1. The manufacturer shall provide an official letter on the application for periodic review and re-examination of the "explosion-proof certificate" three months before the expiration of the expiry date of the explosion-proof certificate. The letter indicates the original product name, model, specifications, number of the explosion-proof certificate, the date of obtaining evidence and the part of the modification of the present product.
2. CQST reviews whether the original product drawings and technical documents have changed. The alteration part shall be re-examined and put on record (two copies of the alteration part of drawings and technical documents shall be submitted for examination).
3. Reviewing and correcting the legacy problems in the original product drawings and technical documents and the problems arising from the revision of the standards.
4. The manufacturer shall provide the existing production prototype for the re-inspection of explosion-proof performance. The prototype shall meet the requirements of the existing product drawings and technical documents, and pay the re-inspection and inspection fees.
5. According to the requirements of the manufacturer, a series of products can be delivered to the factory for service.
6. After reexamination and reexamination, the explosion-proof certificate shall be renewed. The period of validity of the reexamination certificate is five years from the expiration date of the original certificate. If the time of reexamination is delayed, the period of validity of the reexamination certificate will be shortened accordingly. If the expiration date exceeds one year, a complete set of explosion-proof inspection shall be carried out according to the newly delivered products.