scope:

This code applies to the following:

(1) 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

(2) Pulverized fuel systems at any heat input rate

(3) Fired or unfired steam generators used to recover heat from combustion turbines [heat recovery steam generators (HRSGs)] and other combustion turbine exhaust systems at any heat input rate

This code covers design, installation, operation, maintenance, and training.

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

This code does not cover process heaters used in chemical and petroleum manufacture in which steam generation is incidental to the operation of a processing system.

Chapter 5 covers single burner boilers that fire the following fuels:

(1) Fuel gas as defined in 3.3.65.3.

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

(3) Fuel oil as defined in 3.3.65.4

(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 covers multiple burner boilers firing one or more of the following:

(1) Fuel gas, as defined in 3.3.65.3

(2) Fuel oil, as defined in 3.3.65.4

(3) Pulverized coal, as defined in 3.3.65.2.1

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

Chapter 7 covers atmospheric fluidized bed boilers.

Chapter 8 covers HRSG systems and other combustion turbine exhaust systems.

Chapter 9 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 covers boilers that use 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.

NOTICE: An asterisk (*) following the number or letter designating a paragraph indicates that explanatory material on the paragraph can be found in Annex A.

A reference in brackets [ ] following a section or paragraph indicates material that has been extracted from another NFPA document. Extracted text may be edited for consistency and style and may include the revision of internal paragraph references and other references as appropriate. Requests for interpretations or revisions of extracted text shall be sent to the technical committee responsible for the source document.

Information on referenced publications can be found in Chapter 2 and Annex K.