A gas steam boiler from the 1970's and today, has the basic same technology. The standards where adopted in 1899 and other major change to boiler piping in 1919. Not to much has changed as far as theory. At 212 degrees water boils, all we need in a little more heat, and the steam pressure raises. Simple so far...
Installations of new steam boilers lost popularity in the 1940's because of all the labor needed to install those big pipes; and the advent of the circulator pump used in hot water systems made it simpler and cheaper to install, and can even offer zoning. Therefore the craft of steam piping is dead, as are the "DEAD MEN" as Don Holahan (steam and hydronic author & guru) calls them, no longer install steam piping.
Words of advise, don’t change your piping and be careful about replacing your next boiler. Tips to follow soon….
