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D2422-24 – Standard Test Method Technical Guide
🛢️ Introduction and Scope
This classification, D2422-24, applies to petroleum-based and nonpetroleum fluid lubricants for industrial use such as bearings, gears, compressors, and hydraulic systems. It covers kinematic viscosities from 2 cSt to 3200 cSt at a reference temperature of 40 °C, spanning materials from light kerosene to heavy cylinder oils. The system is structured as a mathematical series to allow future extension if industrial practices change.
📊 Viscosity Grade System
The classification defines 20 viscosity grades, each identified by its nominal kinematic viscosity at 40 °C. Permissible tolerances reduce unjustified intermediate viscosities and provide a uniform basis for specification and selection across suppliers and users.
| 🟦 ISO VG | 📏 Nominal Viscosity (cSt) | 📐 Min Viscosity (cSt) | 🎯 Max Viscosity (cSt) |
|---|---|---|---|
| ISO VG 2 | 2.2 | 1.98 | 2.42 |
| ISO VG 10 | 10 | 9.0 | 11.0 |
| ISO VG 32 | 32 | 28.8 | 35.2 |
| ISO VG 68 | 68 | 61.2 | 74.8 |
| ISO VG 100 | 100 | 90.0 | 110 |
| ISO VG 220 | 220 | 198 | 242 |
| ISO VG 460 | 460 | 414 | 506 |
| ISO VG 1000 | 1000 | 900 | 1100 |
| ISO VG 3200 | 3200 | 2880 | 3520 |
⚙️ Significance and Use
This classification establishes definite viscosity levels for industrial fluid lubricants, enabling consistent designation and selection by suppliers, users, and equipment designers. It eliminates unjustified intermediate grades and provides suitable grade increments, a uniform reference temperature, and defined tolerances. It does not evaluate lubricant quality or apply to automotive lubricants with SAE numbers.
💡 Tip: Always measure viscosity at the reference temperature of 40 °C to ensure accurate grade identification per this system.
⚠️ Note: This classification addresses only viscosity at 40 °C and does not imply any evaluation of lubricant quality or performance.
❓ Frequently Asked Questions
🔍 What is the viscosity range covered by this standard?
The standard covers kinematic viscosities from 2 cSt to 3200 cSt at 40 °C.
💡 How are viscosity grades designated?
Grades are designated by their nominal kinematic viscosity at 40 °C, following the ISO VG system.
⚡ What is the reference temperature for measurement?
The reference temperature for viscosity measurement is 40 °C.
📌 Does this standard apply to automotive lubricants?
No, this classification does not apply to automotive lubricants that use SAE viscosity numbers.