July 2019

Even though hidden deep in the sea and invisible to us, submarine cables are of crucial importance for our daily lives. Undersea cables carry 99 percent of all intercontinental communication, which means that business and private communications, as well as financial transactions, are absolutely depending on their efficiency.

Submarine power cables are deployed as well in the offshore industry by oil and gas rigs and marine renewable energy installations to provide power, shore-to-platform and internal platform fiber-optic communications, and oceanographic monitoring and surveillance.

Unfortunately, undersea cables are vulnerable and do break or get damaged by ships’ anchors, trawling, or due to some other environmental issues. For that reason, submarine cables need to be designed and built with additional protection, making them resistant and reliable enough. Submarine cable protection is of crucial importance for every offshore project.

Possible Applications of Submarine Cables

Submarine power cables are dedicated to the transportation of the electric power below the surface of the water. Most of the time, they are coupled with optic fibers in order to monitor the cables but also to ensure the communication of the data. Exposed to tough conditions as heat, cold, and saltwater, but as well to external events such as dragging anchors, dropping objects, and fishing, their protection is crucial to their performance. Their design and, most especially, armoring vary according to the seabed conditions and the expected potential issues.

In general, power and telecommunication submarine cables are deployed for the entire lifetime of the project, from the first step to decommissioning. They are of critical importance for the safe transfer of the power generated. The oil and gas industry is one of the first industries deploying undersea cables to connect oil and gas platforms to mainland power grids.

But despite being examples of advanced technology, submarine cables remain vulnerable and relatively easy to damage.

They can get disrupted for a number of reasons that include natural disasters, fishing trawler nets dragging cables along with the catch, or accidents related to subsea installations. Since the damages happen unexpectedly, the availability of repair vessels is often limited and the elimination of the problem may take some time and incur high expenses.

Governments and industrial key players are uniting their expertise and funds to look for reliable submarine cable protection solutions. Many efforts have been made in design and material selection but also laying and maintenance vessels. The sector is in continuous development and in search of reliable innovative solutions.

Available Submarine Cable Protection Solutions

Depending on the industry, the seabed conditions, and the depth, there are various submarine protection systems available right now at the market. All of them share the same objective: protecting the submarine cables from fatigue, overbending, and external factors.

Bend restrictors, bend stiffeners, protecting and ballasting shells, or split pipes are used at the bottom of the foundations to protect the cable near the platform. Most of the time, the entire system is called a CPS (cable protection system). Bend restrictors are applied to ensure the bending radius of the cable will not exceed the minimum bending radius defined by the manufacturer. Bend stiffeners are especially designed and manufactured for use in dynamic applications to prevent failure as a result of cyclic loading.

The shells, cylindrical half shells, or split pipes usually include bend restrictor functions and other connection elements and, therefore, are used as part of a complete cable protection system most of the time. They are especially adapted for the crossing of the scour protection at the bottom of the platforms as well as for rocky or challenging seabeds thanks to their abrasion resistance and stabilizing/ballasting abilities. This protection adds some stiffness to the point of connection to a rigid structure.

Concrete mattress, rock dumping, and rock bags are used to protect longer cable sections. However, the main solution to protect the longer section of cables (inter-array and export cables) is to bury the cable on the seabed. The rock dumping or the concrete mattress are used when burial is not possible or, in some cases, used as an added measure. The installation of the concrete mattresses is challenging due to the concerns related to the alignment and the “butting up” tolerances. This system requires specific means including frames, ROVs, etc.

Finally, the shells deserve a special word, since this is the only solution that can be used in both applications — in CPS but also to protect longer cable section. Moreover, at the shore landing areas and due to sedimentary movement, the shells are the most suitable solution. The protecting and ballasting shells are a simple, effective and easy-to-assemble solution. They are positioned along the cable and can additionally ballast the installation.

Most of the time, the mentioned solutions are made of composite materials and, most specifically, polymers such as polyurethane. The main advantage of polyurethane is its resistance to corrosion. Cast iron is corrosion resistant as well, and it provides an additional advantage with a ballasting/stabilization function.

