FALL 2000 Issue No - cdn.ymaws.com · fire protection the need for scientific fire investigations...

FIRE PROTECTIONFIRE PROTECTION

THE NEED FORSCIENTIFIC FIRE INVESTIGATIONS

SMOKE-DETECTIONEVALUATION IN ENCLOSURESWITH HIGH-VELOCITY AIRFLOW

PERFORMANCE-BASED ANALYSISOF AN HISTORIC MUSEUM

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PROVIDING PRACTICE-ORIENTED INFORMATION TO FPEs AND ALL IED PROFESSIONALS

FALL 2000 Issue No.8

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SFPE

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ingour 50th Anniversary

CONSIDERATIONS LEGAL

IN FIRE PROTECTION DESIGN CONSIDERATIONSLEGAL

IN FIRE PROTECTION DESIGN

Fire Protection Engineering 1

3 VIEWPOINTThe development of performance-based codes has sparked a reexaminationof the relationship between the legal system and building technology.Vince Brannigan, J.D.

4 THE NEED FOR SCIENTIFIC FIRE INVESTIGATIONSThe lessons learned from fire investigations can be a useful form of feedback for the fire protection engineering community. Leading fire investigation methods are reviewed.Russell A. Ogle, Ph.D, P.E., C.S.P.

11 PATHFINDER: A COMPUTER-BASED, TIMED EGRESS SIMULATIONComputer-based models aid in the prediction of fire effects on a building’senvironment. The Pathfinder model is discussed.Joe Cappucio, P.E.

25 SMOKE-DETECTION EVALUATION IN ENCLOSURES WITHHIGH-VELOCITY AIRFLOWHigh air movement velocities can negatively affect response times of ceilingsmoke detectors. From the research performed, several conclusions aredrawn.Robert M. Gagnon, P.E. and Tyler Mosman

36 ` PERFORMANCE-BASED ANALYSIS OF AN HISTORIC MUSEUMThis life safety analysis of the National Mall in Washington, DC highlightshow renovations of historic buildings can benefit from the use of a performance-based approach.Andrew Bowman

44 CAREER CENTER

45 SFPE RESOURCES

52 FROM THE TECHNICAL DIRECTORProfessional Licensure in California.Morgan J. Hurley, P.E.

contents FA L L 2 0 0 0

14COVER STORYLEGAL CONSIDERATIONS IN FIRE PROTECTION DESIGNFire protection engineers must contend with a variety of legal and governmentalissues while working on a building or product. Current legal cases and approachesto fire protection design are discussed.Christopher B. Wood, J.D.

Subscription and address change correspondence should be sent to: Society of Fire Protection Engineers,Suite 1225 West, 7315 Wisconsin Avenue, Bethesda, MD 20814 USA. Tel: 301.718.2910. Fax: 301.718.2242.E-mail: [email protected].

Copyright © 2000, Society of Fire Protection Engineers. All rights reserved.

FIRE PROTECTIONFIRE PROTECTION

Fire Protection Engineering (ISSN 1524-900X) is published quarterly by the Society of Fire ProtectionEngineers (SFPE). The mission of Fire ProtectionEngineering is to advance the practice of fire protectionengineering and to raise its visibility by providing information to fire protection engineers and allied professionals. The opinions and positions stated arethe authors’ and do not necessarily reflect those of SFPE.

Editorial Advisory BoardCarl F. Baldassarra, P.E., Schirmer EngineeringCorporation

Don Bathurst, P.E.

Russell P. Fleming, P.E., National Fire SprinklerAssociation

Douglas P. Forsman, Oklahoma State University

Morgan J. Hurley, P.E., Society of Fire ProtectionEngineers

William E. Koffel, P.E., Koffel Associates

Jane I. Lataille, P.E., Industrial Risk Insurers

Margaret Law, M.B.E., Arup Fire

Ronald K. Mengel, Honeywell, Inc.

Warren G. Stocker, Jr., Safeway Inc.

Beth Tubbs, P.E., International Conference of BuildingOfficials

Regional Editors

U.S. HEARTLAND

John W. McCormick, P.E., Code Consultants, Inc.

U.S. MID-ATLANTIC

Robert F. Gagnon, P.E., Gagnon Engineering, Inc.

U.S. NEW ENGLAND

Thomas L. Caisse, P.E., C.S.P., Robert M. Currey &Associates, Inc.

U.S. SOUTHEAST

Jeffrey Harrington, P.E., The Harrington Group, Inc.

U.S. WEST COAST

Scott Todd, Gage-Babcock & Associates, Inc.

ASIA

Peter Bressington, P.Eng., Arup Fire

AUSTRALIA

Richard Custer, Custer Powell, Inc.

CANADA

J. Kenneth Richardson, P.Eng., Ken Richardson FireTechnologies, Inc.

NEW ZEALAND

Carol Caldwell, P.E., Caldwell Consulting

UNITED KINGDOM

Dr. Louise Jackman, Loss Prevention Council

Publishing Advisory BoardBruce Larcomb, P.E., BOCA International

Douglas J. Rollman, Gage-Babcock & Associates, Inc.

George E. Toth, Rolf Jensen & Associates

PersonnelPUBLISHER

Kathleen H. Almand, P.E., Executive Director, SFPE

TECHNICAL EDITOR

Morgan J. Hurley, P.E., Technical Director, SFPE

MANAGING EDITOR

Joe Pulizzi, Penton Custom Media

ART DIRECTOR

Pat Lang, Penton Custom Media

COVER DESIGN

Dave Bosak, Penton Custom Media

The legal system has been used tocontrol the safety of buildingssince at least the time of

Hammurabi. However, each time tech-nology changes, there is a reexamina-tion of the relationship between thelegal system and building technology.The development of performance-basedcodes has sparked such a discussion. Ina very real sense, there is nothing really“new” about performance-based design.The Code of Hammurabi illustrates thatthe critical questions for any law deal-ing with building safety were knownfrom ancient times. Each society in itsown era must wrestle with these basicissues.

The first questions deal with whetherthe goals of the code are public or pri-vate. Do codes fundamentally exist toprotect public safety or to protect pri-vate safety interests? The concern withpublic safety is the most obvious. Theproblem of conflagration has evolveddirectly with the development of cities.Cities tended to have very vulnerable,valuable buildings crammed closelytogether. Many of the early fire andbuilding codes were concerned withpreventing the spread of fire throughouta city or district. Brick exterior walls,clay tile roofs, and other traditionalrequirements were combined withwider streets and building setbacks totry to avoid spreading fire from buildingto building. But codes are also used toprovide legal protection for individualsthemselves. In Hammurabi’s famouscode, the focus was on private, notpublic safety.

229. If a builder builds a house forsome one, and does not construct itproperly, and the house which hebuilt falls in and kill its owner, thenthat builder shall be put to death.A second issue involves the question

of whether codes are designed to pro-tect lives or also property. One sugges-tion being made routinely in the perfor-mance-based environment is that codes

should only protect life safety, and thatsomehow property protection is a pure-ly private matter between a buildingowner and an insurer. However, this isclearly a policy choice. All societiesdepend, at least in part, on the preser-vation of property in private hands, andcodes are an effective means of protect-ing that property from wanton destruc-tion. The Code of Hammurabi protectedboth lives and property:

232. If it ruins goods, he shall makecompensation for all that has beenruined, and inasmuch as he did notconstruct properly this house which hebuilt and it fell, he shall re-erect thehouse from his own means.A third major issue is the method by

which the legal system makes sure thatbuilders create safe buildings. Funda-mentally, there are two legal approach-es, direct and indirect. The directapproach is found in the typical codeenvironment; the law works directly byspecifying the required behavior. At thefirst stage of the analysis, it does notmatter whether it s a prescriptive or aperformance code. No matter what formthe code takes, all such approaches aredirect. The code states what has to bedone to be in compliance with the law.

An alternative is the indirect approach.In the indirect approach, the lawdescribes a level of safety which mustbe achieved or states that damages mustbe paid to those whose persons orproperty are injured. The Code ofHammurabi used this indirect approach.

Within the direct approach, there is awide variety of different combinationsof code elements that can be used.Terms such as specification and perfor-mance requirements are normally usedto differentiate these different concepts.In all cases, however, the governmentcontrols what technology can be usedand what types of buildings can be built.

One advantage of the indirectapproach is technological flexibility. Aslong as the losses are fully and fairly

compensated, the builder will have anappropriate incentive to use the mostefficient technology to achieve therequired result.

Direct and indirect approaches can,of course, be used together. We havedirect regulation of driver’s activities,but we also require them to carry auto-mobile insurance to compensate thevictims of driving failure.

A fourth major issue is the point intime when the code is applied. Somecodes rely on a “one-time approval” ofa building, while others use the cradle-to-grave approach, where the buildingis supervised for safety and compliancethroughout its lifetime.

A fifth major issue involves themethod of enforcement of a code.Typical alternative forms of enforce-ment are direct inspection by regulators,self-certification by qualified profession-als, and third-party approvals by autho-rized private bodies.

A sixth issue is the autonomy of theregulator in accepting any kind of vari-ance or equivalence under the code.One of the most important characteris-tics of modern technology is that subtlechanges in the technological mix cancause disproportionate changes in theeffect of the technology. As a result,regulators are often in a difficult posi-tion when approving new technologiesthat do not correspond with traditionalbuilding systems. Do they have theauthority and training to take risks inthe acceptance of a new technology?

Every successful building safetyregime selects a mix of approaches toaddress the issues mentioned above.There is no clear right answer to pro-viding safe buildings. However the legalsystem can be used to flexibly incorpo-rate almost any modern technology toaccomplish the policy goals stated bythe society.

Vince Brannigan, J.D., is with theUniversity of Maryland.

THE REGULATION OF BUILDING SAFETY:

THE EVOLUTION OF TECHNOLOGY AND THE LAW

viewpoint

FALL 2000 Fire Protection Engineering 3

4 Fire Protection Engineering NUMBER 8

By Russell A. Ogle, Ph.D., P.E., C.S.P.

Forensic fire investigations are an importantsource of information about real fires. Firescenes may contain valuable information about

the cause (ignition), growth, and extinguishment ofthe subject fire. The lessons learned from fire investi-gations can be a useful form of feedback for the fireprotection engineering community demonstratinghow materials, products, systems, and people behavein real fires. In the absence of an accurate and reli-able fire investigation, critical fire safety data may belost forever once the fire scene has been rehabilitat-ed. Thus, the fire protection engineering communityshould have a significant interest in the quality of fireinvestigations.

FIRE INVESTIGATION: ART VERSUS SCIENCE

The fundamental objective of a forensic fire investi-gation is to determine the fire origin (where the firestarted) and cause (how the fire started). As is truefor any accident investigation, the fire investigationtask is difficult because an accident is an uncon-trolled event. Some information which may be valu-able to the investigation will be unavailable becauseit was not observed, was not recorded, or was dam-aged by the fire itself. No matter how much informa-tion the investigator may obtain, it will never beequivalent to conducting a carefully controlled exper-iment. Therefore, the investigator is forced to drawinferences from the available (albeit incomplete) data.

SCIENTIFIC FIRE

INVESTIGATIONS

T H E N E E D F O R


The challenge is to draw reliableinferences from the fire scene data.The thesis of this paper is that the sci-entific method provides the best strate-gy for drawing reliable inferences. Thisis also the thesis of NFPA 921, A Guidefor Fire and Explosion Investigations 1,the guidance document published bythe National Fire ProtectionAssociation. This thesis has arousedcontroversy among some fire investiga-tors who argue that fire investigation ismore art than science.2, 3, 4 Their argu-ment is that the art of fire investigation,i.e., the practical judgment gainedthrough experience, is somehow supe-rior to, or at least incompatible with,the methods of science.

The argument favoring art over sci-ence is false. While experience is a val-uable source of personal knowledge, itcan be a capricious and unreliableteacher. An informal generalizationabout fire pattern development formedfrom observation of actual fire scenesis an untested hypothesis. The hypoth-esis may be true or it may be false.The truth of the hypothesis can onlybe determined by testing it against fur-ther evidence. The testing of hypothe-ses to arrive at objective knowledge isthe essence of the scientific method.

This debate over the role of the sci-entific method in fire investigation isnot just a philosophical debate. It hashad a profound impact on the litigationof fire losses.5 The debate may be lesssubstantive than some believe. Theauthor’s own anecdotal experienceshave shown him that many fire investi-gators who have no formal training inscience or engineering do indeed con-duct scientific investigations.6 This isnot a paradox. The scientific methodcan be practiced in virtually any tech-nical art. Indeed, the scientific methodis the best strategy for seeking knowl-edge about the external world. Howthen does the scientific method workin fire investigation?

THE SCIENTIFIC METHOD IN FIRE INVESTIGATION

It is best to first begin by definingsome terms. The scientific method is aprocess of inquiry which relies on fourelements: observation, hypothesis, the-ory, and experiment. The interaction

of these four elements may differ fromone situation to another, but theunderlying objective is always thesame: to obtain an objective under-standing of the physical world.7

Observation is the process of obtainingdata from the external world by senseperception. By extension to instru-ments, observation includes quantita-tive measurements. An hypothesis is atestable proposition (or set of proposi-tions), while a theory is an hypothesiswhich has survived testing. The term“theory” is a bit ambiguous for it mayrefer to a theory of fire causation (i.e.,an explanation) or to a body ofknowledge which is well accepted bythe scientific or engineering communi-ty (e.g., thermodynamics). An experi-ment is a process of investigation inwhich circumstances are controlled sothat variables can be changed one at atime to test an hypothesis. The foren-sic investigator must be cautiousregarding the use of the word “experi-ment” because, in the legal arena, ithas a very specific meaning (i.e., aprecise reconstruction of the accidentcircumstances8) whereas the word“testing” is interpreted more broadly.In this paper, the phrase “empiricaltesting” will be used to denote anexperiment, while the word “test” willbe used to denote an attempt to proveor disprove an hypothesis.

