NFPA 85-2007 Boiler and Combustion Systems Hazards Code
NFPA Technical Committee Document Proposal NOTE All Proposals must be received by 500 pm EST/EDST on the published Proposal Closing Date. FOR OFFICE USE ONLY For further ination on the staNFPA Technical Committee Document Proposal NOTE All Proposals must be received by 500 pm EST/EDST on the published Proposal Closing Date. FOR OFFICE USE ONLY For further ination on the staSequence of Events Leading to Issuance of an NFPA Committee Document Step 1 Call for Proposals Proposed new Document or new edition of an existing Document is entered into one of two yearly revision al Interpretation NFPA 85 Boiler and Combustion Systems Hazards Code 2007 Edition Reference 4.6.3.2.5.2 F.I. No. 85-07-1 Question No. 1 Except for 4.6.3.2.5.2 does 4.6.3.2.5.1 require one 85236 BOILER AND COMBUSTION SYSTEMS HAZARDS CODE Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.3.73.9 Stoker used for . . . . . . INDEX Reburn systems, furnace temperature tests for . . . . . . . . . 6.6.3.5.2, Flow control 85235 6.7.3.5.2, 6.8.3.5.2 Single burner boilers, fuel supply leakage test . . . . . . . . . . . . . . . 85234 Fuel oil systems BOILER AND COMBUSTION SYSTEMS HAZARDS CODE Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.3.149.15 Cold start . Pulverized fuel systems INDEX 85233 Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.3.3.4 Blast furnace injection . . . . . . .85232 BOILER AND COMBUSTION SYSTEMS HAZARDS CODE Oil-fired warm-up burners . . . . . . . . . . . . . 7.8.5.1.3.2, 7.8.5.2.1.2F Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .INDEX Pulverized fuel pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.5.3.2.1.2, 9.5.3.2.2 Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .85230 BOILER AND COMBUSTION SYSTEMS HAZARDS CODE Fuel oil systems . . . . . . . . . . . . . . . . 6.7.4.2, 6.7.5.2.1.3B, 6.7.7.2.1.1, A.6.7.7.2.1.12, B.3.2 Interlocks for . . . . . . . . . . . . INDEX Duct burners . . . . . . . . . . . . . . . . . . . . . . . . . 6.4.2.3.12, A.6.4.2.3.12.15 Fuel gas systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.6.5.1.5.4, 6.6.5.2.1.1, 6.85228 BOILER AND COMBUSTION SYSTEMS HAZARDS CODE Atmospheric fluidized-bed boilers . . . . . . . . . . . . 7.4.3.4.2.3, 7.7.3.2, 7.7.5.2.1.2J, 7.8.3.2, 7.8.5.2.1.2K Definition . . . . . . . . . .INDEX Furnaces . . . . . . . . . . . . . . . . . . . . . . .see also Direct fired system unit system Atmospheric fluidized-bed boilers 85227 Electrical equipment . . . . . . . . . . . . . . . . . .85226 BOILER AND COMBUSTION SYSTEMS HAZARDS CODE Emergency shutdown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.8.9.3 Purge, start-up, operations, and shutdown . . . .INDEX Fixed grate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . G.3.1.2 Flame . . . . . . . . . . . . . . . . . . . . . . . . . . . 85224 BOILER AND COMBUSTION SYSTEMS HAZARDS CODE Single unit, operating as . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.8.5.8.1 Multiple burner boilers . . . . . . . . . . . INDEX Minimum required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.7.4.32 Failure to start . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.8.485222 BOILER AND COMBUSTION SYSTEMS HAZARDS CODE Pulverized fuel systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.4.5.1.1.2, 9.4.6.5 Raw fuel . . . . . . . . . . . . . . . . . . . . INDEX Sequence of operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.5.3 Interlock systems . . . . . . . . . . . . . . . . . . 