Case Study: Protecting and Ballasting Cast-Iron Shells

FMGC is a European leader in the design and manufacture of cast-iron counterweights. Some years ago, the French company started applying its expertise in ballast solutions to the offshore sector. Its participation at the IBOCS projects marks an important milestone in the development of the industry in France. The aim of the project was to develop a full range of articulated cast iron shells that protect, ballast, and stabilize subsea conducts (cables, pipes, etc.).

Made of ductile cast iron, the main goal of the FMGC is to provide a cost-effective solution that can reduce the cost of the cable protection thanks to its specific design. The solution is combining the protection, the stabilization, and the bend restrictor aspect in only one product that can be directly installed on the deck of the laying vessel. Thanks to the specific design, the need for other dedicated means and additional ships is drastically reduced.

These shells can be used as part of a cable protection system in addition to polyurethane products and also for the protection and stabilization of longer sections of cable for the shore landing or for rocky or challenging seabed where burial is not possible.

The solution can be easily adapted to various types of cables: from telecom cable of 20 mm to export cable of 300 mm.

The material choice in this case is important because of the unique mechanical properties of ductile cast iron withstanding the harshness of marine environments, resisting high impact, abrasion, and corrosion.

The French company Enedis, which manages 90 percent of the public electricity distribution network of continental France, has used the FMGC protecting and ballasting shells on several of its most challenging projects. One of the latest applications has been the protection and stabilization of an underwater cable, crossing the Fier d’Ars between Loix and Les Portes en Ré.

The feedback of Kerlann Marine, one of the companies that has been assigned by ENEDIS to lay the cables and install the shells: “After using some models of shells with different designs, the model used for the construction site of Houat 1 — IBL100 is very well studied; the implementation is fast and simple; the weight is correct for the displacement; the shell widths are well studied for curves.”

Floating Offshore Wind Applications

All recent technological advancements in the offshore wind industry result in the increase of the viability of large offshore turbines capable of taking advantage of the higher wind speeds in greater water depths. Traditional bottom-fixed foundations are not suitable to these environmental conditions. Therefore, new floating platforms such as Floatgen, Hywind Scotland, and, most recently, Kincardine are about to rise and make the sector move steadily forward.

All floating structures need submarine cables to run through the water, from their substructure base to the seabed. This is a dynamic cable system that should transmit stable electric power from the floating offshore platform to a substation on land.

Exposed to greater levels of mechanical stress produced by marine currents and the movement of waves, these cables are subject to an increased risk of failure. The dynamic cables are attacked by the sea currents, the action of the waves, and the movement of the floating turbine platform itself; therefore, their protection is of critical importance.

As we have seen, there are quite a few solutions available for traditional subsea cables of a static offshore wind farms. Most of them, with some modifications, would be adaptable as well to dynamic submarine cables.

However, the cast iron protecting and ballasting shells feature best characteristics to adapt to a dynamic solution because of their flexibility and resistance.

While conventional submarine cables are dropped and secured on the seabed, the cables for floating offshore wind are continuously subjected to bending and twisting forces because of the tidal current and floater behavior, and, therefore, they are likely to suffer mechanical damage in various sections.

On the dynamic cable, we can consider the use of cast iron shells on the touch down point of the cable to limit the loads applied and ensure some restoring forces but also as a bend restrictor in the mid-water parts.

In addition, the gravity anchors can be used to offset the buoyancy elements such as on Lazy S or Steep S cable configurations.

The protecting and ballasting shells would easily allow the cables to follow the waves and tidal currents without encountering fatigue and failure.

The use of cast iron for offshore ballasting shells ensures cable protection, stability, strength, and the best possible performance thanks to the mechanical properties of the material able to withstand the harshness of marine environments.

A reliable cable protection system secures the performance of an offshore structure by protecting submarine power cables against various factors. The undersea cable industry is investing a lot in designing and manufacturing cost efficient solutions able to withstand the dynamic forces, but also leaving less footprint. And even though considerable care is taken to limit the factors leading to submarine cable damages, the problem remains and can lead to costly, widespread internet, communications, and power disruptions.

Staying safe while working at height starts on the ground — long before a worker heads up the turbine for a maintenance or repair project.

Equipment Inspections

Regular inspections are the best way to always be aware of the current state of your equipment. Knowing the products’ condition will allow you to take preemptive action if you encounter a problem.

