The connection and difference between API and ASME standards

In the realm of industrial standards, two significant organizations stand out: the American Petroleum Institute (API) and the American Society of Mechanical Engineers (ASME). Both play crucial roles in setting and maintaining standards that ensure safety, reliability, and efficiency in various industries. Here, we explore the background, responsibilities, and differences between API and ASME standards.

API 5L seamless steel pipes

API 5L seamless steel pipes

API: American Petroleum Institute


The American Petroleum Institute, abbreviated as API, was established in 1919. It is the first national trade association in the United States and one of the earliest and most successful standard-setting bodies in the world. API has been instrumental in developing standards that support the oil and natural gas industry.


API is an ANSI (American National Standards Institute) accredited standards-developing organization. Its standards are developed following ANSI’s guidelines for consensus and procedural fairness. API also collaborates with ASTM International to develop and publish standards. API standards are widely used not only by industries within the United States but also by federal and state agencies such as the Department of Transportation, the Department of Defense, OSHA, U.S. Customs and Border Protection, the Environmental Protection Agency, and the U.S. Geological Survey. Internationally, API standards are adopted by ISO (International Organization for Standardization), OIML (International Organization of Legal Metrology), and standards bodies in over 100 countries.


API standards cover various aspects of the petroleum and natural gas industry, including drilling, production, refining, and transportation. They are critical for ensuring safety, operational efficiency, and environmental protection.

ASME B16.9 ASTM A234 WP5 90°LR Elbows

ASME B16.9 ASTM A234 WP5 90°LR Elbows

ASME: American Society of Mechanical Engineers


Founded in 1880, the American Society of Mechanical Engineers (ASME) is a leading international non-profit educational and technical organization with over 125,000 members worldwide. ASME is dedicated to promoting interdisciplinary knowledge and collaboration in engineering, focusing on areas such as basic engineering, manufacturing, and systems design.


ASME’s primary focus is on advancing the science and practice of mechanical engineering and related disciplines. It encourages fundamental research, academic exchange, and collaboration with other engineering societies. ASME is also heavily involved in standardization activities, developing codes and standards that govern mechanical devices and systems. Since its inception, ASME has led the development of over 600 standards, starting with thread standards and expanding to include the Boiler and Pressure Vessel Code (BPVC), which was first published in 1914-1915 and has since been integrated into laws across various states and countries, including Canada.


ASME standards are essential for various engineering disciplines, particularly in mechanical engineering. They cover a wide range of subjects, from the design and construction of boilers and pressure vessels to the development of performance standards for valves, piping, and other mechanical components.

Differences and Connections

Complementary Roles:

API and ASME often complement each other. For example, ASME standards for valves frequently incorporate elements of API standards. While they may share commonalities, their primary focus and industry applications differ, leading to the adoption of different standards.

Industry Focus:

API: Primarily serves the petroleum and natural gas industry, focusing on standards for drilling, production, and refining processes.

ASME: Concentrates on mechanical engineering across various industries, including power generation, manufacturing, and infrastructure.

Standard Development:

API: Develops standards with a specific focus on the petroleum sector, ensuring compatibility with federal and state regulations and international adoption.

ASME: Develops broader engineering standards that are often integrated into national and international regulations and practices.

Standard Overlap:

There are instances where standards overlap or are referenced by both organizations. ASME, for instance, may adopt API standards for certain applications, leading to identical or similar standard numbers but applied within different contexts.

API and ASME are cornerstone organizations in the development of industrial standards, each serving distinct yet sometimes overlapping sectors. API’s focus on the petroleum industry and ASME’s broader engineering scope highlight their unique contributions to industrial safety, efficiency, and innovation. By understanding the roles and standards of each organization, industries can better navigate and apply these guidelines to enhance their operations and comply with regulatory requirements.