What are ANSI, ISO, and ASTM standards for bearings?

If you’ve searched for bearings online, you’ve likely come across product descriptions boasting about meeting ANSI, ISO, or ASTM standards. You know the standards are a sign of quality – but who came up with them, and what do they mean?

Technical standards help both manufacturers and buyers. Manufacturers use them to make and test materials and products in the most consistent way possible. Buyers use them to ensure they’re getting the quality, specifications, and performance they asked for.

ANSI standards

The American National Standards Institute, or ANSI, is headquartered in Washington, DC. Its members include international bodies, government agencies, organizations, and individuals. It was founded in 1918 as the American Engineering Standards Committee when members of the United Engineering Society and the U.S. government Departments of War, Navy, and Commerce came together to form a standards organization. In its first year, it had only one staff member and an annual budget of $7,500. Today it has more than 270,000 member organizations and 30 million individual members.

ANSI does not create technical standards itself. Instead, it oversees American standards and coordinates them with international ones. It accredits other organizations’ standards, making sure that everyone in the industry agrees on how a standard affects their products and processes. ANSI only accredits standards which it deems fair and open enough.

ANSI helped found the International Organization for Standardization (ISO). It’s the United States’ United States’ official ISO representative.

ANSI has several hundred ball-bearing related standards.

ISO standards

Switzerland-based International Standards Organization (ISO) describes its standards as “a formula that describes the best way of doing something.” ISO is an independent, non-governmental international organization which creates international standards. 167 national standards organizations, like ANSI, are members of ISO. ISO was founded in 1947, after delegates from 25 countries came together to plan the future of international standardization. In 1951, ISO created its first standard, ISO/R 1:1951, which determined the reference temperature for industrial length measurements. Since then, ISO has created nearly 25,000 standards for every imaginable process, technology, service, and industry. Its standards help businesses increase the quality, sustainability, and safety of their products and work practices. There’s even an ISO standard way of making a cup of tea!

ISO has nearly 200 bearing standards. Hundreds of its other standards (like those about steel and ceramic) affect bearings indirectly.

ASTM standards

ASTM stands for American Society for Testing and Materials, but the Pennsylvania-based organization is now ASTM International. It defines technical standards for countries around the world.

ASTM has its roots in the railroads of the Industrial Revolution. Inconsistency in steel rails made early train tracks break. In 1898, chemist Charles Benjamin Dudley formed ASTM with a group of engineers and scientists to find a solution to this dangerous problem. They created a standard set of specifications for railroad steel. Over the 125 years since its founding, ASTM has defined more than 12,500 standards for a huge number of products, materials, and processes in industries ranging from raw metals and petroleum to consumer products.

Anyone can join ASTM, from industry members to academics and consultants. ASTM creates voluntary consensus standards. The members come to a collective agreement (consensus) about what a standard should be. The standards are available for any person or business to adopt (voluntarily) to guide their decisions.

ASTM has more than 150 ball-bearing related standards and symposium papers.

ANSI, ISO, and ASTM standards help you buy the best bearings

Technical standards ensure you and a bearing manufacturer are speaking the same language. When you read that a bearing is made from SAE 52100 chrome steel, you can look up the ASTM A295 standard to find out exactly how the steel was made and what ingredients it contains. If a manufacturer says its tapered roller bearings are the dimensions specified by ISO 355:2019, you know precisely what size you’ll be getting. Though technical standards can be extremely, well, technical, they are an essential tool for communicating with suppliers and understanding the quality and specifications of the parts you buy.

If you need help navigating technical standards for bearings, or finding a bearing which meets a specific standard, contact one of our sales engineers. They’ll be happy to assist you.