The zero-span tensile test provides information on the fiber strength of paper and is performed to TAPPI T 231. A tensile load is applied to a test strip with a grip-to-grip separation approaching zero. This causes most of the load to be applied to the cellulose fibers and less to the total fabric of the paper.
- The zero-span tensile test is generally carried out using single-purpose instruments which are correspondingly complex and expensive.
- For occasional tests it is worth making use of the modular building block system of specimen grips and supplementary devices.
- The exact position of the two specimen grip units relative to each other must first be set (once only) with reference to angular position and horizontal position. A mechanical add-on kit is available for this.
- The specimen grips must comply with minimum accuracy requirements, therefore pneumatic grips are needed.
- The jaws required protrude upwards from the base of the grips, allowing a free length of around 0.1 mm.