It takes much time and effort by many people to upgrade existing codes and standards, or to develop new ones. The process begins when a parent standards organization (see below) forms a task group to work and prepare an initial draft or investigate proposed changes to an existing document.
This preparation or revision process is complicated in itself, but then there is the approval process, which is especially cumbersome when a draft is balloted and many comments or negatives are received. These comments and negatives must be addressed before a new (revised) draft is prepared. The whole procedure may repeat itself many times until a final is finally approved by the applicable committee membership.
There are also substantial resources involved in producing or revising a valve standard. Individual volunteers lose time from daily work and spend money on travel. The organizations involved have substantial overhead costs in getting the standard reviewed, addressing comments and going through the voting procedure.
Still, because industrial and public safety are paramount, most industry professionals feel the cost and efforts to resolve negatives is necessary to ensure that the standard is useful for the industry.
Here is a summary of what’s happening that valve professionals are monitoring.
CURRENT CHANGES UNDER WAY
American Society of Mechanical Engineers (ASME)
ASME is working on several issues including:
ASME B16: The ASME B16 Standards Committee is under the ASME Board for Pressure Technology Codes and Standards. Seven subcommittees with balanced memberships are responsible for about 34 standards. The published standards are ANSI accredited.
A new B16 Technical Committee on pressure and temperature (P/T) ratings has been established to provide ratings needed for all ASME standards.
ASME B16.34 (2016) Valves: An addition was published in 2016 in which the scope extension of flanged and weld-end valve sizes was changed from nominal pipe size (NPS) 24 to NPS 60 to match B16.47 flanges.
Paragraph 6.1.2 was balloted and approved for the next edition. The proposal was to revise 6.1.2c and delete sub clauses (1) and (2), which were revised in 2009. This caused some manufacturers of three-piece ball valves to substantially increase the wall thickness of the center body, resulting in additional weight of larger valves. Extensive discussions led to a compromise to offer both options—to use the old or the new methods to calculate wall thickness. A major review of needed material and P/T ratings corrections was conducted and will be included in the new edition. All the tables had to be revised to comply with the new titles and numbers for the materials.
A case to use increased ceiling pressures for creep-strength enhanced ferritic materials (F91, F92 and C12A) was approved. This can be used to increase the P/T ratings.
One of the problems with B16.34 was that it took a long time to add a new material. Because of this, a case was developed and approved to add materials not currently listed in Table 1 of B16.34. This is more of an approval procedure than a case and must be supplemented with actual material strength data. It requires approval by B16 SC-N.
The new edition allows the use of ASTM Editions, other than those referenced in the B16 standard, with stated guidance and conformance. Additionally, International Organization for Standardization and MSS [Manufactured Standardization Society, see below] documents are referenced as guidance for construction of cryogenic bonnet extensions. The Subcommittee N continues to develop a similar standard for plastic valves, although progress is very slow because there are no P/T ratings for many of the plastic valves.
B16.10 (2016) Face to Face, End to End: A new edition of this was published in 2016. Major changes and additions include:
Sizes are extended to NPS 60 and new face-to-face dimensions including API 6D, AWWA [American Water Works Association] and MSS Standard Practice (SP)-135. Knife gate valve dimensions were adopted. These changes and additions were major revisions to B16.10.
ASME B16.5 (2016) and B16.47 (2016), Pipe Flanges: New editions were published in 2016. NPS 22 was added to complete the sizes range in B16.5, and P/T tables were reviewed to correct discrepancies.
B16.11 (2016), Forged Fittings: A new edition was published in 2016 that restricted production to disallow non-cylindrical fittings to be made directly from bar. This edition also added coverage for “branch outlet fittings” other than couplings.
16.24 (2016), Cast Copper Alloy Pipe Flanges and Flanged Fittings, and Valves: A new edition was published in 2016 and the title was changed to include “Valves” because it now covers cast copper alloy valves. The scope was incorporated to include C95200 and C95400 copper alloy valve construction data and P/T tables were developed.
ASME B 16.25 (2012), Buttwelding Ends: The next edition will be published in 2017. It will include the addition of NPS 1/2–2 and NPS 50–60 in Table 1. There were some incorrect dimensions in Figure 1. The dimension described at tnom in the figure is not shown correctly in the original so the symbol was eliminated and the requirements were clarified. Also, a ballot was approved to revise Figure 1 to add B36.19 SS piping BW end geometries.
American Petroleum Institute (API)
API’s main body is the Committee for Refinery Equipment. Two working subgroups are the Gate, Globe & Check Valves and the Quarter Turn Valves & Quality. The committee has a balanced membership and the standards are ANSI accredited.
