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D2985 – Standard Test Method Technical Guide
📜 Scope and Applicability
ASTM D2985/D2985M −92 (Reapproved 2019) outlines a standard test method for determining the color, whiteness, and yellowness of asbestos using a photoelectric reflectometer. This method is applicable to all grades and varieties of homogeneous milled asbestos. While the method can be applied to non-dry, non-homogeneous, or impure samples, results from such samples may not be comparable with those obtained from clean dry samples. The standard explicitly defines values in both SI units and inch-pound units, which must be used independently to avoid non-conformance.
⚙️ Test Method Principles and Instrumentation
The test method relies on a photoelectric reflectometer to assess the psychophysical color characteristics of the sample. It quantifies the daylight 0.785 rad, 0 rad (45°, 0°) luminous directional reflectance to derive color dimensions, such as CIE tristimulus values. For sampling, the standard references Test Methods D2590 (Chrysotile Asbestos) and D3879 (Amphibole Asbestos). Users seeking comparable data from spectrophotometers are directed to Practice E308 for computing colors using the CIE system.
⚠️ Health Hazard Alert: Breathing of asbestos dust is hazardous and presents demonstrated health risks. Users must minimize dust, adhere to the “Safe Use of Chrysotile: A Manual of Preventive and Control Measures,” and establish appropriate safety, health, and environmental practices in compliance with regulatory limitations.
📊 Terminology and Referenced Standards
The standard provides specific terminology to ensure uniform interpretation of color measurements. Correct understanding of terms like “psychophysical color” and the specified illumination geometry is critical for accurate testing.
| 📖 Term | 🎯 Definition per Standard |
|---|---|
| Black | Color name applied to opaque objects highly absorbing throughout the visible spectrum. |
| Color, Psychophysical | Characteristics of a color stimulus denoted by three dimension values (e.g., CIE tristimulus values). |
| CIE Source C | A standardized daylight source used for colorimetric measurements. |
💡 Technical Note: The standard allows the use of either SI or inch-pound units, but strictly cautions against combining values from the two systems. Selecting one system and adhering to it throughout the entire test is required for conformance.
| 📄 Designation | 📌 Title of Referenced Standard |
|---|---|
| D2244 | Practice for Calculation of Color Tolerances and Color Differences |
| D2590 | Test Method for Sampling Chrysotile Asbestos |
| D2946 | Terminology for Asbestos and Asbestos–Cement Products |
| D3879 (Withdrawn 2009) | Test Method for Sampling Amphibole Asbestos |
| E308 | Practice for Computing the Colors of Objects by Using the CIE System |
| E259 | Practice for Preparation of Pressed Powder White Reflectance Factor Transfer Standards |
❓ Frequently Asked Questions
🔍 What is the primary purpose of ASTM D2985?
It covers the determination of color, whiteness, and yellowness of asbestos by means of a photoelectric reflectometer. It is applicable to all grades and varieties of homogeneous milled asbestos.
💡 Can the test be performed on non-homogeneous or dirty samples?
Yes, the method may be applied to samples that are not dry or homogeneous, or that contain impurities. However, results from such samples may not be directly comparable with those obtained on clean dry samples.
⚡ What is the key safety warning associated with this standard?
Breathing of asbestos dust is hazardous. Users must establish appropriate safety practices, minimize dust, and refer to the “Safe Use of Chrysotile: A Manual of Preventive and Control Measures” for safe handling guidelines.
📌 What instrumentation is specified for this test?
The test method specifies the use of a photoelectric reflectometer. For those wishing to use a spectrophotometer, Test Method E308 must be followed to obtain similar results.