The implementation of the scientificmethod requires two forms of reason-ing: inductive and deductive.9

Inductive reasoning is an argument inwhich the conclusion is probable.Deductive reasoning is an argument inwhich the conclusion is certain. NFPA9211 describes the implementation ofthe scientific method (pp. 9-10) andidentifies the role of reasoning in twodistinct steps: analyze the data (induc-tive reasoning) and test the hypothesis(deductive reasoning). In analyzing thedata, the fire investigator is urged todevelop a set of reasonable hypothe-ses as possible explanations for thecause of the fire. Then, the investigatoris to challenge these hypotheses in anattempt to refute them. The onlyacceptable hypothesis is the onewhich survives these challenges and isbest supported by the empirical data.The accepted hypothesis can then beconsidered to be the best explanation(theory) for fire causation.

There are several criteria which canbe used to test fire causation hypothe-ses. These criteria can be ranked inorder of strength, from stronger(empirical data obtained from the spe-cific fire scene under investigation) toweaker (based on empirical data fromother fire scenes). The suggested hier-archy of criteria is: physical evidence,empirical testing, engineering analysis,witness statements, and experience.The justification for the suggested hier-archy is based on the degree to whichthe criterion is susceptible to indepen-dent confirmation.

Physical evidence from the firescene includes the physical appear-ance (fire patterns) of the fire sceneand the physical objects and debrisfound at the scene. The location andorientation of fire damage patterns canreveal clues about the origin andcause of the fire. Documentation ofthe fire scene with still photography,sketches, and field notes provides thebasic observational data for the fireinvestigator’s future analytical efforts.In addition to documenting the firescene, the fire investigator may collectphysical artifacts from the fire scene,such as samples of unburnt materials,fire debris, consumer products, appli-ances, or equipment. The collectedartifacts can then be subjected to


examination and empirical testing.Although the specific documentationand evidence collection efforts dependon judgments made by the investiga-tor, the data are independent of theinvestigator and his interpretation oftheir significance. Thus, physical evi-dence, including the fire scene itself, isthe strongest criterion for testing firecausation hypotheses.

Empirical testing in this contextrefers to an inquiry into the fundamen-tal nature of the artifact or sample.Individual artifacts can be examinedvisually or microscopically so that fea-tures of interest can be interpretedusing scientific principles. Samples ofmaterials can be tested for physicalproperties, chemical composition, orflammability characteristics. Devicescan be tested for performance undernormal and abnormal conditions. Thedevelopment of fire damage patternscan be investigated under simulatedfire conditions. The observations andmeasurements produced by testing canbe independently analyzed by otherinvestigators. Since empirical testingresults in data derived from conditionsoutside the subject fire, the physicalevidence obtained from the subject firescene is considered to be a slightlystronger criterion than the resultsderived from empirical testing.

Engineering analysis is a form ofdeductive reasoning in which scientificlaws are used in conjunction with theempirical data derived from the firescene to establish logical conclusionsregarding fire origin and cause.Engineering analysis can provide auseful framework for understandingthe significance of physical evidence,designing empirical test programs andanalyzing test data, corroborating wit-ness statements, and testing physicalintuition (experience). Examples ofengineering disciplines which mayhave relevance in analyzing fire causa-tion are thermodynamics, heat transfer,fire dynamics, and materials science.Engineering analysis is another form ofevidence which can be independentlyconfirmed. But engineering analysis isanother step removed from the firescene, and uncertainty is introducedthrough the use of assumptions andestimated parameters. Thus, engineer-ing analysis is a weaker criterion for

testing hypotheses than physical evi-dence or empirical testing.

Witness statements can provideinvaluable observation data if the state-ments are both precise and accurate.The reliability of witness statementscan depend as much on the objectivityof the interrogator as the witness.Simultaneous observations from multi-ple witnesses may provide one meansof independent verification, but this isnot a common situation. Dependingon the specific circumstances of thesubject fire, the witness observationsmay be susceptible to empirical testingor engineering analysis, but this, too, isnot a common situation. Thus, witnessstatements are less susceptible to inde-pendent confirmation than physicalevidence, empirical testing, and engi-neering analysis.

Experience is highly regarded insome quarters of the fire investigationcommunity.2 With each new fire sceneinspection, the investigator acquiresnew observations of fire damage pat-terns. It is tempting for the investigatorto develop generalizations based onthis growing set of observations.While experience is unquestionably aninvaluable source of physical intuition,it is potentially misleading if theseinductive generalizations are not testedscientifically. For example, similar firedamage patterns observed at differentfire scenes may have a very differentsignificance. The significance maybecome apparent through empiricaltesting or engineering analysis, but it isunlikely that experience alone willanswer the question. The value ofexperience is that it can become a richsource of insight and perspective. Butuntested knowledge gained from expe-rience is less reliable than knowledgewhich has been tested. For this reason,experience is the weakest criterion fortesting hypotheses of fire causation.

THE ROLE OF FIRE DYNAMICS

Fire dynamics is one body of engi-neering knowledge which can play aparticularly important role in fire investi-gations. Fire dynamics is the study ofthe ignition, growth, and extinguishmentof fire.10, 11 Fire dynamics is based on thedisciplines of thermodynamics, fluidmechanics, heat transfer, mass transfer,

and chemical kinetics. The analyticaltools of fire dynamics can be used toestimate the size of a fire which is capa-ble of causing the observed fire patternsor to estimate flame spread rates basedon witness observations.

The power of fire dynamics as aconceptual framework for the analysisof fire causation can be illustrated withan example. Assume that two compet-ing fire causation hypotheses can bedivided into four distinct elements(compare with Ogle and Schumacher12):

• Ignition Source• First Item Ignited• Second Item Ignited• Magnitude of Fire DamageThe purpose of the fire dynamics

analysis is to determine the fire char-acteristics necessary to cause theobserved fire patterns. The first threeelements relate to the initiation andspread of the fire. Fire dynamics calcu-lations can specifically test whether theignition source is capable of ignitingthe first item in the fire. Given ignitionof the first item, further analysis candetermine if the fire can spread fromthe first item to the second. The mag-nitude of the fire damage refers to theareal and spatial extent of the firedamage, i.e., did the fire achieveflashover? The presence or absence offlashover fire damage can establish anupper limit (failure to flashover) or alower limit (achievement of flashover)on the heat release rate of the fire.These calculations can then be used totest how well the competing fire cau-sation hypotheses are supported byfundamental scientific principles.

The methods of fire dynamics arenot limited to fire protection engi-neers. Quintiere’s recent book13, NFPA921, and the Fire ProtectionHandbook14 all present fundamentaltools from fire dynamics in a formateasily accessible to an experienced fireinvestigator. Thus, any experiencedfire investigator has access to the toolsnecessary to scientifically evaluate firecausation hypotheses.

Ultimately, however, there will be anumber of fire scenes which will defyquantitative analysis. In these situations,the fire investigator must rely on theuse of inductive and deductive reason-ing as his scientific tools for finding thebest explanation of the fire cause. In


this respect, the fire investigator is following a strategyemployed not only by scientists and engineers, but also histori-ans, police detectives, automotive mechanics, businesspeople,and lawyers. Regardless of the practical art of interest, if thepractitioners seek reliable knowledge about the world aroundthem, they must employ a form of the scientific method. In fireinvestigations, this reduces to developing and testing compet-ing hypotheses.

THE SCIENTIFIC METHOD AND THE RELIABILITY OFEXPERT TESTIMONY

The 1993 decision by the U.S. Supreme Court on Daubertvs. Merrell Dow Pharmaceuticals highlighted the legal signifi-cance of reliable scientific testimony. The decision establishedthe role of federal judges as gatekeepers of expert testimony,allowing testimony which satisfied certain criteria and barringtestimony which did not. The criteria for reliable scientific tes-timony, often called the Daubert criteria,15 are:

• Whether the technique or theory has been tested;• Whether the technique or theory has been a subject of

peer review or publication;• The known or potential error rate; and• The degree of acceptance of a technique or theory within

the relevant scientific community.The Daubert criteria have been applied to a broad array of

expert testimony, including fire investigation2. Another recentdecision by the U.S. Supreme Court, Kumho Tire vs.

Carmichael, has reinforced the gate-keeping role of federaljudges by affirming that expert testimony from engineeringand other technical arts must satisfy the Daubert criteria.4, 16

How will the Kumho Tire decision ultimately affect fire inves-tigators? The answer, as revealed through case law, will evolveover time. From an engineer’s perspective, it appears that thefederal courts may hold fire investigators to a higher standardthan mere professional experience. Scientific knowledge,with its interplay of inductive and deductive reasoning, maybecome the standard for reliable expert testimony of fire cau-sation. If the objective of fire investigation is to seek the bestexplanation of fire causation, then the ultimate consequencesof Daubert and Kumho Tire should be positive.

Russell Ogle is with Packer Engineering, Inc.

REFERENCES

1 NFPA 921. A Guide for Fire and Explosion Investigations.National Fire Protection Association, Quincy, MA, 1998.

2 International Association of Arson Investigators. Amicus curiabrief filed for Michigan Millers Mutual Insurance Co. vs.Benfield, 140 F3d 915 (11th Circuit 1998).

3 International Association of Arson Investigators. Press releaseentitled, “Fire Investigation not Junk Science. IAAI Says DaubertDoesn’t Apply to Fire Investigators,” November 16, 1997.

4 M. Pavlisin and S. Moran. “Are Fire Investigators ConsideredScientists? Case Law, NFPA Provide Clues,” Claims. Vol. 47, No.5, pp. 28-end, May 1999.

5 T.D. Hewitt, A Fire Litigation: The Role of NFPA 921,” NFPAJournal. March/April 1996, pp. 40-43.

6 W.N. Buxton. “Guest Editorial: Yes, It Is Science and Art,” Fireand Arson Investigator. Vol. 48, October 1999, pp. 4-5.

7 R. Giere. Understanding Scientific Reasoning, Third Edition.Harcourt Brace Jovanovich College Publishers, Fort Worth, TX,1991, pp. 37-39.

8 D. A. Bronstein. Law for the Expert Witness. Lewis Publishers,Boca Raton, FL, 1993, pp. 85-88.

9 I.M. Copi and C. Cohen. Introduction to Logic, Tenth Edition.Prentice Hall, Upper Saddle River, NJ, 1998, pp. 546-556.

10 D. Drysdale. Introduction to Fire Dynamics, Second Edition.John Wiley & Sons, Chichester, England, 1999.

11 B. Karlsson and J.G. Quintiere. Enclosure Fire Dynamics. CRCPress, Boca Raton, FL, 2000, pp. 11-24.

12 R.A. Ogle and J.L. Schumacher. “Application of Fire Modelingand Testing in a Forensic Investigation,” Second InternationalConference for Fire Research and Engineering, Society of FireProtection Engineers, Bethesda, MD, 1997.

13 J.G. Quintiere. Principles of Fire Behavior. Del Mar Publishers,Albany, NY, 1998.

14 A.E. Cote (ed.), Fire Protection Handbook, 18th Edition.National Fire Protection Association, Quincy, MA, 1997.

15 K.R. Foster and P. W. Huber. Judging Science. MIT Press,Cambridge, MA, 1997, pp. 283-285.

16 T.L. Mullin, Jr. “Applying Daubert to Fire Origin and CauseInvestigations,” For the Defense. Vol. 41, No. 10, October 1999, pp. 36-end.


By Joe Cappucio, P.E.

INTRODUCTION

The FPE community continues tofoster performance-based fire protec-tion and life safety design. An impor-tant milestone in achieving perfor-mance-based design is to develop ana-lytical tools, like computer models,that assist with quantitative hazardanalysis.

Computer fire models predict theeffects of fire on a building’s environ-ment, including the time to untenableconditions, but they do not determinewhether occupants can evacuate inthat time. The SFPE Handbook of FireProtection Engineering, 2nd Edition,1

documents an hydraulic model ofemergency egress that calculates occu-pant egress time. PathFinder uses thismethodology to calculate occupantegress time, and it then displays occu-pant location through animation.

MODEL DEVELOPMENT

The goal of this project was to devel-op an analytical egress simulation toolthat could be coupled with a fire modelto form a portion of a hazard analysis.The egress methodology implementedin PathFinder follows the spirit ofNelson and MacLennan in theirEmergency Movement chapter of theSFPE Handbook1. One differencebetween the PathFinder method andthe method in the SFPE Handbook isthat PathFinder tracks individuals whilethe Nelson and MacLennan model doesnot. The advantage of this capability isthat the PathFinder simulation can track

the process of evacuation by room orfloor, whereas the methodology in theSFPE Handbook can only provide anindication of time at endpoints of ananalysis. Note that the SFPE methodcan generate information on specificrooms; however, the method has diffi-culty determining the time for floorevacuation due to the intermingling ofoccupants from various floors withinthe exit stairways and a nondiscretemethod of handling occupants.

PathFinder establishes occupantloading through a user interface thatallows population by density or by dis-crete numbers of occupants. Occupantsare initially dispersed randomly withineach compartment that contains an ini-tial occupant load. Boundary layers

within rooms and along the path ofegress, occupant flow rates, and travelspeeds are consistent with the method-ology in the SFPE Handbook.

MODEL PLATFORM

An important goal of the project wasto use .dwg and .dxf drawings as thebackground for model data entry andoutput animation. After reviewing sev-eral potential platform programs, Actrix,produced by Autodesk, was chosen asthe platform for PathFinder. Actrix is aCAD-based drawing software package,similar to AutoCAD, although it hasfewer capabilities. Actrix has beenunder development by Autodesk inparallel with the development of the

PATHFINDER:

During the simulation, the user is able toview the animation of each floor of themodel. The user is also able to view a sum-mary of the simulation as it progresses. Thisimage shows the number of occupantsremaining on a floor in the Floor Occupantscolumn.

SIMULATION SUMMARY

A COMPUTER-BASED, TIMED EGRESS SIMULATION

The Stairway Occupants columns showthe relative percentage of occupants withinthe stairway compared to the number ofoccupants who, if they were in the stair-way, would result in a flow that approach-es zero. (This is represented by the portionof the depiction box that is colored redcompared with that portion that is coloredwhite.) Since the discharge level for thisexample is the first floor, the values indi-cated at this level represent persons tohave discharged the building, hence thegreen color.

