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D1113-13 – Standard Test Method Technical Guide
📐 Test Method Overview
This test method, designated as D1113-13, covers the determination of oven-dried, ash-free, alcohol extractive-free vegetable matter and other alkali-insoluble impurities in scoured wool. It is also applicable to related fibers such as goat hair, camel hair, alpaca, and other animal fibers. The method is essential for assessing wool quality and is referenced in other standards like Test Method D584 for clean wool fiber content and Practice D2720 for commercial weight calculation.
⚙️ Procedure and Conditions
The procedure involves dissolving the wool sample in a boiling 3% sodium hydroxide solution or a hot 10% sodium hydroxide solution under specified controlled conditions. The undissolved residue is collected, oven-dried, and ashed to determine the alkali-insoluble components. The weights of the ash-free, oven-dried components are converted using tabulated factors to obtain the vegetable matter base and other impurities. Proper safety measures are required due to the use of hot caustic solutions.
| 🟦 Method | ⚡ NaOH Concentration | 📏 Temperature | 🎯 Application |
|---|---|---|---|
| Standard | 3% | Boiling | Routine laboratory testing |
| Alternate | 10% | Hot (controlled conditions) | Faster dissolution |
⚠️ Safety: Handling hot sodium hydroxide solutions requires appropriate safety equipment. Refer to Section 8 of the standard for specific hazard statements.
📊 Key Measured Properties
The key measured properties include the oven-dried, ash-free vegetable matter content and other alkali-insoluble impurities. This test method is used for acceptance testing of commercial shipments and is recognized by the U.S. Customs Service for determining vegetable matter allowances in raw wool imports. The results help calculate clean wool fiber present and commercial weight and yield. In case of disputes, comparative testing between laboratories is recommended using statistical analysis like Student’s t-test.
💡 Note: This method is widely used in conjunction with Test Method D584 for determining clean wool fiber content. For accurate results, follow the specified controlled conditions for alkali digestion.
❓ Frequently Asked Questions
🔍 What is vegetable matter in scoured wool?
Vegetable matter includes burrs, seeds, leaves, and other plant material that are alkali-insoluble and remain after dissolution of wool fiber.
💡 Why is this test method important?
It is used for acceptance testing of commercial shipments and for customs purposes to determine the vegetable matter content, which affects wool classification and duty.
⚡ What are the typical conditions for the NaOH solution?
The standard method uses boiling 3% sodium hydroxide, while an alternate method uses hot 10% sodium hydroxide under controlled conditions.
📌 What fibers are covered by this method?
This test method covers scoured wool and related fibers such as goat hair, camel hair, alpaca, and other animal fibers.