Enterprises use non-compulsory inspection measuring instruments can not be periodic calibration?

According to our company's situation and my personal opinion, just for your reference. Measurement law is a small law, in the current requirements are not strict. Requirements for strong inspection is not necessarily strong inspection. Like our unit is completely self-submitted inspection. Mainly based on the security protection, trade settlement, measurement standards and other instruments to be sent for inspection. Non-compulsory inspection according to the company's internal measurement management system will manage the apparatus. As for the need for periodic calibration, also depends on the strictness of the management system, as well as customer requirements. For our company from time to time there will be customers to audit the company, will require which instruments need to be tested. In the production process, the necessary measuring instruments or need to manage up, will be included in the management account. For example, our company: electronic scales, scales, pressure gauges, thermocouples, RTDs, standard measuring instruments included in the ledger. Like wearing parts densitometer, measuring cylinders and what is not included in the ledger, that is, there is no periodic calibration work, not out of the critical, the main production process of measuring instruments, there is no calibration.