Here’s guidance on what is considered “regular” in the industry and who should be doing equipment inspection:

According to OSHA 1926.502(d)(21), personal fall arrest systems must be inspected prior to each use. This includes particular focus on wear, damage, and other deterioration, and defective components. If any of these issues are identified, the product must be removed from service.

ANSI A10.32-2012 states all fall-protection equipment should be inspected at least every six months after its initial service; inspection should be conducted by a competent person.
ANSI Z359 says equipment should be inspected by the user before each use and, additionally, by a competent person other than the user, at intervals of no more than one year.

Employers may create their own inspection criteria; however, it must be at least as stringent as those established by the relevant industry standards or the equipment manufacturer.

A competent person is someone assigned by the employer, who “is capable of identifying existing and predictable hazards in the surroundings or working conditions, which are unsanitary, hazardous, or dangerous to employees, and who has the authorization to take prompt corrective measures to eliminate them.”

Competent persons are fully aware of and know how to recognize potential dangers on the jobsite. They are trained in the proper use of fall-protection equipment, from harness and lanyards, to anchors, guardrails, and ladders, including their proper maintenance. They are also able to take corrective measures to eliminate fall hazards, up to and including halting operations until the hazards have been mitigated. While the everyday care of fall-protection equipment is the responsibility of its user, the competent person plays a key role in making sure that care happens.

To make this easy to remember: A worker should inspect his/her gear, personally, before every use. A competent person should inspect the equipment once a year or more, as required by the manufacturer or local jobsite policies. Guardian Fall Protection, for example, requires a competent person inspection every 12 months per their product instructions. Having a person other than the user as part of the process means more eyes on the gear and more opportunities to catch something the first person missed.

Inspections should be recorded in a log of gear inspections. Many manufacturers provide templates to use, and most include helpful diagrams of the specific products to help inspectors “check off” all key components of the product. An example of comprehensive inspection forms can be found at tinyurl.com/inspectionforms.

Proper Maintenance

Ongoing maintenance of fall protection equipment goes hand-in-hand with regular inspection to keep everything in working order and workers as safe as possible.
Here are tips for proper care of fall-protection products:
• Keep harnesses and any gear with webbing away from sharp or rough surfaces.
• When gear gets dirty, use only water or a mild soap-and-water solution to clean it; more powerful cleaners can compromise the integrity, and thus the strength, of the material components.
• Store harnesses and lanyards in a cool, dry place free of moisture and ultraviolet (UV) rays. Excessive exposure to UV rays can degrade webbing integrity over time.
• If gear becomes wet, don’t leave it in a heap after wearing because doing so will spur growth of mildew. Hang wet gear in a dry area in a configuration that exposes its webbing material, so it can dry slowly and naturally. Do not use a heat source, such as a hair dryer or sunlight, to speed drying.
• Consider using a dedicated storage bag for the product when not in use. A durable gear bag makes storage and portability easier and is an excellent way to keep track of one user’s complete set of fall-protection equipment.

Every jobsite should implement proper equipment inspection and maintenance procedures to take care of the equipment that takes cares of employees. Include step-by-step instructions in employee training, reinforce these behaviors when you see them at work, and take time to explain the importance of them when an employee is non-compliant with these processes. Consider a monthly inspection- or maintenance-focused toolbox talk to review new procedures and to give workers an opportunity to clarify any questions that may have come up over the course of their work.

Lifesaving equipment has an important job. Make sure it’s tended to with intention and commitment, so it can do its job to the best of its abilities.

According to Energy.gov, the “United States is home to one of the largest and fastest-growing wind markets in the world.” This growth emphasizes the importance of developing an efficient and effective rescue plan for those working inside and outside of turbines.

Rescue kits can be one element of developing a simple and effective rescue plan and can range from auto-descent devices to haul systems with a self-braking descender.

Developing a Rescue Plan

According to Occupational Health and Safety’s “Subpart M,” fall protection is required at “heights of six feet or greater above a lower level” or at “heights of less than six feet when working near dangerous equipment.” These plans should not only identify anchor points, egress, access, and hazards but also a cohesive and simple rescue procedure.

Additionally, OSHA requires that “the employer shall provide for prompt rescue of employees in the event of a fall or shall assure that employees are able to rescue themselves (1926.502(d)(20)).” A rescue plan should focus on removing fallen victims to the ground and hand off care to someone with advanced medical training. When developing a rescue plan, best practice is to identify factors such as the remoteness of the site, realistic response times, and what type of equipment and training can be provided.

