Some international valve standards have been more successful in crossing international boundaries intact. For example, the British Standards Institute (BSI), BS 6364, Cryogenic Testing of Valves, has been the primary standard for low-temperature testing for over 25 years. Although other standards-producing bodies have created cryogenic testing documents, the British Standard is still the document most referenced today.

Probably the most visible international influence on U.S. valve specifications has been the nearly universal move to adopt metric units of measurement. In most cases, the imperial units are still listed, but they are secondary to metric units. Sometimes the imperial units are published in appendices or annexes in the back of the document. While the aim of this process is to help metrificate the industrial process industry, it has created a culture where many standards users hang onto old standards (with only the imperial units) so they can easily access the information they need. Old habits are hard to break, especially among the pre-retirement baby-boomers!

TESTING STANDARDS

One area where valve standards are extremely critical is pressure testing. Today, API’s 598, Valve Inspection & Testing, is the most widely recognized standard for this area. However, the ISO document 5208, Industrial Valves—Pressure Testing of Metallic Valves, is gaining popularity throughout the global valve community. ISO 5208 was revised in 2008, and in many ways, is now almost identical to API 598. For pipeline valves, API 6D, Pipeline Valves, has specific testing requirements for valves in pipeline service, including holding times much longer than API 598 and ISO 5208. MSS SP-61 offers an alternative to the API and ISO testing documents for those who manufacture and use products that would not fit the scope of API 6D, API 598 or ISO 5208.

A unique testing document published by the Fluid Control Institute (FCI) is the ANSI-approved, ANSI/FCI 70-2, Control Valve Seat Leakage test specification. This document was initially an ASME document, B16.104. Although aimed primarily at the control valve segment, 70-2 is specified whenever exacting leakage rates are required. FCI/ANSI has six classes of leakage from no testing required (class I) through very tight metal seat (class V) and soft seat (class VI).

While British Standard BS 6364 is still the most popular document that specifies cryogenic testing procedures, others exist and are in use. MSS created a cryogenic valve standard in 2006, SP-134-2006a, Valves for Cryogenic Service Including Requirements for Body/Bonnet Extensions. SP-134 contains cryogenic testing specifications slightly different from those found in the British standard, especially in the area of allowable leakage rates. ISO is creating a third cryogenic valve standard, but it is still in the developmental stage.

Fugitive emissions control has become an important issue in the industrial valve sector, particularly on the refining and petrochemical side. Initially, little guidance existed for quantifying valve fugitive emissions leakage, with only one standard, EPA Method 21, Determination of Volatile Organic Compound Leaks, available as a reference. Method 21 is a specification for measuring leaks in the field and does not apply to valve qualification or production testing prior to installation. Currently five non-company specific documents are in use for valve qualification and production fugitive emissions testing. They are: ISO 15848, Industrial Valves – Measurement, Test and Qualification Procedures for Fugitive Emissions, parts 1 & 2; API 622, Type Testing of Process Valve Packing for Fugitive Emissions; ISA 93.00.01, Standard Method for the Evaluation of External Leakage of Manual and Automated On-Off Valves; FCI/ISA 91.1, Standard for Qualification of Control Valve Stem Seals; and a German specification,Technical Instructions on Air ­Quality Control, better known as TA Luft.  While API 622 is actually a packing evaluation document, it contains a very useful and practical fugitive emissions testing procedure.