1、NFPA550 Guide to the Fire Safety Concepts Tree 2012 Edition NFPA, 1 Batterymarch Park, Quincy, MA 02169-7471 An International Codes and Standards Organization Become a MemberSubscribeto theRegister forSeminars, Webinars, and Online CoursesVisit theNFPA CatalogNOTICE AND DISCLAIMER OF LIABILITY CONCE
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24、ould be sent to NFPA headquarters, addressed to the attention of the Secretary, Standards Council, NFPA, 1 Batterymarch Park, P.O. Box 9101, Quincy, MA 02169-7471; email: stds_adminnfpa.org For more information about NFPA, visit the NFPA website at www.nfpa.org. 12/11Copyright 2012 National Fire Pro
25、tectionAssociation.All Rights Reserved.NFPA550Guide to theFire Safety Concepts Tree2012 EditionThis edition of NFPA 550, Guide to the Fire Safety Concepts Tree, was prepared by the TechnicalCommittee on Fire RiskAssessment Methods. It was issued by the Standards Council on Decem-ber 13, 2011, with a
26、n effective date of January 2, 2012, and supersedes all previous editions.This edition of NFPA550 was approved as anAmerican National Standard on January 2, 2012.Origin and Development of NFPA 550The NFPA Committee on Systems Concepts was organized to be responsible for develop-ing systems concepts
27、and criteria for fire protection in structures.Aprimary accomplishmentof this committee was the development of the Fire Safety Concepts Tree. This Guide to the FireSafety Concepts Tree was developed by the Committee on Systems Concepts in 1985. Apprecia-tionisextendedtoDr.JohnM.Watts,Jr.,oftheFireSa
28、fetyInstituteforhismajorcontributionto the contents of this document.The Committee on Systems Concepts was discharged in October 1990, at which time theStandards Council assumed responsibility for this document.The1995editionrepresentedareconfirmationofthe1986editionwitheditorialclarifications.The 2
29、002 edition represented the majority of the 1995 edition with changes reflectingNFPAs requirements for document uniformity as prescribed by the Manual of Style for NFPATechnical Committee Documents. The changes consisted of formatting, renumbering, and edito-rial clarifications. Minor changes were m
30、ade to content and several deletions made withrespect to unreferenced text.The 2007 edition represented a reconfirmation of the 2002 edition.The 2012 edition represents a reconfirmation of the 2007 edition with updates to refer-enced publications where necessary.5501NFPAand National Fire ProtectionA
31、ssociation are registered trademarks of the National Fire ProtectionAssociation, Quincy, Massachusetts 02169.Technical Committee on Fire Risk Assessment MethodsDouglas Crawford, ChairOffice of the Fire Marshal of Ontario, Canada, Canada EJustin B. Biller, Roanoke County Office of BuildingSafety, VAE
32、Shane M. Clary, BayAlarm Company, CAMRep.Automatic FireAlarmAssociation, Inc.D. Allan Coutts, URS Safety Management Solutions LLC,SC UWilliam W. Doerr, FM Global, MAIKenneth W. Dungan, Risk Technologies, LLC, TN SEMichael A. Falzarano, Tyco Electronics, PAMRussell P. Fleming, National Fire Sprinkler
33、Association,Inc., NY MSimon Foo, Public Works thereisnoredundancy.“And”gatesintheFireSafetyConceptsTreerepresent checklists of items that are necessary to achieve theoutput objective or strategy.4.4.3 The plus and dot symbols used for “or” gates and “and”gates (see Figure 4.4.3) also are used in fau
34、lt trees. They are thestandard symbols for these logic operations, which are used inelectronic circuit diagrams and Boolean algebra. They are de-rived from the algebra of probabilities.4.5 Manage Fire Impact. The “Manage Fire Impact” side of thetree has two major branches as inputs to an “or” gate:
35、“ManageFire safety objective(s)Manage fireimpactControl fuel Manage fireControl heat-energy source(s)Control source-fuel interactionsPrevent fireignitionSuppress fireControl combustion processControl fire by constructionSafeguard exposedLimit amount exposedManage exposedSee Figure 4.4.1See Figure 4.