The Discharge Exit Usage columnsshow the number of occupants who havedischarged from the various exits, and itwill also indicate the number of occupantspredicted to reach areas of refuge whenthat design option is used in an analysis.


PathFinder model. This required ourdevelopment team to use several itera-tions of alpha and beta test versions ofActrix and to coordinate the PathFindermodel with these versions. A distinctadvantage has been the ability to assistin the development of Actrix throughfeedback to Autodesk.

The PathFinder model accepts .dwgand .dxf files. Drawing files are notrequired to develop an egress modelusing PathFinder. Although the intentis to utilize drawing files, users maysketch floor layouts without CAD-baseddrawing files. The user then inputs atopological mapping of the building(by floor). This topology describeshow the various rooms and spaces areinterconnected.

TOPOLOGY

Building topology can be simplydescribed as how the surfaces of thebuilding interconnect and form thespaces in which the building occu-pants and building equipment arelocated. These spaces become therooms, corridors, and stairways thatsupport the building’s normal occu-pancy and utility. Specific surfaces –those with openings capable of allow-ing human passage (doorways) – gen-erate “human paths” between individ-ual spaces. These paths must ultimate-ly permit an occupant to move fromany occupied building space to theoutside or area of refuge, either during

the normal course of occupancy orduring an emergency such as a build-ing fire. Geometric features of thesesurfaces and spaces determine pathlengths to exits, areas of refuge, andthe outside. The time required foroccupants to reach exits, areas of ref-uge, and the building exterior can becalculated with the incorporation oftravel speed and occupant flow in con-junction with the geometry and topol-ogy of the building.

The electronic drawing files containlittle direct topological information.The topology is provided by the user,who recognizes such topological fea-tures on displayed drawings as con-nected surfaces that form a room and adoor of a certain width between twospaces. Once the topology of a build-ing or building portion is developedfrom the drawing file, it is preserved aspart of the PathFinder analysis and canbe updated to include modifications tobuilding geometry and topology.

POST-SIMULATION DATA

A variety of data can be extractedfrom the simulation. The simulation’sdata structures have been developedto allow users to retrieve the followingpost-simulation data:1 The number of people that have

used an exit.2 The minimum, maximum, and aver-

age time for people to exit thebuilding from a given room.

3 The time a room, hall, or stairwaybecomes empty.

4 The time a floor becomes empty.5 The time the building becomes

empty.6 The time when everyone on a floor

is safe (entered a stairway exit,entered a horizontal exit, or dis-charged from the building to theexterior).

7 The maximum queue size for agiven exit door at any time duringthe simulation, and the time atwhich the maximum queue sizeoccurs.

8 The maximum number of personson a given stair segment at any timeduring the simulation, and the timeat which that maximum occurs. (Astair segment is defined as the areainclusive of the stairway landing ata floor level and the descendingstair treads, including intermediatelandings prior to the next floor levellanding below.)

9 The time when all occupants in thebuilding are safe (left the building,entered an exit, or entered a hori-zontal exit).

10 The minimum, maximum, and aver-age distance traveled to a point ofsafety (an exit or a discharge) byroom, by floor, or overall withinthe building.

This output data are tracked inter-nally by the model. Final output datareporting by the simulation has notbeen definitively determined by thedevelopment team.

The simulation provides an optimi-zation of egress time, since behavioralaspects of occupant evacuation are notincluded in the model. However, theuser can superimpose the effects ofoccupant activities, such as investiga-tion or providing aid to others on theresults of the simulation.

Joe Cappucio, P.E. is with Rolf Jensen& Associates.

REFERENCES

1 Nelson, H. & MacLennan, H. “EmergencyMovement,” The SFPE Handbook of FireProtection Engineering, 2nd Ed., NationalFire Protection Association, Quincy, MA,1995.

PathFinder simulates occupantevacuation and displays resultsas both text reports and throughsimulation. This image showsthe location of occupants on afloor of an office building at thebeginning of a simulation. Thevarious colored areas representthe types of occupancies thatinhabit the floor. These differentoccupancies have varying occu-pant densities, and the coloringscheme allows the user to quick-ly assess the types of occupancies and their locations on the floor. The CAD background ofthe floor is also visible and allows the user to identify the various portions of the means ofegress during the simulation.

ANIMATION


consider what may happen well afterthe project or product is built and inuse. This article uses the United Stateslegal and governmental systems to illus-trate the design issues discussed andentities with which the engineer/design-er must contend while working on abuilding or product.

The United States system discussionwill directly apply to the many U.S.readers and will also apply to the read-ers from other countries that sell prod-ucts in the U.S. The discussion shouldalso provide guidance for the engi-neers/designers who fall under similar

legal and governmental systems.Although this paper may help identifyissues for consideration, it cannot sub-stitute for good legal advice. Engineersand designers are encouraged to find agood attorney for assistance withresearch in finding applicable codesand other requirements as discussedbelow.

This article is divided into five majorsections. The first section describes thelegal and political systems’ influenceson the design process and some of therelationships between the federal andother levels of government. The next

By Christopher B. Wood, J.D.

INTRODUCTION

Issues relating to design liabilityinvolve many components and entities.These issues range from legal actionsstemming from negligence to govern-mental actions under a variety of lawsand regulations. This article will serveto review (1) the United States legalsystem, (2) the types of legal caseswhich might arise out of fire protectionengineering/design,a and (3) someapproaches to engineering/design that

Legal Considerations in

FIRE PROTECTIONDESIGN


three sections give some overview oflegal cases, the most common cause ofaction for design failures (negligence),and legal considerations in engineeringpractice. The article concludes with aseries of points to keep in mind whenperforming design work and in practic-ing the profession.

THE LEGISLATIVE, EXECUTIVE,AND JUDICIAL SYSTEMAFFECTING DESIGN

Fire protection engineering crossesso many bounds that a large number ofentities have input into the process.For example, the recently publishedSFPE Engineering Guide toPerformance-Based Fire ProtectionAnalysis of Design of Buildings1 has aseemingly daunting list of entities desig-nated as “stakeholders,” but those aregenerally the ones with active inputinto a project (i.e., in person or bydirect correspondence). In addition,many other entities (such as the ulti-mate user) may exercise some control(possibly implicit control) and/ordesign constraints on the project.Defining the legal system and its com-ponents will help to clarify the identityof some of these other entities. We willnecessarily have to cover a large num-ber of entities before being able tobring them together and demonstratetheir interaction with the engineering/design project.

The three basic “levels” of govern-ment can be defined as federal, state,and local. Most projects fall under thefirst two levels, and these first twohave substantially similar organizations.The federal (national) level is estab-lished by and governed under theUnited States Constitution. The stateb

(province) level is established undereither a state constitution or a statecharter. The local level is generally acity or town, but may be a county,water district, fire district, or someother established entity with the powerto impose control and/or sanctions onprojects/buildings. Regional differencesare especially evident at the local level.For example, while the Eastern parts ofthe United States have most powerconcentrated at the city or town level,many Midwest and Western states havemore power concentrated at the districtor county level.

The division of powers referred to asbranches, within the state and federalgovernments, are substantially similarand will be addressed together. Thethree branches of government are (1) legislative, (2) executive, and (3) judicial. These three branches allhave control and input into design pro-jects based upon their granted powersand historic use of those powers. Toappreciate how their action has inputinto the design process, it is importantto first understand what they are andwhat they do.

LEGISLATIVE BRANCH

The legislative branch at the federallevel contains the House ofRepresentatives and the Senate which,when referred to as a single unit, con-stitute the Congress. Some state gov-ernments have only one body referredto as a House. Members of the legisla-tive body are elected. The Congress’duty is to pass and repeal laws(statutesc) deemed necessary toachieve certain goals in the society.Understanding this role is importantbecause only through the passage oflaws can the other two branches ofgovernment act. In a certain sense,Congress is the starting place becausethe other branches of government onlyexecute and interpret the laws madeby Congress. Congress receives itspower from the Federal Constitutionand is limited to those powers.Similarly, state legislatures receivegrants of power from their charters orconstitutions.

EXECUTIVE BRANCH

The second branch of government isthe executive branch. The executivebranch is headed by the President at

the federal level and, generally, theGovernor at the state level. “Managing”or upper-level members of the execu-tive branch are elected or appointed.While initially established to “execute”(i.e., enforce) the laws through the mili-tary, militia, and police agencies,Congress has greatly expanded the roleof the executive branch over the pastseveral decades through “enabling” leg-islation. Such enabling legislation grantscertain rule-making authority to variousagencies in the executive branch.

At the federal level, these executiveagencies include groups such as theOccupational Safety and HealthAdministration (OSHA), the Environ-mental Protection Agency (EPA), theFood and Drug Administration (FDA),the Consumer Product Safety Commis-sion (CPSC), and the Department ofTransportation (USDOT) as well asmany others. Most of the federal agen-cies have regulations that relate to firesafety design issues. State agenciesunder the executive branch mayinclude groups such as a state buildingboard, fire prevention board, and/or astate department of transportation, etc.

Because the executive agencies arecreated by legislative enactments, anagency’s rule-making authority is limit-ed to its enabling legislation. Theenabling legislation generally affordsthe agency the power to pass, promul-gate, and generally enforce rules orregulationsd necessary to perform theagency’s function. Sometimes, theenabling legislation also contains otherprovisions not necessarily reiterated orenumerated in the agency’s rules.Therefore, it can be helpful and instruc-tive to read the agency’s enabling legis-lation when trying to understand thescope and goals of various promulgat-ed rules. Because the rules come undertheir enabling legislation, they have theforce of law when enacted under thelegislatively established rule-makingprocess.


At times, litigation may be necessarywhen an agency prevents a particularcourse of action or design and theagency’s preventing actions go beyondits legislative grant of authority or usethat authority in an “arbitrary or capri-cious” manner – the legal test for mis-use of power. A denial of variance froman appeal’s board, for example, maylead to litigation that tests the board’sauthority on the particular issue.Engineers may provide guidance to thecourt or expert testimony to assist thecourt in making a determination aboutthe board’s or agency’s previous pro-ceedings.

The legislatures have provided therule-making process because it is moreadept at handling public input whichallows agencies to be more responsiveto public needs. Also, many agencieshave a formal “interpretation” processso that questions, which may not haveclear answers under the rules, can beconsidered and ruled upon before adesign continues past a certain point.Many engineers are familiar with similarprocesses under the National FireProtection Association (NFPA) interpre-tation process and the use of code com-mentaries from model building codeorganizations such as the Building andOwners Code Administrators International(BOCA), the International Conference ofBuilding Officials (ICBO), and theSouthern Building Code CongressInternational (SBCCI). These modelcodes are often adopted by state build-ing boards or governmental agencies.

JUDICIAL BRANCH

The third branch of government isthe judiciary, or courts. In so manyways, this branch is where “the rubbermeets the road” for design liabilityissues. The judiciary provides the inter-pretation of laws and the “legality” oflaws. Legality involves interpretation oflaws under their enabling authority.

The interpretation of laws and regu-lations is the issue over which mostpeople find themselves in court. Thereare two generally accepted sources oflaw in the U.S. legal system and thosesystems of similar lineage. The firstsources of laws are statutes passed bythe Congress, state legislatures, or ordi-nances passed by cities and towns atthe local level. Rules or regulations, as

discussed above, derive their authorityfrom enabling legislation previouslypassed by an appropriate legislativebody. The body of fire protection regu-lations and adopted codes and stan-dards fall in this category of rules andregulations.

The second source of laws is the tra-dition of the court often referred to as“case law.” Our U.S. legal heritagecomes from the lineage of English CaseLaw because much of our legal systemevolved from the English tradition. Caselaw, which is the body of publishedcase opinions interpreting both statuto-ry and other case law, becomes prece-dent and law to each subsequent deci-sion. The published opinions then pro-vide notice of the interpretations ofstatutes and other precedents. Thisprocess provides consistency andallows people to make appropriatedecisions on how to conduct them-selves under the law. Thus, in additionto researching statutes and regulations,a given set of facts should be reviewedagainst relevant legal decisions whichhave previously interpreted the issue orlaw at hand. This means that fire pro-tection engineering design can be guid-ed by the findings of previous courts inconsideration of, for example, allegeddesign negligence.

LEGAL CASES

This section will consider the mannerin which legal cases come about andthe specifics of negligence cases thatcommonly arise. The cases consideredwould be those that are adjudicated incourts established under the judicialbranch as opposed to those decidedunder arbitration, mediation, or in thequasi-courts of the executive branch,such as administrative law proceedingsunder the CPSC. A review of the termi-nology that describes the parties andthe differentiation between varioustypes of actions is required to beginthis limited discussion of legal cases.

There are two types of cases thatmay occur in the judicial system: crimi-nal cases and civil cases. Most peopleare familiar with the concept of “crimi-nal” actions. In all criminal cases, acrime is considered to be committedagainst society or the state. As such, thecase is prosecuted by the state, whichis represented by an attorney (referredto as the prosecution) who is a mem-ber of the executive branch (i.e., districtattorney, attorney general, etc.). Theperson charged with the crime is the“defendant.” In a criminal case, thedefendant has a legal right to represen-tation, and an attorney will be providedif the defendant is indigent. Althoughfire protection engineering analysis maybe performed for some arson cases andcriminal negligence cases, criminal lawhas many requirements that differ fromnoncriminal (civil) cases. (Althoughcriminal cases will not be consideredfurther in this paper, some criminalnegligence cases have occurred fornegligent design.)

The beginning of a civil case beginswith a “wrong” for which the“wronged” or “injured” party seekscompensation in a suit. The injuredparty is the “plaintiff.” The plaintiff isthe one considered to be in the bestposition and with the most interest tofully pursue the case. The plaintiff mustprove the elements of its case so that itis “more likely than not”e that the plain-tiff’s allegations are true. The partyagainst whom the action is initiated isthe “defendant,” as in criminal cases. Toadd to the overall complexity, a defen-dant may also sue the plaintiff (counter-suit), multiple defendants may sue eachother (cross-claims), and, generally,defendants may bring in additional par-ties (third-party defendants) who mightmake claims against any of the otherparties.

