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D3483-14 – Standard Test Method Technical Guide
📐 Overview of Test Methods for Accumulated Deposition
These test methods cover the determination of the weight per unit area of waterside deposits on heat-transfer surfaces of steam generator tubes. Three test methods are included: Test Method A (mechanical removal by scraper), Test Method B (chemical removal by solvent), and Test Method C (mechanical removal by glass-bead blasting). Each method is generally applicable to deposits ranging from 1 to 100 g/ft², with precision determined in collaborative studies over specific ranges.
Test Method A allows for further chemical analysis of the removed deposit, while Test Methods B and C average out heavier and lighter deposited areas. The solvent solution from Method B can be analyzed, but the deposit from Method C is not suitable for further chemical analysis.
| 🟦 Test Method | 📏 Applicable Range (g/ft²) | 🎯 Precision Range (g/ft²) | ⚡ Further Analysis |
|---|---|---|---|
| Test Method A | 1 to 100 | 16 to 76 | Yes |
| Test Method B | 1 to 100 | 28 to 73 | Yes (solvent solution) |
| Test Method C | 1 to 100 | 17 to 88 | No |
⚙️ Test Procedures and Considerations
Test Method A involves mechanical removal using a scraper or vibrating tool, allowing discretionary selection of the sampling area on the tube. This is particularly important for rifled tubes where grooves tend to hold more deposit. In such cases, the user must decide whether to sample from grooves or lands and report the choices made.
Test Method B uses a chemical solvent to remove deposits, averaging out variations across the tube. The resulting solvent solution can be used for further chemical analysis. Test Method C employs glass-bead blasting for mechanical removal, which also averages deposits but does not permit further analysis of the removed deposit.
🔍 When using Test Method A on rifled tubes, be aware that grooves on the tube may hold more deposit. Carefully choose the sampling area to reflect the deposit distribution, and clearly report your method in the final report.
For tubes with obvious fire side and casing side differences, internal deposition is often greater on the fire side. Users may choose to test only one side, both sides separately, or average the results. It is crucial to specify the approach in the report.
📊 Key Measured Properties and Precision
The primary measured property is the weight per unit area of deposit, reported in g/ft² or g/m². Precision was determined through collaborative studies for each method within specific deposit weight ranges. The standard emphasizes that the test methods are validated for typical waterside deposits on heat-transfer surfaces of steam generator tubes.
| 🟦 Test Method | 📐 Collaborative Study Range (g/ft²) | 📏 General Applicability |
|---|---|---|
| Test Method A | 16 to 76 | 1 to 100 g/ft² |
| Test Method B | 28 to 73 | 1 to 100 g/ft² |
| Test Method C | 17 to 88 | 1 to 100 g/ft² |
⚠️ The user is responsible for ensuring the validity of these test methods for other types of deposits or high-temperature scale. These methods are generally evaluated on typical waterside deposits found on steam generator tubes.
❓ Frequently Asked Questions
🔍 What is the main difference between Test Methods A, B, and C?
Test Method A uses mechanical removal and allows for further chemical analysis of the deposit. Test Method B uses chemical solvent removal and produces a solvent solution for analysis, averaging out deposit variations. Test Method C uses glass-bead blasting, which averages deposits but does not allow for further chemical analysis of the removed deposit.
💡 How should deposits on rifled steam generator tubes be handled?
For rifled tubes, Test Method A requires careful choice of sampling area due to differences between grooves and lands. Test Methods B and C naturally average out these differences. Always report the choices made when using Test Method A.
⚡ What deposit weight range is applicable for these methods?
All methods are generally applicable for deposits ranging from 1 to 100 g/ft². Precision was determined in collaborative studies over sub-ranges: 16-76 g/ft² for Method A, 28-73 g/ft² for Method B, and 17-88 g/ft² for Method C.
📌 Can these test methods be used for deposits other than waterside deposits?
These methods are primarily evaluated for typical waterside deposits on heat-transfer surfaces. Users must validate the methods for other types of deposits or high-temperature scale to ensure accuracy.