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D3705-14 – Standard Test Method Technical Guide
ASTM D3705-14 (Reapproved 2019) is the standardized test method for determining the misting characteristics of lubricating fluids used in industrial mist lubrication systems. Administered by Subcommittee D02.L0.01 on Metal Removal Fluids and Lubricants, this method quantifies critical performance parameters such as generator output, reclassified oil, line condensate, and stray mist through a gravimetric procedure.
⚙️ Scope and Test Summary
This test method specifically covers the determination of the misting characteristics of lubricating fluids. As stated in Note 1 of the standard, it must not be used to evaluate fluids containing solid additives such as graphite.
⚠️ Critical Constraint: This test method should not be used to evaluate fluids containing solid additives, such as graphite (see Scope 1.1, Note 1). For specific safety warnings, refer to Sections 7 and 8 of the standard.
The test procedure involves charging an oil mist generator with the sample and operating the system for a precise period of 19 hours. The mist generator, line condensate bottles, and reclassified oil collector are weighed immediately before and after the test. The output from the generator and the percentages of reclassified oil, line condensate, and stray mist are mathematically determined from these weight changes.
🛠️ Apparatus and Key Terminology
The apparatus is centered around an Alemite No. 383802-B43 oil mist generator combined with the specific ASTM-ASLE mist head (383803-B4). The test rig utilizes distinct tubing geometries to separate oil fractions. Oil coalescing in the 38 mm (1½ in.) tubing and the diagonal 19 mm (¾ in.) tubing is classified as line condensate. Conversely, oil coalescing in the vertical 19 mm (¾ in.) tubing is classified as reclassified oil.
💡 Unit Standardization: According to Section 1.2, SI units are regarded as the standard for the method, though Inch-pound units are specifically used to describe the various tube fittings and thread sizes shown in the standard’s figures.
| 🟦 Component | 📏 Specification | 📐 Function / Note |
|---|---|---|
| Oil Mist Generator | Alemite No. 383802-B43 | Core unit for generating the mist cloud |
| Special Mist Head | ASTM-ASLE 383803-B4 | Precision atomization component |
| Line Condensate Tubing | 38 mm (1½ in.) & Diagonal 19 mm (¾ in.) | Collects coalesced oil unavailable for lubrication |
| Reclassified Oil Tubing | Vertical 19 mm (¾ in.) | Collects coalesced oil available for lubrication |
According to the terminology defined in the standard, line condensate is oil mist which has coalesced in the distribution lines and is not available for lubrication purposes. Reclassified oil is the lubricant that has coalesced into larger droplets at the points of required lubrication.
📊 Key Measured Properties
The performance of the lubricating fluid is evaluated through gravimetric analysis, resulting in specific performance indicators. The calculations provide a breakdown of how the oil mist distributes throughout the system. The standard serves as a guide for evaluating misting characteristics, though it explicitly states that the degree of correlation between this test and actual service performance has not been fully determined.
| 🎯 Measured Parameter | ⚡ Definition & Calculation Basis |
|---|---|
| Generator Output | Total mass of oil expelled from the mist generator during the 19-hour test |
| Reclassified Oil | Percentage of the output that coalesces in the vertical tubing, representing oil available for lubrication |
| Line Condensate | Percentage of the output that coalesces in the horizontal/diagonal tubing, representing oil lost in distribution |
| Stray Mist | Percentage of the output not captured in the collectors, determined by the remainder calculation |
❓ Frequently Asked Questions
🔍 What does ASTM D3705 specifically evaluate?
It evaluates the misting characteristics of lubricating fluids, quantifying how much oil mist becomes line condensate (lost in the lines), reclassified oil (available for lubrication), and stray mist (unaccounted aerosol).
💡 Can this test method be used for any type of lubricant?
No. As per Note 1 of the standard, this test method should not be used to evaluate fluids containing solid additives such as graphite. It is specifically designed for liquid lubricating oils.
⚡ What is the established duration of the standard test procedure?
The mist generator is operated for a total of 19 hours. The weights of the generator, line condensate bottles, and reclassified oil collector are taken immediately before and after this defined period to calculate the results.
📌 What is the difference between line condensate and reclassified oil?
Line condensate is defined as oil mist that has coalesced in the distribution lines (collected in the 38 mm and diagonal 19 mm tubing) and is unavailable for lubrication. Reclassified oil is the lubricant that coalesces into larger droplets at the points of required lubrication (collected in the vertical 19