This standard will address the control functions associated with the selective catalytic reduction systems on fossil fired steam boilers greater than 200,000 lbs/hr and combustion turbines greater than 25 megawatts. This includes the outlet NOx control using ammonia flow control, startup and shutdown logic, bypass/isolation logic, dilution air system control, ammonia storage and delivery system control, and catalyst cleaning systems. Urea to ammonia systems are excluded from the scope of this document.


The purpose of this standard is to establish the minimum design requirements for the functional design specifications of selective catalytic reduction control systems for use in fossil fired power plants.

A Word from the Chairman

The standard ANSI/ISA-77.82.01-2011, Selective Catalytic Reduction (SCR) Control Systems, has been published. The subcommittee typically holds a face-to-face meeting in conjunction with the POWID Symposium in June.  If you would like more information about this subcommittee, please contact

Eliana Brazda
ISA Standards Administrator
(919) 990-9228

Cyrus Taft
ISA77.82 Chair