(under the class definition) Horizontal cylindrical boilers having a firebox located beneath one end of the boiler and having one or more water walls forming the sides of the firebox.
SEE OR SEARCH THIS CLASS, SUBCLASS:
58+, and 90+, for horizontal fire tube boilers with various types of water fireboxes.
139, 141 and 146, for horizontal flue boilers with water fireboxes.
