37 Spring 2025 Proceedings Using Research to Challenge Assumptions Evaluating International Orange alternatives by Joshua d. peNNiNGtoN Research Physical Scientist Research and Development Center U.S. Coast Guard A s the nation’s lead maritime regulatory body, the U.S. Coast Guard is charged with promul- gating regulations that support its 11 statutory missions. One of these missions, marine safety, includes the approval of lifesaving equipment intended for use on commercial vessels. Title 46 of the Code of Federal Regulations (CFR) Subchapter Q contains strict prescrip- tive and performance requirements to which equipment must be manufactured and independently tested prior to receiving Coast Guard approval. One of those require- ments is color. Currently, permitted colors for Coast Guard-approved lifesaving equipment are variations of orange or red- dish orange, including Indian Orange, International Orange, Scarlet Munsell 7.5 Red 6/10, and Vivid Reddish Orange—or a fluorescent color of similar hue.1 The deci- sion to select these colors originated from a 1955 U.S. Navy research project that determined orange and simi- lar hues were the most detectable color in the largest variety of weather and light conditions.2 Similarly, the International Convention for the Safety of Life at Sea, an international treaty formed to increase ship and mariner safety,3 requires compliance with the International Life- Saving Equipment Appliance (LSA) Code and specifies International Orange, Vivid Reddish Orange, or a com- parably highly visible color.4 In 2012, the International Maritime Organization published unified interpretation MSC.1/Circular 1423, titled Unified Interpretation of Paragraph 1.2.2.6 of the LSA Concerning Lifeboat Exterior Colour. This permit- ted member governments to accept a comparably highly visible color for lifeboat exteriors in lieu of International Orange or Vivid Reddish Orange.5 In accordance with the circular, several member governments approved, or requested their maritime administrations approve, alternative colors for lifeboat exteriors, particularly lifeboats carried aboard large pas- senger vessels and cruise ships. These actions have been a catalyst for increased requests to the Coast Guard for alternative colors for lifeboats, as well as other Coast Guard-approved lifesaving equipment. In response, the Lifesaving and Fire Safety Standards Division (CG-ENG-4) in the Office of Design and Engineering Standards at Coast Guard Headquarters sponsored a Coast Guard Research and Development Center (RDC) project to evaluate the detectability of alternative lifesav- ing equipment colors in the maritime environment. The Science of Color Evaluating a color’s influence on the detectability of an object, or target, is a complex problem and requires knowledge of several multidisciplinary topics such as electromagnetic energy, human color perception, and precision color measurement and comparison techniques. Energy emitted by the sun is composed of electromag- netic waves emitted across a broad spectrum of energy, frequencies, and wavelengths called the electromagnetic spectrum.6 The range of wavelengths that encompass all colors detectable by the human eye is called the visible spectrum and spans from approximately 400 nanometers Coast Guard recruits conduct survival float training at U.S. Coast Guard Training Center Cape May, New Jersey, on July 13, 2023. Navy photo by Petty Officer 2nd Class Gregory Schell
