Section I applies to several types of boilers and components of boilers, such as economizers, superheaters, reheaters, and, in some circumstances, feedwater heaters. Although its title is Rules for Construction of Power Boilers, its scope is somewhat broader. The Preamble to Section I explains that it covers electric boilers, miniature boilers, high-temperature water boilers, heat recovery steam generators, certain fired pressure vessels, and organic fluid vaporizers. Since the precise definitions of these various types of boilers are not generally known, the following definitions, found in footnotes to the Preamble, are helpful:

Power boiler—a boiler in which steam or other...