Tuesday, December 13, 2011

Best Practices: Diving and Salvage

Diving Risk Management and Technology
Working on around or under water is inherently risky, to the personnel performing the work as well as the environment, but with the proper preparation, the right equipment and an attention to safety, those risks can be minimized.

Avoiding Contaminant Risk
Though contaminated water diving is not new to commercial divers, it is probably reasonable to say there is increasing awareness of the potential risks it represents. While advancing technologies such as ROV’s have played a major role in reducing the risks to divers by decreasing the time of exposure to contaminates, many operations still require diving. Though diving continues to be dangerous, steps can be taken to reduce exposure risks to the diver.

In theory, it would be ideal to test the water before an operation and then tailor the equipment to the specific contaminants in the water. Besides the obvious impracticality of that endeavor, we are still faced with the inherent limitations of chemical testing.

Chemical testing of the personal protective equipment of the diver has always been done on new suits, at 1 atmospheric pressure and only one chemical at a time. It is reasonable to assume that the age and condition of the suits, the pressure at which the diver is working and/or the effects of multiple chemical contaminants will affect the drysuit’s resistance to contamination. And of course, the entire system is rarely tested. Quite often, the only information available to the diving supervisors is the resistance of the drysuit material to chemical permeation. Even then the tests are run on pristine (new) fabric.

It is important to note that no one system that can protect the diver from all types of contaminants. However, by always diving a completely encapsulated system, divers can minimize their exposure to contamination. It is critical to remember that the system is only as effective as its weakest link. For example, if the diver is wearing a drysuit yet wet gloves, the potential for exposure is high. The weak link can even be in the equipment itself, including the valves, zipper and breathing system. How can those be addressed?

Diving Unlimited International, Inc. (DUI) has developed a drysuit designed for contaminated water applications in which the company addresses some of these weaknesses. The CXO (Contaminated eXtreme Operations) drysuit is made with polyurethane material, double taped seams, polyurethane waterproof zipper, contaminated water valves and field replaceable gloves, seals and attached hood. DUI is also partnering with other companies to develop innovative technologies to mechanically attach full-face masks to the suit as well as easy-to-use decontamination products and procedures for easy on-site and definitive decontamination. Minimizing cross contamination after the dive operation can be just as critical as minimizing exposure during the dive.

Safer equipment cannot replace the training and education required to dive in hazardous environments. Common sense and knowledge are necessary to evaluate the mission requirements, the environmental conditions and various risk factors including contaminated water. Thorough training combined with a fully encapsulated system is the best way to minimize risks to commercial and public safety divers.

Oil and Wreck Containment and Removal
The removal from the Columbia River of the final section of a WWII Liberty Ship Davy Crockett marks the conclusion of a carefully engineered effort to prevent more than 32,000 gallons of bunker oil from escaping into the river from the various double-bottom tanks and other holds. The vessel was believed to have been weakened by scrapping activities that likely caused it to buckle and partially sink, releasing an estimated 70 gallons of oil.

The operation involved stabilizing the vessel and containment of the pollution threat. When local facilities were unavailable for deconstruction, a sheet pile cofferdam containment was erected, allowing the vessel to be deconstructed in the water. Internally it was lined with an impermeable silt barrier and additional sorbent materials to collect any oil that escaped during the response. The project obtained all necessary environmental permits. Throughout the project, water and sediment samples have been taken to monitor the site.

During the 211-day operation, under the direction of the United States Coast Guard and unified command consisting of both Washington and Oregon Department of Ecologies, crews from the prime contractor Ballard Diving & Salvage removed 4.45 million pounds of steel and another 824,822 pounds of debris, including wire, bricks and oiled sorbent materials and 1.6 million gallons of water contaminated with oil or other hazardous waste. All recovered materials were taken off-site for proper disposal.

While demolition has been completed, crews from Ballard Diving and Salvage will continue to collect steel chunks and operate the water filtration system inside the cofferdam. Sediment cleanup inside the cofferdam will follow before the sheet pile walls are removed.

Near record river levels, high river currents due to abnormally heavy spring runoff, heavy snow and often zero visibility all created a challenging environment for the many commercial divers involved in the operation, which is estimated to cost approximately $20 million. The response is funded by monies from the National Oil Spill Liability Trust Fund.

Risk Management
Risk is commonly defined as exposing someone or something to danger, harm, or loss. Commercial diving is perceived to be an inherently risky profession; however, those knowledgeable within the marine industry know otherwise. The professionalism and competency of a qualified commercial diving contractor can be the difference on whether diving should be considered “risky”. The combination of safety measures created by governing agencies, internal company policies and safety programs, the development of state of the art diving equipment, and the many redundancies that have been developed elevate the standard for working underwater and further mitigate the risk factor.