36、5.2.1See Figure 4.5.1FIGURE 4.3 Top Gates of the Fire Safety Concepts Tree with Selected Lower-Tiered Gates.PreventfireignitionControl fuelControl source-fuelinteractionsControl heat-energytransfer processesControl fuel transportEliminate fuel(s)Control fuel ignitibilityControlheat-energysourcetrans
37、portControlrate ofheat-energyreleaseEliminateheat-energysource(s)Controlheat-energysource(s)+Provide separationProvide barrierControl conductionControl convectionControl radiationProvide barrierProvide separationControl fuelpropertiesControl theenvironment+ +FIGURE 4.4.1 “Prevent Fire Ignition” Bran
38、ch of the Fire Safety Concepts Tree.5508 FIRE SAFETY CONCEPTS TREE2012 EditionFire” and “Manage Exposed” (see Figure 4.5). This is the basic ap-proach to loss control (i.e., to limit the magnitude of the hazardor to minimize the effects).4.5.1 Manage Fire. The objectives of the “Manage Fire” strat-e
39、gy are to reduce hazards associated with fire growth andspread, and to thereby reduce the impact of the fire. Ap-proaches to fire management are as follows:(1) Control the rate of production of smoke and heatthrough alteration of the fuel or the environment.(2) Control the combustion process by manu
40、al or automaticsuppression.(3) Control fire propagation with venting or containment, orboth (see Figure 4.5.1).Key+ = “or” gate= “and” gateFIGURE 4.4.3 Logic Symbols Used in the Fire Safety Con-cepts Tree.ManagefireimpactManagefireManageexposed+FIGURE 4.5 Major Branches of “Manage Fire Impact.”Manag
41、e fireControl fire by constructionControl combustionprocess+Control fuelControl theenvironment+ +Control fuel propertiesLimit fuel quantityControl fuel distributionControl physical properties ofenvironmentControl chemical composition ofenvironmentControl movement of fireProvide structuralstabilityVe
42、ntfireConfine/ contain fire+Suppress fireAutomaticallysuppress fireManually suppress fireDetect fireApply sufficientsuppressantCommunicatesignalDetect fireDecide actionRespond to siteApply sufficientsuppressantFIGURE 4.5.1 “Manage Fire” Branch of Fire Safety Concepts Tree.5509STRUCTURE OF THE FIRE S
43、AFETY CONCEPTS TREE2012 Edition4.5.1.1 Again,the“or”gateindicatesthatthesestrategiescanbeapplied simultaneously for increased reliability of managing thefire. Note that controlling fire propagation with venting or cur-tains includes managing fire products such as smoke.4.5.2 Manage Exposed.4.5.2.1 “
44、Manage Exposed” means to coordinate measures in-volving any or all of the items specified in the fire safety objec-tives (e.g., people, property, activities, or other valuable con-siderations). The “Manage Exposed” branch is achieved byeitherlimitingthenumberofindividualsandamountofprop-erty that ar
45、e exposed or safeguarding all persons and propertysubject to exposure (see Figure 4.5.2.1). In the case of propertyor immobile persons, such as nonambulatory hospital pa-tients,theexposedissafeguardedmostoftenbydefendingtheoccupied space from fire exposure.4.5.2.2 “Hardening against fire” is another
46、 term for the strat-egy of making the exposed resistant to the effects of fire. Formore mobile occupants, the most common strategy for safe-guarding the exposed is to relocate the exposed while protect-ing the route for the duration of transit. This includes smokemanagement as described by the “Vent
47、 Fire” and “Confine/ContainFire”elementsunderthe“ControlMovementofFire”branch of the tree.4.5.2.3 The transfer symbol labeled “entry point” in the key tothe Fire Safety Concepts Tree is shown in Figure 4.5.2.3. Thistransfersymbolindicateswhereportionsofthetreearerepeated.In Figure 4.5.2.1, the porti
48、on of the tree under the element “De-fend Exposed in Place” is repeated under the elements “ProvideSafe Destination” and “Provide Protected Path.”Chapter 5 Applications5.1 General. The Fire Safety Concepts Tree is a general quali-tativeguidetofiresafety.Itisaflexibletoolthatcanbeusedina number of di
49、fferent ways.5.2 Communications. Perhaps the most important use ofthe tree is for communication with architects and otherprofessionals involved in building design and management.Codes and standards are not intended to be tutorial; theypresume a significant level of comprehension of the prin-ciples of fire protection engineering. The Fire Safety Con-cepts Tree is a simple visual representation of the total con-cept of fire safety incorporated in codes and standards. Itcan be used as a means of commu
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