Q: Which CPSIA lead limits apply to zipper sliders and pulls?
Under CPSIA, zipper sliders, pulls, teeth and stops are treated as accessible component parts of a children's product, so each metallic part is screened for total lead. The substrate limit for a children's product is 100 ppm. Painted or plated finishes that can be scraped off are assessed as a surface coating, where the limit is 90 ppm, so a plated slider may need both a coating test and a substrate test.
Screen with XRF first, then confirm by acid digestion and ICP-MS. Keep each homogeneous material and finish separate; grinding the whole assembly into one composite can hide a failing slider behind passing brass. Report results in mg/kg with the method and the sample mass, and photograph the parts tested. Conditioning, digestion and detection limits are set in the test method, so refer to the standard text for the exact procedure.
Acceptance is judged per homogeneous material, not on the average of the assembly. Every material must sit below its limit, and the report must name the part, the finish and the date. Retest whenever an alloy, plating bath or paint colour changes, and keep the reports with the bill of materials so the garment maker can support its children's product certificate.