ASTM D6413 Flame Resistance of Textiles

ASTM D6413 is the international standard that measures the flame resistance of fabrics, also known as a vertical test, given by the American Society for Testing and Materials. This test ensures the quality of flame-resistant fabrics and protective clothing. In this test, the FR fabric is subjected to a flame for 12 seconds to measure glow time and char length.

Purpose of ASTM D6413 

ASTM D6413 Standard is the vertical burn test method popularly referenced by standard specifications for materials protecting flame and thermal hazards.

This method measures the after-flame time, glow time, and char length of a 12-inch-long fabric specimen after a 12-second exposure to a one-and-a-half-inch-tall burner flame.

This test ensures the quality of flame-retardant fabrics and flame-resistant materials according to standard requirements.

ASTM D6413 Vertical Test Procedure                     

Test Equipment  

Here, to measure the flame resistance of FR fabrics using the vertical test method, we will use ASTM D6413 Fabric Flame Retardant Tester YG (B) 815D by Darong Company.

Sample Preparation 

The textile fire resistance test is performed on protective clothing and flame-retardant fabrics, so we will use flame-retardant fabric for the test. The specimen is cut through the template at 76 × 300 mm.

As per standard, we will take a specimen for testing from the flame retardant fabric 150 mm away from the selvage. The specimen will be cut according to the template size from directions, warp and weft.

We will mark P on the specimen parallel to the warp and mark parallel to the weft. Three specimens should be taken in each direction. The specimens are cut diagonally from the sample fabric.

After cutting the specimen, make two sets of three specimens, one for warp and one for weft. After that, samples are ready to install on the specimen holder.

Place Specimen in Holder

The specimen holder is 76 mm in width and has a total height of 442 mm. The specimen holder is in the form of a clamp. The specimen is placed in the specimen holder length-wise.

The edges of the holder should be aligned. The specimen holder is closed after placing and tightening the fabric specimen using a clamp to avoid the fabric sample displacement during the testing.

Turn on Flame Chamber

Now, turn on the flame chamber. The flame chamber must have an exhaust so that the smoke formed during the burning can quickly exit the chamber.

Here is an ASTM D 6413 vertical flame tester with a control panel. The control panel controls a burner in the flame chamber. The holder assembly hangs the fabric specimen with the holder. The flame test equipment must have these dimensions.

Ignite the Burner Flame  

The burner flame height should be 38mm. The flame ignition time is set to 12 seconds for this standard. You must use a facemask during the testing so that the smoke emission does not hurt you during the testing.

The specimen holder fits in the assembly. After setting the specimen holder, turn on the machine. Once the test is started by clicking the start button, the burner will move underneath the fabric specimen.

The distance between the fabric specimen and holder is kept at 1.5 cm. The burner will remain under the fabric specimen for 12 seconds, and the flame will remain in contact with the flame-retardant fabric specimen for up to twelve seconds.

Turn off Burner Flame

As the burner flame moves away from the fabric sample after a set time, turn off the burner flame.

We have to see whether the specimen glows or not. This means we must check whether the fabric keeps burning or extinguishes after removing the flame.

If the sample keeps burning, we will not see the burning time, which is called after-flame glow time.

Fail Test Condition

If the specimen catches fire and burns after the burner flame is removed, the test will be considered a failure.

Char Length Measurement  

The second thing we have to measure is the char length. To measure it, we will create a hole in one corner of all specimens at a height of 06 mm from the burnt side.

We will use this hole to hang the weight freely, and then we will measure the char length. There are different categories of weight for measuring the char length. If your fabric sample GSM (fabric GSM definition) is up to 200, we will use 100 gm weight.

If the fabric has 200 – 303 GSM, we will use 200 gm of weight. The 300 gm weight is used for fabric specimens with GSMs from 303 to 430. The 400 gm weight is used for fabrics with GSMs of 430 to 550.

The 500 gm weight is used for fabrics with GSMs greater than 550. You must use the weight according to the GSM of your tested fabric sample.

We will hold the weight in the fabric hole and then freely hang it. The one corner with the hole will have weight, and you have to use the other corner of the fabric to pull the weight upward to the point where it hangs freely in the air.

The fabric will tear due to a weight load. The place on the fabric up to tears is called the specimen’s char length, measured in mm.

Passing Test Criteria

The test passing criteria for flame retardant fabric are less than 100 mm and a glow time of zero seconds.

Conclusion

ASTM D6413 testing method measures the after-flame time, glow time, and char length of a 12-inch-long fabric specimen after a 12-second exposure to a one-and-a-half-inch-tall burner flame.

The test passing criteria for flame retardant fabric are less than 100 mm and a glow time of zero seconds. If the specimen catches fire and burns after the burner flame is removed, the test will be considered a failure.

Related Resources

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