Codes, Regulatory Requirements, Standards, Specifications and Recommended Practices are used in all aspects of construction, fabrication, manufacturing and inspection. The following is a brief description of each of these categories along with examples of how they are used. In some way this order can represent a hierarchy of the strength of the application of each term.
Codes are generally the top-tier documents, providing a set of rules that specify the minimum acceptable level of safety for manufactured, fabricated or constructed objects. These may incorporate regulatory requirements and will often refer out to standards or specifications for specific details on additional requirements not specified in the Code itself.
Regulations are generally issued by a state or federal agency when public safety is an issue.
Standards are documents that establish engineering or technical requirements for products, practices, methods or operations.
Specifications provide specific requirements for materials, components or services and are often generated by private companies to address additional requirements applicable to a specific product or application.
Recommended practices provide guidelines for performing operations or functions.