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D2494-13 – Standard Test Method Technical Guide
📐 Scope and Sampling Requirements
ASTM D2494-13 (Reapproved 2020) specifies the test method for determining the commercial mass of a shipment of yarn or manufactured staple fiber or tow. It applies to all fiber types in yarn form except silk, glass, asbestos, and bast. For tops and slivers, the test method excludes wool, silk, glass, asbestos, and bast. The sampling procedures outlined are designed primarily for acceptance testing between buyer and seller, rather than continuous production control monitoring.
🔧 Technical Note: Section 1.1.1 indicates that while this standard governs acceptance testing, manufactured fiber producers typically sample on an ongoing basis for their own process control, making this standard a key fixture in contractual compliance testing.
⚖️ Commercial Mass Calculation Methods
Commercial mass is defined as the billed mass determined by a generally accepted method. The standard establishes three distinct calculation bases depending on the state of the material and the intended commercial agreement.
| 🟦 Basis Type | 📏 Material State | 📐 Calculation Formula |
|---|---|---|
| Unscoured Basis | Dried, unscoured yarn or fiber | Dry Mass + Commercial Moisture Regain |
| Scoured Regain Basis | Dried, scoured yarn or fiber | Dry Scoured Mass + Commercial Moisture Regain |
| Scoured Allowance (CAS) | Dried, scoured yarn or fiber | Oven-dry Scoured Mass + Commercial Allowance |
The specific percentages for Moisture Regain and Commercial Allowance are defined in Standard D1909. The Commercial Allowance (CAS) basis is specifically covered under Terminology D4849 and applies to scoured materials with a fixed additive allowance.
⚠️ Exclusion Warning: This test method does not apply to glass, asbestos, or bast fibers. For wool top and noil, refer entirely to Practice D2720.
🟦 Key Referenced Standards
Accurate execution of D2494 requires strict adherence to several companion ASTM standards for sampling and material preparation.
| 🟦 Standard | 🎯 Application in D2494 |
|---|---|
| D1909 | Tables of Commercial Moisture Regains and Allowances (core data source) |
| D2257 | Test Method for Extractable Matter in Textiles (scouring procedure) |
| D2258 / D3333 | Sampling Yarn / Sampling Manufactured Staple Fibers |
| D629 | Quantitative Analysis of Textiles (for blends) |
The proper conditioning, sampling, and scouring of test specimens per these standards are critical to ensuring a legally defensible commercial mass value.
❓ Frequently Asked Questions
🔍 What is the primary purpose of ASTM D2494?
The primary purpose is to provide a standardized measurement of the commercial (billed) mass of a shipment. It ensures that the buyer and seller have a clear, reproducible method for determining the weight upon which the invoice is based.
💡 What is the difference between a moisture regain and a commercial allowance?
A commercial moisture regain is a standard percentage of the oven-dry mass allowed for moisture content. A commercial allowance is a broader percentage that may include moisture, finish, or other natural or added non-fiber matter, and is often applied to scoured materials.
⚡ Can this standard be used for production quality control?
Section 1.1.1 clarifies that the sampling in this method is primarily for acceptance testing. While the calculation principles are the same, manufacturers typically use internal continuous sampling procedures for production control rather than applying this specific shipment-based standard.
📌 Which ASTM standard provides the exact regain values for D2494?
Standard D1909 (Standard Tables of Commercial Moisture Regains and Commercial Allowances for Textile Fibers) is the definitive source for the specific percentage values required to complete the commercial mass calculation in this test method.