Retrotec USACE - Manual (Page 183)

Appendix D D53
D.4.1.16 Steam Line Serving Unused Areas (Waste)
Figure D90. Construction of underground
piping valve pit showing isolation valves.
Figure D89. Building’s steam pressure
reducing station and hot water heat
exchangers, where isolation valves are
present.
Steam is used for building heating and for process needs. The process steam
users need steam throughout the year, whereas heating is a winter event. It is
not uncommon to fi nd steam pressure on all the steam lines in a building year-
round, even though there are only a few summertime steam demands. This
causes an energy waste at this time of year due to heat losses in the system.
At times, a process gets moved and the steam line that served it in the initial
location remains energized. Steam lines that no longer serve a process or have
seasonal use should be isolated by valves so they can be deenergized when
steam is not needed (Figures D89 and D90).
D.4.1.17 More Than 20% Excess Oxygen in Flue Gases
(Ineffi ciency)
Figure D91. Combustion gas monitors for
sensing the oxygen or carbon dioxide content
of fl ue gases.
Boilers need the proper amount of oxygen (air) for optimum combustion and
effi cient operation. If there is excess air fl ow to the burner and up the stack, the