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D3513-02 – Standard Test Method Technical Guide
⚙️ Scope, Apparatus, and Sampling
ASTM D3513-02 (Reapproved 2024) provides a standard test method for determining the percent by number of overlength or multiple length fibers in a sample of manufactured cut staple. The method is broadly applicable to fiber taken immediately after manufacturing, from the bale, or from partially processed stock. Sampling should be conducted in accordance with Practice D3333. The core apparatus includes the Fibrosampler Model 335A or 335B and the Fibrosampler combs Model 336.
The selection of the Fibrosampler model depends entirely on the nature of the fiber stock to be tested:
| 🟦 Model | 📏 Unit System | 🎯 Sample Plate Hole Diameter | ⚡ Recommended Application |
|---|---|---|---|
| 335A | Inch-Pound | 15.8 mm (5/8 in.) | Blended staple taken from the fiber blender or carding machine |
| 335B | SI | 10 mm (0.4 in.) | Unblended staple taken from the fiber cutter or a bale of staple fiber |
⚠️ Critical System Independence Requirement: The values stated in either SI units or inch-pound units are to be regarded separately as the standard. The values in each unit are not exact equivalents; therefore, each unit must be used independently of the other throughout the entire test.
📏 Summary of Test Procedure
Fibers are caught randomly on a comb to form a fiber beard. The test specimen naturally exhibits a specific bias; the probability that a given fiber length group appears in the beard is proportional to the ratio of the total length of that fiber length group to the total fiber length of the original sample. This means the beard is inherently biased in favor of long fibers.
The fiber beard is brushed out and laid on a specimen board. The density of the beard tapers to a distinct line that is parallel to the base of the comb. Overlength fibers are observed to extend noticeably beyond this density line, allowing them to be identified easily. The noticeably longer fibers are then pulled from the fiber beard, verified for over- or multiple-length characteristics, and counted to determine the final percentage by number.
💡 Complementary Standard: For measurement of length and length distribution of manufactured staple fibers using a single-fiber test, refer to Test Method D5103.
📊 Key Measured Properties and Terminology
The primary result determined by this test method is the percent by number of overlength or multiple length staple fibers. This metric is crucial for verifying cutter performance and ensuring consistency in downstream processes. Formal definitions for terms such as fiber beard, staple, overlength staple fibers, and multiple-length staple fibers are provided in Terminology D4849. Additional textile terminology can be found in Terminologies D123, D3888, and D3990.
❓ Frequently Asked Questions
🔍 What specific metric does ASTM D3513 measure?
It measures the percent by number of overlength or multiple length fibers present in a sample of manufactured cut staple fiber.
© 2026 TNLab — This article is a technical interpretation for reference only. The original standard as published by ASTM International takes precedence.