This document provides 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 saturatedsteam 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.