Suits can quickly involve multipleparties. A common example wherethird-party suits come into existenceinvolves workers compensation cases,for example, an employee burned dur-ing a plant fire or explosion. Underworkers’ compensation laws, theemployee relinquishes the right to suethe employer for workplace injuriesunder a guaranteed compensation plan.The worker may, however, sue manu-facturers of equipment involved in aworkplace injury. The manufacturer, in


turn, may sue the employer, allegingthat the employer’s actions, rather thanthe equipment, were the cause of theemployee’s injuries, and should theemployee recover on the claim againstthe equipment manufacturer, theemployer could be found responsibleand required to indemnify or pay theaward for the defendant.

AN ACT OF NEGLIGENCE

Negligence is a specific area withinthe general designation of “torts.” A tortis “a private or civil wrong or injury ...for which the court will provide a rem-edy in the form of an action for dam-ages.”2 An insight into why the theoryof negligence exists is evident in thefollowing observation: “It has beennoted that tort liability for negligencehas the effect, and to a degree the pur-pose, of regulating a defendant’s futureconduct.”3 This approach aims to havethe societal/economic system be self-regulating by eliminating dangerousproducts and careless manufacturersfrom the marketplace through the eco-nomic incentive to limit their liabilitythrough good engineering/design.

In order to understand how the lawof negligence influences the engineer-ing/design process, the engineer musthave an understanding of the elementsof negligence. Through this understand-ing, the engineer or designer seeksways to limit liability from negligence.A successful action of negligence mustprove four components: (1) the defen-dant owed the plaintiff a duty of care,“duty”; (2) the defendant breached theduty, “breach”; (3) the defendant’sbreach of the duty is the legal cause ofthe plaintiff’s damages, “causation;” and(4) the plaintiff suffered an injury,“damages.”

The duty of care extends to a num-ber of classes of people. In general, thepurchaser and user will be in the class ofpeople to whom the engineer/designerowes a duty. However, the protectionextends to many others, including those for whom injury is foreseeable.Designers and engineers owe a duty tothose for whom an effect from thebuilding or product is reasonably fore-seeable. For a building, the list mightinclude tenants, employees, visitors,etc. For a product, the list might

include maintenance personnel or usersof manufacturer-expected after-marketaccessories.

Duties can be inferred from laws orregulations and can include an act orthe omission of an act. In some jurisdic-tions, the mere violation of a statute isnegligence per se which, once shown,shifts the burden of proof to the defen-dant to prove the act or omission wasnot unreasonable (negligent). In otherjurisdictions, such a violation is onlyevidence of negligence, and the plain-tiff must show the defendant’s specificbreach of a duty owed to the plaintiff.Additional sources to show the dutywould include the customary usage inthe trade, industry, profession, or eventhe internal standards of a particularcompany. These might be shown byNFPA codes, standards, and guides(whether or not adopted), SFPE Guides,NFPA and SFPE handbooks, and modelbuilding codes or company policies.An egress example might involve theegress time calculations for a quadri-plegic rehabilitation center thatassumed travel speeds associated withunimpaired pedestrians in an uncrowd-ed passageway when clearly lower trav-el speeds should be utilized. Failure toconsider an alternative design when thetechnology is available, such as a“defend in place strategy,” might alsobe considered negligence.

Two special notes must be made tothe foregoing sources of evidence onduties. First, the customary usage canbe negligent. This approach eliminatesthe argument that “if everyone else isdoing it, it must be OK.” Numerouscourts have decided that “everyone”can be doing a “legally” unacceptablejob and held engineers/designers to ahigher standard than what the industrywas doing. Similarly, codes and stan-dards should be considered minimumrequirements that may not represent“reasonable” care under particular cir-cumstances. Second, if engineers/designers either have specializedknowledge or hold themselves out ashaving specialized knowledge, then thecourts may hold them to the higherlevel of knowledge.

The proving of a breach of dutyinvolves a number of tests. In part, thebreach consideration is linked with theduty consideration above. The second

part involves the concept of the specificact or omission alleged by the plaintiff.Often this component is termed the“reasonable person test.” Did the defen-dant act in a “reasonable” way. Thereasonable person realizes that his orher act (or omission) would create a“risk and its [the act or omission] unrea-sonable character.”4

The necessary steps and costs toeliminate a risk were succinctly put for-ward by Judge Learned Hand. He stat-ed that “the responsibility is a functionof three factors: the likelihood that [theengineer’s/designer’s] conduct willinjure others, taken with the serious-ness of the injury if it happens, andbalanced against the interest which hemust sacrifice to avoid the risk.”5 Thisdefinition does not establish the prem-ise that everything must be done toeliminate every risk. However, the easeof reduction or elimination of the riskas compared to the probability of therisk and severity of the outcome is tobe considered. In building fire protec-tion design, for example, this leadsdirectly into the analysis of the fire sce-narios developed and the limitationsexplicitly described in a fire designbrief.f

The last two components of negli-gence, causation and damages, aremore legal issues than engineering/designissues. Causation relates the breach tothe damages. Causation is not to be con-fused with “comparative” negligence.g

Comparative negligence relates theplaintiff’s own actions to the damagesincurred and reduces the monetaryaward by the extent (usually a percent-age) to which the plaintiff’s own negli-gence contributed to the plaintiff’sinjuries. Under negligence, the court fol-lows the legal fiction that all such dam-ages can be reduced to monetary com-pensation. There are numerous ways tocalculate the appropriate damages.

The following example shows howthe engineers/designers should at leastconsider other persons that mightbecome involved with a productbeyond the expected purchaser. Whilechildren may not be the intended usersof a cigarette lighter, it is reasonablyforeseeable that the lighter might fallinto the hands of a child6 so that thechild or damages suffered at the handsof the child’s operation of the lighter, a


foreseeable event, may be one that amanufacturer should consider in thedesign. Whether or not the manufactur-er breached the duty will encompassconsiderations such as the technical fea-sibility, cost of implementing a safetydevice, and the utility of the productwith the safety device. In buildingdesign, the use and occupancy forwhich the design was originally devel-oped, foreseeable changes may includeissues such as area and height limita-tions or fire-resistive construction underapplicable building codes. This high-lights the need to clarify for theowner/operator the limits outside ofwhich additional analysis must occur forany proposed new use. This exampleis readily extended to sprinkler designinvolving issues such as water density,design area, hazard classification, etc.

This section has examined a varietyof components that feed into the legalsystem and the most common cases inengineering/design, negligence. Someattempts have been made to introducethe variety of laws and regulations thatimpact a project. The very importantarea of warnings has not been coveredhere, but there is clearly a duty to warnwhen a safer design is impracticable.Warnings are a complex area andshould be examined closely whenneeded to implement a useful productfor which the risk cannot be eliminat-ed. For example, CPSC and USDOThave statutory wording for a variety ofproducts using labeling trigger wordssuch as “WARNING” or “DANGER.”

LEGAL CONSIDERATIONS INENGINEERING

There are many sources of engineer-ing and design liability in the processof any particular project. The mostcommon legal action against the engi-neer/designer is one of design negli-gence. The best protection againstthese suits is to act as a “reasonableperson,” seek to identify foreseeablefailure modes, design them out or warnusers against them, and provide guid-ance for the user to avoid the loss.Engineers/designers will be held to thehighest of (1) the minimum practice inthe industry, remembering that courtshave held industry practices to beunreasonable, (2) the person’s specific

or specialized knowledge when thatknowledge is greater than the industry,(3) the specialized skill or knowledgethat the engineers/designers represent-ed they possessed, or (4) applicablelaws and regulations. These burdenscan be met through the application ofroutine practices.

The first practice involves continualprofessional development. All personspracticing in the profession shouldundertake to maintain their knowledgeat the industry level. This goal generallytakes a multipronged approach. Eachengineer/designer will benefit from reg-ular attendance (i.e., annual/biennial) atseminars and other recognized trainingcourses. These courses will help tokeep the attendee “up to date” ondevelopments in the industry andapplicable codes and regulations.Similarly, the engineers/designersshould seek to remain current withpublications that depict the latest devel-opments in the industry. This knowl-edge is part of the “stock in trade” ofthe design professional.

The second piece of controllingdesign liability could be considered“diligence in design.” Whether designinga building, a building system, or a prod-uct, diligence in design involves a three-pronged approach. The three legalprongs can be condensed into threewords: (1) “laws,” (2) “imagination,” (3)“documentation.” There are, of course,many other specifications and require-ments so that the project (building orproduct) meets its intended goal andfunctionality. Those requirements arenot considered here, although, ofcourse, at times they may be inconsis-tent with some of the suggestions madehere. When conflicts occur, only theproject-specific facts and good engineer-ing judgment can determine which fac-tor must give way to the other.

The first prong is to determine theapplicable laws and regulations underwhich the product or building will bedesigned. Ensure that all applicablerequirements have been met and thatthey meet or exceed the industry stan-dards and the engineer’s/designer’s spe-cialized knowledge. Performance-baseddesign objectives must not be belowthese applicable standards and areimplicitly imposed on every project.This is the point at which engineering

judgment becomes critical in makingsure that the project design is “safe”through the fundamental design, imple-mentation of safety devices, and appro-priate warnings.

A project may involve the use ofunfamiliar regulations (from a fire safetyperspective) such as the design of a haircare product, which falls under the FDAfor regulation. Although such productsdo not fall under the CPSC, thatagency’s labeling and other require-ments may actually be more instructivethan the FDA’s, which introduces thesecond prong of “imagination.” Theengineer/designer may need to invokethe assistance of a research or law firmwith access to computerized legalresearch tools/databases to determineall of the applicable laws and prece-dent-setting case law. The engineer/designer may need to work closely withthe research firm so that appropriate“keywords” and search criteria are usedto achieve an effective search.

In some cases, the engineer/designermay have to think as a Walt Disney®“Imagineer.” The engineer/designermust not only think of the appropriatemanner(s) in which to use a productbut must go beyond that to reasonablyforeseeable fire scenarios, failuremodes, abuses, misuses, and unintend-ed users. The period of use being con-sidered may begin with distribution,first use, and/or commissioning throughdecommissioning and disposal of aproduct or building. Such thinking maylead to formalized exercises such asfault-tree analysis for components of aproduct or the various fire protectiondevices in building design. The resultsof this analysis should be stored in thelast prong (i.e., documentation).

This third prong is often key in beingable to convey the appropriateness of aparticular design to users or authorities.Do not assume that the state of the art,as understood during the design, will beunderstood at the time of a lawsuit foran injured party’s damages many yearslater. Engineers/designers should makean effort to retain documents used inthe development and analysis of adesign. This documentation shouldinclude the applicable laws and regula-tions researched and employed, theapplicable design decisions made withthe reasons for those decisions, the sce-


narios considered for the design’s useand misuse, and the calculation proce-dures and methodologies used.Documentation of design limitations,warnings, and their development shouldalso be retained. Although applicablecodes may not be copied into each pro-ject’s file, the codes should be main-tained in a way that they do not becomelost when the next code version arrives.That is, maintain an archive copy of thecode (maybe one for each office) forlater reference in researching the codethat existed at the time of the design.

Documentation of considered lawscan be formalized in a “code-trace.”The code-trace document lists the lawor regulation considered down to thespecific sections examined including thesection designation, title, and applicableyear. A summary of the requirementsand how the requirements are met willassist when questions arise many yearslater. Clearly the presumption here isthat the design is being made under theguide of “good engineering judgment.”As such, documenting the design willallow for the engineers/designers to“refresh their memories” at the time anyquestion arises. Presuming good engi-neering judgment was used during thedesign, a failure to recall why a designdecision was made can cause a jury toquestion the credibility of the testifyingengineer, leading to the conclusion thatsomething was done incorrectly.Documentation made at the time of thedesign can provide good evidence as tothe “hows” and “whys” of the finaldesign. For those who have beeninvolved in design law suits, one litiga-tion is all it takes to show the value ofthis documentation. Because the engi-neer/designer never has any knowledgebefore the fact of which project willlead to a lawsuit, this documentationshould be done for every project.Finally, the documentation shouldinclude the limits of the design and thereasons for those limitations.

CONCLUDING REMARKS

Those who observe the legal systemof the United States, both within thecountry itself and from other nations,may feel that the amount of litigation isexcessive and a negative influence onthe flow of economic activity, particu-

larly in the area of negligence in thedesign and manufacturing process. Aspreviously stated in this paper, the legalprocess is a part of the national regula-tory philosophy. The legal system is analternative for specific regulation or lawin regard to each transgression per-ceived to be in need of restraint or con-trol. Law, once made, is difficult tochange and consumes considerabletime in meeting the ever-fluid needs ofa dynamic economy. In the alternative,lawsuits and the threat of legal processprovide an incentive for the designerand producer to “protect before thefact” rather than to “produce and sufferthe consequences.” This process leadsto a self-regulating effect, and the law-suits, once decided, provide the princi-ples on which subsequent designersand producers can reasonably rely forfuture activities.

BIBLIOGRAPHY

This list will help to give the engi-neer/designer some additional resourcesto consider. It is by no means exhaus-tive, but should give leads to additionalresources. Some of the resources mayonly be available in a law library if notpurchased from the publisher.

Berry, Dennis J., Fire LitigationHandbook, NFPA, Quincy, MA, 1984.

Cushman, Kenneth M. (Chair),Handling Construction Risks, AllocateNow or Litigate Later, Practicing LawInstitute, New York, NY, May, 1999.

Cushman, Robert F. and Hedemann,G. Christian, Architect and EngineerLiability, Claims Against DesignProfessionals, 2nd Edition, John Wiley& Sons, New York, NY, 1995 (with 1999supplement).

Sweet, Justin, Legal Aspects ofArchitecture, Engineering and TheConstruction Process, 5th Edition, WestPublishing Company, New York, NY,1994.

Weinstein, Alvin S., et al, ProductsLiability and the Reasonably SafeProduct: A Guide for Management,Design, and Marketing, John Wiley &Sons, New York, NY, 1978.

Witherell, Charles E., How to AvoidProducts Liability Lawsuits andDamages, Practical Guidelines forEngineers and Manufacturers, NoyesPublications, Park Ridge, NJ, 1985.

Christopher Wood is with CusterPowell, Inc.

