Standards have different purposes. The purpose of the standard determines its type. Some standard types include:

Voluntary Standards

Most standards are voluntary. These standards increase safety, ease of manufacturing and interactions between products, and thus are widely used across industry. Governments generally do not mandate that engineers and manufacturers follow these voluntary standards.

japanese teapot, piles of looseleaf tea, in front of cherry blossoms

An example of a voluntary standard is ISO 3103 which documents a method for brewing tea that could be used to compare blends.

Mandatory Standards

Mandatory standards must be followed. The federal government, a government agency, or governmental departments enforce these standards. They are adopted out of concern for safety. Failure to follow such standards results in legal penalties and liability.

One type of mandatory standard is a building code or a fire code adopted by a city's code of ordinances.

For example, the International Fire Code, 2015 (excerpt pictured above) is a mandatory standard because the City of Ann Arbor adopted it in Chapter 111 of its city code. Builders in Ann Arbor need to use this code to inform their building practices.

Voluntary Standards that Become Mandatory

Sometimes, voluntary standards become mandatory as was the case with ASTM F963-23 Standard Consumer Safety Specification for Toy Safety, which the U.S. Consumer Product Safety Commission adopted. It is now mandatory. This standard increases safety for children who play with toys.

Below is a paper insert that one of the engineering librarians found in a Kinder Egg mentioning standard ASTM F963.

image of the standard inside the kinderegg

Definition Standards

Standards that provide standard measurement, symbology or terminology are definition standards. These create a foundation on which many other standards can be created. The metric system is an example of a definition standard.