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Achieving Predictable Valve Performance for Safety Applications

Achieving Predictable Valve Performance for Safety Applications

A focus on having the proper specificati...

Putting Servo Valves Back to Work

Putting Servo Valves Back to Work

Industries as varied as paper production...

Corrosion and Fouling: Is There a Solution?

Corrosion and Fouling: Is There a Solution?

According to a 1998 study released by the ...

Valves with All the Trimmings

Valves with All the Trimmings

The term valve trim has been around for ...

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Industry Headlines

Strong Momentum for M&A Activity in the Chemical Industry

Monday, 19 February 2018  |  Chris Guy

Global chemical mergers and acquisitions (M&A) activity in 2018 is expected to remain strong, as higher valuations continue to be mitigated by imp...

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Valve Positioners Offer Improved Control Valve Performance

Valve Positioners Offer Improved Control Valve Performance

Monday, 19 February 2018  |  David Matherly

From time to time, we are re-posting well-received or particularly valuable articles that have previously run on VALVEMagazine.com so that those who m...

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Industry Headlines

ValvTechnologies ITC 2018 Recap

3 DAYS AGO

The biennial ValvTechnologies’ International Technical Conference and Users Group (ITC) was held on February 8-9 in Houston. Seeking to educate, inspire and engage attendees over a two-day period, the event brought together hundreds of attendees from across the globe to share valuable insight ...

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Matthew Davis Named Field Service Manager at Weir

4 DAYS AGO

Weir Valves & Controls USA (WVC USA) has appointed Matthew Davis to the position of field service manager. In his new role, Davis will be responsible for managing the WVC USA Field Service crew and organizing WVC Service jobs for power plants worldwide.

Davis joins WVC USA with over 20 years of ex...

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Strong Momentum for M&A Activity in the Chemical Industry

11 HOURS AGO

Global chemical mergers and acquisitions (M&A) activity in 2018 is expected to remain strong, as higher valuations continue to be mitigated by improving global economic conditions, continued inexpensive financing, and an appetite amongst industry participants for growth and transformative M&...

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TransCanada Turns Attention to Natural Gas System

4 DAYS AGO

TransCanada Corp. will move forward with a $1.9 billion expansion of its NGTL System to connect incremental supply and expand basin export capacity by one billion cubic feet of natural gas per day at the interconnection with its Canadian Mainline. NGTL expects to begin construction in 2019.

The increme...

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Construction Starts in 2017 Decline 7%

11 HOURS AGO

Many of the leading U.S. metropolitan areas for commercial and multifamily construction starts showed reduced activity in 2017 compared to levels reported during 2016, according to Dodge Data & Analytics. Of the top ten markets ranked by the dollar amount of construction starts, seven registered...

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Philly Fed: Manufacturing Activity Expanded Solidly

14 HOURS AGO

The index for manufacturing activity in the Philadelphia Federal Reserve region increased 4 points in February to a reading of 25.8. The index has stayed within a relatively narrow range over the past nine months. Nearly 41% of the firms indicated increases in activity this month, while 15% reported...

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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.

—————

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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