A standard is a document that provides requirements, specifications, guidelines or characteristics that can be used consistently to ensure that materials, products, processes and services are fit for their purpose. International standards ensure that products and services are safe, reliable and of good quality.
Source: ISO Standards
The costs associated with the development, publication, and distribution of standards are significant expenses, which is why standards organizations do not provide access to standards for free. In addition, there are copyright restrictions on standards that typically prohibit users from copying, printing, or reproducing any part of the document. These restrictions can make it difficult for libraries to provide access to standards.
Sources: Telecommunications Industry Association Standards Education and Resources
How to best use IEC and ISO Standards: a user guide on licensing options and respecting copyright
Some standards organizations make access to their standards for viewing or download available for no cost.