All units subject to the emission specifications in §117.205 of this title (relating to Emission Specifications for Reasonably Available Control Technology (RACT)) must be operated to minimize nitrogen oxides (NOX ) emissions, consistent with the emission control techniques selected, over the unit's operating or load range during normal operations. Such operational requirements include the following.(1) Each unit controlled with post-combustion control techniques must be operated such that the reducing agent injection rate is maintained to limit NOX concentrations to less than or equal to the NOX concentrations achieved at maximum rated capacity.(2) Each gas-fired lean-burn stationary reciprocating internal combustion engine must be checked for proper operation of the engine according to §117.8140(b) of this title (relating to Emission Monitoring for Engines).