END NOTES

a Engineering and design will be usedinterchangeably in the paper. There maybe some differences in specificsbetween, for example, design of build-ings versus design of products, but manyof the general concepts of design liabilityare shared between the two.

b The term “state” here is used broadly todescribe states and commonwealths.

c Statutes are published within the UnitedStates Code (USC or “Code”) at the fed-eral level or “General Laws” at the statelevel (e.g., Massachusetts General Laws,MGL, or Massachusetts General LawsAnnotated, MGLA).

d These rules at the federal level are foundrecorded in the Code of FederalRegulations (CFR), and most states ahave a similar document at that level.

e “More likely than not” can be thought ofas some scintilla of evidence greater than50/50, otherwise judgment must be forthe defendant because the plaintiff didnot prove its case.

f See the SFPE Engineering Guide toPerformance-Based Fire ProtectionAnalysis and Design of Buildings.

g At one time, the concept of “contributorynegligence” was used. If found on thepart of the plaintiff, contributory negli-gence was an absolute bar to the plain-tiff’s recovery. In various forms, all U.S.jurisdictions now use some form of com-parative negligence.

REFERENCES

1. SFPE Engineering Guide to Performance-Based Fire Protection Analysis andDesign of Buildings, NFPA, Quincy, MA,2000, 4.2.4.

2. Black’s Law Dictionary, 6th Ed., WestPublishing, St. Paul, MN, 1990.

3. 57A Am Jr 2d 1.

4. 2 Restatement of Torts 2d, 284, commenton clause (a).

5. Conway v. O’Brien, 111 F.2d 611, 612, (2Cir. 1940) quoted from Prosser, et al,Torts, Cases and Materials, 7th Ed., UCB-1.

6. Am Law Prod Liab 3rd, 28:1.


By Robert M. Gagnon, P.E., andTyler Mosman

INTRODUCTION

The rapid air flow velocities withincomputer server machine rooms, espe-cially underfloor, have necessitated anevaluation of the effectiveness of thesmoke-detection systems installed inthese rooms. Air movement is neededto cool electronic components, whichhave the potential to heat to the pointof ignition without such cooling. Air-handling units in computer servermachine rooms force cool air into theunderfloor area, through racks of verti-cal electronic server units mounted to

floor openings, into the abovefloorregion, and back to the air-handlingunits for cooling.

Smoke-detection systems, typicallyused as initiating devices for alarm sys-tems and as mechanisms for operatingfire protection systems in computerrooms, are installed in accordance withthe requirements of the authority havingjurisdiction, using NFPA 72, the NationalFire Alarm Code®, as the basis forimplementation of acceptance criteria.

The 1999 edition of NFPA 72, Table5-3.6.6.3 and Figure 5-3.6.6.3, providessmoke-detector spacing requirementswithin abovefloor enclosures where airmovement is not expected to exceed 60air changes per hour. Air velocities can

greatly exceed 60 air changes per hourin the constricted underfloor region andin the area above suspended ceilings.

Interviews with plant personnel fora major Internet company yielded evi-dence of infrequent smoldering firesinvolving overheated electronic com-ponents in machine rooms, withsmoke stratification being observedwith the air conditioners operating. Inthese reported fires, smoke detectorsactuated, and the notification systemoperated, but the preaction sprinklersystem did not discharge. High airmovement velocities enhance thechances for stratification and can nega-tively affect response times of ceilingsmoke detectors.

SMOKE-DETECTION

EVALUATION

IN ENCLOSURES

WITH

HIGH-VELOCITY AIRFLOW


DETECTION SYSTEM ARRANGEMENT

The test room is a computer serverroom whose smoke detection systemshad completed acceptance testing inadvance of occupancy. Permission wassecured to perform smoke detection

research that could influence futureserver room detection design. The fol-lowing detection systems were installedin the test room, as shown on Figure 1.1. A photoelectric spot smoke detection

system was installed in the test roomat the bottoms of the beams at ceil-ing level.

2. An ionization spot smoke detectionsystem was installed in the test roomat the bottoms of the beams at ceil-ing level, staggered between thephotoelectric detectors, as shown onFigure 1. The resulting spacing of thestaggered arrangement is 120 ft2 (11m2) per detector.

3. Staggered photoelectric and ioniza-tion spot detectors installed withinthe 2' 4" (0.71 m) deep exposedbeam pockets at the ceiling.

4. Staggered photoelectric and ionizationspot detectors mounted to the lighttracks below the ceiling beams at anelevation of 14 ft (4.3 m) above thefloor.

5. One photoelectric and one ionizationspot detector installed at the air inletto each air conditioning unit.

6. An incipient air sampling smokedetection system was installed in thetest room at the air inlets of theroom air conditioning units.

7. A photoelectric smoke detection sys-tem was installed in the 2' 0" (0.61 m)deep underfloor area, at a spacing of120 ft2 (11 m2) per detector.

DETECTION LOGIC

The fire alarm control panel has beenprogrammed to issue a trouble signal tothe constantly occupied main controlroom on the receipt of a signal fromany detection device. Upon receipt of asecond detection signal, an alarm signalwill be issued via the building notifica-tion appliance system, and the solenoidvalve for the appropriate preactionvalve serving the room will be opened.Once the solenoid valve is opened, thepreaction valve will not open until asprinkler opens, releasing pressurizedair from the piping system and openingthe pneumatic actuator.

RESEARCH OBJECTIVE

The objective of this research is todetermine which smoke detectors reactthe fastest in the presence of lightsmoke production and high-velocity air-flow. Based on the results of the tests,decisions will be made relative to theplacement of detectors that is believedto be capable of detecting a smolderingelectronics fire in its incipient stage.

900 (83.6)

800 (74.4)

700 (65.5)

600 (55.7)

500 (46.5)

400 (37.2)

300 (27.9)

200 (18.6)

100 (9.3)

ft2 (

m2 )

per

det

ecto

r

Air changes per hour60 50 40 30 20 10 0

Figure 5-3.6.6.3 High air-movement areas (not to be used forunderfloor or above-ceiling spaces).*

* Reprinted with permission from NFPA 72-1999, National Fire Alarm Code, Copyright © 1999, National FireProtection Association, Quincy, MA 02269. This reprinted material is not the complete and official position of the NFPAon the referenced subject, which is represented only by the standard in its entirety. National Fire Alarm Code is a registered trademark of the National Fire Protection Association, Quincy, MA.

Table 5-3.6.6.3 Smoke Detector Spacing Based on Air Movement*

Spacing perDetector

Minutes per Air Changes _____________Air Change per Hour ft2 m2

1 60 125 11.61

2 30 250 23.23

3 20 375 34.84

4 15 500 46.45

5 12 625 58.06

6 10 750 69.68

7 8.6 875 81.29

8 7.5 900 83.61

9 6.7 900 83.61


RESEARCH RATIONALE

Fires in computer machine rooms arerare. A fire in a machine room will mostlikely involve the overheating of anelectronic computer component mount-ed in a vertical rack and is characterizedby a wispy plume of smoke with a lowvolumetric rate of smoke production inits incipient smoldering stage. Fullydeveloped flaming electronics fires caninundate a large computer server roomwith smoke. NFPA 72 largely assumesthat in the room of fire origin, smokewill rise in a vertical plume to the ceil-ing and distribute along the ceiling in aceiling jet sufficient to actuate spotsmoke detectors spaced in accordancewith NFPA 72 and in accordance withthe listing of the detectors.

The electronics fires in computer

servers can be attributed primarily tofailure of a printed wiring board con-tained within. Failure modes for printedwiring boards, in addition to loss ofcooling airflow, include power surgesthrough the board and component fail-ure. Literature was studied relative toflaming circuit board heat release rates,but smoldering fires would have asmall fraction of the flaming heatrelease rate. NFPA smoke detectionspacing is predicated upon a design fireof 100 kW, an order of magnitude lessthan the design fire of 1 MW used forheat detectors. This research is centeredupon the smoldering condition, whichwould be expected to be significantlyless than 100 kW. It is the intent of thefire protection engineer to determinewhether it is feasible to design firealarm systems capable of initiating noti-

fication and either manual or automaticsuppression sufficiently in advance ofthe flaming mode to avoid major dam-age and excessive Internet downtime.

In the room used for this research,the ceiling is in excess of 20 ft (6.1 m)in height, the ceiling configuration fea-tures 2' 4" (0.71 m) deep exposed con-crete structural tees, an underfloorplenum is present, and air handlingunits constantly circulate large volumesof air at high velocities. While NFPA 72has detector spacing adjustment factorsfor ceiling heights in excess of 10 ft (3 m)(which apply to heat detectors only),spacing advice for beamed ceiling con-figurations, and spacing modifiers as afunction of air changes per hour, thecombination of these input variablesmade for a challenging smoke detec-tion situation in this room.

Figure 1. Test room layout.


The concern that inspired theresearch was that fires producing lowheat release rates and low volumetricrates of smoke may result in lengthysmoke detector response times. Theresearch objective is to provide smokedetection systems that will provide effi-cient notification of an electronics fireinvolving low volumetric rates ofsmoke production in the presence ofhigh air velocity movement.

To accomplish the research objective,we used smoke producing machinescapable of simulating the low volumetricrates desired, with the objective of mak-ing observations relative to the perfor-mance of a variety of smoke detectionsystem arrangements in the presence ofsuch a smoke production scenario.

THE SMOKE MACHINE

The smoke machine used was athermal aerosol generator capable ofproducing a steady fog output using aconcentrated liquid fog fluid.

The smoke machine has a calibratedremote control dial that is capable ofbeing set to a level of between 0 and11, with a setting of 0 producing nofog, and a setting of 11 producing anextremely dense fog. It is known fromprevious tests that a setting of 11 willcompletely fill the room with smokeand rapidly actuate all smoke detectorsin the vicinity of the smoke machine.The lowest useful setting for these testsis 2.5, which produces a light wispyplume, congruent with the researchrationale.

The fog consists of fluidized dropletsranging from a particle size of 0.25 to60 microns in diameter. The machineuses up to 0.66 gal (2.5 liters) of glycol-water fog concentrate per hour at a set-ting of 11.

The mixture is pumped into a car-tridge heater within a heat exchangerand is exposed to a temperature of500°F (260°C), vaporizing the fluid. Thefog produced is expelled from the out-put orifice, and its temperature is 125°F

(52°C) at a distance of six inches (150mm) from the discharge side of the ori-fice. At low volumetric production rates,the fog cools as it rises to the ceilingdue to entrainment of cool ambient airinto the plume.

The initial warmness of the fog pro-duced by the machine is responsiblefor the vertical buoyancy of the fog.This plume effect does a creditable jobof simulating a small electronics fire.Rapid cooling of the smoke in a rapidlymoving air stream could result insmoke stratification in the presence ofhigh-velocity airflow.

NFPA 72 SMOKE DETECTIONDESIGN

Table 5-3.6.6.3 and Figure 5-3.6.6.3,provide design advice for detectorspacing in rooms with high air move-ment, requiring a maximum abovefloorspot smoke detector spacing of approx-imately 130 ft2 (12 m2) per detector inrooms subjected to 55 air changes per

Figure 2. Air velocity profiles in test room (section view).

1 ft/min = 5x10-3 m/s


hour. The configuration of the testroom is amenable for detectors spacedat 120 ft2 (11 m2).

The 1999 edition of NFPA 72,Paragraph 5-3.4.6.1, requires detectorswithin every beam pocket when thebeams exceed 12 inches (300 mm) indepth and the ceiling height exceeds 12 ft (3.7 m). For this research, wehave installed spot smoke detectorswithin beam pockets to ascertain theireffectiveness relative to detectorsspaced at the bottoms of the beams.

NFPA 72 (1999) states that Table 5-3.6.6.3 and Figure 5-3.6.6.3 do notapply to underfloor areas. As can beseen, with a value of 520 air changesper hour underfloor, no correspondingvalues can be ascertained. Photoelectricspot smoke detectors have beeninstalled at 120 ft2 (11 m2) per detectorin the underfloor space. In advance ofthis research, it was a matter of debateas to whether underfloor detectorswere doing any good at all.

NFPA 72 (1999) has a spacing adjust-ment factor for heat detectors mountedto ceilings in excess of 10 ft (3 m), butprovides no such advice for smokedetectors within the standard. NFPA 72Appendix B provides adjustment forceiling height, but it is assumed that theheat output from an incipient smolder-ing electrical fire would not be of suffi-cient energy intensity to warrant theuse of Appendix B, which was devel-oped by using geometrically growingflaming fires as its basis.

AIR VELOCITY MEASUREMENT

The test room was fitted with anHVCA system that provided 55 airchanges per hour in the abovefloorspace and 520 air changes per hourunderfloor. The air movement patternin the test room is shown in Figure 2.A handheld anemometer was employedas the airflow-measuring device for thisresearch.

The air is drawn from the abovefloorspace by the air conditioning units, dis-charged under the floor for distributionthrough the vertical rack units, thenreturned to the air conditioners, creat-ing a circular air flow pattern, as shownin Figure 2. Further, a parabolic velocitycurve can be interpreted from this fig-ure by observing a vertical plane six ft

(1.8 m) from the air conditioner, fromfloor to ceiling.

The circular air movement could helpto predict a predisposition for stratifica-tion, and detectors positioned directly inthe stratified layer would be expected toactivate in advance of other detectors inthe room. In a stratified scenario, detec-tors at the light tracks would be expect-ed to actuate in advance of detectors atthe ceiling beams.

TEST PROCEDURE

SCENARIO 1: WISPY SMOKE PRODUCTION ABOVEFLOOR

Scenario 1 used smoke machine loca-tion 2 and a setting of 2.5, the lowestsetting capable of producing visiblesmoke.

A photoelectric detector mounted tothe light track adjacent to the air condi-tioner actuated within seconds. Twodetectors at the bottoms of the ceilingbeams also quickly actuated, and adetector in a beam pocket actuatedmuch later in the test.

Neither the underfloor detectors northe incipient air smoke detection sys-tem activated during this experiment.The incipient air smoke detection con-trol panel fluctuated between 0.3 and0.10, but would not sustain a 0.8 valuefor the period of time it would havetaken to issue a trouble alarm.

