Beckhoff: Get ready for the next automation revolution
Industrial Ethernet Book Issue 112 / 8
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Industrial Ethernet: optimal for harsh oil and gas demands

A robust Industrial Ethernet network using environmentally hardened cabling, connectivity and active components is essential to long-term performance and reliability in the oil and gas industry. Open, standards-based Ethernet communications offers Internet and enterprise connectivity, anytime and anywhere.

FOR YEARS ETHERNET HAS BEEN GRADUALLY ousting conventional databus technology from the field of industrial automation. Traditional communications technology is relatively simple and extremely reliable, but it does not easily lend itself to networking.

Plus, many of the available forms are mutually incompatible, meaning that we cannot interconnect systems to achieve the single integrated network we now need to solve application challenges in the oil and gas industry.

Ethernet has the advantage of allowing individual subscribers to be networked, and it is also a standardized technology (IEEE 802.3), available all over the world. Ethernet-based networks bring a number of benefits, not the least of which are greater flexibility and the levels of system interconnection that can be achieved.

Today, industrial Ethernet is the principal network infrastructure choice for mission-critical operations. Built on the same standards-based networking platform as enterprise Ethernet, which has long reigned as the universal network solution, Industrial Ethernet connects the office with the control room through a single platform.

This convergence of open, standards-based Ethernet communications enables secure, seamless interoperability among manufacturing enterprise networks - from corporate offices to the operations areas to remote locations - and offers Internet and enterprise connectivity, anytime and anywhere.

While Ethernet technology is globally available, most of the equipment available is not suitable for installation within a majority of oil and gas environments. This is because, in general, the environment is extremely challenging for electronic devices, both electrically and physically.

Regardless of your role-distributor, system integrator, design engineer, IT manager, OEM or end-user-everyone who touches the oil and gas industry has a stake in the successful design of the communications network.

Without strong infrastructure, costly network downtime can occur. This results in less productivity, delayed downstream processes and loss of service to customers relying on the production of oil and gas.

It′s important that teams across every step of oil and gas production, including upstream (hydraulic fracturing, oil field monitoring and offshore rigs), midstream (pipeline monitoring and pumping stations) and downstream (refineries and gas stations) applications, use dependable network components, such as Ethernet, that can withstand harsh industrial conditions for the highest network reliability and availability.


Reliability and performance of network connectivity and cabling are essential in oil and gas environments.

Challenges for oil and gas networks

Quick and easy networking design that offers the utmost commissioning and control is key for success in the control room and across all oil and gas applications, especially in the face of new and complex threats.

Cyber security, for example, is quickly becoming a big concern for industries everywhere, especially oil and gas. Between 2011 and 2015, the U.S. Department of Homeland Security registered more than 350 incidents and 900 security vulnerabilities with U.S. energy companies, which is higher than any other industry.

A major contributing factor to oil and gas company vulnerability is that many have outdated, aging control systems in their facilities that rely on non-standard and insecure network components. And with the rise of the Industrial Internet of Things (IIoT) and an increased reliance on connected devices, the security challenges will become even greater.

Safety, uptime, control paramount

The Oil and Gas Market is made up of 3 key sub segments:

Upstream

  • Wellhead Monitoring
  • Rig Surveillance
  • Control Room
  • Vessel Control
  • ROV′s

Midstream

  • Pipeline Monitoring
  • Separation Stations
  • Tank Storage Monitoring
  • Pumping Stations

Downstream

  • Gas and Liquid Detection
  • Metering Systems
  • DCS Systems
  • Refinery Surveillance
  • Gas Stations

Networks in all of these market sub segments must perform in extreme and often hazardous environments and every sector has its own set of environmental challenges. Analysts report that an overwhelming percentage of unplanned downtime in industrial operations can be attributed to network infrastructure failure. According to one network report, fully 72 percent of network faults can be attributed to failure at the OSI (Open Systems Interconnection) Layer 1 (Physical Media), Layer 2 (Data Link) and/or Layer 3 (Network).

Untimely and costly service disruptions can largely be prevented by installation of a robust network infrastructure utilizing environmentally hardened, components in all three OSI layers. A ruggedly designed framework enables operators to carry out their mission-critical functions by providing the highest possible levels of:

Safety. Optimum safety is critical in all oil and gas operations, for both employees and in certain applications, customers as well. Full safety demands fail-safe reliability and redundancy of data transmissions, as well as network components that meet and exceed industrial requirements for potentially hazardous environments.

Uptime. In the oil and gas industry, uptime is critical. Any disruption can prove extremely costly. Prevention of signal transmission problems is a major factor in ensuring consistent and dependable network uptime and service reliability. Whether an operation involves control room or pipeline monitoring, refinery and rig surveillance or even distribution of news and information at the pump, keeping operations running smoothly and reliably assures optimum uptime and peace of mind.

