk paper shall be tightly wrapped on a smooth white pine board with a thickness of about 10 mm as the laying bottom layer, and it shall be placed 200 mm ± 5 mm below the position where the needle flame is applied to the test sample.

2. Turn on the power.

3. Check that the burner is on the left side of the test flame section. Otherwise, click the "reset" key, and the burner will move to the leftmost position.

4. Click the "start" key to ignite the blowtorch.

5. Adjust the "flame adjustment (flow meter)" to make the height of the flame to the test 12 ± 1mm.

6. Click the "temperature rise test" button, and the blowtorch will automatically move to the flame intensity temperature rise test place.

Note: the distance between the head of the combustion tube and the temperature sensing copper block is 6.0 ± 0.5mm,

7. Check whether the temperature can reach the test temperature rise time. (check the temperature control meter, after the temperature reaches 100 ℃, test the temperature rise time, and check whether the temperature rise time from 100 ℃ to 700 ℃ is 23.5 ± 1.0s. )

8. Clamp the sample according to the standard size.

9. Click the "test" button, the blowtorch will automatically move to the sample test place to start the test.

Note: the distance between the burner and the test sample is shown in Figure 4.

10. After setting the "combustion time" test, click "test", when the burner reaches the test area, the combustion time will automatically start timing (please refer to the standard level setting for the time setting).

11. Record the continuous combustion time after the combustion stops, i.e. after the combustion time reaches.

12. At the end of the test, turn off the gas, then press the "exhaust" key to remove the harmful gas that may be generated in the test chamber, and finally turn off the power supply.

13. After the test, click the "reset" button, and the blowtorch will automatically return to the original position to prepare for the next group of tests.

IV. observation and measurement

1) During the test, the test sample, surrounding parts and the underlying layer shall be observed.

2) If the test sample and its surrounding parts, or the primer under it ignites, measure and record

Record combustion duration (TB).

The burning duration refers to the time interval from the moment when the test flame moves away to the time when the flame goes out, or until the test sample or its adjacent parts or the bottom layer used for the test can no longer see the burning phenomenon.

3) If the relevant standard specifies to measure the burning length of the sample, the test sample shall be cooled to near room temperature and cleaned with a clean dry cloth before measurement.

F observe the characteristics of combustion:

According to the relevant standards, visually inspect the physical damage of the test sample and test the mechanical / electrical parameters.

F test result evaluation

Unless otherwise specified in relevant standards, the test sample can be considered to stand the needle flame test if it meets one of the following conditions.

a) The test sample does not produce flame and burning phenomenon, and when using wrapping silk paper and white pine board, wrapping silk paper does not burn or white pine board does not carbonize.

b) After removing the needle flame, the flame or burning duration of the test sample, surrounding parts and the underlying layer shall be less than 30s, that is, within TB ＜ 30s, the parts and the underlying layer around the test sample shall not continue to burn, and when the packaging silk paper or white pine board is used, the packaging silk paper shall neither burn nor carbonize the white pine board.