UFC 3 -430-11
14 February 2001
CHAPTER 1
INTRODUCTION
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PURPOSE AND SCOPE. This document p rovides criteria for the design of
heating plant instrumentation. A heating plant contains one or more boilers. The plant
may be an individual plant serving a single building or a compact group of buildings, or
a central plant serving many buildings and facilities through an extensive distribution
system. The heating plant instrumentation discussed is, in general, for a saturated-
steam power boiler heating plant. The typical saturated -steam power boiler heating
plant discussed will operate at a design steam pressure of between 1.03 bar (15 psig)
and 20.68 bar (300 psig), with a heating capacity of greater than 422 megajoule/h
(400,000 Btu/h).
The information provided may also be applicable to Low, Medium, and High
Temperature Hot Water heating plants, but does not cover all of the requirements of
those plants, such as control of water pressurization and circulation systems. The
information may also be applicable to superheated-steam power plants, but does not
cover the all of the requirements of those plants, such as steam extraction, reheating,
steam turbine control, and cooling water controls.
Instrumentation is a rapidly changing field. The options available in choosing
and designing plant instrumentation are numerous. A boiler plant includes a large
number of instrument items, all of which have to be specified in the procurement of a
boiler plant. This handbook does not attempt to cover all details. Rather, its purpose is
to present general guidelines for selecting and designing instrumentation for boiler
plants.
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REFERENCES . Refer to Appendix A for references applicable to this
document.
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DEFINITIONS.
Heating Boiler A boiler operated at pressures not exceeding 1.03 bar (15
psig) for steam, or for Low Temperature Hot Water (LTW ) at pressures not exceeding
10.98 bar (160 psig) and temperatures not exceeding 121.1 degrees C (250 degrees F)
for water.
High Pressure Power Boiler A power boiler operated at pressures
exceeding 20.68 bar (300 psig) for steam, or for High Temperature Hot Water (HTW) at
pressures exceeding 10.98 bar (160 psig) and temperatures exceeding 176.6 degrees
C (350 degrees F) (but not exceeding 215.5 degrees C (420 degrees F)) for water.
HTW pressure must exceed saturation pressure plus 1.72 bar (25 psig) to avoid
Power Boiler A boiler operated at pressures more than 1.03 bar (15 psig)
(but not more than 20.68 bar (300 psig)) for steam, or for Medium Temperature Hot
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