Physical Address
304 North Cardinal St.
Dorchester Center, MA 02124
D5734-95 – Standard Test Method Technical Guide
📋 Test Overview and Scope
This test method, ASTM D5734-95 (Reapproved 2001), covers the measurement of the average force required to propagate a single-rip tear starting from a cut in a nonwoven fabric using a falling-pendulum (Elmendorf) apparatus. It applies to most nonwoven fabrics, treated or untreated, including heavily sized, coated, or resin-treated materials, provided the tear occurs in the direction of the applied force. Values are stated in SI units with approximate inch-pound equivalents.
If the tear does not occur in the direction of the test, the fabric is considered untearable in that direction by this test method. Careful marking of lengthwise and widthwise directions is essential for valid results.
⚙️ Apparatus and Specimen Preparation
The standard Elmendorf tear tester with interchangeable pendulums is preferred for determining tearing strength up to 6400 grams-force. For forces above 6400 grams-force, a high-capacity instrument with augmenting weights is specified. Older instruments with augmenting weights may be used when agreed upon between parties. Specimens must be conditioned according to Practice D1776 to ensure consistent moisture content.
| 🛠️ Equipment Type | ⚡ Capacity (grams-force) |
|---|---|
| Standard Elmendorf tester | Up to 6400 |
| High-capacity tester (with augmenting weights) | Above 6400 |
| Older instrument (with augmenting weights) | Upon agreement |
Always condition textiles in accordance with ASTM D1776 prior to testing to minimize the influence of moisture on tearing strength results.
📊 Key Measured Properties and Terminology
Tearing strength is defined as the force required to start, continue, or propagate a tear under specified conditions. In practice, tearing force is recorded as the maximum force needed to continue a tear from an initial cut. Other key terms include length of tear, measured on the fabric before tearing, and tearing energy, which is the work done during the tearing process. These definitions align with Terminologies D123 and D4848.
| 📐 Term | 📖 Definition |
|---|---|
| Tearing strength | Force required to start, continue, or propagate a tear |
| Tearing force | Average force to continue a tear (recorded as maximum) |
| Length of tear | Fabric length torn, measured before tearing |
| Tearing energy | Work done in tearing the specimen |
❓ Frequently Asked Questions
🔍 What is the scope of ASTM D5734-95?
This method measures tearing strength of nonwoven fabrics using an Elmendorf apparatus, applicable to most nonwovens except those that do not tear in the direction of force.
💡 What apparatus capacity is available?
The standard tester handles up to 6400 grams-force, while a high-capacity version with augmenting weights covers forces above 6400 grams-force. Older instruments may be used upon agreement.
⚡ How is tearing strength defined?
Tearing strength is the force required to start, continue, or propagate a tear; it is recorded as the maximum force during the test.
📌 Why is direction marking critical for nonwovens?
Nonwovens may lack a distinct grain pattern. Clear marking of lengthwise and widthwise directions ensures the tear propagates in the intended direction, avoiding invalid results.