7.5.4, 7.9, A.7.9.1.1 to A.7.9.85220 BOILER AND COMBUSTION SYSTEMS HAZARDS CODE Index Copyright 2007 National Fire Protection Association. All Rights Reserved. The copyright in this index is separate and distinct from the copyriANNEX N ANSI/ISA 77.43, Fossil Fuel Plant Unit/Plant Demand Develop- --,,,,,,,,,,,,,,--,,,,,,,--- ASME Boiler and Pressure Vessel Code, 1998. 85219 ment Drum Type, 2002. ISA S7785218 BOILER AND COMBUSTION SYSTEMS HAZARDS CODE Table M.1 NFPA Codes and Full Titles NFPA Code Title 85A 1964 85C-T 1964 85 1965 85A 1982 8501 1992 85B 1966 85D 1969 85E 1971 85G 19ANNEX M L.5.2 Recommendations. Recommendations are as follows 1 Operators should be trained for the possibility that cal- cium sulfide in FBC waste products could lead to the re- lease of H2S in wa85216 BOILER AND COMBUSTION SYSTEMS HAZARDS CODE b Solids stored in the cyclone or loop seal for ex- ample, due to blockage could suddenly be re- leased and flow into another space when the bloANNEX L 85215 accordance with NFPA 30, Flammable and Combustible Liq- uids Code, to contain spills in the event of tank rupture or overflow. 4 Plant layout and tank location should include consider85214 BOILER AND COMBUSTION SYSTEMS HAZARDS CODE make certain that all coals received are within the specific range of the coal-handling and coal-burning equipment. To ensure that the type of coal anANNEX K 85213 2 Small oil leaks can result in serious fire damage. 3 Water or sludge in fuel oil storage tanks or improperly located suction takeoffs from the storage tank can result in hazardous85212 BOILER AND COMBUSTION SYSTEMS HAZARDS CODE equipment and should be in contact preferably visual con- tact with those inside. 7 Provision of safety belts or harnesses, which should be tied oANNEX J 85211 SECTION 2 Any person who shall violate any provision of this code or standard hereby adopted or fail to comply there- with； or who shall violate or fail to comply with any order made t85210 BOILER AND COMBUSTION SYSTEMS HAZARDS CODE allow the manufacturer to extrapolate an ignition tempera- ture based on the results of a given test and similar tests on fuels fired at other actual ANNEX H different designs and shapes, depending on the fuel and the 85209 The FBC supplier and operator should be aware of the manufacturer. G.3.1.4 A spreader stoker system can include a cinder retu85208 BOILER AND COMBUSTION SYSTEMS HAZARDS CODE FIGURE G.2.12 Side View of a Traveling Grate Overfeed Stoker. Reprinted with permission of Detroit Stoker Company. G.3.1 General. G.3.1.1 The spread Grate tuyere blocks Air control damper ANNEX G Flexing plates Overfire air Coal hopper Coal gate Vibration generator 85207 FIGURE G.2.11 Side View of a Water-Cooled Vibrating Grate Stoker. Reprinte85206 BOILER AND COMBUSTION SYSTEMS HAZARDS CODE admitting grate area. Maximum grate heat release rates per linear dimension of stoker width should be 8.66 MWtper lin- ear meter 9.0 million Btu/hr p F.6.3 Specific Fuels. F.6.3.1 Bagasse. ANNEX G Grate Grate 85205 F.6.3.1.1 Bagasse is the portion of sugar cane remaining after sugar is extracted. It consists of cellulose fibers and fine par- ticl85204 BOILER AND COMBUSTION SYSTEMS HAZARDS CODE 3 Group 3, Sub-Bituminous “C” Coal, has a calorific value equal to or greater than 19.3 MJ/kg 8.3 kBtu/lb but less than 22.097 MJ/kg 9.5 kBtu/lbANNEX F compare burner airflow with burner fuel flow as determined by windbox-to-furnace differential and burner header pres- sure. The ratio thus determined, plus the open register proce- dure, provi85202 BOILER AND COMBUSTION SYSTEMS HAZARDS CODE Table C.2.5.3 Operator Actions, Normal Shutdown Cycle Operator Actions 1 Reduce boiler load until main fuel control valve 1 None. is closed. Main