SCENARIO 2: WISPY SMOKE PRODUCTION ABOVEFLOOR WITHINCREASED AIR ENTRAINMENT

Scenario 2 used smoke machine loca-tion 3 and a fog setting of 2.5.Location 3 was selected because it wasnoted in Scenario 1 that a visible streamof fog was taking a path directly intothe air conditioning units. It wasdesired that a smoke machine positionbe selected to attempt replication of astratified smoke layer. Location 3 fea-tured placement of the smoke machineoutput in front of a perforated floor tile,with rising cool air directing the smokeinto a vertical plume, which couldreplicate a smoldering fire in a compu-ter rack unit.

A significant observation during thisexperiment was that the smoke levelwas very light and was stratified quite

distinctly below the light track level.This observation conforms to the airvelocity profile given in Figure 2. Spotdetectors at the light track and at theinlet to the air conditioning unit werethe first to actuate. One detector at thebottom of the ceiling beams went intoalarm. The incipient air smoke detec-tion system showed values of 0.01 to0.02, significantly less then the requisitelevel for alarm notification.

This was the most challenging sce-nario. Air forced through the perforatedfloor tiles was entrained into the smokeplume and cooled the smoke veryrapidly, resulting in a distinctly stratifiedsmoke layer. Even in the presence ofstratification, one smoke detector at thebottom of the ceiling structural teesactuated. No detectors in beam pocketsactuated during this scenario.

SCENARIO 3: MODERATE SMOKEPRODUCTION ABOVEFLOOR

The smoke machine at location 1 andat setting 3 issued a steady plumewhich activated a photoelectric smokedetector mounted to the light track clos-est to the air conditioner within sec-onds. The second detector actuatingwas a photoelectric detector mounteddirectly above an air conditioner inlet.Ten underfloor detectors and two detec-tors mounted to the bottoms of ceilingbeams activated early in the test. Onlyphotoelectric detectors responded to thesmoke produced. While one detectormounted within a beam pocket actuat-ed, it occurred very late in the test.

The incipient air smoke detectionsystem went into “alert” mode slightly 3minutes after the first spot smokedetector actuated, at a sustained settingof .08 on the control panel monitor,and later went into “fire” status at asustained setting of 2.0.

SCENARIO 4: MODERATE SMOKEPRODUCTION UNDERFLOOR

Scenario 4 used smoke machinelocation 2, located under the raisedfloor, and a fog setting of 3. This loca-tion was intended to replicate a cablefire beneath the raised floor.

Four underfloor detectors directlyadjacent to smoke machine location 2activated within one minute of com-


mencement of smoke production.However, no abovefloor detectors acti-vated, and the incipient air smoke detec-tion system did not record the requisitelevel of smoke to emit a trouble signal.

An interesting observation was that,even though the underfloor area wasfilled with smoke, smoke above thefloor was almost visually imperceptible.A real cable fire would most likely haveemitted a distinct acrid odor, enhancingthe probability of human verification ofan underfloor detector alarm or troublesignal, even when visible smoke is notapparent.

SCENARIO 5: HEAVY SMOKE PRODUCTION ABOVEFLOOR

Scenario 5 featured smoke machinelocation 3 and a fog setting of 3.8.While 3.8 produces only a fraction ofthe smoke production capability of themachine, it still issued a very heavyplume in comparison to the wispysmoke observed at setting 2.5.Scenarios using fog settings in excess of3.8 were judged to be unnecessary.

At this setting, there was more of aflooding of the room with smoke, andthe stratification noted in Scenario 2 wasnot nearly as pronounced. As expected,the heavy smoke production resulted inalmost immediate response from the firealarm system, with numerous detectorsgoing into alarm. A detector mounted toa light track was the first actuating, withmore than a dozen ceiling detectorsactuating shortly thereafter. Detectors atthe bottoms of the beams actuated sig-nificantly faster than detectors mountedwithin beam pockets.

Clearly, an electronics fire of majorconsequence will rapidly actuatenumerous detectors in the computermachine room. Higher volumetric ratesof smoke production would yieldresults congruent to Scenario 5 in theearly stages, with expanding numbersof adjacent detectors actuating.

CONCLUSIONS

Early notification in the presence oflow volumetric rates of smoke produc-tion was the research objective. Wehave studied the literature on hotplateignition of electronic components, andsuch scenarios are capable of inundat-ing the room with smoke, which was

not our objective. While the idealexperimental situation would seeminglyhave been to replicate an electronicsfire by heating an electronic componentto ignition on a hot plate, it was feltthat the lighter smoke production ema-nating from the smoke machine at alow setting of 2.5 more accurately simu-lates the volume of smoke produced bya smoldering fire in its early stages.

From the research performed, severalconclusions can be drawn:

Conclusion 1Placement of smoke detectors at the

bottom of the exposed structural tees ismore advantageous to early detectionof smoldering fires in machine rooms,given the airflow scenario encounteredin this research, than the NFPA 72placement of smoke detectors withinbeam pockets. When detectors in thebeam pockets did actuate, theyresponded much later in the experi-ment than nonpocketed detectors, andin the presence of stratified smoke, didnot actuate at all.

Conclusion 2Looking especially at Scenario 1,

where two detectors mounted to thebottoms of the ceiling structural teesactuated in the presence of very light,wispy smoke, it is apparent that adetector spacing of 120 ft2 (11 m2) isadequate. Even in the most challengingscenario of stratified smoke in Scenario2, one detector at the bottom of thestructural ceiling tees actuated andemitted a trouble signal to the controlpanel. While detector spacing was not avariable that was modified for this test,detector spacing greater than that usedin this study would be expected toresult in increased response times.

Conclusion 3The underfloor arrangement of

photoelectric detectors spaced at 120 ft2

(11 m2) appears effective in respondingto light abovefloor and underfloor fogproduction, even in the presence of airvelocities up to 1000 ft/m (5 m/s).

Conclusion 4Photoelectric detectors responded to

light fog production earlier than ioniza-tion detectors in these tests. Ionizationdetectors are more likely to be affectedby air velocity and less likely to rapidly

respond to the atomized liquid dropletsproduced by the fog machine thanphotoelectric detectors, but would bemore likely to rapidly respond in thepresence of solid soot particles pro-duced by burning circuit boards.

Conclusion 5The incipient air detection system, in

the presence of wispy smoke produc-tion, did not respond as rapidly as theceiling and underfloor spot detectorsthat actuated during this research. Anexplanation for this is that the air aspirating analysis method is primarilylooking for particulate soot found inmost smoke samples. The alcohol/waterfog-produced by the smoke machine,especially at low fog production set-tings, may not be presenting a suffi-cient contrast for optimal evaluation ofthe air aspirating analyzer. It was alsodetermined that the air aspirating pipeinlet orifice sizes and location requiredadjustment and retesting, which wassubsequently performed.

Conclusion 6While the response of the photoelec-

tric smoke detectors at the air condi-tioning units and on the light trackswas impressive, spot detectors installedat these locations were not judged tobe cost-productive. Sufficient numbersof detectors at the bottoms of the ceil-ing structural tees actuated in the pres-ence of wispy stratified smoke to con-clude that detectors at these locationswill adequately respond without addi-tional detectors. Placement of detectorsat the light tracks is of questionablevalue if the smoke does not stratify. Airaspirating smoke detection is being rec-ommended in lieu of spot smokedetectors at the inlets to the air condi-tioning units.

Conclusion 7Airflow patterns, as measured during

this experiment and as shown onFigure 2, demonstrate a propensity forsmoke stratification at the light tracklevel, at low volumetric smoke produc-tion rates, as might be concluded fromevaluating the parabolic air velocityprofiles recorded.

Robert Gagnon is with GagnonEngineering. Tyler Mosman is with CCGConsultants.


By Andrew Bowman

Renovation projects in historicbuildings are routinely facedwith achieving the seemingly

incompatible goals of preserving his-toric architecture and complying withthe life safety provisions of modernbuilding codes. The challenge in thesesituations is to provide a solution thatcan meet the code-intended level ofsafety while minimizing the impact onthe historic fabric of the building.

This article describes a performance-based life safety analysis conducted byGage-Babcock & Associates at the Artsand Industries Building (AIB) on theNational Mall in Washington, DC. Thisarticle not only presents the technicalframework of the analysis but alsohighlights how renovations of historicbuildings can benefit from the use of aperformance-based approach in lieu ofcompliance with traditional prescriptiverequirements.

BACKGROUND

The Arts and Industries Building hadalmost become a forgotten treasureamong the Smithsonian Institution’s six-teen world-famous museums. Originallyconstructed in 1881 as the United States

National Museum, the facility has beenovershadowed by the more-acclaimedmembers of the Smithsonian familysuch as the National Air and SpaceMuseum, the National Museum ofNatural History, and the NationalMuseum of American History. Recently,significant effort has been devoted todetermine the feasibility of renovatingthis museum and restoring the interiorto its original historic appearance. Therenovation of the AIB, as proposed bythe design team headed by the PolshekTobey + Davis Joint Venture, involvesremoving infill areas that have beenadded throughout the years and return-ing the building to its original configu-ration, while providing the mechanical,electrical, telecommunication, and fireprotection systems required in modernbuildings.

PROJECT DESCRIPTION

The Smithsonian Institution, servingas the owner and reviewing authority,has adopted the 1999 edition of theBOCA National Building Code1 whileincorporating the 1997 edition of theLife Safety Code2 (LSC) in lieu of BOCAChapter 10. While not adopted at thetime of the analysis, the 2000 Edition3

of the LSC was used for guidance.

Additionally, given the building’s loca-tion on the National Mall and its his-toric designation, approval of plans bythe Fine Arts Commission and theNational Capital PreservationCommission (NCPC) was required.

The original interior configuration ofthe Arts and Industries Building can belikened to modern two-story retailmalls. The centers of the first and sec-ond floors are open with various occu-pancies such as offices, a daycare cen-ter, a gift shop, and a theater locatedon the outer perimeter. There is a net-work of balconies that serves the entiresecond floor. The majority of the openareas of the first and second floor willbe used as exhibit space. At the centerof the building is a large 80-foot-highrotunda. The first floor area is approxi-mately 95,000 ft2 (8,000 m2) while thesecond floor is approximately 35,000 ft2

(3,300 m2). The calculated occupantload for the building is approximately4,550 people, which is based on meth-ods from the LSC and is supported asthe worst-case scenario based on his-torical information and projections pro-vided by Smithsonian.

The AIB has several fire protectionfeatures that exceed minimum prescrip-tive code requirements. Smithsonianregulations require that all buildings

The Arts and Industries Building:A Case Study

PERFORMANCE-BASEDANALYSIS OF

AN HISTORIC MUSEUM


have complete automatic smoke detec-tion and sprinklers throughout.Complete smoke detection coverage isnot required for buildings such as theAIB by any of the model buildingcodes. Additionally, the Smithsonianrequires all of its automatic sprinklersystems be designed per NFPA 13Installation of Automatic SprinklerSystems4 with a design density ofOrdinary Hazard Group II, far exceed-ing the Light Hazard design density thatwould be required in office areas,which comprises a large portion of thefloor area of the second level. Thedesign density of Ordinary HazardGroup II is consistent with the expect-ed fuel loading in the exhibit spacesand the gift shop. The Smithsonian hasalso developed criteria which severelyrestrict the amount of combustiblematerials that may be used in the con-struction of its exhibits. This is coupledwith an exhaustive review and over-sight process by Smithsonian’s own fireprotection engineers to ensure compli-ance with Smithsonian regulations. Inaddition, the Arts and IndustriesBuilding has a security staff that istrained to assist in fire emergencies.The diligence of the Smithsonian inproviding proactive fire safety measurescontributes significantly to the overalllevel of life safety within their build-ings. When conducting a prescriptive-based design, these additional featuresare typically not considered whendetermining compliance.

HISTORIC CONSIDERATIONS

Since the scope of the projectinvolved a complete interior renova-tion, the AIB was expected to complywith current construction and designregulations that were not required dur-ing the original construction. As expect-ed with many renovation projects inhistoric buildings, several egress-relatedconcerns were identified. These con-cerns were related to one major archi-tectural feature. In the AIB, all of themain exits in the building are on thefirst floor of the two-story building. Thisled to prescriptive code deficiencies,such as extended travel distance(approximately 350 ft (110 m) from themost remote areas) and insufficientarrangement of exits (all of the second Photographs reproduced with permission from the Smithsonian Institute.


floor exit stairs discharge onto the firstfloor instead of at least half dischargingdirectly to the exterior). Since the interi-or and exterior of the building are his-toric and could not be altered withoutapproval of the Fine Arts Commissionand the NCPC, traditional solutionssuch as providing reconfigured exitswere not considered feasible. Thisprompted the desire for a performance-based analysis and design, since virtual-ly no architectural solution could satisfyexisting prescriptive code requirementsas well as the concerns of the Fine ArtsCommission and NCPC. The conflictingobjectives created by trying to balancehistoric preservation concerns with pre-scriptive code compliance necessitateda performance-oriented solution, thegoals of which were to preserve thehistoric integrity of the national land-mark building and provide an accept-able level of safety.

PERFORMANCE-BASEDAPPROACH

The approach used in developing theperformance-based fire and life safetyanalysis was based on the guidelinesidentified in the SFPE EngineeringGuide to Performance-Based FireProtection Analysis and Design of

Buildings5 and Chapter 5 of the 2000edition of the LSC. These documentsoutline a structured approach to pro-ceeding through a performance-basedanalysis. Key topics include definingproject scope, identifying goals, defin-ing stakeholder and design objectives,developing performance criteria, devel-oping design fire scenarios, and devel-oping and evaluating trial designs.

PROTECTION GOALS ANDPERFORMANCE OBJECTIVES

The main fire protection goaladdressed in the performance-based lifesafety analysis was that of minimizingfire-related injuries and preventingundue loss of life. This was selected inlieu of other potential goals such asproperty protection and business inter-ruption since only the means of egressdeviated from the code-prescribed mini-mum criteria.

