Q: What surface resistance range makes a zipper anti-static?
The answer comes from the application, not from a universal number. A common industrial convention treats surfaces between about 10 to the 6 and 10 to the 9 ohms as dissipative, and between 10 to the 9 and 10 to the 12 ohms as anti-static in the looser sense. Above that, charge drains slowly and clinging and sparking become likely. Electronics, cleanroom and explosive-atmosphere users each set their own ceiling.
For a garment zipper, the practical complaint is clinging, crackling or a spark when the wearer touches grounded metal, so the specification should state the resistance band, the test atmosphere and the measurement method. Test the assembled tape, not the raw yarn, because weaving, dyeing and finishing can change the conductive network. Where the requirement is ESD protection rather than comfort, the standard and the acceptance band must come from the customer's safety assessment.
Write the acceptance as a range with a stated method and humidity, and test a defined number of specimens per lot. A single reading below the floor should be treated as a deviation, not a bonus, because a conductive zipper can create its own hazard in the wrong environment.