The evolution of the safety standards over the last few decades has had a profound impact on the expectation of protection for all those working underwater. During operations, divers must carry a ‘bail-out’ air bottle, their umbilical cord enables physical retrieval, a separate standby air supply on the surface is kept in case of mechanical failure or contamination of a diver’s air supply – and these are just a few of the industry standard safety measures. Seattle’s Global Diving & Salvage furthers their commitment to safety through the company’s Health, Safety, Environmental, and Compliance Group, a four person team explicitly tasked with providing the company the guidance and support necessary to continually employ the safest working conditions possible.

Prior to any diving operation being undertaken a detailed Site-Specific Dive Plan is developed, which summarizes the tasks of the particular job. Tasks for a salvage job could include items such as preparing the vessel, including removing loose materials, contaminates and potential pollutants. Other tasks could include identifying how to stabilize the vessel, installing the lift bags or lifting slings and preparation of the lift. Also included in a Dive Plan are the important contact information for the specific job-site, location and directions to the closest hospital, contact information for local emergency agencies and the parties involved in the operation.

Another component in the Dive Plan is the relevant “Job Safety Analysis,” commonly referred to as the JSA, which identifies the potential exposure of specific tasks and micro-activities and outlines the appropriate preventative action. In a marine construction project, if a high-pressure water jet is being used to move material from the base of a pile or wall, a JSA would consequently identify safe operation of a high pressure pump. Global Diving has developed and continues to expand a library of hundreds of JSAs, covering topics such as high-pressure water blasting, suction dredging, and concrete removal operations.

Global has an established safety culture, and over the last thirty plus years has identified that the key to risk management and personnel exposure begins with proper planning.

Alternative Risk Management
Diving as a means of getting to work has always carried a higher level of risk than any other construction activity according to the various government agencies who track the statistics. A Coastguard document, recently acquired through the Freedom of Information act, indicates total commercial diver fatalities in America from 1990 to 2010 as 428. That’s an average of more than 20 per year.

One way to minimize physical risks in a diving operation is to remove as many of those risks as possible while maintaining the required operational capability. Depending on environmental factors such as depth, visibility, current and access to the work site, a method to minimize diving risk is to use Atmospheric Diving Suits (ADS) in place of traditional soft suit diving. The Hardsuit has been in operation commercially and with several Navies (primarily for submarine rescue) since its introduction in 1986 with NO fatalities or injuries.

Phoenix International Inc. operates Hardsuit atmospheric diving systems. Used mainly in the offshore oil fields they have also performed well in dams where the system eliminates the uncertainties of using dive tables at high altitudes while minimizing the dive spread footprint. With no need of chambers and compressors they can be trucked easily to remote sites.

A cast aluminum suit, adjustable for diver height, that maintains the diver at 1 atmosphere, the Hardsuit allows the diver to travel from the surface to -1200 feet, or anywhere in between, without any of the pressure related hazards faced by an air or mixed gas diver. A combination of thrusters mounted behind the arms, controlled by footpads in the boots, and a neutral tether allows the Hardsuit diver to travel easily in the water column or on bottom while patented joint technology ensures agility and flexibility unrivalled by any previous ADS system. Life support is carried onboard with sufficient redundancy to last for 48 hours with the tether only supplying power and communications. All life support functions in the suit have onboard battery backup, and an Orcatron through-water communication system ensures contact with the surface even in the unlikely event of a tether being severed.

Not only does the ADS eliminate decompression issues, bottom time restraints, ascent rates, pneumothorax, ear squeeze, sinus problems and other pressure related concerns, but it also insulates the diver from the environment. This eliminates or minimizes risks due to marine organisms, chemical and biological contamination, infections, heat, cold and cuts or abrasions.

The combination of reduced diver risk with Hardsuit system portability make this Atmospheric Diving System a viable tool for diving risk management.

High Current Environments
Throughout the summer of 2011 divers from Associated Underwater Services (AUS) assisted in the installation of a temporary cofferdam dam in the Snoqualmie River located in North Bend, Washington, just outside of Seattle. The project was performed for Barnard Construction of Bozeman, Montana who is the prime contractor for the rehabilitation of the 100 years old Snoqualmie Falls hydroelectric facility.

The cofferdam consisted of one-cubic-yard “super sack” bags which were place individually within 100 feet of the Snoqualmie Falls, a 270 foot waterfall on the Snoqualmie River in Washington State. The proximity of the waterfall drop off, and the high and/or fluctuating current, necessitated numerous safety measures in addition to safety redundancies normally present in surface supplied diving operations.

In addition to the snap shackle that normally secures the diver’s umbilical to the diver’s harness, each diver used a man-rated carabineer from umbilical to harness. Depending on the river flow, one or two tenders per diver were used to tend the divers umbilical. Once several bags were in the river the bags themselves provided a “lee” from the current and the divers were able to secure themselves to the dam itself by holding onto the handles of the super sack bags.

Any personnel walking on the installed dam wore fall protection harness with retractable “yo-yo” safety lanyards. This included the all tenders and the diving supervisor inside the diver control station.

With the implementation of these additional safety procedures Barnard construction and AUS were able to install and remove more than 2,300 super sack bags during the summer season of 2011, despite challenging rivers conditions.