From this fire protection goal evolvedthe design objectives. The design objec-tives were based upon examples foundin Table B-1 of the SFPE EngineeringGuide to Performance Based FireProtection Analysis and Design ofBuildings5 and are summarized as “pro-viding adequate time for those peoplenot intimate with the first materials

burning, those people outside the roomor compartment of fire origin, andthose people outside the floor of fireorigin to reach a place of safety withoutbeing overcome by the effects of fireand fire effluents.”

These performance objectives areevaluated through the use of fire andegress modeling. Fire modeling helpsto evaluate the interior environmentduring a fire for a wide range of sce-narios. Egress modeling is used todetermine a range of times in which itis expected that the entire building canbe reasonably evacuated. The results ofthese two models are then compared todetermine if at any time the paths ofegress are considered untenable. This isaccomplished by comparing the pre-dicted conditions to predeterminedthreshold levels for criteria such as tem-perature, carbon monoxide, and visibili-ty. This comparison is then used toassess whether or not the performanceobjectives have been met.

SELECTION OF THE FIRE MODEL

The fire model used for the analysis,Fire Dynamics Simulator6 (FDS) version1.0, represents a significant advance-ment in modeling the effects of fire incomplex buildings such as the AIB.FDS, developed by the NationalInstitute of Standards and Technology(NIST), is a field model capable ofdescribing the transport of mass,momentum, and energy from fire-induced flows across hundreds of thou-sands of separate volumes within abuilding. Because of this capability, thetechnical output of the model is wellsuited for complex buildings. The abili-ty to monitor and record values forimportant fire phenomena at specificlocations throughout the building is animportant capability when conducting acomplex performance-based analysis.Besides the extensive technical capabili-ties, FDS includes extremely usefulvisual output. The visual outputincludes a three-dimensional viewingprogram that illustrates the geometry ofthe building as well as providing a real-time visual representation of fire phe-nomena. Given the complex nature ofthe AIB, the ability to visually verify theinterior geometry and the resulting fire-growth phenomena is essential in com-

Figure 1. FDS modeling of a fire.


municating the results. These factorsled to the selection of a field modelover a zone model. Zone models, whilepossessing a wide range of capabilities,did not appear to provide sufficientlevel of detail on the effects of fire(temperature, carbon monoxide, andvisibility) given the large-volume natureand extremely complex geometry ofthe AIB. The hot upper layer and coldlower layer approach of zone modelsdid not provide the level of detail nec-essary to monitor various conditions onbalconies and other egress pathsthroughout the building.

EGRESS MODELING

In analyses where life safety is evalu-ated, determining how much time isnecessary to evacuate the occupants isessential. One method for predictingevacuation times is through the use ofa computer-based egress model. Theegress model used for this analysis,EVACNET47, is an hydraulic flow-typemodel requiring specification of initialoccupant loads, occupant locations,speed of travel, available egress width,and flow characteristics. EVACNET4assumes that individuals inside thebuilding take the most direct route outof the building. Since this approach isnot initially conservative, the selectedinput parameters for the AIB analysiswere chosen to reflect nonideal condi-tions. These input parameters includedincreased occupant loading (abovewhat is expected), reduced travelspeed, increased travel distance,reduced exits available (assuming thatthe largest exit is blocked), delayed ini-tiation of egress, and neglecting conve-nience stairs, that while likely to beused, are not part of the requiredmeans of egress. A fifty percent factorof safety was applied to the calculatedresults to reflect uncertainty in themodel. An additional three minutes wasfactored in to account for detectiontime and the inevitable time delaybetween the first fire alarm and whenpeople actually start to evacuate. Thethree minutes was a combination ofcalculated smoke detector activationtime along with assumptions about typ-ical egress initiation delays. Results ofthe modeling were then compared withthreshold values for toxicity and tem-

perature determined as part of the per-formance criteria.

PERFORMANCE CRITERIA ANDTHRESHOLD VALUES

The SFPE Engineering Guide toPerformance-Based Fire ProtectionAnalysis and Design of Buildings5

defines performance criteria as “criteriastated in engineering terms with whichthe adequacy of any developed trialdesigns will be judged.” This definitionis further clarified as “threshold values,ranges of threshold values, or distribu-tions that are used to develop and eval-uate trial designs for a given designsolution. Performance criteria mightinclude temperatures of materials, gastemperatures, smoke concentration orobscuration levels, carboxyhemoglobin(COHb) levels, and radiant flux levels.”Selection of performance criteria fromwhich to judge the results of the modelis one of the most challenging aspectsof a comprehensive analysis.

Three performance criteria (tempera-ture, carbon monoxide concentration,and visibility) were evaluated in theAIB analysis and are included in TablesA, B, and C. For many analyses, selec-tion of threshold values is difficultgiven the wide range of available dataand the even wider range of humanresponse to the various criteria. Thismakes selecting conservative valuesimperative. The threshold criteria in thisanalysis were determined by the calcu-lation procedures in the SFPEHandbook of Fire ProtectionEngineering8. The thermal tenability forthis analysis was determined by calcu-lating the temperature in which an indi-vidual could withstand exposure forthirty minutes. The time period of thirty

minutes conservatively correlates to themaximum calculated length of time anoccupant would take to exit the build-ing. However, for the analysis, if thiscalculated temperature was exceededfor any length of time (as opposed tothirty minutes) in an area, the area wasconsidered untenable. The samemethod was used for determining thethreshold level for carbon monoxide.The threshold level of visibility wasdetermined to be 10 meters as support-ed in Section 2, Chapter 8 of the SFPEHandbook. The threshold values werethen compared to the results obtainedby placing simulated “thermocouples”throughout the building to monitortemperature, carbon monoxide, andvisibility. This highlights one of theadvantages of field models over zonemodels since zone models would notprovide the flexibility to monitor sepa-rate points throughout a space with thesame level of detail.

DESIGN FIRE SELECTION

Selection of appropriate design firescenarios is a significant challenge inpreparing a performance-based analy-sis. However, the 2000 Edition of theLife Safety Code provides a series of

Table A – Representative Temperature Results for a Design Fire Scenario*

Egress Path Second Floor First Floor Rotunda Exit 1 Exit 2 Exit 3Locations Balcony Exhibit

Space

Time at which last 14.8 20.8 13.5 21.5 21.8 20.9person has evacuatedthe area **(minutes)

Threshold 65 °C 65 °C 65 °C 65 °C 65 °C 65 °CTemperature

Calculated 32.0 °C 36.7 °C 30.5 °C 31.0 °C 35.9 °C 35.5 °CTemperature***


eight design fire scenarios that must beaddressed. Exceptions are made forscenarios that are demonstrated to beinappropriate for the building use andconditions. Using this approach, therequired design fire scenarios wereagreed upon and several other designfire scenarios added. While all eightdesign fire scenarios were evaluated,particular consideration was paid tothose fire scenarios addressing exhibitsin the open exhibition areas. This wasbased on preliminary calculationsinvolving expected fuel loading, occu-pant density, sprinkler effectiveness,complete smoke detection coverage,and fire-rated separations between theexhibit halls and all surrounding areas.The next step, selection of fire charac-teristics, was based upon not only theexpected fuel loading but also tookinto account several Smithsonian safety

measures that are specifically aimed atlimiting the combustible materials usedto construct exhibits. These measurescontribute to a reduced fuel size whilealso impacting how rapidly the fire willextend beyond the area of ignition.Proactive fire safety measures are espe-cially helpful in potentially high fueldensity occupancies such as museums.While not typical of most buildings,these measures were a significant partof the design fire scenario selection forthis performance-based analysis.

Each design fire consisted of multiplefuel packages that were arranged tosimulate fire spread through an exhibitspace. The fire growth curve used todescribe a single fuel package was thatof a large upholstered sofa with a maxi-mum heat release rate of approximately3.1 MW. Based upon the expected fuelloading, the number of fuel packages

for a given design fire was varied.Therefore, the overall heat release ratefor each of the design fires differedbased upon the expected fuel loading.For a majority of cases, the effect ofsprinkler control was evaluated. Severalfire growth curves were used to deter-mine the worst case fire size at the timeof sprinkler activation. The heat releaserate was then maintained at that levelfor the course of the simulation. Thisresulted, for some scenarios, in firesizes of approximately 4.8 MW for thelength of the simulation.

CONSERVATIVE ASSUMPTIONS

Conservative assumptions play a sig-nificant role in performance-basedanalyses since the characteristics of firein an enclosure are reliant upon manyindeterminate variables. One use ofconservative assumptions is to fill gapsin the available data or technologyused in the analysis. Another use is tohelp streamline the analysis by utilizingconservative assumptions for marginallyimportant criteria that would not have adramatic impact on the results, butcould significantly increase the com-plexity of the analysis. A third role ofconservative assumptions is to narrowthe infinite number of possible designfire scenarios down to a manageablenumber. For the AIB performance-based analysis, conservative assump-tions for variables such as sprinklereffectiveness, performance criteria,detection time, fuel loading, fire depart-ment response, occupant loading,egress characteristics, and other perti-nent factors fulfilled all three roles.

RESULTS

The results demonstrated that at nopoint during the necessary evacuationtime was the threshold criteria for tem-perature, carbon monoxide concentra-tion, or visibility reached. These resultswere obtained using conservativeranges for the design fires, occupantloading, egress characteristics, and per-formance criteria. The results wereespecially favorable given the extent ofthe conservative assumptions.

Based upon the results of the analysisand the overall design philosophy, sever-al fire protection and life safety features

* This design fire scenario assumes one of the four exits is blocked with a maximum heat release rateof approximately 7.5 MW.

** Represents time from ignition, which includes expected delay in detection of fire, delay until evacua-tion begins, and 50% safety factor.

***Highest recorded value at several points in each location.

Table C – Representative Visibility Results for a Design Fire Scenario*


Space


Threshold 10 meters 10 meters 10 meters 10 meters 10 meters 10 metersVisibility

Calculated 70 meters 95 meters 120 meters 94 meters 92 meters 90 metersVisibility***

Table B – Representative Carbon Monoxide Results for a Design Fire Scenario*


Space


Threshold Carbon 950 ppm 950 ppm 950 ppm 950 ppm 950 ppm 950 ppmMonoxide Concentration

Calculated Carbon 127 ppm 106 ppm 100 ppm 100 ppm 106 ppm 103 ppmMonoxide Concentration***


were recommended to be provided orimproved. These included quick-response sprinklers throughout the build-ing, passive fire protection separatingoccupancies and some egress routesfrom the exhibit areas, six new code-compliant stairs from the second floor inaddition to the four existing monumentalstairs, and recommendations and guide-lines to limit the extent of fuel loading inan individual exhibit area. Even thoughstairs discharging directly to the exteriorwere not part of the design recommen-dations, protection of existing internalstairs in the remote corners of the build-ings was recommended to facilitate safertravel from the upper level to the lowerlevel for those occupants with the great-est required travel distance.

Tables A, B, and C provide a repre-sentative summary of the results fromthe fire and egress modeling in com-parison to the predetermined thresholdcriteria. The results outline the calculat-ed temperature and carbon monoxideconcentrations as well as visibility for aspecific area at the time when it isexpected that the last occupant has leftthat location. As an example, the resultsof the egress model, along with the fac-tors of safety, indicate that the last per-son will have left the rotunda approxi-mately 13.5 minutes after the fire starts.At that time, the calculated temperatureand carbon monoxide concentrationare 47% and 11% of the predeterminedthreshold, respectively. Visibility isapproximately 113 meters.

CONCLUSIONS

Renovations in historic buildingshave traditionally produced fire and lifesafety challenges, since the originalarchitecture of the building was notintended to comply with modern-daybuilding codes. However, as renova-tions of these historic buildings occur,there is a need to provide a high levelof life safety while preserving the his-toric construction. The emergence ofperformance-based codes and analyticaltools such as advanced fire modelingprovides a means for identifyingacceptable solutions. The application ofa performance-based approach canidentify where modifications are neces-sary for life safety, while helping toensure that the impact on historic archi-

tecture is minimized. As demonstratedby the results of the analysis, historicstructures such as the Arts andIndustries Building can benefit greatlyfrom performance-based codes.Compliance with prescriptive criteriawritten and intended for modern build-ings with little regard for important his-toric architecture is no longer the soleoption available for the fire protectionengineer.

Andrew Bowman is with Gage-Babcock and Associates, Inc.

REFERENCES:

1 The BOCA National Building Code,Building Officials and CodeAdministrators International, Country ClubHills, IL, 1996.

2 NFPA 101, Life Safety Code, National FireProtection Association, Quincy, MA, 1997.

3 NFPA 101, Life Safety Code, National FireProtection Association, Quincy, MA, 2000.

4 NFPA 13, Installation of AutomaticSprinkler Systems, National Fire ProtectionAssociation, Quincy, MA, 1999.

5 The SFPE Engineering Guide toPerformance-Based Fire ProtectionAnalysis and Design of Buildings, Societyof Fire Protection Engineers, Bethesda,MD, 2000.

6 Fire Dynamics Simulator Users’ Guide,National Institute for Standards andTechnology, Gaithersburg, MD, 2000.

7 Kisko, T. M., Francis, R. L., and Nobel, C.R., EVACNET4 Users’ Guide, University ofFlorida, Gainesville, FL, 1998.

8 Purser, D., “Toxicity Assessment ofCombustion Products,” The SFPEHandbook of Fire Protection Engineering,2nd Edition, National Fire ProtectionAssociation, Quincy, MA, 1995.

Fire protection engineering is a growing profession with many challenging career opportunities. Contact the Society of Fire Protection Engineers at www.SFPE.org or the organizations below for more information.


Explore your full potential! Come join the team at TVA Fire & Life Safety, Inc. – a growing international fire protection engi-

neering/consulting firm headquartered in San Diego, CA, w/officesin CA, MI, GA, NJ, and TX.

Qualified individuals are Registered PEs with 3+ yrs. exp., in-depthknowledge of Model Codes and NFPA stds., and excellent communi-cation/interpersonal skills. Duties include, but are not limited to:• Preparing studies of industrial, commercial, and other properties considering

factors such as fire resistance, usage or contents of buildings, water suppliesand delivery, and egress facilities.

