Three levels of standards are recognized in legislation and trade agreements amongst many countries: 

• International Standards are voluntary sets of specifications approved through consensus by an accredited international standardizing body that is registered with, and that operates in alignment with the WTO "Code of Good Practice for the Preparation, Adoption and Application of Standards". In this context, a standard is a “document approved by a recognized body, that provides, for common and repeated use, rules, guidelines or characteristics for products or related processes and production methods, with which compliance is not mandatory." 
• National Standards are voluntary sets of specifications approved through consensus by any national governmental or non-governmental body that is registered with, and that operates in alignment with the WTO's abovementioned provisions. National standards must conform with international standards except when no applicable international standard exists, or when international standards would be an ineffective or inappropriate means to fulfil legitimate objectives of the domestic regulation or standard. 
• Industry Standards are specifications adopted by broadly-based industry consortia which have not been submitted to or approved by fully-accredited international or national standards bodies as defined under the WTO. These may include self-management and self-regulatory agreements which represent consensus within an industry association. These may exist as general guidelines, or  they may be detailed and specific requirements backed by compliance assurance mechanisms.