Valve Test Standards – Saudi Aramco API/NACE/ BI/ISO/API/ASME/ANSI

Valve Test Standards – Saudi Aramco API/NACE/ BI/ISO/API/ASME/ANSI

Main Valve Test Standards

API 598 Valve Inspection and Test

The most widely used test specification in the world. The standard covers all types of valves (soft & metal seated) in sizes up  to 600NB (NPS 24). It also includes leakage rates and testing criteria for metal-seated and resilient-seated valves. Also mirrored by ISO 5208 Test standard.

API6D Pipeline Valves Test Standard

Used for API 6D ball valves, plug valves and API 6D design pipeline check/gate valves (also now adopted as part of ISO 14313). ISO 5208 leakage rate tables are often referred in conjunction with API 6D tests.

ISO 14313 (Section II) Valve Test Standard

Mirrors API 6D above.

ISO 5208 Valve Test Standard

Incorporates an adoption of API 598 test standard. In addition, ISO 5208 includes leakage rate tables. Example – Leakage rate A is specified for soft seated valves and plug valves (zero leakage*). ISO 5208 includes standards for gate, globe and check valves (EN 122661-1).

BS 6755 Valve Test Standard

Previously used by some European Manufacturers, now superseded by ISO 5208 (EN 12266-1) standard. It includes leakage rates and testing  criteria for metal and resilient seated valves.

ASME B16.34 Valves – Flanged, Threaded and Welding End

The primary valve design standard, it also contains pressure/temperature charts for determining the working pressures of  valves to be used in conjunction with other test standards, such as API 598.

ASME PTC 25 Pressure Relief Devices

The main reference document for the testing of pressure relief valves, PTC 25 contains detailed procedures for testing relief  valves with air or steam.

API 527 Seat Tightness of Pressure Relief Valves

This covers the seat tightness of pressure relief valves. It also includes allowable leakage rates for testing with steam, water  and air.

FCI 70-2* Control Valve Seat Leakage

This document contains detailed test procedures and leakage rate classes for control valves. The leakage classes are also  occasionally referenced by other documents and used as acceptance criteria. Supersedes ANSI B16.104. Class VI is the  highest shut off class*.

ISA S75 Hydrostatic Testing of Control Valves

This standard provides a procedure for the hydrostatic shell testing of control valves. Seat testing and acceptance criteria are  out of the scope of this document and usually are covered by referencing FCI 70-2.

ISO 5208 Industrial Valves, Pressure Testing of Valves

ISO’s primary testing standard, this document covers all types of valves and has four levels of allowable closure test leakage  rates.

MSS SP70 Cast Iron Gate Valves, Flanged and Threaded Ends

The primary design standard for cast iron gate valves, it also contains testing procedures and acceptance criteria.

MSS SP71 Iron Swing Check Valves, Flanged and Threaded Ends

The primary design standard for cast iron check valves also contains testing procedures and acceptance criteria.

MSS SP61* Hydrostatic Testing of Steel Valves

Similar to API 598 (in the case of soft seated valves) this document has some minor variations in test holding times and  leakage rates. Metal seated valves the leakage can be a little higher than API598.

MSS SP78 Cast Iron Plug Valves, Flanged and Threaded Ends

The primary design standard for cast iron plug valves also contains testing procedures and acceptance criteria.

MSS SP80, Bronze Gate, Globe, Angle and Check Valves

The primary design standard for commodity bronze valves also contains testing procedures and acceptance criteria.

MSS SP85, Cast Iron Globe & Angle Valves

The primary design standard for cast iron globe valves also contains testing procedures and acceptance criteria.

* See below for “Explanation of Zero and Low Leakage Test Standards”.


In general, specification such as API598 or MSS SP-61 that govern leakage for soft seated valves call  for ‘0’ bubbles of air or ‘0’ drops of water under the specified test conditions over the minimum test time  period. These valves are therefore sometimes referred to as ‘zero leakage’ valves. In reality, there really  is no such thing as ‘zero leakage’, since microscopic amounts of material may indeed cross the seat or  packing boundaries, especially if helium or hydrogen or other small molecule gases are used. Another  common term for soft seated valves is ‘bubble tight’.

Less frequently, the leakage performance for soft seated valves is referred to as Class VI, which is the  tightest leakage under FCI 70-2, and generally applies to resilient seated control valves (as opposed to  metal seated control valves or soft seated shut off valves). In fact, FCI 70-2 Class VI (formerly ANSI  B16.104) allows a small number of bubbles per minute, increasing with valve size, during the test,  whereas API598 and MSS SP-61 do not (for soft seat, but does for metal seat). FCI 70-2 Class VI is for soft seated control valves but is frequently used as a leakage acceptance test  criteria for metal seated isolation valves such as ball and butterfly valves. FCI 70-2 only requires a low  pressure test, consequently closure and seat tests should also be done per API 598 or MSS SP-61.

In actual fact even for metal seat valves the API 598 leak acceptance criteria for metal seated valves  allows less leakage than FCI 70-2 Class VI above 150NB (6”) and 50NB (2”) and under. For  zero leakage metal seated valves API 6D or API 598 soft seated zero leakage criteria can be specified  (such as triple offset metal seated butterfly valves and some metal seated ball valves). Special provisions for zero  leakage gate valves can also be specified to BS 6755 and ISO 5208 under special zero leakage classes. Metal seated valves, on the other hand, usually (not always, triple offset butterfly and ball valves for  instance are available bubble tight) have some level of acceptable leakage when tested, defined first as  some acceptable amount of liquid, under test conditions and over the time period of the test.

ISO 5208 (EN 12266-1) supersedes BS 6755-1 and specifies acceptable leakage rates such as ‘Rate A’ and ‘Rate B’. Rate A allows ‘no visible leakage’, similar to API 598 for resilient seated valves. Rate B is used for gate valves.


For cross reference tables and charts of ASTM/ANSI specifications covering equivalent materials used for valves, flanges &  fittings got to:

For other ANSI, ASME, ISO, API, valve related technical cross references relating to pressure, temperature, application,  suitability, equivalents, valve body & trim materials, valve manufacturing & test standards, etc., go to the technical section of our  website.

If we don’t have the valve in stock we can source it from our overseas network of stockists and very short lead-time specialty  manufacturers. We can even supply exotic grades like Nickel, Super Duplex F55 and Monel (ASTM A494-M35-1) Cd4M-Cu,  Hastealloy C (ASTM A494 CW12MW), 317 (C8G8M) in short lead-time.

For technical references and cross reference information on stainless, duplex, chrome-moly and Alloy steel used in valves and  piping systems in the petrochemical and refining industry go to:

We stock valves in A105, LF2, 304, 304L, 316, 316L, F51, CF8, CF3, F82, WC5, WC6, WC9, F11, F5, Bronze, Iron, etc. Ball,  Butterfly, Check, Control, Gate, Globe, Needle, Parallel slide, Plug, etc. Valves are manufactured to API 600, API 602, API 603,  API 6D, BS1868 and numerous other standards.

At Global Supply Line the same knowledge and effort we put into this web site goes into every product we sell.  If this web site helps you, please reward GSL with your business and tell your engineers, plant managers,  purchasing officers and project managers about us!

Also Read:  What is the Difference ASTM vs ASME Standard

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