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Feature Article

Electrical Penetrators for Saturation Diving System
High-Pressure Testing for Subsea Connectivity in 12-Man Portable SAT VI System Rated to 1,000 Feet of Seawater

Feature Author
Amy Brown
Director of Corporate Communications
Oxnard, California

IUC Group's 12-man SAT VI system.
Electrical penetrators for man-rated subsea systems are rugged connector systems that transmit power and communication signals through a vehicle's pressure boundary, decrease electrical complexity and reduce dependence on operator skill. They are tailored for rigorous conditions and have a variety of advantages for subsea applications, including low maintenance and potential long-term use.

BIRNS Inc. (Oxnard, California) was asked in June 2011 by the IUC Group (Mount Kisco, New York) to develop a set of 22 custom electrical penetrators for a 1,000-feet-of-seawater-rated saturation diving system. The project included providing connectivity for the main deck hyperbaric chamber, the three-man diving bell and the transfer under pressure (TUP) unit. IUC's 12-man portable SAT VI is a 50-by-38-foot modular system with split-level operations and configurations for dive-bell launching, tailored for a variety of vessels.

General Penetrator Requirements
BIRNS developed three sets of National Pipe Thread (NPT) penetrators for each system, certified to the American Bureau of Shipping (ABS) product design assessment. One set had nine BIRNS P25N-16-RA-LS units, where P25N indicates a 1-inch NPT shell size, 16 is the number of No. 16 American wire gauge (AWG) electrical conductors, RA means right angle and LS stands for low-smoke zero-halogen (LSZH) cables. Another set comprised nine P25N-12-RA-LS units, in which 12 is the number of No. 16 AWG electrical conductors. The third set had P25N-4-RA-LS units, with four No. 12 AWG electrical conductors.

NPT penetrators' standard tapered threads were a good fit for the diving bell and decompression chamber as they are easy to install and service, and the overmold on the outboard side allows for a junction box close to the penetrator, unlike other through-hull systems that require the box directly on top of it. The BIRNS penetrators for the SAT VI were specified with 30-foot outboard cables to allow them to reach junction boxes without the need for splicing. Each penetrator had a 36-millimeter diameter and 130-millimeter-long polyurethane overmolding for the outboard side. The shells were constructed of American Iron and Steel Institute 316 stainless steel, passivated per American Society for Testing Materials A967-05 with an environmentally friendly citric acid passivation method. They were fabricated with neoprene (polychloroprene) cable jackets rated for use up to 80° C.

The SAT VI system was built in accordance with performance and safety regulations from ABS, the American Society of Mechanical Engineers (ASME), Pressure Vessels for Human Occupancy (PVHO) and the International Marine Contractors Association.

Penetrator Development
Each penetrator insert was developed by technicians certified to J-STD-001 class-3 requirements for soldered assemblies and WHMA-A-620-A class-3 requirements and acceptance for cable and harness assemblies.

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Amy Brown is the director of corporate communications for BIRNS Inc. and is responsible for developing and managing a comprehensive set of strategic external marketing, media relations and internal communications programs. She has held leadership roles in marketing for companies with applications in the marine electronics industry since 2004.

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