Control. Continuous monitoring, management and control, as well as operational efficiency, require continuity in data transmission and network availability. Any network failure, and subsequent downtime, can result in severe and extremely costly consequences.

The Real Costs of Network Failure

Maximum productivity with minimal downtime is a key goal, and 24/7 network performance and reliability are critical to achieving that goal. No matter what the industry, if a switch, connector or cabling system fails, the cost of replacement parts and repair represents only a tiny fraction of the overall costs associated with production downtime.

Many instances of unplanned downtime in industrial operations can be attributed to network infrastructure failure, and that downtime can be costly. For example an estimated daily downtime for large rigs can cost anywhere from $500K to $650K per day.

The indirect costs of Ethernet system failure in any industry must take into account lost productivity, delayed downstream processes, cost of system shut-down and start-up, and the potentially devastating loss of service to customers relying on the facility′s mission-critical output. If a cabling system component or Ethernet switch fails, the repair and labor costs alone could be 15-20 times the cost of the component itself. Depending on the industry and overall operating costs, these indirect effects can send total downtime costs soaring to hundreds of thousands, even millions of dollars.

That is why investing in a high-quality, rugged Ethernet infrastructure designed specifically for use in harsh environments is the obvious business choice - one that can provide tremendous peace-of-mind to network engineers and administrators and the organizations they serve.

"Ruggedized" Ethernet hardware

In selecting physical media, data links and network hardware for the oil and gas market, multiple factors should be considered to ensure optimal performance, ease of maintenance and long-term reliability.

Key considerations in specifying industrial-grade network components include:

MTBF (Mean Time Between Failure). Industrial Ethernet products are designed to provide a long product lifespan. Typically the average lifespan is 15 to 30 years or more. By comparison, typical commercial-grade products are built to achieve a 5-year average lifespan.

Mounting options. Industrial Ethernet hardware devices are usually DIN rail mounted.

Small form factor. Today′s industrial equipment is designed to occupy less space to allow greater density within a control panel.

Ventilation without fans. Industrial Ethernet devices rely on passive heat dissipation.

Protection class. Devices must be available in dustproof and waterproof housings.

Conformal coating. A special coating is applied to PCBs to protect electronic components in damp or corrosive environments.

Redundancy. Redundant power, redundant media paths and even redundant devices can assure 24/7 uptime.

Scalability. With an ever-increasing number of Ethernet-enabled devices being added to networks, the design needs to be able to provide data rates for the future, thus eliminating the need for any upgrades to cope with the system innovations in the future.

Hardened network protections

As stated previously, an overwhelming percentage of network performance problems are due to failure at OSI Layer 1, Layer 2 or Layer 3. Therefore, it is critical to ensure that components at all three layers - physical media, data links and active network devices - are designed and constructed to withstand the operational and environmental stressors to which they are subjected. For each category, multiple factors need to be considered to ensure optimal performance, ease of maintenance and long-term reliability of the mission-critical network.

Industrial Ethernet Cable Selection

Fiber Optic Ethernet cables represent the ultimate in future-proofing and are available for indoor (riser or tray) or outdoor use (including direct burial). Typical designs use multi-mode fibers in a loose tube configuration, usually available in 2- to 72-fiber constructions. For plenums, tight buffered, 2- or 6-fiber single-mode or multi-mode constructions are typically available.

  • To handle Gigabit Ethernet light sources and any expanded bandwidth requirements some cables use a laser-optimized fiber.
  • For moisture protection, a water-blocking agent should be included in the cable′s construction.
  • For trackside environments, a CPE outer jacket will provide additional protection against chemicals or abrasion; an armor tape or aluminum/steel armoring may also be appropriate for the extreme environments, including some burial situations.
  • Ratings include: UL Type: OFNR3, cUL Type: OFN FT44.

Copper Ethernet cables are the more traditional option for oil and gas applications especially pipeline and pump station monitoring. Available for either Category 5e, Category 6, Category 6a and Category 7 applications. Category 5e cables are the dominant choice today, while Category 6, 6a and 7 cables are finding increasing use where Gigabit speeds and increased bandwidth are desired and/or for future-proofing purposes. Twisted pair cables are available using any number of conductor types, insulations, shielding and jackets.

Armoring

Armoring is also available for extremely harsh environments. Construction selection criteria includes:

Unshielded or shielded? Unshielded products can be used in most environments; shielded products are recommended for harsh environments, which is primarily what is found in the oil and gas industry.

