scope:

This code shall apply to single burner boilers, multiple burner boilers, stokers, and atmospheric fluidized-bed boilers with a fuel input rating of 3.7 MW_t (12.5 million Btu/hr) or greater, to pulverized fuel systems, to fired or unfired steam generators used to recover heat from combustion turbines [heat recovery steam generators (HRSGs)], and to other combustion turbine exhaust systems.

This code shall cover design, installation, operation, maintenance, and training.

This code shall cover strength of the structure, operation and maintenance procedures, combustion and draft control equipment, safety interlocks, alarms, trips, and other related controls that are essential to safe equipment operation.

Coordination of the design and operating procedures of the boiler furnace or HRSG system and any flue gas cleanup systems downstream of the postcombustion gas passes shall be required. Such coordination shall include requirements for ensuring a continuous flow path from the combustion air inlet through the stack.

Chapter 5, Single Burner Boilers, covers single burner boilers that fire the following fuels:

(1) Fuel gas as defined in 3.3.74.

(2) Other gas having a calorific value and characteristics similar to natural gas

(3) Fuel oil as defined in 3.3.73.3

(4) Fuel gas and fuel oil that are fired simultaneously for fuel transfer

(5) Fuel gas and fuel oil that are fired simultaneously and continuously

Chapter 6, Multiple Burner Boilers, covers multiple burner boilers firing one or more of the following:

(1) Fuel gas, as defined in 3.3.74

(2) Fuel oil, as defined in 3.3.73.3

(3) Pulverized coal, as defined in 3.3.73.2.1

(4) Simultaneous firing of more than one of the fuels stated in 1.1.5(1) through 1.1.5(3)

Chapter 7, Atmospheric Fluidized-Bed Boilers, covers atmospheric fluidized-bed boilers.

Chapter 8, Heat Recovery Steam Generators and Other Combustion Turbine Exhaust Systems, covers HRSG systems or other combustion turbine exhaust systems.

Chapter 9, Pulverized Fuel Systems, covers pulverized fuel systems, beginning with the raw fuel bunker, which is upstream of the pulverizer, and is the point at which primary air enters the pulverizing system, and terminating at the point where pressure can be relieved by fuel being burned or collected in a device that is built in accordance with this code. The pulverized fuel system shall include the primary air ducts, which are upstream of the pulverizer, to a point where pressure can be relieved.

Chapter 10, Stokers, covers boilers using a stoker to fire the following fuels:

(1) Coal

(2) Wood

(3) Refuse-derived fuel (RDF)

(4) Municipal solid waste (MSW)

(5) Other solid fuels

Where solid fuel is fired simultaneously with other fuels (e.g., a solid fuel stoker fired in combination with fuel gas, fuel oil, or pulverized auxiliary fuel), additional controls and interlocks shall include those covered in Chapters 5, 6, and 9.

Exception No. 1: The purge requirements of Chapters 5 and 6 shall not be required when the stoker is firing and the boiler is on-line. In those cases, if no cooling air is being provided to the auxiliary burners, a purge of their associated air supply ducts shall be provided.

Exception No. 2: Where fuel oil or fuel gas is fired in a supervised manual system in accordance with Chapter 5, the excessive steam pressure interlock shall not be required.