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D2962-23 – Standard Test Method Technical Guide
📐 Scope and Significance
This standard practice, designated ASTM D2962-23, provides a standardized methodology for calculating the volume-temperature correction for liquid coal-tar pitches. Because different pitches expand or contract at varying rates directly related to their relative density, a uniform calculation method is essential for custody transfer, inventory control, and regulatory compliance. The values stated in inch-pound units are regarded as the standard. This practice is under the jurisdiction of ASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants.
⚙️ Procedure for Volume Correction
The procedure calculates the expansion factor A using the relative density and coefficient of expansion. First, determine the relative density of the pitch at 60°F/60°F (15.6°C/15.6°C) in accordance with Test Methods D70 or D71, whichever is most suitable. Next, find the coefficient of expansion per degree from Table 1. Multiply this coefficient by the temperature difference between the standard temperature and the actual temperature of the material. Add 1.000 to this product to obtain A. If the material temperature is above the standard, divide the measured volume by A. If it is below the standard, multiply the measured volume by A.
Example Calculation: A tank contains 95,000 gallons of pitch at 350°F (177°C). The relative density at 60°F/60°F according to Test Method D70 is 1.28. From Table 1, the coefficient is 280 × 10⁻⁶ per °F. The temperature difference is 350 – 60 = 290°F. The product is 290 × 280 × 10⁻⁶ = 0.0812. The expansion factor A is 1.0812. The corrected volume at 60°F is 95,000 / 1.0812 = 87,865 gallons.
📊 Coefficient of Expansion Table
Table 1 lists the volume-temperature correction coefficients for coal-tar pitches. The coefficient of expansion varies in relation to the relative density of the material, as illustrated by the sample values below.
| 🟦 Relative Density (60°F/60°F) | 📏 Coeff. per °F (×10-6) | 📐 Coeff. per °C (×10-6) |
|---|---|---|
| 1.20 | 310 | 558 |
| 1.25 | 290 | 522 |
| 1.28 | 280 | 504 |
| 1.32 | 260 | 468 |
| 1.35 | 245 | 441 |
💡 Technical Tip: Accurate density measurement is critical. Ensure the sample temperature is precisely 60°F (15.6°C) when performing Test Methods D70 or D71 to select the correct coefficient from Table 1.
⚠️ Important Warning: The expansion coefficients in this standard are specifically derived for coal-tar pitches. These values must not be applied to petroleum-based asphalts, cutbacks, or other bituminous materials.
❓ Frequently Asked Questions
🔍 Why is volume correction necessary for coal-tar pitches?
Coal-tar pitch is often stored and shipped at elevated temperatures. Without a standardized correction to 60°F (15.6°C), volume discrepancies caused by thermal expansion would lead to significant inaccuracies in custody transfer, inventory valuation, and compliance.
💡 How do I choose between Test Method D70 and D71?
Test Method D70 (Pycnometer Method) is designed for semi-solid to liquid pitches. Test Method D71 (Displacement Method) is used for solid pitches. The standard requires selecting the method that is “most suitable” for the physical state of the sample material.
⚡ What is the correct calculation when the pitch temperature is below 60°F?
When the measured temperature of the material is below the standard temperature of 60°F (15.6°C), the pitch has contracted. In this case, the standard specifies that you must multiply the measured volume by the expansion factor A to find the corrected volume at standard temperature.
📌 Where can I find the standard terminology references?
Terminology related to this practice is defined in Terminology D4175, which governs terms for Petroleum Products, Liquid Fuels, and Lubricants. This practice is directly under the jurisdiction of ASTM Subcommittee D02.02 on Hydrocarbon Measurement for Custody Transfer.