08292016Mon
Last updateMon, 29 Aug 2016 5pm

i

Valve Basics Training Helps Fill Industry Skills Gap

Valve Basics Training Helps Fill Industry Skills Gap

One of the most keenly felt needs in tod...

An End-User’s Perspective on Valve Selection and Risk

An End-User’s Perspective on Valve Selection and Risk

I am not a valve expert, although I ofte...

New Test Stamp and More Updates on Pressure Vessel Codes

New Test Stamp and More Updates on Pressure Vessel Codes

A new test organization program and stam...

The Weekly Report

New Products

  • ja-news-2
  • ja-news-3

Industry Headlines

Why Some Manufacturers Are Returning to the U.S.

Monday, 29 August 2016  |  Chris Guy

According to The Reshoring Initiative, “between 2009 and 2016 more than 250,000 jobs were created or brought to the U.S. from other countries,&r...

Readmore

Loading...
Advertisement
i

Industry Headlines

ValvTechnologies Successfully Completes NUPIC Audit

5 DAYS AGO

ValvTechnologies, Inc. recently achieved NUPIC-approved suppliers list status, upon successful completion of the Nuclear Procurement Issues Committee (NUPIC) audit conducted at the Houston facility. NUPIC members include all domestic U.S. nuclear utilities as well as several international members.

Form...

Readmore

GE Oil & Gas Supporting ONGC’s Exploratory Drilling Campaign in India

5 DAYS AGO

GE Oil & Gas has been awarded a multi-million-dollar frame agreement by Oil and Natural Gas Corporation Limited (ONGC), India’s largest exploration and production company. Under the agreement , GE will provide an estimated 55 subsea wellheads (SG5) over next three years for the operator&rsqu...

Readmore

Oil Refiners Face Reprieve as Maintenance Tames Fuel Glut

5 HOURS AGO

“Oil refiners reeling from tumbling profits can expect some reprieve in the coming weeks as lower production could tame a huge global excess of gasoline and diesel,” Reuters reports .

“Dozens of plants that will switch off for regular autumn maintenance will help slow the downward spir...

Readmore

Chemical Activity Barometer Suggests Accelerated Business Activity

6 DAYS AGO

The Chemical Activity Barometer (CAB) expanded 0.4% in August following an upward revision for July. This marks the barometer’s sixth consecutive monthly gain. Accounting for adjustments, the CAB is up 3.2% over this time last year, the strongest year over year growth since January 2015. All d...

Readmore

Why Some Manufacturers Are Returning to the U.S.

5 HOURS AGO

According to The Reshoring Initiative, “between 2009 and 2016 more than 250,000 jobs were created or brought to the U.S. from other countries,” PBS NewsHour reports .

“A number of factors have influenced the creation of jobs in the U.S., including rising labor costs overseas, higher fr...

Readmore

Manufacturing Productivity in U.S. Higher Than Other Nations

4 DAYS AGO

“U.S. productivity unexpectedly declined for a third straight quarter in the three months through June, Labor Department figures showed. On a year-over-year basis, it fell for the first time since 2013,” Bloomberg reports .

But on a more positive note, “the U.S. still blows other natio...

Readmore

Extreme Valve Testing

VM-smr11-cryogenic_testTwo commonly used low temperature tests today measure the degrees for liquid nitrogen and liquid natural gas.

Valves today face more challenging conditions from a wider range of applications. As a result, users are asking for more and better testing.

Filling a valve up with water, adding pressure and looking for leaks might work for some valve specifications, but many of today’s demanding valve requirements call for much more stringent testing and evaluation. Special service applications such as hazardous fluids, nuclear power plants, high-pressure pipelines and more dictate a much broader testing and inspection regimen than traditional simple tests.

Many users are requesting valve manufacturers prove their products will operate satisfactorily at the higher and lower temperatures and more extreme pressures that their valves are advertised to reach. These may be the lowest cryogenic temperatures or elevated temperatures close to 1000° F (538° C). Such tests call for specialized equipment and test procedures.

VM-smr11-cryogenic_test_2Cryogenic testing is generally performed at temperatures ranging between -50° F (-46° C) and -320° F (-196° C).The most common of these more extreme tests is cryogenic testing. Such testing is generally performed at temperatures ranging between -50° F (-46° C) and -320° F (-196° C)—most often at -320° F (-196° C), which is the temperature of liquid nitrogen (LN). Standard practice is for the valve to be immersed in the LN up to the packing gland area, if the valve is equipped that way. The packing must be kept out of the LN or it could freeze the packing, seizing the stem and causing the valve to lock up and fail to operate. Because polymer seals do not function well at cryogenic temperatures, valve end connections must be the type that makes a solid mechanical connection. These include threaded, flanged or caps welded onto buttweld-end ends. Socketweld-end and buttweld-end valves without welded-on caps are very difficult to test at the lowest cryogenic temperatures.

One of the most popular low temperature services today is liquid natural gas (LNG). Valves for LNG are sometimes tested at -320° F (-196° C), but a more accurate test is performed at the actual LNG temperature of -260° F (-162° C).

Cryogenic testing is costly and hazardous and should only be performed by experienced, trained personnel. The test procedures for cryogenics are available from several standards-making-organizations, as well as end users. The most significant differences in testing procedure documents are allowable leakage rates.


VM-smr11-cryogenic-table1

PIPELINE VALVES

Pipeline safety has come to the forefront lately because of catastrophic pipeline failures. These failures have occurred primarily on older pipelines because quality requirements for new pipeline construction are very stringent. Valves for pipeline service are also scrutinized very closely. While all pipeline valves are hydrostatically tested at the factory, usually in accordance with API 6D, additional tests are almost always performed. The most common extreme test for pipeline valves is a long duration shell test, which is carefully monitored by a recording device tracking the pressure and the temperature of the valve as it is tested.

During these enhanced duration shell integrity tests, the pressure on the valve must be maintained, or the pressure drop must coincide with a proportional drop in temperature to avoid valve failure. It is not uncommon for test durations to run several hours long.


FUGITIVE EMISSIONS TESTING

VM-smr11-preparing_for_fugitive_emissions_testA valve is prepared to undergo fugitive emissions tests.The desire to keep our nation’s air clean is manifested in the valve industry through the Clean Air Act and various state and local regulations. For manufacturers to meet today’s low emissions requirements, valves must be tested to determine their ability to contain these fugitive emissions (FE). FE testing is now a requirement by most refiners and chemical companies that must contain hazardous fluids as part of their everyday processes.

FE testing requires the valve be pressured up with an easily measurable gas such as methane or helium, and then checking the body and seals, particularly the packing, for leakage. An alternative method is to create a vacuum drawn on the valve through a closed piping system and introducing a tracer gas into the areas of the valve exterior susceptible to FE leakage.

Two distinct schools of thought exist on what gas should be used to FE test a valve—schools separated by the Atlantic Ocean. In Europe, it is deemed unsafe to test with methane, so all testing must be performed with helium; in the U.S., the preferred test media is methane, which more closely resembles the molecular structure of the volatile organic compounds (VOCs) that both industry and government are working hard to control.

  • Latest Post

  • Popular

  • Links

  • Events

Advertisement

Looking for a career in the Valve Industry?

ValveCareers Horiz

To learn more, watch the videos below or visit ValveCareers.com a special initiative of the Valve Manufacturers Association