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D1815-00 – Standard Test Method Technical Guide
📐 Scope and Significance
This standard, designated ASTM D1815‑00 (Reapproved 2021), covers the determination of the amount of water absorbed by leather at 23 ± 2 °C by immersion under static conditions. It is particularly adapted for vegetable‑tanned sole leather and is widely used to determine compliance with specifications for impregnated sole leather. The standard explicitly does not apply to wet blue. Users must recognize that the significance of the test method is limited by the static conditions employed; results do not reflect water absorption under the dynamic conditions of flexing. If required, results may be corrected for any water‑soluble material removed from the leather during the test.
⚙️ Apparatus and Specimen Geometry
The test method requires a specific set of apparatus. The test specimen is a rectangle of leather approximately 2 by 4 in. (51 by 102 mm). Unless otherwise specified, one specimen from each test unit shall be tested.
| 🟦 Apparatus | 📏 Specification / Requirement |
|---|---|
| Immersion Dish | Glass or noncorrosive material; flat bottom, min 3 × 5 in. (76 × 127 mm) |
| Balance | Sensitive to 0.01 g |
| Steel Scale / Tape | Conforming to Test Method D1516 |
| Thickness Gauge | Conforming to Test Method D1813 |
| Crystallizing Dish | Borosilicate glass, 50 mm tall, 70 mm outside diameter |
| Support / Weight | Pieces of glass rod for supporting and weighting the specimen |
⚠️ Crucial Note on Static Conditions: This test method measures water absorption under static conditions. It does not replicate the dynamic flexing conditions leather may encounter in service. Results must be interpreted strictly within this limited scope.
💧 Test Procedure and Key Measured Properties
The procedure begins by determining the length, width, and thickness of the specimen in accordance with Test Method D1516 and Test Method D1813, calculating its volume in cubic centimetres. The specimen is weighed to the nearest 0.01 g; this mass is recorded as W1. The specimen is then placed in the immersion dish in a horizontal position with the grain side up. It is supported on glass rods or beads and weighted with pieces of glass rod to keep it submerged with all surfaces exposed.
After the specified immersion period, the amount of water absorbed is measured. The result is expressed as a percentage of the original mass (W1) or related to the specimen volume.
| 📐 Parameter | 🎯 Specification / Calculation |
|---|---|
| Test Temperature | 23 ± 2 °C (room temperature) |
| Specimen Position | Horizontal, grain side up |
| Initial Mass (W1) | Weighed to nearest 0.01 g |
| Water Absorption | Calculated from the increase in mass relative to W1 or per unit volume |
💡 Tip for Accurate Results: When removing the specimen from the water, blot it lightly with blotting or filter paper to remove surface water only. Avoid squeezing the specimen, which could force water out of the leather structure and invalidate the static absorption measurement.
❓ Frequently Asked Questions
🔍 What types of leather does ASTM D1815‑00 apply to?
It is particularly adapted to vegetable‑tanned sole leather, though it may be used on all types of leather except wet blue.
💡 What is the required size of the test specimen?
The test specimen must be a rectangle approximately 2 by 4 inches (51 by 102 mm).
⚡ Why is this test method considered limited in its significance?
The results are based on static conditions and do not reflect water absorption under the dynamic conditions of flexing.
📌 How is the water absorption result corrected for soluble materials?
If required, the result may be corrected for any water‑soluble material removed from the leather during the test.