ASTM standards to determine the flammability of jute fibers

Determining the flammability for jute fibers, especially when used in textiles or composites, is typically done using standardized test methods that measure characteristics like burning rate, after-flame time, and char length. The most frequently cited ASTM standards used for testing the flammability of natural fiber materials like jute are:

1. ASTM D6413 (Vertical Flame Test)

This is the most common test method used for evaluating the flame resistance of textiles, including jute fabric, especially those intended for protective clothing or use in high-risk environments.

• Test type:Vertical Flammability Test (Small Scale).
• Procedure:A vertically oriented fabric specimen is exposed to a controlled flame for 12 seconds.

Metrics measured

• After-flame time:The time the material continues to flame after the ignition source is removed.
• After-glow time:The time the material continues to glow after the flame disappears.
• Char length:The extent of the material damaged by the flame, measured after applying a specified tearing force.

2. ASTM D2863 (Limiting Oxygen Index - LOI)

This standard offers a precise, numerical measure of a material's inherent combustibility, which is highly useful in materials research and quality control.

• Test type:Limiting Oxygen Index (LOI).
• Procedure:A vertically mounted specimen is burned by a downward-moving flame in a controlled mixture of oxygen and nitrogen.

Metric measured: The minimum concentration of oxygen (expressed as a percentage) required to sustain candle-like combustion. A higher LOI value indicates better flame resistance.

3. ASTM D635 (Horizontal Burning Rate for Plastics)

While jute fibers themselves are textiles, they are frequently used in polymer composites (like jute-epoxy or jute-plastic sheets). When testing the flammability of a jute composite material, you may see standards intended for plastics:

• Test type:Rate of Burning and/or Extent and Time of Burning of Plastics in a Horizontal Position.
• Procedure:A specimen is mounted horizontally and ignited at one end.

Metric measured: The rate of burning (e.g., in mm/min) or the material's ability to self-extinguish. This test is often referenced for the UL 94 HB rating.

Other relevant standards

For materials like jute that are often treated with flame retardants, you may also encounter:

• ASTM D1230:Standard Test Method for Flammability of Apparel Textiles (uses a 45∘ angle test).
• NFPA 701:A standard often used for draperies and other hanging textiles in public spaces, which is similar in principle to vertical flammability tests.