Q: How is surface resistance measured on anti-static zipper tape?
Surface resistance is measured by placing two electrodes on the specimen at a defined separation, applying a known voltage and reading the resistance after a defined electrification time. Ring or parallel-plate electrodes are used on flat material, and the result is expressed in ohms or ohms per square. The reading depends heavily on humidity, so the specimen must be conditioned in the specified atmosphere before testing.
For a zipper, the measurement is taken on the tape face and, where relevant, along the chain, because the conductive path may run through the tape rather than through the teeth. Clean the surface, avoid touching the test area, and record the voltage used; a low-voltage reading on a humid day can flatter a material that would fail at a higher voltage. Electrode geometry and conditioning time are fixed by the method, so refer to the standard text.
Acceptance is normally a band rather than a single number: a surface resistance below the agreed ceiling for the application, and above the floor that would indicate a conductive, potentially unsafe material. Report the test atmosphere with the result, and retest whenever the tape's carbon or conductive yarn content changes.