When analyzing offshore operations and those of shipping terminals, the vast size of the operations can be daunting when considering each component that acts as a critical cog in the wheel. The loading and unloading of cargo through ship-to-ship (STS) hose transfer reveals itself as a vital framework within that cog of complexity, and Trelleborg has blazed a new path in ensuring safety, quality, and efficiency during these transfers with a hose solution that surpasses industry regulations.
According to Jonathan Petit, Trelleborg’s Oil and Marine Hose Manager, the company is a significant subject matter expert in STS hose transfer operations. While the industry mandates specific guidelines and standards stipulating the types of hoses used in those types of operations, some nagging issues surface. He indicates a historical battle exists between CapEx and OpEx spending, with companies focusing on purchase price instead of the actual lifecycle of the product. He, however, feels that his clients look past purchase price, but the challenge is making the entire industry understand the benefits gained by exceeding regulations and expectations. For many, meeting the minimum standards influences a halt in striving for an even better effort in quality and safety. Although some meet the minimum standard, it does not mean they automatically skate potential issues or have secured the best process or product available.
“If you focus on just purchase price, you might miss a hidden cost that potentially arises and enacts an increase in lifecycle costs,” says Petit.
As the industry has revolutionized, the need to intensify and improve hose solutions has grown proportionately. Petit says this is primarily due to the products flowing through hoses now. New biofuels and additives being transferred by hose demand a solution supporting this type of transfer. Trelleborg recognized this need early on and has worked to develop a new hose transfer solution.
Rooted in offshore operations
The offshore industry operates within strict guidelines derived from technological advancement and response to tragedy. EN1765 is the key regulatory standard for STS transfer hoses and has encouraged the adoption of textile-reinforced nipple hoses. However, Trelleborg’s solution utilized the GMPHOM 2009 “Guide to Manufacturing and Purchasing Hoses for Offshore Moorings” offshore standard. This standard is equal to or more demanding than EN1765, which encourages the adoption of dual-carcass hose STS transfer hoses based on offshore marine hose designs.
“We propose the KLELINE STS hose for these applications, which is derived from our offshore hoses based on a dual carcass construction,” says Petit.
The KLELINE STS hose solution offers a sealing solution that prevents conveyed fluid from contacting the hose flange and structure. By limiting stress concentration, fatigue, and aging are reduced. The KLELINE STS hose additionally provides resistance to accidental kinking and crushing, therefore avoiding potential deformation and permanent damage.
The design comprises a compact flange with a bumper on top, made possible by an oil-resistant continuous Nitrile rubber inner liner and a built-in gasket. That dual carcass technology of steel cable layers reinforces the body structure within the compact flange. The compact flange allows for continuous and homogeneous curvature in the sag of the U shape catenary despite the short distance between the two vessels. Furthermore, the compact flange minimizes the stress concentration that occurs when a nipple hose connection is located at the same place. Trelleborg’s design allows for a spool piece or emergency release coupling to be utilized when connecting to a manifold.
Enjoying the benefits
According to Petit, STS transfers call for high velocities and sudden changes in pressure of fluids. As a result, hoses can shift or move between the manifolds, which could lead to a hazardous situation, resulting in an incident or injury. In fact, high flowrate is indeed prone to generate sudden pressure change especially during the beginning or end of the STS transfer. High flowrates could generate vibration of the STS hoses. The KLELINE STS much more rigid than usual textile reinforced ones, hence, does not vibrate during transfer nor during start or end of the pumping operations.
Hoses often succumb to damage due to vacuuming and crushing. The KLELINE STS dual-carcass design resists internal pressure, loads, and stresses while protecting the primary carcass from the external environment. This resistance enables KLELINE hoses to avoid vacuuming and crushing effects.
“During STS transfer, the hoses are used at high velocity to make the transfer as short as possible,” says Petit. “At the end of the transfer, there is some vacuum created along the piping and the hoses tend to collapse, surge, and vibrate. In our KLELINE STS solution, the hose remains steady with no movement, collapsing, or surging during the entire transfer.”
The dual carcass design additionally provides secondary containment. This second carcass does not participate in pressure containment; it reinforces the hose against tensile and bending loads while acting like a shield to protect the inner one from damage coming from outside the hose.
In addition to all the positive features offered to the user, the KLELINE STS hoses meet all applicable standards like the GMPHOM 2009 “Guide to Manufacturing and Purchasing Hoses for Offshore Moorings.” The hoses also conform to EN 1765:2016/L15 requirements and achieve compliance with OCIMF guidelines for the “Handling, Storage, Use, Maintenance and Testing of STS hose (May 21).”
“The EN 1765 standard requires a safety factor of four,” says Petit. “We at Trelleborg demand a safety factor of 5.”
Implementing for use
With a design that meets all required standards, Trelleborg ensures the user has the best solution for achieving successful STS transfer operations. This further sets the stage for success because Trelleborg not only meets those standards but surpasses them. Their demand for a greater safety factor only solidifies this notion.
The KLELINE STS technology enables success. The user must commit to investing in the technology and implementing it in daily activity. Through correct application use, including visual pre-use inspections and annual pressure testing, Trelleborg has provided a methodology for enhancing STS operations with positive realizations in safety and efficiency.
“The introduction of our solution is a means to raise the bar in quality and safety during STS transfers,” says Petit.
Nick Vaccaro is a freelance writer and photographer. In addition to providing technical writing services, he is an HSE consultant in the oil and gas industry with twelve years of experience. Vaccaro also contributes to SHALE Oil and Gas Business Magazine, American Oil and Gas Investor, Oil and Gas Investor, Energies Magazine and Louisiana Sportsman Magazine. He has a BA in photojournalism from Loyola University and resides in the New Orleans area. Vaccaro can be reached at 985-966-0957 or [email protected].
