Continuous emission monitoring system
Continuous emission monitoring system or CEMS means the equipment required under subpart HH of this part to sample, analyze, measure, and provide, by means of readings recorded at least once every 15 minutes (using an automated data acquisition and handling system (DAHS)), a permanent record of nitrogen oxides emissions, stack gas volumetric flow rate, stack gas moisture content, and oxygen or carbon dioxide concentration (as applicable), in a manner consistent with part 75 of this chapter. The following systems are the principal types of continuous emission monitoring systems required under subpart HH of this part:
(1) A flow monitoring system, consisting of a stack flow rate monitor and an automated data acquisition and handling system and providing a permanent, continuous record of stack gas volumetric flow rate, in standard cubic feet per hour (scfh);
(2) A nitrogen oxides concentration monitoring system, consisting of a NOX pollutant concentration monitor and an automated data acquisition and handling system and providing a permanent, continuous record of NOX emissions, in parts per million (ppm);
(3) A nitrogen oxides emission rate (or NOX-diluent) monitoring system, consisting of a NOX pollutant concentration monitor, a diluent gas (CO2 or O2) monitor, and an automated data acquisition and handling system and providing a permanent, continuous record of NOX concentration, in parts per million (ppm), diluent gas concentration, in percent CO2 or O2; and NOX emission rate, in pounds per million British thermal units (lb/mmBtu);
(4) A moisture monitoring system, as defined in ยง 75.11(b)(2) of this chapter and providing a permanent, continuous record of the stack gas moisture content, in percent H2O;
(5) A carbon dioxide monitoring system, consisting of a CO2 pollutant concentration monitor (or an oxygen monitor plus suitable mathematical equations from which the CO2 concentration is derived) and an automated data acquisition and handling system and providing a permanent, continuous record of CO2 emissions, in percent CO2; and
(6) An oxygen monitoring system, consisting of an O2 concentration monitor and an automated data acquisition and handling system and providing a permanent, continuous record of O2, in percent O2.
Source
40 CFR § 96.102
Scoping language
The terms used in this subpart and subparts BB through II shall have the meanings set forth in this section as follows: