BY CLEVELAND A. HEATH, TECHNICAL PROGRAM MANAGER AND SUSAN L. KRANTZ, TEXTILE TECHNOLOGIST NAVY CLOTHING AND TEXTILE RESEARCH FACILITY
Welding is a mission-critical process required for the sustainment of many essential U.S. Navy/Department of Defense maritime and aviation assets. Welders perform their work in very tight spaces such as the inside of ship’s tanks and hull voids, submarine ballast tanks and bilge spaces, aircraft fuselages and other extremely confined spaces. Welders are exposed to extreme environmental temperatures, ultraviolet radiation and molten metal slag from the welding process.
The welder’s coveralls must provide protection against flame and heat since the falling molten metal slag poses a significant burn risk. This risk is magnified by the awkward and contorted body positions required to perform their tasks which subjects the welder’s arms, neck, and hands to contact with falling molten metal slag.
The Navy Clothing and Textile Research Facility (NCTRF) sought to address these concerns through collaboration with the user community to define requirements, and utilizing their clothing design and textile expertise, to select appropriate material solutions and design concepts for a preliminary wear test.
Designing a Better Coverall
The focus of the effort was to identify alternative fabrics for incorporation into a coverall design and to improve protection against falling molten metal, improve durability to extend wear life and to enhance comfort through fabric selection with regard to improved breathability, flexibility and other human factor considerations.
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A prototype coverall design with leather sleeves and stand-up collar. (Photo by David J. Kamm, Army Strategic Communication Team, Natick, Massachusetts)
The user community was asked to assist in identifying requirements and desires. Following these discussions, six customized prototypes representing two designs from three fabrics were produced by NCTRF’s Pattern and Prototyping Group for an initial rapid wear test.
Prototyping and Testing
A Wear Test Questionnaire was provided along with a coverall to the six testing participants. Various welding tasks were performed during the wear tests that included both carbon arc and stick welding. The test participants were asked to wear the prototypes for a minimum of two weeks to assess durability, comfort and functionality while standing, lying down and working overhead.
Following the wear test, a meeting was held with representatives from the welding community which included the test participants, their supervisors and industrial engineers to ascertain likes, dislikes and a path ahead. Findings from the wear test included the preference for one of the woven materials due to its durability, lighter weight, perceived breathability and its ability to self-extinguish sparks.
The preferred design utilized a double fabric layer along the entire sleeve to provide full protection and allowed better mobility than a leather concept which proved to be too stiff and heavy. The addition of cuff tabs at the ankles and wrists were also well received, since they afforded tight closures and prevented molten slag and other debris from entering. The collars were deemed to be lower than desired so future designs will incorporate the design utilized in the current coverall.
Given the positive responses received from the initial wear test, NCTRF intends to engage a manufacturer to produce a larger number of garments incorporating the design and material preferences identified by the welding community and conduct a broader and more comprehensive field evaluation.
The initial conclusions are very encouraging; however a proposed extended field evaluation will provide additional performance data and insight to a potential reduction of life cycle costs through the use of laundering the coveralls.