A review on chemical oxygen supply technology within confined spaces: Challenges, strategies, and opportunities toward chemical oxygen generators (COGs)

Chemical oxygen generators (COGs) have been used worldwide in confined spaces as an emergency oxygen supply technology, mainly because they are independent and have a long shelf life. However, a number of challenges related to COGs remain unsolved, and a literature review of the current state of the technology is needed. First, the present article summarizes the basic information and applications of COGs, including their oxygen production mechanism, components, forming technology, and ignition system. Four current challenges encountered in applying COGs are discussed, along with the strategies adopted thus far to solve these problems, as found in the published literature. The literature survey reveals that, although much effort has been devoted to controlling the oxygen production rate and the heat output of COGs, the mechanism of producing toxic gases remains unclear and a reliable and safe ignition system has not been fully developed. Finally, future opportunities in the development of COGs are briefly listed.