In the field of engineering construction, the terms "standards," "codes," and "procedures" are the three most frequently used basic terms and also the ones that people find the hardest to understand. The concept of standards has been discussed earlier. According to the General Terminology for Standardization and Related Fields, Part One: Basic Terms (GB3935.1), codes generally refer to a series of regulations made for technical matters such as design, construction, manufacturing, and inspection in industrial and agricultural production and engineering construction. Procedures, on the other hand, are unified regulations made for technical requirements and implementation processes related to operations, installation, appraisal, safety, management, etc.