The API 682 seal codes have changed with every issue.

There is no exact equivalent. That API 610 code describes a balanced single seal (pusher or bellows) with a fixed throttle bushing using Viton secondary sealing elements; seal faces are carbon vs cobalt bound tungsten carbide. In API 682 4^th edition, a somewhat similar code might be 21A-FFM-050-11 which indicates Category 2, Arrangement 1, Pusher, Fixed throttle bushing, Viton, carbon vs nickel bound tungsten carbide, 50mm shaft size, Plan 11 flush.

Pumping ring performance curves must be provided for Category 3 or if specified by the purchaser.  The performance curve should be for the size, shaft speed, fluid and general configuration that is being sold.  Usually at least one of these parameters is not identical to the qualification test parameters and therefore the performance curve that is to be provided will be a calculated curve based on the qualification test and/or additional independent pumping ring tests.

Containment seal test results are to be reported using a form similar to API 682 Figure I.10 for the tests specified under clause I.4.5.  This allows the containment seal to be considered as a “seal type” for purposes of transferring qualification.  A complete test of the containment seal includes procedures per I.3.13; those tests are to be reported using a form similar to Figure I.9.

An Engineered Seal is a seal that is outside the scope of API 682.   Clause A.1.2 in Annex A of the standard outlines various service conditions that define what is outside the scope of the standard.

Per API 682, Engineered Seals are not required to meet any of the design or testing of the standard. Customer testing may be done on demand, but at a price as defined by the testing requirements.

Yes, API 682 has been expanded to include dry gas seals for pumps.

Yes, there is a well-defined set of default and optional materials for API 682.

In order to fully comply with API 682, the seal that is being sold must be fitted with the same face material pair that was used during the qualification test.   Therefore, to be in compliance with the standard, substitute materials cannot be used.  If materials are changed due to specific service conditions or even at a customer’s request, the purchaser should be informed as to what materials have changed from those used in the qualification test.

The default or standard material of construction for a seal is completely defined in API 682. For example, the API 682 Type A seal has reaction bonded silicon carbide mating ring, premium grade carbon primary ring, Fluoroelastomer O-ring, Hastelloy C springs, and 316SS hardware. Any variations are specified as special features, such as Perfluoroelastomer for elevated temperatures or as purchaser specified item on the API 682 seal data sheet.

Yes, as the use of API 682 is completely voluntary, the purchase may choose to remove certain requirements or add additional ones. It is very common for major companies to write their own specifications that follows or interprets API 682.  Such specifications are known as “overlays” to API 682.

API is written for seals applied to API 610 Seventh Edition, or more recent, pumps.  If any other pump has a stuffing box similar to the seventh or eighth edition pumps, then standard API 682 products should fit.  For older pumps, the seal chambers may be smaller and there are no standard dimensions.  In many cases, API 682 products can be engineered to fit the older pumps but usually exceptions to API 682 are required.  In some cases, it will not be possible to fit API 682 products into older pumps.

Yes, in order to maximize compliance with API 682, most seal OEMs have designed and designated certain products to be “API 682” products.

No, because API 682 does not recognize all seal types.  For example, API 682 does not include wedge or U-cup designs, elastomeric bellows, outside mounted seals, etc.  Further, a seal is not fully “per API 682” unless it has been qualification tested.

Beginning with 2^nd edition, API 682 includes large bore ANSI pumps.  This inclusion is largely based on Category 1 seals.  For other non-API pumps, API 682 seals may not fit or may not perform as expected.

While the standard’s title implies both centrifugal and rotary pumps, the seal chamber dimensions in API 682 apply only to centrifugal pumps meeting API 610 7th and more recent editions or ASME B73.1 and B73.2. The typical rotary pump, unless designed with special seal chambers, does not conform to these dimensions; therefore API 682 seals will not normally fit into typical rotary pumps without considerable modifications.

Yes, pumping ring minimum clearances are different in 1^st, 2^nd/3^rd, and 4^th editions of API 682.  However, API standards are not retroactive.  For example, if a pumping ring was provided per 1^st edition, it should be repaired per 1^st edition requirements  unless an update is requested.

API no longer sells their standards directly. The most straightforward way to purchase API 682 is to buy it from IHS.com or TechStreet.com.  The API website, API.org, will direct you to TechStreet.com.

API 682 is a standard governing mechanical seals for centrifugal and rotary pumps. It was first published in October, 1994 by the American Petroleum Institute and is now in edition four.    By default, the latest version of the standard is always used unless an older version is specifically referenced.

API standards are written primarily by the end user members of the American Petroleum Institute.  Equipment manufacturers are generally requested to act as advisors and reviewers of the specifications.  The first draft of API 682 was prepared by a committee of ten end user members that were advised by four representatives from seal manufacturers.  Drafts are reviewed by API committees.

API standards are non-compulsory. However, many companies in the oil refining and chemical processing industries use API or ISO  standards.

API 682 is essentially the only available seal specification.  Seals that follow the general guidelines of API 682 but are not completely compliant may be acceptable.  The seal supplier should note exceptions to API 682.

API 682 is essentially the only available seal specification.  Seals that follow the general guidelines of API 682 but are not completely compliant may be acceptable.  The seal supplier should note exceptions to API 682.

Strictly speaking, yes. API 682 was the first of the API standards to be issued as a metric standard.   Metric units govern throughout the standard.  US customary units are “soft conversions” and are shown for reference only.

Strictly speaking, yes. API 682 was the first of the API standards to be issued as a metric standard.   Metric units govern throughout the standard.  US customary units are “soft conversions” and are shown for reference only.

Consistency of approach in seal selection and application is one of the main advantages. Also, designs for API 682 must be tested in representative fluids with various specified operating conditions. The seal manufacturer is to make the qualification test results available to the purchaser for evaluation. Additionally each seal must pass an air integrity test prior to shipment.

Seals and support systems meeting API 682 are considered to be “heavy duty”.  Therefore, features may be included that can result in a higher expense to the purchaser than seals and systems previously used.

API 682 is essentially the only available seal specification.  Seals that follow the general guidelines of API 682 but are not completely compliant may be acceptable.  The seal supplier should note exceptions to API 682.

No, there is no requirement for a constant pressure differential or constant pressure ratio.

API 682 includes a number of tests:

• First, a seal must be qualified in one of 5 fluid groups (water, propane, caustic, cold oil, or hot oil). A seal is qualified by testing a “small” seal (usually about 2 inch (50 mm)) and a “large” seal (usually about 4 inch (100 mm)). Both the large and small seal must perform satisfactorily in the test. The qualification test is specific to seal type, face materials, seal arrangement and the fluid group.
• Secondly, there are integrity test such as hydrotesting of the glands, reservoirs, heat exchangers. Per API these are to be hydrotested at minimum of 1.5 times the rated pump working pressure for at least 1/2 hour.
• Thirdly, there is an integrity test requirement of air test on the assembled cartridge seals to determine that the assembly was done properly.
• Finally, there are several scenarios of pump performance testing by the OEM that can have an impact on the seal. Unless otherwise specified, the job seal is installed for the pump performance.

No. Clause 10.3.1.2.2 states that the seal must be tested in the appropriate test fluid as given in Table I.2.  A note to this clause states:  “It is not necessary to test a commercial product in all qualification test fluids.”

Yes, the seal is qualified only with the face materials that were used in the test. API 682 does not recognize families of seal face materials.  This means that many tests are required.