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111111 TUNNEL
- - - HIGH PRESSURE
_ _ LOW PRESSURE
FIG. 1
Branches were taken off, extensions were added
and Pittsburgh's "Golden Triangle" was furnished
with heat for its various needs. The tunnel system
became its backbone and any serious dislocation
or outage became a major catastrophe to the Company. This was emphasized during the flood of
1936 and again in the breakage of the water main
in late 1957, which flooded the tunnel to the extent
that the heating system was completely shut-down
as mentioned and on the following start-up had
to be split into two separate divisions until such
time as the trouble could be corrected. This was
the mishap written up in the April-1958 issue of
District Heating.
As one looked at the general picture at that
time, the Heating Company consisted of two heating plants located at the two corners of a triangle
and connected together by a distribution system
made up by two legs of a triangle but not by the
third and shortest leg. The long route between.
generating plants multiplied the possibilities of
trouble spots that might cause a split-up of the
whole system into two smaller systems. This was
especially serious in the off heating season when
only one generating station is in operation to carry
the load. It could have meant the emergency
start-up of a cold and unmanned plant with the
possibility that much of the equipment would be
unusable because of major maintenance work in
progress.
By 1950, the development and reconstruction
of the Gateway Center area located at the confluence of the rivers and the apex of the triangle
began to take shape. This included the removal
of old and obsolete buildings with the construction
of modern skyscraper-type buildings in their stead.
This rebuilding also carried with it a shift in the
load demand and the additional desirability of
being able to serve this new and important district
from either plant and with the additional security
of two routes for steam transmission. The steam
demands of this newly developed area were of such
a magnitude that to assure continuous service to
this section, it was imperative to find a means of
supplying it even if trouble should develop at the
Stanwix plant or within the two-sided triangular
distribution system connecting the two plants
together.
For several years, the planning division had
advocated and placed in their preliminary construction budgets, items for the installation of a
major capital improvement to complete the piping
triangle which would in reality make a loop of the
distribution system. As this was a sizable expenditure, it was postponed year after year, and the
burden placed upon the operating personnel to
keep the system in operation. Even the rate at
which the load was added at the Gateway Center
area did not create major operating difficulties or
cause the seriousness of the situation to be apparent