Table C.2.5.2 Operator Actions, Light-Off Cycle Operator Actions 1 Adjust register of burner to be lighted to 1 None. light-off position, if necessary. Airflow at purge rate. 2 Confirm that bur85200 BOILER AND COMBUSTION SYSTEMS HAZARDS CODE --,,,,,,,,,,,,,,--,,,,,,,--- R S R1 S U QQ Oil supply Atomizing medium supply T O T PSL O PI D1 D J R A PSL S1 PI PI G PSL TI TSL Gas supply T F K E ANNEX C C3 E S PI V1 R2 PSL T3 T3 Igniters permanently installed 85199 --,,,,,,,,,,,,,,--,,,,,,,--- C3Igniter atmospheric vent valve E Igniter safety shutoff85198 BOILER AND COMBUSTION SYSTEMS HAZARDS CODE Table C.2.5.1 Operator Actions, Prefiring Cycle Operator Actions* 1 Inspect furnace for unburned oil accumulations. 2 Confirm burner gun for propeANNEX C 2 If the trip was caused by loss of draft fans, or if draft fans also have tripped, all dampers in the air and flue gas pas- sages of the unit should be opened slowly to the fully open posit85196 BOILER AND COMBUSTION SYSTEMS HAZARDS CODE Table C.1.5.2 Operator Actions, Light-Off Cycle Operator Actions 1 Adjust register of burner to be lighted to light-off position, if necessary. Airf Gas supply T F K E ANNEX C C3 E S PI V1 R2 PSL T3 T3 T3 Igniters permanently installed 85195 C3Igniter atmospheric vent valve E Igniter safety shutoff valve F Igniter fuel control valve K Pressure85194 BOILER AND COMBUSTION SYSTEMS HAZARDS CODE 8 The operator should observe main flame stability while making any register or burner damper adjustments. Table C.1.5.1 Operator Actions, Prefiring Table B.3.4.7 Operator Actions, Normal Shutdown Cycle Operator Actions 1 Reduce boiler load until main fuel control 1 None. valve is closed. Main fuel bypass control valve will assume control at 85192 BOILER AND COMBUSTION SYSTEMS HAZARDS CODE Table B.3.4.6 Operator Actions, Light-Off Cycle for Additional Burners When Fuel Pressure of Operating Burners Is Above Light-Off Pressure Operator AcANNEX B Table B.3.4.5 Operator Actions, Light-Off of Subsequent Main Burners at Light-Off Fuel Pressure Operator Actions Interlock Functions 1 Adjust register of burner to be lighted to 1 Prove th85190 BOILER AND COMBUSTION SYSTEMS HAZARDS CODE Table B.3.4.3 Operator Actions, Light-Off Cycle Subsequent Igniters Operator Actions 1 Adjust register of burner to be lighted to light-off positi Table B.3.4.1 Operator Actions, Prefiring Cycle Operator Actions* 1 Inspect furnace for unburned oil 1 None. accumulations. 2 Confirm burner guns have proper tips and 2 None. sprayer plates. 85188 BOILER AND COMBUSTION SYSTEMS HAZARDS CODE should elapse before attempting to light this or any other igniter. 11 Operation at less than 25 percent of load is permitted, provided burners mainANNEX B Table B.2.4.6 Operator Actions, Light-Off Cycle for Additional Burners When Fuel Pressure of Operating Burners Is Above Light-Off Pressure Operator Actions Interlock Functions 1 Place combus85186 BOILER AND COMBUSTION SYSTEMS HAZARDS CODE Table B.2.4.5 Operator Actions, Light-Off Cycle for Subsequent Main Burners at Light-Off Fuel Pressure Operator Actions 1 Adjust register of burner ANNEX B Table B.2.4.4 Operator Actions, Light-Off Cycle First Main Burner Operator Actions Interlock Functions 1 Adjust register of burner to be lighted to 1 Prove that airflow has not dropped b85184 BOILER AND COMBUSTION SYSTEMS HAZARDS CODE Table B.2.4.1 Operator Actions, Prefiring Cycle Operator Actions* Interlock Functions 1 Confirm individual burner safety shutoff valves are closed. Oil supply T O S PI D D1 J A ANNEX B S PI N PSL S1 PI U TI R PSL Y SS T5 Y Other burners B PI S W PI S1 Other burners Y Burner