Shields: Typically a foil or braid is used to protect the integrity of the signal and to screen out any undesirable interference or noise. However, to provide extra durability and noise protection, a foil/braid combination can be used.

Solid or stranded conductors? Solid conductors are appropriate for most installations; stranded conductors provide extra flexibility for better handling in close environments.

Pair conformity/centricity: Bonded-Pair cables provide resistance to the rigors of installation by utilizing a manufacturing technique that affixes the insulation of the cable pairs along their longitudinal axes so no gaps can develop between the conductor pairs; a non-bonded-pair cable construction can be susceptible to pair-gapping (and impedance mismatches) during installation and throughout the cable′s life. Pair-gapping is the primary cause of noise.

Insulations: Most industrial-grade Ethernet cables utilize polyolefin insulation. For extreme temperatures, however, an FEP insulation (and jacket) is recommended.

Jackets: Oil- and sunlight-resistant cables typically have a PVC jacket.

If the cables are exposed to moisture, a water-blocking agent should be part of the cable′s construction, as well as inner and outer PE jackets if the cable is buried. Gas-resistance calls for an FEP-jacketed cable, while low smoke zero halogen (LSZH) PVC jackets are available for environments where smoke/flames are a risk. For extreme temperature environments, the cables should feature an FEP jacket (for an extended operating temperature of -70°C to +150°C).

Proof in the testing

A series of rigorous tests conducted by Belden on Commercial Off The Shelf (COTS) cables versus industrial-grade cables has proven that the COTS cables simply do not stand up as well as industrial-grade Ethernet cables in harsh environments. All nine tests were performed on state-of-the-art testing equipment, and all the cables used in the study initially tested as fully compliant to ANSI/TIA/EIA 568-B.26 Cat5e standards.

The following is a summary of tests performed and the results:

Abrasion. Using a fixed drum covered with sandpaper, cables were stretched across a portion of its circumference, then moved back and forth cyclically for 25 cycle counts. At that point, the conductors of the COTS cable could be seen through breaks in the jacket, which would cause it to lose mechanical and electrical integrity. The pairs of the armored industrial cable were not compromised.

Cold Bend. Conducted per UL 4447, samples of cables were left in a controlled temperature and humidity chamber called a cold box. They remained for one hour prior to testing. They were then tested (at -80°C, -60°C, and -40°C) by being partially wound around a 3-inch diameter horizontal mandrel with one end of the cable under tension from an aluminum weight.

The cables were then unrolled and visually inspected to check for cracks in the jacket. The COTS cable became brittle and showed visible cracks. The industrial-grade high/low temp cable had no visible damage.

Cold Impact. In this test, also conducted per UL 444, an aluminum weight was dropped down a hollow guide-tube to smash against a segment of cable under test. The impact force delivered 24 in-lbs or 2.7 joules of impact energy. Each length of cable had been previously cooled; and a total of ten samples were inspected at a series of increasingly lower temperatures to determine if the cables′ jacket integrity was damaged, a condition which could allow ingress of chemicals and moisture and could potentially lead to a conductor-to-conductor short or even catastrophic failure.

The standard jacketed COTS cables failed at -20°C. The industrial-grade cables, protected by high-low temperature jackets, did not crack until impacted at -70°C.

Crushing. In this test, an Instron machine head brings a 2-inch by 2-inch plate down on a segment of cable to crush it-with failure defined as the point at which the cable would no longer reliably support Cat5e performance. Each cable′s electrical characteristics were measured throughout the testing.

At 400 lbs. applied force, the COTS cable with PVC jacket failed-it was smashed flat and would not spring back to its original shape or transmit an electronic signal. The industrial-grade, black-jacketed armored cable had a failure value of 2,250 lbs. - over a ton.

Cut-Through. In this test, based on CSA standard #22.28, a chisel-point mandrel on an Instron machine was lowered onto a segment of cable to test the cable′s susceptibility to a cut-through leaving the conductor exposed. Several kinds of cable were sliced by the chisel to the point where a short circuit was sensed across the conductors, creating a potentially hazardous situation.

The COTS cable shorted out at 92 lbs. of applied force. Two unarmored industrial-grade cables took 205 lbs. and 346 lbs. of applied force to short. The armored industrial cable took 346 lbs. applied force to pierce the armor; however, the conductors did not short until a force of 1,048 lbs. was applied.

High Temperature. In this test, three spools of cable were suspended from a mandrel in a high-temperature oven. The blue cable in the middle is a COTS Cat5e cable with standard PVC jacket. The other two are black industrial-grade Cat5e cables, one with a PVC jacket, the other jacketed in FEP.

