The 2012 edition of NFPA 70E has gotten specific about zipper tape. In the previous edition there was no specific mention about the zipper tape fabric requirements. Keeping an arc rated garment closed during an arc flash incident can be important. And because the zipper tape can be an important component in keeping a garment closed it was felt that adding wording about the material characteristics of that tape was important. Therefore in section 130.7(C)(11) the following wording is now in the standard.
“Clothing consisting of fabrics, zipper tapes, and findings made from flammable synthetic materials that melt at temperatures below 315°C (600°F), such as acetate, acrylic, nylon, polyester, polypropylene, and spandex, either alone or in blends, shall not be used.”
This means the zipper tape must basically be FR. It is not stated in the standard but it is a good practice to cover the exterior face of the zipper and zipper tape as much as possible so as to protect the zipper tape even better. Because the zipper tape is not likely to have as high of an arc resistance as the garment fabric itself, the fabric covering will help prevent the zipper tape from breaking open during an arc event. It is also required to have FR fabric between the zipper and the skin as specified in ASTM F1506.
Workrite uses Nomex zipper tape, has an interior layer of fabric behind the zipper and fabric covering most if not all of the exterior of the zipper.