Standard
A  technical standard is an established norm or requirement.  It is usually a formal document that establishes uniform engineering or technical criteria, methods, processes and practices.
A technical standard can also be a controlled artifact or similar formal means used for calibration.  Reference Standards and certified reference materials have an assigned value by direct comparison with a reference base. A primary standard is usually under jurisdication of a national standards body. Secondary, tertiary, check standards  and standard materials may be used for reference in a metrology system.
This article discusses formal technical standards.  A custom, convention, company product, corporate standard, etc which becomes generally accepted and dominant is often called a de facto standard.
A technical standard can be developed privately or unilaterally, for example by a corporation, regulatory body, military, etc.  Standards can also be developed by groups such as trade unions, and trade associations.  Standards organizations usually have more diverse input and usually  develop voluntary standards:  these might become mandatory if adopted by a government,  business contract, etc.
The standardization process may be by edict or may involve the formal consensus  of technical experts.

# Types of Standards
The primary types of technical standards are:
- A standard specification  is an explicit set of requirements for an item, material, component, system or service. It is often used to formalize the technical aspects of a procurement agreement or contract.  For example, there may be a specification for a turbine blade for a jet engine which defines the exact material and performance requirements.
- A standard Goal
- A standard test method describes a definitive procedure which produces a test result.  It may involve making a careful personal observation or conducting a highly technical measurement. For example, a physical property of a material is often affected by the precise method of testing:  any reference to the property should therefore reference the test method used.
- A standard  procedure (or standard practice) gives a set of instructions for performing operations or functions.   For example, there are detailed standard operating procedures for operation of a nuclear power plant.
- A standard guide is general information  or options which do not require a specific course of action.
- A standard definition is formally established terminology.

# Enforcement
Many standards are written as voluntary standards.  Interested parties may participate in the development voluntarily and the use of the finished standard is voluntary.  The standards organization usually does not have any way to impose their use or to enforce compliance.   People and organizations may choose to use or not to use a published voluntary standard.
Some standards are written to be mandatory standards.  A defense standard is mandatory in relation to that use: It may be voluntarily referenced by a different organization. A standard written and published by a government regulator is mandatory for that use. (A standard which is enforced by law is sometimes called a de jure standard.)  A corporation may write its own standard for its mandatory use.
The use of some voluntary standards may sometimes become mandatory.
- A voluntary standard may be referenced or adopted by a government or regulatory body.  Its use becomes mandatory within the scope of its legal reference.  Enforcement is by the regulator or government body which chose to reference the standard.  
- A voluntary standard may be referenced or adopted by a private organization or become part of a legal contract.  The voluntary standard becomes mandatory within the scope of that usage or contract. 
- A voluntary standard sometimes may sometimse become  so common and dominant that its use becomes expected.. Enforcement of a de facto standard is usually by free market forces.

# Availability
Standards may be:
- Public documents available on the internet,  public library, etc.  (Some technical standards may be found at a major central library or at the library of a good technical university.)
- Published documents which are available for purchase.
- Private documents owned by an organization or corporation.  These are used and circulated as they determine necessary or useful.
- Documents open for public use but with intellectual property (copyright, etc) associated with them. 
- Closed or controlled documents which contain trade secrets or classified information.

# Geographic levels
When a geographically defined community needs to solve a community-wide coordination problem, it can adopt an existing  standard, or produce a new one.
The main geographic levels are:
- National standard:  by National standards organizations.
- Regional standard: see standards of the Regional standards organizations. For example, CEN standards.
- International standard: see  International standards organizations Example, ISO and ASTM International.
National/Regional/International standards is one way of overcoming technical barriers in inter-local or inter-regional commerce caused by differences among technical regulations and standards developed independently and separately by each local, local standards organisation, or local company. Technical barriers arise when different groups come together, each with a large user base, doing some well established thing that between them is mutually incompatible. Establishing national/regional/international standards is one way of preventing or overcoming this problem.

# Usage
The existence of a published standard does not imply that it is always useful or correct. For example, if an item complies with a certain standard, there is not necessarily assurance that it is fit for any particular use. The people who use the item or service (engineers, trade unions, etc) or specify it (building codes, government, industry, etc) have the responsibility to consider the available standards, specify the correct one, enforce compliance, and use the item correctly. Validation of suitability is necessary.
Standards often get reviewed, revised and updated.  It is critical that the most current version of a published standard be used.  The originator or standard writing body often has the current versions listed on its web site.