All cables were first tested at an ambient temperature of 20°C and were then tested again after being exposed to a high temperature of 60°C over time. The COTS cable functioned acceptably at 20°C but, over time, at 60°C, attenuation increased to where the cable would not support a run distance of 100 meters. The industrial-grade cables, even after exposure to 60°C over time, continued to support the maximum run distance.

Oil Resistance. In this test, conducted per UL 12779, lengths of cable were immersed in containers of oil, which in turn were immersed in a water bath that was placed in a chamber held at 125°C for 60 days.

After the test period, cable segments were removed and their jackets evaluated for tensile and elongation properties. Exposure to oil and lubricants can make jacketing brittle and fragile, even at room temperature, resulting in loss of mechanical properties and reduced service life. The blue COTS cable showed signs of this type of deterioration. The industrial cable′s jacket did not, because the materials and jacket thickness are rated for exposure to oil and other substances, even at elevated temperatures.

UV Exposure. In this procedure-based ASTM G 154 test10 segments of various cables were affixed to panels that were mounted so that the cables directly faced a fluorescent light source whose output range was adjusted to match that of solar radiation levels.

The cables were exposed to light for 720 hours (30 days), then their jackets were visually checked for discoloration, as well as for signs of degradation in tensile strength and elongation.

The COTS cable was not sunlight-resistant and these jackets showed discoloration, a precursor to degradation of the jacket material. The industrial-grade cables were rated to resist the effects of sunlight and other UV sources and showed no jacket damage.

Water Immersion. In this test, the electrical properties of the cables (primarily attenuation) were measured initially. Then the cables were coiled into a dry container, and water was added to submerge them. The cables were tested intermittently over a six-month period. The COTS cable showed increased attenuation as soon as the cable was immersed in water and this continued to degrade over the half-year immersion. After six months of immersion, the industrial-grade cable showed only a slight increase in attenuation - and the cable still exceeded the Cat5e requirements.

Components match application

As with selection of the network′s cabling, it is critical to ensure that the specifications of the active hardware are suited to the application. Some factors to keep in mind when making buying decisions include:

Temperature. Standard commercial requirements are 0-60°C (a standard met by most industrial switches), but some applications can present an ambient temperature as high as 85°C and as low as -40°C. Note: Although most switches will run at extremely low temperatures, many will not start up after having been idle.

Moisture. Conformal coating or IP67 housing solutions can negate these issues. The IP67 connectivity of choice is the ODVA-approved M12 D-coded Ethernet connectors (a 4-pin circular connector that is available as a field-installable IP67/waterproof connector or as pre-terminated patchcords using Cat5e with an industry-appropriate jacket material).

Shock and vibration. Even the minutest vibration on a plant floor can wear on RJ45 connections over time, causing intermittent data communication. For applications such as this, look for switches that utilize the M12 D-coded connector.

Industry Approvals. It is essential that all of the components on an Ethernet system meet the relevant transportation standards.

  • UL CMR-CMX Outdoor: the basic and most common safety standard for communication cable
  • C(UL) CMG FT-4: the basic and most common safety standard for Canada
  • UL Verification Cat 5e/6/6a: third-party testing of electrical performance
  • UL Power Limited Tray Cable (PLTC): the basic rating for installation in 300V power trays
  • UL Tray Cable (TC) - the basic rating for installation in 600V power trays

Summary

Most industrial organizations, including businesses within the oil and gas industry, invest significantly to protect the safety and security of their production processes and to provide workers with safety and protective gear where needed.

Doesn′t it make good business sense to invest wisely to preserve, protect and defend the network infrastructure that supports all of the facility′s mission-critical information, automation and control functions?

The most effective and cost-effective way to ensure long-term network performance and reliability is to invest in an Industrial Ethernet infrastructure with networking components designed and rated specifically for use in harsh and demanding environments. Components in the physical layer are especially vulnerable and costly to replace.

It′s also important to keep in mind that Enterprise-grade products are neither designed for, nor intended for use in, industrial markets or applications; do not risk your network uptime by using COTS cables, which cannot stand up to harsh environments.

Industrial-grade products are far more ruggedly engineered and constructed, and they incorporate design features and materials capable of withstanding the severe environmental and physical stressors to which they are subjected every day.

During the product selection process, it is important to take the time to evaluate the marketplace and select a qualified supplier capable of providing a top-quality, end-to-end Ethernet framework tailored to the specific application and environmental conditions.

As many adopters of Industrial Ethernet have already discovered, taking a "total system" approach will result in a more integrated system with all products seamlessly matched to deliver interoperability and consistently reliable performance day after day, and year after year.

Technical report by Belden.


Source: Industrial Ethernet Book Issue 112 / 8
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