Physical Address
304 North Cardinal St.
Dorchester Center, MA 02124
D2290-19 – Standard Test Method Technical Guide
🎯 Scope and Procedure Selection for D2290-19a
ASTM D2290-19a is the standard test method for determining the apparent hoop tensile strength of plastic or reinforced plastic pipe. The standard covers both reinforced-thermosetting resin pipe (RTRP) and extruded or molded thermoplastic pipe. It defines five distinct procedures (A through E), where the selection depends on the pipe material, nominal diameter, and wall thickness. All values are reported in inch-pound units, which are regarded as the standard per the designation.
Conditioning of specimens follows Practice D618, while force verification of test machines complies with Practices E4. The test method is comparative and is performed under defined conditions of pretreatment, temperature, humidity, and machine speed.
| 🟦 Procedure | 📏 Material | 📐 Nominal Diameter | 🎯 Wall Thickness |
|---|---|---|---|
| A | Reinforced Thermosetting Resin (RTRP) | Any | Any |
| B | Thermoplastic (All Types) | Any | Any |
| C | Thermoplastic | ≥ 4 ½ in. (110 mm) | Any |
| D | Polyethylene (PE) | ≥ 14 in. (350 mm) | ≥ 1 in. (25 mm) |
| E | Polyvinyl Chloride (PVC) | ≥ 14 in. (350 mm) | ≥ 0.5 in. (12.7 mm) |
🛠️ Fixture Configuration and Loading Principles
The standard recognizes the inherent challenge of testing ring segments under tension. For Procedures A, B, and C, a self-aligning split disk test fixture (Fig. 1) is used. While this fixture applies tensile stress, it induces a bending moment at the split due to the change in contour of the ring as the disk sections separate. This is why the result is termed apparent tensile strength; the fixture is designed specifically to minimize this bending moment.
Procedure D uses a pair of ring segment test specimens loaded into self-aligning fixtures (Fig. 2). These fixtures apply direct tensile stress to the reduced areas of the specimens (Fig. 3) with minimal bending moment. Procedure E utilizes a single ring segment specimen in a self-aligning fixture (Fig. 4) also designed for direct tensile stress on reduced sections (Fig. 5/Fig. 6).
| ⚙️ Fixture Feature | 📐 Proc A / B / C | 📐 Proc D | 📐 Proc E |
|---|---|---|---|
| Fixture Type | Split Disk (Self-Aligning) | Ring Segment Pair | Single Ring Segment |
| Figure Reference | Fig. 1 | Fig. 2 & 3 | Fig. 4, 5, 6 |
| Stress Application | Tensile (with bending moment) | Direct Tensile | Direct Tensile |
| Bending Moment Induced | Present (minimized by design) | Minimal | Minimal |
📊 Significance of Test Results
When properly interpreted, the split disk and ring segment tensile tests provide reasonably accurate information regarding the apparent tensile strength of the pipe material. The apparent nature of the value is a direct result of the bending moment imposed by the split fixture, preventing a pure tensile state. This test method is distinct from the short-time hydraulic pressure test (D1599) but is commonly used for quality control, material specification compliance, and comparative analysis of pipe performance.
💡 Practical Guidance: The “apparent” nature of the result in Procedures A, B, and C must be carefully considered when comparing materials. Procedures D and E are specifically engineered to apply direct tensile stress to reduced areas, providing a closer approximation to true tensile strength for large-diameter pipes.
❓ Frequently Asked Questions
🔍 Why does D2290 define an “apparent” tensile strength rather than a true tensile strength? In Procedures A, B, and C, the split disk fixture induces a bending moment at the split line due to the change in ring contour as the disks separate. This prevents the measurement of a pure tensile stress, hence the term “apparent” hoop tensile strength.
💡 Which procedure applies to a 20-inch PE pipe with a 1.5-inch wall thickness? Procedure D. This procedure is specifically designated for polyethylene pipe with a nominal diameter of 14 in. (350 mm) and greater, preferably having a wall thickness of 1 in. (25 mm) and greater.
⚡ What is the role of Figures 5 and 6 in the standard? Figures 5 and 6 illustrate the specific ring segment test specimen geometry for Procedure E. This procedure is used for PVC pipe with a nominal diameter of 14 in. (350 mm) and greater, and a wall thickness of 0.5 in. (12.7 mm) and greater.
📌 What are the key referenced ASTM standards for this test method? The standard directly references Practice D618