API 594, Check Valves: It took a long time to get this standard through because several revisions were proposed and had to be included. The 8th edition has been approved and is in the process of being published. Sizes are covered to NPS 48. However, they were extended to include odd sizes such as NPS 26, NPS 28, NPS 32, NPS 34, NPS 38, NPS 40, etc., to be sure all the industry sizes were covered. Figure 1 has been revised concerning gasket interruption to align better with designs being manufactured currently on retainer-less products.
A new table was added listing new face-to-face dimensions to provide double flange valves in all sizes and pressure classes. Table 3 was created so that double flanged valves could be purchased in many sizes (they are only offered as lug presently).
One major discussion involved insisting that a pipe plug must be seal-welded when it is used as a pin retainer on type B valves (bolted swing check). Several major failures had been reported.
As of this publication, 594 is not released yet, but it will come into force six months after publication of the standard.
API 599, Metal Plug Valves: The 7th edition was published in 2013, and a task force has been formed to update provisions. The committee is looking for comments from the field to develop the first draft for balloting.
API 600, Gate Valves: The 13th edition came out in January 2015 and extended the size range to NPS 48 and included NPS 26, NPS 28, NPS 32 and more. The Trim Table was revised to eliminate Trim #1 (410 SS) and Trim #2 (304 SS).
A requirement in this latest edition is that valves must be capable of being installed and operated with the stem in the horizontal position and comply with API 624 on fugitive emissions. Those who do not conform cannot call the valve API 600 compliant. Gasket confinement in bonnet and packing chamber design was addressed.
API 607, Fire Testing: The 7th edition published in 2016 allows a valve to be in the closed position prior to testing. An open position test was evaluated, but not allowed. Material qualification remained in three groups: ferritic, austenitic and duplex. Also, the new edition allows the same through-seat and external leakage rate, which is higher during burn than the fourth edition allows.
API 608, Metal Ball Valves: The 5th edition was published in 2012 and a task force is working to update the next edition. A section is being added to note double-piston-effect seats are outside the scope of the standard, and an option is being added for parallel threads for plugs. Direct mounting of actuators will be addressed.
API 623, Globe Valves: The 1st Edition covering globe valves was published in 2013. Stem diameters increased and material requirements were improved over older stem valves that were having many problems. Operational requirements for stop check valves are described and hardfacing of seat and disc seating surfaces is required for greater than Class 900. A task force has been formed to start the revision process for the next edition.
API 641, Fugitive Emission Testing, Quarter Turn Valves: The 1st edition was just published in October of 2016. It sets out requirements and acceptance criteria for type testing of valves based on EPA Method 21. The test medium must be methane with 97% purity; no helium is allowed in this particular standard.
Valves greater than NPS 24 and Class 1500 are outside the scope of this standard. There is a total of 610 mechanical and three thermal cycles beginning at ambient temperature and maximum leakage of 100 parts per million by volume, static and dynamic. No stem seal adjustments are allowed during valve testing.
Manufacturers Standardization Society (MSS)
Membership is comprised exclusively of manufacturers. Because of the lack of a balanced membership, the standards are not automatically ANSI approved. If MSS wants a standard approved by ANSI, it must go through an ANSI canvas approval process. Many technical committees are responsible for the updating of standards every five years as well as developing new ones.
Steel Flanges (TC 110): SP-44 steel flange standard was revised to comply with API and other organization reviews. It was published in 2016, but a new SP for slip-on and lap-joint flanges is being evaluated.
Quality (TC 304): A newer standard, SP-147, Quality Standard for Steel Castings was issued in 2014, and the newest (for plastic-lined ferrous metal valves) is being finalized. The standard was requested by Exxon. It is nearly finished and going to ballot. If the results are positive, it will be published in 2017.
Butterfly Valves (TC 407): Two types of butterfly valves are covered. SP-67 is basically the common single- rubber-lined butterfly valve. No changes were made. However, SP-68 covers high-pressure butterfly valves with offset design, and it is being revised to align requirements with API 598 and ASME B16.34.
There is a new SP-150, valves for hydrogen peroxide service, issued in 2015. It is the only standard in the industry for valves in hydrogen peroxide service.
Knife Gate Valves (TC 409): SP-135, High-Pressure Knife Gate Valves was published in 2016 and a new SP-151, pressure testing of knife gate valves was also published in 2016.
New SP for class-rated double block and bleed knife gate valves is being evaluated and is in the process.
MSS Active Projects: The committee is working on a general review of SP-134, Valves for Cryogenic Service including body/bonnet extension requirements to be aligned more closely with industry requirements. Also in the works are new SPs for severe service valves, fugitive emission testing of instrument valves and for special leak-test methods and procedures for valves for high-pressure testing for gas.
The above are a few of the current events in the standards world. Stay tuned to VALVE Magazine and VALVEmagazine.com for updates.