Mains

Definition and stakes

William S. Monroe,  Steam Heating and Ventilation (1902)

“ The Chicago Athletic Club, a building ten stories in height, is heated by exhaust steam with this system of piping with a pressure of not over 2 pounds in the coldest weather, and with little, if any difficulty with water-hammer. In such a plant the risers as well as the mains must be of ample size, and the latter must have sufficient pitch and be thoroughly drained. ”
Source: Wikisource

William S. Monroe,  Steam Heating and Ventilation (1902)

“ Radiator connections.—The connections from the risers to the radiators are always made somewhat larger in proportion than the mains and risers, and Table IV gives sizes which represent good practice for low-pressure systems.
Carpenter and Sickles' rule for steam pipe sizes.—In designing piping for large systems it must be borne in mind that there are many things which affect the flow of steam in a piping system, and special cases must have special consideration. Elbows, bends and valves greatly increase friction in the pipes.
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Source: Wikisource

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