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D2497-07 – Standard Test Method Technical Guide
📐 Scope and Terminology
ASTM D2497-07 (Reapproved 2018) establishes standard tolerances for first-quality, manufactured, organic-base filament single yarns, governing permissible variations in linear density, tenacity, elongation, twist, and commercial weight (Section 1.1). The standard applies regardless of package type or aesthetic finish (e.g., bright, semi-dull, dull, solution-dyed, bleached, unbleached). It explicitly excludes rubber yarns, spandex yarns, metal-covered yarns, bulk yarns, and industrial filament yarns due to the lack of standardized test methods for these types (Section 1.1.1). Note 1 clarifies that tolerances for inorganic glass yarns are provided under D578/D578M. Terminology specific to this standard is governed by D4849, while general textile terminology follows D123. This standard represents only a framework for tolerances; specific quality levels and specifications are subject to agreement between the purchaser and the supplier (Section 1.2).
⚙️ Test Methods and Measured Properties
To ensure uniformity in evaluation, the standard mandates specific ASTM protocols and sampling procedures. Section 5 requires sampling strictly in accordance with Practice D2258/D2258M before testing. The following table summarizes the referenced methods:
| 🟦 Property Category | 📏 Mandated Test Method | 🎯 Measured Output |
|---|---|---|
| Linear Density (Yarn Number) | D1907/D1907M | Skein Count (Denier, Tex, Metric Number) |
| Twist per Unit Length | D1423/D1423M | Direct Twist Count (TPI, TPM) |
| Tensile Properties | D2256/D2256M | Single-Strand Breaking Force |
| Commercial Mass | D2494 | Invoice Weight Verification |
While the standard permits application of tolerances to yarn extracted from fabric (Note 2), users must note that properties of such reclaimed yarns are likely to differ significantly from their original levels.
📊 Commercial Application and Tolerance Agreements
The tolerances listed in this standard are designed to serve as a guide in purchaser and supplier disputes and to assist in assigning nominal values for linear density and twist (Section 4.1). They represent the maximum variations deemed acceptable in the trade rather than fixed pass/fail limits. As specified in Section 6.1, the average linear density of a lot must conform to the value agreed upon between the parties, with acceptable deviations defined by the tolerances in Table 1. Strength tolerances are assessed on a per-packing-case basis for cases containing ten or more yarn packages.
⚡ Critical Distinction: This standard strictly covers tolerances for permissible variation around an agreed-upon nominal value. It does not independently dictate specifications or quality levels—those are subject to mutual agreement by the purchaser and the supplier (Section 1.2).
💡 Practical Application: These tolerances serve as a baseline for acceptance criteria during commercial transactions. For accurate results, always adhere to the sampling requirements of D2258/D2258M and the specific test methods listed in Section 5.1.
❓ Frequently Asked Questions
🔍 Which yarn types are specifically excluded from these tolerances?
Per Section 1.1.1, the standard explicitly excludes rubber, spandex, metal-covered, bulk, and industrial filament yarns. Inorganic glass yarns are covered under a separate standard, D578/D578M.
💡 How are tolerance disputes resolved using this standard?
Section 4.1 states that the tolerances are intended to be used as a guide in purchaser/supplier disputes. The maximum variations listed for each property represent the boundary of what is deemed acceptable in the trade.