The starting point for the distribution
system is the boiler house, where it is often convenient for the
boiler steam lines to converge at a steam manifold usually referred
to as the main distribution header. The size of the header will
depend upon the number and size of boilers and the design of the
distribution system. In a large plant, the most practical approach
is to distribute steam via a high pressure main around the site.
High pressure distribution is generally preferred as it reduces
pipe sizes relative to capacities and velocities. Heat losses
may also be reduced due to lower overall pipe diameters. This
allows steam supplies to be taken from the main, either direct
to high pressure users, or to pressure reducing stations providing
steam to local users at reduced pressure. A steam header at the
boiler house provides a useful centralized starting point.
It provides an extra separating function if the boiler is overwhelmed,
and a means of allowing the attached boilers to share the distribution
system load.
