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D5006-24 – Standard Test Method Technical Guide
📏 Scope and Summary
ASTM D5006-24 is a standard test method for measuring the concentration of Diethylene Glycol Monomethyl Ether (DiEGME) in aviation fuels. This method is essential for determining the level of fuel system icing inhibitors (FSII) in fuel, ensuring safe operation in cold conditions. The test involves extracting a measured volume of fuel with a fixed ratio of water and analyzing the extract using a refractometer. The method is validated for the concentration range of 0.01 % to 0.25 % by volume, with precision estimates determined for specific extraction ratios across a wide variety of fuel types.
🔬 Test Method and Equipment
The procedure requires precise water extraction, where the fuel sample is mixed with water in a specific ratio, allowing the DiEGME to transfer into the aqueous phase. The refractive index of this extract is then measured. The standard defines several types of refractometers: analog refractometers (which project a shadowline onto a scale etched into a glass reticle), digital refractometers (which use a solid-state image sensor to convert refractive index into percent DiEGME), and Brix refractometers (which display readings on the Brix scale, expressing the relationship between refractive index and sucrose concentration). All refractometers must be calibrated to ensure accurate readings within the specified range.
📊 Key Specifications and Data
The standard provides precision estimates for DiEGME using specific extraction ratios optimized for handheld refractometers without compromising accuracy or linearity. The concentration range of interest from 0.01 % to 0.25 % by volume covers typical FSII levels. Referenced documents include Specification D4171 for fuel system icing inhibitors and Practices E29 for significant digits.
| 🟦 Parameter | 📏 Specification | 📐 Description |
|---|---|---|
| Additive Measured | Diethylene Glycol Monomethyl Ether (DiEGME) | Primary FSII in aviation fuels per D4171 |
| Concentration Range | 0.01 % to 0.25 % by volume | Validated for accuracy and linearity |
| Extraction Method | Water extraction with fixed ratio | Ratio depends on fuel type; high enough for portable refractometers |
| Refractometer Types | Analog, digital, Brix | As defined in Section 3 of the standard |
| Precision Basis | Extraction ratios for various fuels | Wide variety of fuel types included |
⚠️ Warning: Mercury is designated as hazardous by many regulatory agencies. Handle mercury and mercury-containing products with caution. Refer to the Safety Data Sheet (SDS) and comply with local or national laws regarding mercury sales, use, and disposal.
💡 Tip: Regular calibration of refractometers is critical. Maintain the exact water-to-fuel extraction ratio specified for the fuel type being tested to ensure measurement precision within the 0.01 % to 0.25 % range.
❓ Frequently Asked Questions
🔍 What is the purpose of ASTM D5006-24?
This standard provides a test method for measuring the concentration of Diethylene Glycol Monomethyl Ether (DiEGME) in aviation fuels to determine the level of fuel system icing inhibitor (FSII) present, ensuring fuel performance in low-temperature conditions.
💡 How does the water extraction process work?
A fixed ratio of water is mixed with a measured volume of fuel. DiEGME is soluble in water and transfers to the aqueous phase, which is then analyzed with a refractometer to determine the FSII concentration.
⚡ What types of refractometers are allowed by the standard?
The standard defines analog refractometers (shadowline scale), digital refractometers (solid-state sensor with direct DiEGME readout), and Brix refractometers (converted from Brix units). All must be suitable for the concentration range of 0.01 % to 0.25 % by volume.
📌 What safety concerns are highlighted in the standard?
The standard emphasizes the hazards of mercury, requiring caution with mercury-containing products. Users must establish appropriate safety, health, and environmental practices and comply with regulatory limitations, including potential sales prohibitions.