Physical Address
304 North Cardinal St.
Dorchester Center, MA 02124
D2889-24 – Standard Test Method Technical Guide
🧪 Scope and Key Limitations
ASTM D2889-24 standardizes the calculation of true vapor pressures for petroleum distillate fuels. The method relies on distillation data generated in accordance with Test Method D86. It calculates vapor pressures across a wide temperature range, specifically between the 0% equilibrium flash vaporization temperature and the critical temperature of the fuel.
⚠️ Important Applicability Warnings
The test method is not reliable for distillate fuels having a boiling range of less than 100 °F (38 °C) between the Test Method D86 10% by volume and 90% by volume distilled temperatures. Additionally, the sample must not reach a decomposition point prior to obtaining 90% by volume distilled.
| 📏 Key Parameter | 📐 Specification / Value |
|---|---|
| Standard Units | Inch-pound (SI provided for information) |
| Max D86 Volume before Decomposition | 90% by volume |
| Minimum Required Boiling Range (10%–90%) | 100 °F (38 °C) |
| Calculation Temperature Limits | 0% EFV temp to Critical temp |
⚙️ Methodology and Data Requirements
The core procedure calculates Equilibrium Flash Vaporization (EFV) temperatures from standard D86 distillation data. These calculated EFV points, combined with the API gravity of the sample (determined per Test Method D287), are applied to a graphical correlation procedure using the Temperature Pressure Conversion Chart adjunct. This process generates two pairs of temperature-pressure coordinates that define the bubble-point line of the fuel’s phase diagram.
The true vapor pressure at a specified temperature is obtained by reading the pressure at the intersection of the bubble-point line and that temperature. The standard provides flexibility: if critical pressure and temperature are known, these values are used directly as the critical point in Fig. 1, bypassing the focal point calculation in Section 7.5.4. A known true boiling point or EFV temperature at 0% distilled defines the lower limit of the bubble-point line.
💡 Using Determined Values
If a determined true boiling point or determined equilibrium flash vaporization temperature at 0% distilled at atmospheric pressure is known, the standard explicitly requires using these determined values to establish the lower limit of the bubble-point line, enhancing the accuracy of the vapor pressure calculation.
| 🟦 Data Requirement | 📏 Source / Method | 🎯 Role in Calculation |
|---|---|---|
| Distillation Data | ASTM D86 | Calculation of EFV temperatures |
| API Gravity | ASTM D287 | Input for graphical correlation |
| Bubble-point Coordinates | Graphical Correlation | Define the bubble-point line on the phase diagram |
| Critical Temp/Pressure (Optional) | User Provided | Establishes the upper critical point on Fig. 1 |
📊 Key Parameters and General Applicability
ASTM D2889-24 includes provision for calculating a critical temperature for fuels where it is not known, ensuring the phase diagram can be completed for a wide range of distillate fuels. The values stated in inch-pound units are regarded as standard. This standard does not purport to address all safety concerns; it is the responsibility of the user to establish appropriate safety, health, and environmental practices.
❓ Frequently Asked Questions
🔍 What is the primary purpose of ASTM D2889-24?
This standard describes the calculation of true vapor pressures for petroleum distillate fuels using distillation data from Test Method D86. It utilizes a graphical correlation with API gravity to construct a phase diagram and derive the vapor pressure.
💡 What key inputs are required for the calculation procedure?
The primary inputs are the D86 distillation data, the calculated Equilibrium Flash Vaporization (EFV) data, and the API gravity of the sample. Optional inputs that can improve accuracy include known critical temperature and pressure or a determined true boiling point.
⚡ When is this test method considered not reliable?
The method is explicitly stated as not reliable for distillate fuels with a narrow boiling range, specifically less than 100 °F (38 °C) between the 10% and 90% D86 distillation points. It is also not applicable if the fuel decomposes before reaching 90% by volume distilled.
📌 How is the bubble-point line established?
The bubble-point line is established by calculating two pairs of temperature-pressure coordinates from the EFV data and API gravity using a graphical correlation. The true vapor pressure at a desired temperature is then read at the intersection of this line with the specified temperature.