API Standard 682, titled "Pumps - Shaft Sealing Systems for Centrifugal and Rotary Pumps," is the American Petroleum Institute (API) standard for end-face mechanical seals. The purpose of API 682 is to assist in the selection and operation of end face mechanical seals in centrifugal pumps. 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 often referenced for other types of equipment and industries. The API has approximately 500 technical standards for processes and components. Background and development By the late 1980s, mechanical seals had been accepted as the preferred method for sealing rotating pumps for many years. However, 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. API 610 is the API standard about centrifugal pumps and is primarily intended for use in the petroleum, natural gas and chemical industries. Although the 1st through 7th Editions of API 610 included specifications for mechanical seals, beginning with the 8th Edition, API 610 defers to API 682 for seal specifications. In the late 1980s 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 composed of fourteen members from various refineries, seal and pump manufacturers. API 682, First Edition, was published in October 1994. 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. 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. Subsequent editions of API 682 have been published. The