First things first:  SealFAQs is not a substitute for the official standard  “Shaft Sealing Systems for Centrifugal and Rotary Pumps”  published by the American Petroleum Institute.  The reader should have access to the complete standard.

Copies of API 682 are available from:

American Petroleum Institute
1220 L Street, N.W.
Washington, D.C. 20005
(800) 854-7179
www.global.lhs.com

In the event of conflicts between SealFAQs  and the official API 682, the official version of API 682 should be applied.

The American Petroleum Institute (API) was founded in 1919 as a national trade association for the oil and gas industry. It is the only US trade association that represents all aspects of the oil and gas industry.  The API represents some 400 member companies.  API is privately funded through dues, standards and certifications.  The API Standards Committees publish over 550 technical standards and publications.  Refining standards are handled by the Committee on Refinery Equipment (CRE).  Pumps and seals are addressed through the Subcommittee on Mechanical Equipment (SOME).

API Standards are reviewed every five years and must be renewed every ten years after publication.

API 610 is the API standard about centrifugal pumps. It is based on the combined knowledge and experience of pump manufacturers, engineering companies and end users.  API 610 is primarily intended for use in the petroleum, natural gas and chemical industries.  Although the 1^st through 7^th Editions includes specifications for mechanical seals, beginning with the 8^th Edition, API 610 refers to API 682 for seal specifications.

API 682 is the API standard about mechanical seals.  It is based on the combined knowledge and experience of seal manufacturers, engineering companies and end users.  API 682 is primarily intended for use in the petroleum, natural gas and chemical industries but is also referenced for other types of equipment and industries.  The purpose of API 682 is to assist in the selection and operation of mechanical seals in centrifugal pumps.

One interesting aspect of API 682 is that it includes a strong set of defaults. That is, unless the user indicates otherwise, API 682 makes default choices for specifics such as:

• Seal type
• Rotating or stationary
• Seal arrangement
• Seal configuration/orientation
• Materials
• Piping plan
• … many others.

Many users do not like the strong handed approach used by API 682. However, with a little study of API 682, the user can easily learn to specify his preferences in detail using the seal data sheet.

Some statements within API 682 are normative, that is, required, whereas others are informative, that is, descriptive but not required.  In particular, many of the illustrations are informative.  This distinction has not always been apparent to the reader.

In spite of its strong handed approach, API 682 encourages innovative or developing technology. However, non-standard alternatives should be carefully discussed between the purchaser and seal company.

It is important to realize that API 682 is a users’ standard; it was written by and for the end users of mechanical seals and these users wanted to force changes.  The result was an entirely new standard written around a limited set of seal types, arrangements and materials that were favored by the end users in refineries.  These new seals were also required to be proven through a series of rigidly prescribed tests.  Although everyone agreed that API 682 seals were robust and well suited to the best practices of the refining industry, cost quickly became a limiting factor to the specification.  Consequently, API 682 1^st Edition was not applied as extensively as had been anticipated. Subsequent editions have had an increase in the scope and also are more flexible with respect to defaults and options.

It is important to know the background and development of API 682 in order to fully understand and apply the standard. The story of API 682 begins in the late 1980’s.

By the late 1980’s, mechanical seals had been accepted as the preferred method for sealing rotating pumps for many years. However, prior to API 682, mechanical seal standards were generally buried in other standards such as DIN 24960, ANSI B73 and API 610. All of these standards were primarily pump standards and any references to seals were directed at how mechanical seals would interact with pumps.

In the late 1980’s a group of refinery equipment engineers and managers began to compare sealing solutions in refinery applications. This group, led by V. R. Dodd of Chevron, came up with a general plan and the American Petroleum Institute (API) agreed to establish a standard for mechanical seals: API 682.   A Task Force was formed in 1990 and the first meeting was held in January 1991.  This Task Force was comprised of fourteen members from various refineries, seal and pump manufacturers.   API 682, First Edition, was published in October 1994.

Subsequent editions of API 682 have been published.   The current edition is 4th Edition; the 5th Edition taskforce is being organized.