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D628 – Standard Test Method Technical Guide
📐 Scope and Composition Requirements
This specification, designated D628/D628M – 95 (Reapproved 2017), covers woven and braided asbestos tubular sleeving. The material must contain a minimum of 75 mass % of asbestos fiber, specifically the chrysotile serpentine mineral (Mg3Si2O5(OH)4), excluding the mass of any other inorganic strands that may be present in the construction. The standard operates under the jurisdiction of ASTM Committee C17 on Fiber-Reinforced Cement Products.
The standard strictly mandates that the values stated in either SI units or inch-pound units be regarded separately as standard. Combining values from the two systems is prohibited and may result in non-conformance with the specification.
⚠️ Health Hazard Warning: Breathing of asbestos dust is hazardous. Asbestos and asbestos products present demonstrated health risks for users and those with whom they come into contact. When working with asbestos-cement products, minimize the dust that results. Refer to the “Safe Use of Chrysotile Asbestos: A Manual on Preventive and Control Measures” for detailed information on safe handling practices.
⚙️ Terminology and Testing Conditions
The standard establishes precise terminology to ensure consistency across testing, classification, and quality assurance. For general textile terms, it references Terminology D123. For asbestos-specific terms, it relies on Terminology D2946. The table below summarizes the critical definitions provided within the standard for material qualification.
| 🟦 Term | 📏 Definition |
|---|---|
| Asbestos Fiber | The hydrous magnesium silicate serpentine mineral designated as chrysotile (Mg3Si2O5(OH)4). |
| Sleeving | A woven or braided fabric of tubular form. |
| Atmosphere for Testing | Air maintained at a relative humidity of 50 ± 2 % at a temperature of 21 ± 1°C. |
📊 Regulatory Framework and Referenced Documents
Compliance with D628 requires familiarity with a defined set of associated ASTM standards for material characterization and testing. These references form a complete framework for evaluating the physical, mechanical, and electrical properties of the sleeving. The standard was developed in accordance with internationally recognized principles established by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
📌 Key Testing Standards: The specification requires users to consult several specific standards for testing methods. These include D299 (Asbestos Yarns), D1777 (Thickness of Textile Materials), D1918 (Asbestos Content of Asbestos Textiles), and D2100 (Asbestos Textiles for Electrical Insulating Purposes).
| 📐 Standard | 🎯 Application |
|---|---|
| D76 | Specification for Tensile Testing Machines for Textiles |
| D1118 | Test Method for Magnetic Rating of Asbestos Fiber and Asbestos Textiles |
| D1777 | Test Method for Thickness of Textile Materials |
| D2100 | Specification for Asbestos Textiles Used for Electrical Insulating Purposes |
The safety hazards caveat provided in Section 1.4 of the standard pertains specifically to the test methods described in Section 13. It is the responsibility of the user to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
❓ Frequently Asked Questions
🔍 What is the minimum asbestos fiber content required by D628?
The specification requires a minimum of 75 mass % of asbestos fiber, excluding the mass of any other inorganic strands which may be present in the sleeving construction.
💡 What specific type of asbestos is designated in this standard?
The standard defines asbestos fiber strictly as the hydrous magnesium silicate serpentine mineral designated as chrysotile, with the empirical formula Mg3Si2O5(OH)4.
⚡ What are the standard atmospheric conditions for testing this sleeving?
Per the standard, the atmosphere for testing asbestos textiles must be air maintained at a relative humidity of 50 ± 2 % at a temperature of 21 ± 1°C (70 ± 2°F).
📌 Can SI and inch-pound units be used together in this specification?
No. The values stated in either system must be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.