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Human Factors Can Cause a Disaster—or Prevent One

Human Factors Can Cause a Disaster—or Prevent One

Process industry plants are complex and ...

Improving Valve Sealing Performance and Reliability

Improving Valve Sealing Performance and Reliability

From time to time, we are re-posting wel...

A Primer on Fugitive Emissions

A Primer on Fugitive Emissions

Fourscore and seven years ago, no one ha...

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Industry Headlines

Industry Headlines

Emerson Expanding Mississippi Facility

3 DAYS AGO

Emerson plans on delivering $500,000 in new equipment to its facility in Sherman, MS. Because of this investment , and its promise of new jobs for the region, the Sherman Economic Development Corp. has approved $150,000 in grants for Emerson.

"We have a relatively new Fisher product that will be reloca...

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REXA and CCC Form Joint Initiative

3 DAYS AGO

REXA and Compressor Controls Corporation (CCC) have formed a joint initiative to modernize steam turbine controls for enhanced performance based upon each company’s core competency.

There are more than 10,000 turbomachinery trains worldwide powered by CCC. By upgrading mechanical and hydraulic go...

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Chevron and Pembina Sign Deal to Build Pipelines, Other Facilities

3 DAYS AGO

Calgary-based Pembina Pipeline Corp. has signed a 20-year deal with Chevron to build natural gas pipelines and processing facilities for a potential production operation in northwest Edmonton, Alberta. The infrastructure developed over the term of this agreement has the potential to represent a multi-...

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U.S. in Midst of Biggest Drilling Surge Since 2012

3 DAYS AGO

“U.S. drillers pushed ahead on the biggest surge in oil drilling since 2012 as companies take advantage of oil prices that have held steady above $50 for almost three months,” Bloomberg reports .

“Drilling is booming in a few shale plays -- led by the Permian Basin in West Texas and Ne...

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U.S. Private Sector Growth Slows from January’s 14-Month Peak

3 DAYS AGO

At 54.3 in February, the seasonally adjusted Markit Flash U.S. Composite PMI Output Index dropped from 55.8 in January but remained above the 50.0 no-change value for the twelfth consecutive month. The latest reading signaled that private sector output growth moderated from the 14-month high recorded ...

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NAM Kicks Off Tour at Emerson Innovation Center in Austin

3 DAYS AGO

The National Association of Manufacturers (NAM) kicked off the 2017 State of Manufacturing Tour at Emerson Innovation Center in Austin, TX—a “hotbed of modern manufacturing.” The event is the first in a series of stops in six states throughout the next week, including a visit with Pr...

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A Guide to Valve Cleaning and Specifications

Most of the time we only require that valves be free of basic dirt and debris before they are put in service. However, occasionally service requirements dictate that all traces of oil, dust and grease be removed. A prime example is valves to be used with oxygen. In that case, even a small speck of oil in a 100% oxygen environment can create a devastating explosion. One tiny metallic sliver could cause a minute spark, which is all that would be required to trigger the destruction.

 

Other media that require this level of cleanliness include numerous other pure gases, chlorine, paints and some chemicals. What all this means is that a standard, off-the-shelf valve cannot be used in these media unless it has been properly processed before installation. Decades ago, achieving this degree of cleanliness required the use of vapor degreasing machinery filled with a chlorinated solvent such as trichloroethane. These chemicals worked marvelously to clean, but they have been proved to be carcinogens, so their industrial cleaning usage has all but disappeared. In their place, environmentally friendly aqueous-based cleaners, such as Simple Green, have become the norm.


Follow the Specs

Even with the use of the right cleaning agent, however, it takes more than a simple “wash behind the ears” to ensure that a valve is clean enough for intended service. This is where cleaning standards and specifications come in. Fortunately, there are very good specifications to guide valve assemblers and technicians in the cleaning process. In fact, the American Society for Testing and Materials (ASTM) has a committee that works solely on specifications for oxygen service applications: Committee G04. This group produces ASTM G93, “Standard Practice for Material and Equipment Used in Oxygen-Enriched Environments,” which is a very thorough document and an excellent reference for valve cleaning procedures.

The Compressed Gas Association (CGA) publishes another often referenced cleaning standard: document CGA G-4.1, “Cleaning Equipment for Oxygen Service.” Many end-users that don’t have their own specific procedure reference the CGA 4.1 standard. The Manufacturers Standardization Society (MSS) also recently created a valve cleaning standard, MSS SP-138-2009, “Quality Standard for Oxygen Cleaning of Valves & Fittings.” This document is derived from many end-user specifications as well as CGA G-4.1. For chlorine service cleaning, the Chlorine Institute references cleaning procedures in its document: “Piping Systems for Dry Chlorine.”

The common denominator for all the cleaning standards is removal of all traces of oils, grease, dirt and other contaminants. The methods prescribed include scrubbing, ultrasonic cleaning, pressure blasting and sand blasting.


Rust Elimination

One important issue in cleaning is the presence of rust on carbon steel components after cleaning. With any of the prescribed cleaning processes, the protective film or rust preventative on the steel is removed, which exposes the metal to rapid oxidation, a problem that is particularly acute in humid environments. In many cases, a light blush of rust is acceptable, but gross deposits would not be. As a result, cleaning may need to be performed in a non-humid area. Additionally, carbon steel valves and components that have been cleaned require some form of corrosion protection—either desiccant bags inserted in the valve bore or an exterior wrapping with vapor phase inhibitor paper, or both.

After valves have been carefully cleaned and checked for proper cleanliness, they are usually put in protective heavy-gauge plastic bags to ensure they stay clean until installation.

Cleaning of valves is a straight-forward process that requires some diligence and quality control. However, guidance is available from various standards and specifications. Also, since the valves must be disassembled for most cleaning procedures, it’s important that the personnel involved be familiar with proper disassembly and re-assembly of the valves to be cleaned.

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Greg Johnson, a contributing editor to Valve Magazine, is president of United Valve (www.unitedvalve.com), which offers factory-authorized valve modifications and repair from its Houston, TX facility. Reach him at This email address is being protected from spambots. You need JavaScript enabled to view it..

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