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D1267-23 – Standard Test Method Technical Guide
🧪 Overview and Scope of D1267-23
The ASTM D1267-23 standard defines a specific methodology for determining the gauge vapor pressure of liquefied petroleum gas (LP-Gas) products. This test method is applicable at temperatures starting from 37.8 °C (100 °F) and extending up to a maximum test temperature of 70 °C (158 °F). It is crucial for ensuring the safe handling and storage of these highly volatile substances.
The standard emphasizes that values stated in SI units are to be regarded as the standard, while values in parentheses are provided for informational purposes only. It is the user’s responsibility to establish appropriate safety and environmental practices prior to use.
⚠️ Critical Safety Warning: This standard deals with extremely flammable gas. Inhalation may be harmful. Strict adherence to safety protocols outlined in Section 1.1 and Annex A2 is mandatory when conducting this test method.
⚙️ Test Procedure and Key Parameters
The test apparatus consists of two interconnected chambers equipped with a suitable pressure gauge. The procedure begins by purging the system with a portion of the sample, which is discarded. The apparatus is then completely filled with the sample to be tested.
Immediately after filling, between 33⅓% and 40% of the sample volume must be withdrawn to create sufficient free space for product expansion during heating. The sealed apparatus is then immersed in a water bath maintained at the standard test temperature or an optional higher temperature up to 70 °C (158 °F).
| 🟦 Parameter | 📏 Specification / Range |
|---|---|
| Standard Test Temperature | 37.8 °C (100 °F) |
| Maximum Optional Temperature | 70 °C (158 °F) |
| Sample Volume Withdrawn | 33⅓% to 40% |
| Measured Value | Gauge Vapor Pressure at Equilibrium |
📊 Significance and Data Reporting
Determining the vapor pressure of LPG is critical for designing storage vessels, shipping containers, and utilization equipment to ensure safe handling. The observed gauge pressure at equilibrium must be corrected for gauge error and standardized to a reference barometric pressure. This corrected value is reported as the LPG Vapor Pressure at the selected test temperature.
The test method specifies terminology defined in D4175 and references key ASTM standards for sampling and alternative testing procedures.
| 📐 Designation | 🎯 Title / Description |
|---|---|
| D323 | Vapor Pressure of Petroleum Products (Reid Method) |
| D1265 | Practice for Sampling Liquefied Petroleum (LP) Gases, Manual Method |
| D6897 | Test Method for Vapor Pressure of LPG (Expansion Method) |
| D4175 | Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants |
✅ Alternate Method Notice: An alternative procedure for measuring the vapor pressure of liquefied petroleum gases is outlined in Test Method D6897 (Expansion Method). While D1267-23 involves a liquid bath and specific sample volume withdrawal, D6897 provides a different technical approach for the same fundamental determination.
❓ Frequently Asked Questions
🔍 What is the standard test temperature range for D1267-23?
The standard test temperature is 37.8 °C (100 °F), but the method allows for testing up to a maximum of 70 °C (158 °F) depending on the product’s specific requirements.
💡 Why is 33⅓% to 40% of the sample withdrawn after filling the apparatus?
This specific volume of sample is withdrawn to create adequate free space (vapor head) within the test chamber. This allows the liquefied gas to expand safely as it is heated to the test temperature without generating dangerously high pressures.
⚡ What are the key safety hazards associated with this test method?
The primary hazard is dealing with an extremely flammable gas that may be harmful when inhaled. The standard requires strict adherence to specific safety warnings and proper ventilation throughout the testing process.
📌 What is the relationship between D1267-23 and D6897?
Both standards measure the vapor pressure of LPG, but they use different apparatus and procedures. D1267-23 is the traditional “LP-Gas Method” involving a liquid bath and specific volume withdrawal, while D6897 is the “Expansion Method”. They provide alternative means for the same fundamental determination.