Since the boom of wind energy in the early 2000s, OSHA has set certain requirements for training employees; however, most countries don’t have standards for the wind industry. The Global Wind Organisation, based in Denmark, was created to help establish minimum standards in the wind industry. As it remains though, contractors and operators are responsible for developing rescue plans and training for their employees.

Why Rescue Kits?

Personal protective equipment is the first step in arresting a fall, but what happens after a serious fall? Suspension trauma, or orthostatic intolerance, “can result in unconsciousness, followed by death, in less than 30 minutes,” according to the OSHA Safety and Health Information Bulletin. Symptoms of suspension trauma include dizziness, fatigue, sweating, and weakness.

The threat to fallen workers is a long period of immobility, which causes “an accumulation of blood in the legs (and) reduces the amount of blood in circulation.” Providing a rescue kit on hand can minimize the amount of time a worker is suspended, which is why mechanical advantage haul kits have been in demand and used for many years.

All Shapes and Sizes

There are two common types of rescue kits available for those who work at height. Deciding between the two depends on factors such as price, compactness, and ease-of-use. Some manufacturers provide auto-descent systems that range from a two- to three-foot-per-second descent and can evacuate one to two people. Others manufacture rescue kits using a pulley system with a descent control device. Petzl, a manufacturer of professional safety equipment for more than 25 years, wanted to offer a closed, clean, and efficient system for workers in confined and vertical environments and developed the JAG RESCUE KIT®.

Advancing Rescue Kit Simplicity

Petzl’s JAG RESCUE KIT® is a compact, lightweight, and ready-to-use rescue kit. As a leader in technical rescue equipment in specialized markets, Petzl wanted to offer a solution for at-height workers in all markets. The JAG RESCUE KIT® is designed for a pick-off rescue of an injured or incapacitated worker using a 4:1 mechanical advantage due to the double pulleys on the operator and victim end. Pulley sheaves are mounted on sealed ball bearings, which makes the JAG RESCUE KIT® highly efficient. A flexible cover around the 8mm haul rope gives the user a compact and tangle-free rescue option. Both ends are color-coded to differentiate the victim and operator end.

“This equipment was designed to perform two key ​functions: transfer the load of the casualty from his/her fall arrest system onto the rescue lowering system and to control the descent of the casualty to the ground,” said Michel Goulet, professional division national sales manager at Petzl.

Benefits of the Self-Braking Descender

The newest JAG RESCUE KIT® version uses an I’D EVAC, a self-braking descender designed to handle a one- or two-person load. Since the JAG RESCUE KIT® is often rigged in a vertical plane, with an anchor point directly above the casualty, the I’D EVAC® is designed with a handle specifically oriented to allow for comfortable descent control when lowering from the anchor.

The operator controls the incapacitated worker descent by pulling on the handle and controlling the descent speed by holding the rope with the brake hand as it slides through an auxiliary friction brake. An anti-panic function limits the risk of an accident due to uncontrolled lowering. Self-braking descenders provide rescuers the option to perform an accompanied or unaccompanied rescue operation depending on psychological, environmental, and physical obstruction factors.

JAG RESCUE KIT® for Wind

If not properly prepared and trained in rescue, the potential for things to go wrong — or get worse — during an actual rescue operation is increased. The advantage of Petzl’s pre-rigged JAG RESCUE KIT® is the ease of which a rescuer can quickly transfer the suspended casualty’s weight from the structure, or fall arrest lanyard, to the lowering system without having to re-position or disconnect any of the kit components when switching between hauling and lowering modes. Like with all equipment, users of the JAG RESCUE KIT® should be properly trained before a real-life situation occurs.

According to the American Wind Energy Association, “U.S. wind power has more than tripled over the past decade” with more than 56,600 turbines “operating in 41 states, Guam, and Puerto Rico.” The wind industry is growing at a rapid speed, which means fewer workers are hired with high-level rope access training and at-height rescue. With the development of the JAG RESCUE KIT®, Petzl is dedicated to creating new systems for specialized markets such as the wind industry, and encourages the growth and success of renewable energy.