typical H 85183 Oil return --,,,,,,,,,,,,,,--,,,,,85182 E Igniter safety shutoff valve F Igniter fuel control valve BOILER AND COMBUSTION SYSTEMS HAZARDS CODE W G Individual igniter safety shutoff valve O Cleaner or strainer S Fuel pressure gauge T ANNEX B G --,,,,,,,,,,,,,,--,,,,,,,--- G C5 G C5 G 85181 Gas supply T F K S PI Igniters permanently installed G C5 G C5Individual igniter atmospheric vent valve F Igniter fuel c85180 BOILER AND COMBUSTION SYSTEMS HAZARDS CODE Annex B Multiple Burner Boiler termined and corrected. With airflow maintained at the Supervised Manual Systems purge rate, repurge is not needed, butANNEX A 12 Gases are released from freshly crushed fuel. Accumula- tions of flammable or explosive mixtures occur in bins 85179 good repair to prevent air from bypassing the fuel bed and to distrib85178 DM1DM2DM4BOILER AND COMBUSTION SYSTEMS HAZARDS CODE Note 1 HRSG DM3Combustion turbine Burner Note 2 DM1Bypass damper DM2HRSG isolation damper DM3Stack damper DM4Air inlet damper Notes 1. The f Oil return H S PI ANNEX A W Y Main burner Scavenging medium 85177 Oil supply T O S PI F M R1 PSL A II R PSL QQ TSL D D1 B Y Other main burners typical A Main safety shutoff valve B Individual burn85176 BOILER AND COMBUSTION SYSTEMS HAZARDS CODE W Scavenging Light oil supply T O F medium S PI E Y G Y Igniter typical E Igniter safety shutoff valve F Igniter fuel control valve G Individual ign Gas supply T F E S PI C5 E C4 ANNEX A G Igniter typical Other igniters 85175 R1PSL C4Igniter header atmospheric vent valve optional C5Igniter supply atmospheric vent valve E Igniter header safet85174 BOILER AND COMBUSTION SYSTEMS HAZARDS CODE Vent to atmosphere Gas supply T O S PI J T M F S PI R PSL A C2 A D Q PSH S PI Main burner A Main burner safety shutoff valve To ignition system See FANNEX A However, the parameters vary for each installation and are unique. As a minimum, consideration should be given, but not be limited to, the following 1 Ductwork and stack geometry 2 HRSG g85172 BOILER AND COMBUSTION SYSTEMS HAZARDS CODE 6 Consideration should be given to all levels and types of electrical interference that can be tolerated by the hard- ware without compromising its ANNEX A 85171 A.8.4.3.5.1.7 Such transients are generated by burner shutoff valves, dampers, and other components that operate at speeds faster than the response speeds of other components in the sys85170 12 Protective systems BOILER AND COMBUSTION SYSTEMS HAZARDS CODE turbine wheel and blade assemblies, resulting in shaft 13 Degree of automation and complexity of control systems 14 OperatANNEX A 85169 It is possible to experience conditions conducive to a fur- nace explosion without detection of such conditions by any of the mandatory automatic trip devices, even though they are prop85168 BOILER AND COMBUSTION SYSTEMS HAZARDS CODE and flue gas removal systems. This could result in exposure of the furnace to excessive fan head capability. The rapid decrease in furnace gas tempera Furnace To induced ANNEX A 85167 The requirement is for the FBC designer to furnish a Forced draft fans B C A Grid plate D draft fan and stack temperature-measuring system and logic to provide a r85166 BOILER AND COMBUSTION SYSTEMS HAZARDS CODE or special duct arrangements or special instrumentation or control should be investigated. The rapid decrease in furnace gas temperatures and pres- suANNEX A 85165 some plants to fire intermittently. This practice is not recom- mended. A.6.8.5.2.1.12 Such an inspection is particularly important for a cold start where the fuel burned prior to
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