• Designing or recommending materials/equipment such as structural componentsprotection, fire detection equipment, alarm systems, extinguishing devices and systems, and advising on location, handling, installation, and maintenance.

• Consulting with customers to define needs and/or issues and gathering informa-tion to determine the scope of work.

• Conducting meetings with fire and building officials to discuss upcoming and existing projects and answering any questions that may arise.

• Advising customers on alternate methods or recommending specific solutions tosolve problems that may arise.

• Conducting job site inspections, preparing and providing a technical report of findings to customers and/or AHJs.

Enjoy a competitive salary, medical/dental benefits, profit-sharing,401(k), and company stock purchase plan. (EOE) Send your résumé to: HR Department, TVA Fire & Life Safety, Inc.

2820 Camino del Rio South, Suite 200 San Diego, CA 92108Fax: 619.296.5656 E-mail: [email protected]

Arup Fire has immediate openings for fire protection engineers inNew York. Successful candidates will play a very active role in

developing the practice in the USA and will work closely with manyof the world’s leading architects and building owners developinginnovative design solutions for a wide range of building, industrial,and transport projects.

Candidates should possess a Fire Protection Engineering degree,approximately five years of experience, and preferably an FPE – PE.Risk management, industrial fire engineering, and computer model-ing skills will be highly regarded.

Similar opportunities available in London, Leeds, Dublin, HongKong, and Australia, with opportunities available in Boston, SanFrancisco, and Los Angeles in the near future.

Arup Fire offers competitive salaries and benefit packages. Pleasesubmit résumé and salary history to:

Chris Marrion, PEArup Fire Ove Arup & Partners 155 Avenue of the AmericasNew York, NY 10013Telephone: +1.212.896.3269Fax: +1.212.229.1986E-mail: [email protected]

EQUAL OPPORTUNITY EMPLOYER

Harrington Group, Inc., is focused on continuous, profitable growthand currently has openings in Atlanta for fire protection engineers.

For full details on current job openings, please visit our Web site atwww.hgi-fire.com or submit your résumé via e-mail or fax to:

Ms. Patsy Sweeney [email protected] Fax: 770.564.3509 Phone: 770.564.3505

Harrington Group is a full-service fire protection engineering designand consulting firm. Founded in 1986, Harrington Group has con-sistently provided a high level of quality and value to clientsthroughout North America, South America, and Germany.

Should you be interested in us? YES! If:

• You want a career with increasing responsibility and compensation.• You care about quality and service delivered to the client.• You have strong engineering skills and people skills.• You are creative and desire to use your creativity.• You are honest and hard-working.• You want to be trusted and respected by your company.• You want to participate in the financial aspects of your company – like owners do.• You are in a dead-end where you are now.

Check us out, and discover whatmakes Harrington Group such anexcellent career opportunity.

Fire ProtectionEngineers






As the global leader in fire protection, security, and life safety solutions, Rolf Jensen & Associates, Inc., is always looking for

talented, dynamic individuals. Opportunities exist throughout oureleven offices for engineering and design professionals looking forgrowth. We are looking for engineers with experience in fire alarm,sprinkler, and security design; code analysis; and business develop-ment.

Check out our Web site at www.rjagroup.com for more details. Send your résumé to:

Ralph Transue, PEThe RJA Group, Inc.549 W. Randolph St., 5th FloorChicago, IL 60661

RJA EmploymentOpportunities

RJA EmploymentOpportunities


Founded in 1973, Code Consultants, Inc. (CCI), is a nationally recog-nized fire protection engineering firm providing professional con-

sulting and design services to developers, owners, architects, and othersignificant clients throughout the United States. With a staff of 55, CCIis a dynamic, growing firm that has an unmatched reputation fordeveloping innovative fire protection and life safety solutions, codecompliance guidance, and cost-effective designs which are equallywell received by clients and governing officials. CCI’s projects includesome of the nation’s largest shopping malls, retail stores, stadiums andarenas, hospitals, convention centers, detention/correctional facilities,transportation (air and rail) facilities, warehouses, and theaters for theperforming arts, to name a few.

The firm is seeking degreed fire protection engineers and otherdegreed individuals with a high level of experience applying ModelCodes and NFPA standards to service clients and projects throughoutthe country.

These positions offer a unique income opportunity, including partici-pation in CCI’s lucrative performance incentive program. The positionrequires residency in the St. Louis area.

Code Consultants, Inc.1804 Borman Circle Dr.St. Louis, MO 63146314.991.2633

Koffel Associates, Inc., is a fire protection engineering and codeconsulting firm with offices in Connecticut, Maryland, and

Tennessee that provides services internationally. Positions are avail-able at the following levels:

Senior Fire Protection EngineerRegistered Fire Protection EngineerFire Protection Engineers (BS or MS in FPE)Fire Protection Engineering Technician (AutoCAD experience,

NICET, or technology degree desirable)

Responsibilities may include:• Fire protection engineering and life safety surveys• Design and analysis of fire protection systems including automatic sprin-

klers, clean agent, fire alarm and detection, water supply, and smoke man-agement systems

• Code consultation with architects, engineers, developers, and owners during design and construction

• Post-fire analysis and investigation• Computer fire modeling• Fire risk and hazard assessments• Codes and standards development

Koffel Associates, Inc., personnel actively participate in the activitiesof professional engineering organizations and the codes and stan-dards writing organizations. The firm offers a competitive salary andbenefits package including conducting its own in-house professionaldevelopment conference for all employees.





Established in 1939, Schirmer Engineering was the first independent fireprotection engineering firm to assist insurance companies in analyzing

and minimizing risk to life and property. Since then, Schirmer Engineeringhas been a leader in the evolution of the industry, innovating for tomor-row with science and technology; using insight from tradition and experi-ences of our past. Today, Schirmer Engineering, with a staff of 180employees, is synonymous with providing high-quality engineering andtechnical services to both national and international clients.

Career growth opportunities are currently available for entry-level andsenior-level fire protection engineers, design professionals, and codeconsultants. Opportunities available in the Chicago, San Francisco, SanDiego, Los Angeles, Dallas, Las Vegas, Washington, DC, and Miamiareas. Our firm offers a competitive salary and benefits package,including 401(k). EOE.

Send résumé to:

G. JohnsonSchirmer Engineering Corporation707 Lake Cook Rd.Deerfield, IL 60015-4997

Fax: 847.272.2365e-mail: [email protected]





OPPORTUNITY • CHALLENGE • RECOGNITIONThe Choice is Yours at AHA Consulting Engineers

OPPORTUNITY At AHA over 120 professionals work collaborativelyon a wide variety of MEP/FP assignments including healthcare, biotech,institutional and corporate projects.

CHALLENGE Our high energy atmosphere gives experienced engi-neers, designers and drafters first-hand opportunities to test the limits oftheir knowledge.

RECOGNITION AHA employees work hard. Our benefits packagerewards that effort. We offer competitive salary, comprehensive medical& dental insurance, 401k, tuition reimbursement and flexible hours, justto name a few.

We are seeking Fire Protection Project Engineers & Designers. Workingknowledge of fire protection systems including production of drawings,specifications, hydraulic calculations, survey reports, inspection services,reviews of contractor submittals and general code consulting. CAD 12or higher needed. F.E. with ability to become registered preferred. Priorhealthcare, biotech, institutional or corporate experience a plus.

Send your resume to:Michael Joanis, PEFire Protection Department ManagerAHA Consulting Engineers10 Maguire Road, Suite 310Lexington, MA 02421Fax: 781.372.3100e-mail: [email protected]

EOE

This two-hour seminar will lead par-

ticipants through a detailed review

of the new SFPE Engineering Guide

to Performance-Based Fire Protection

Analysis and Design of Buildings. Oriented

toward the allied professional, it will feature presentations on each section of

the guide, including: definition of project scope, setting project objectives,

developing performance criteria, selecting design fire scenarios, developing trial

designs, probabilistic and deterministic analysis methods, and creating project

documentation. The role of the Guide in the fire safety design process and

examples of its application will also be presented. October 25, 2-4 p.m. EST.

Equip yourself fortomorrow’s performance-based designenvironment with publications andtraining from SFPE.Contact SFPE at [email protected].

Performance-Based DesignAudiotape

An introduction to the most dynamic new design approach in fire

protection today. Focuses on what performance-based design is and how

it differs from prescriptive-design methods. Outlines the process and

benefits of PBD as well as the qualifications for a PBD professional.

Convenient audiocassette program together with an illustrated wall chart

of the PBD process. $44.00

Performance-

Based Design

Online Seminar:


Fire Sprinkler Systems Industry

BFGoodrich seeks a sales professionalfrom within the fire protection industryfor the NORTHWEST U.S.A. territory.Candidates must have a demonstratedability to promote products by callingon fire sprinkler contractors, AHJs,specifying engineers, the fire servicecommunity and builders/developerscreating awareness and developingprimary demand for BlazeMaster®CPVC Fire Sprinkler Systems.

Candidates should have a collegedegree, 3+ years experience in the fireprotection industry with experience infire sprinkler contracting a plus.Extensive travel required.

We offer a competitive salary, incen-tive package, benefits plan, and com-pany car. Please send resume in strictconfidence to:

Gary Johnson, BFGoodrich, 11 Randolph Avenue,

Cape Charles, VA 23310. An Equal Opportunity Employer.

SALES PROFESSIONAL

Introduction to Performance-Based Fire Safety,by Richard L. P. Custer & Brian J. Meacham, 1997. This 11-chapter illus-trated book presents the basic concepts of performance-based fire safetyengineering and includes chapters on design vs. codes, fire dynamics andmodeling, hazard analysis and risk assessment, performance criteria,human factors, and a case study illustrating the process. 260 pages $74.25


The F.P. Connection

An electronic, full-service fire protection resource Web site.

The F.P. Connection offers posting of employment opportunitiesand résumés of fire protection professionals. If, as a fire protec-

tion service provider or equipment manufacturer, your Web site is dif-ficult to locate using search engines and keywords, let us post yourbanner and provide a direct link for use by our visitors who mayrequire your services.

Please visit us at www.fpconnect.com or call 724.746.8855.

For posting information, e-mail [email protected].

Fax: 724.746.8856

The F.P. Connection

SFPE

AN INVITATION TO JOINBENEFITS OF MEMBERSHIP

• Recognition of your professional qualifications by your peers •• Chapter membership •

• Fire Protection Engineering magazine •• SFPE Today, a bi-monthly newsletter •

• The peer-reviewed Journal of Fire Protection Engineering •• Professional Liability and Group Insurance Plans •• Short Courses, Symposia, Tutorials & Seminars •

• Representation with international and U.S.A. engineering communities •

Ask for our membership applicationSociety of Fire Protection Engineers

7315 Wisconsin Avenue, Suite 1225W • Bethesda, MD 20814

301-718-2910www.sfpe.org [email protected]

Society of Fire Protection EngineersA growing association of professionals involved in advancing the

science and practice of fire protection engineering

Engineering Guide to Performance-Based FireProtection Analysis and Design of Buildings, by the SFPE Task Group on Performance-Based Analysis and Design,2000. This guide outlines a process for carrying out these designs and isessential for anyone who will apply, approve, or be affected by perfor-mance-based codes and standards. Chapters cover such topics as defin-ing your project scope and identifying goals; specifying stakeholders anddesign objectives; developing performance criteria; creating design firescenarios and trial designs; evaluating trial designs; and documentationand specifications. Equip yourself for the coming era of performance-based codes with this unique guide!

SFPE/NFPA Member Price: $46.75 Nonmember Price: $52.00

Working withCode Officials inPerformance-Based Design –extended abstracts fromthe 1998 SFPE EngineeringSeminars – contains theAHJ and fire protectionengineer perspectives onseveral recent case studiesof performance-baseddesign. 79 pages $35.00

BRAIN TEASER

Solution to last issue’s Brainteaser

A grocer purchased 100 kg of potatoes. When they were purchased,the moisture content of the potatoes was 99.0%. Prior to selling thepotatoes, the grocer checked the moisture content of the potatoes and determined that it was now 98.0%. How many kilograms of potatoes did the grocer now have to sell?

The following equation can be used to express the mass of the potatoes as a function of water and dry potato mass:

mt =mdp + mw

Since mt = 100 kg and mw = 0.99mt, the dry potato mass, mdp, is 1 kg.When the moisture content drops to 98%, mw = 0.98mt. Substituting,

mt = 1kg + 0.98mt

Solving for mt, the grocer now has 50 kg of potatoes.

• Ansul .....................................................Page 13

• BF Goodrich.........................................Page 31

• Central Sprinkler ..................................Page 46

• Chemguard ...........................................Page 49

• Edward Systems ...........................Page 26 - 27

• Fenwal Protection

Systems ............................Inside Back Cover

• Fike Protection Systems.......................Page 51

• Grinnell Fire Protection Systems.........Page 17

• Grinnell Supply Sales & Marketing ....................................Back Cover

• Koffel Associates ....................................Page 5

• Master Control Systems........................Page 39

• NOTIFIER Fire Systems ............Page 2 and 35

• Protection Knowledge Concepts.........Page 10

• Protectowire .........................................Page 24

• The RJA Group ...................Inside Front Cover

• Reliable Automatic Sprinkler...............Page 21

• Simplex ...................................................Page 9

• TVA Fire & Life Safety, Inc. .................

• Viking Corporation ..............................Page 23

• Wheelock, Inc. .....................................Page 18

• Worcester Polytechnic Institute (WPI) ..Page 40

Index of Advertisers

ADT, Inc.Arup Fire Automatic Fire Alarm AssociationBFPE InternationalBourgeois & Associates, Inc.Central Sprinkler Corp.The Code Consortium, Inc.Code Consultants, Inc.Copper Development AssociationDemers Associates, Inc.Draka USADuke Engineering and ServicesEdwards Systems TechnologyFactory Mutual Research Corp.Fike CorporationFire Consulting Associates, Inc.Fire Suppression Systems AssociationGage-Babcock & Associates, Inc.Grinnell IncorporatedHarrington Group, Inc.HSB Professional Loss ControlHubbell Industrial ControlsHughes Associates, Inc.Industrial Risk InsurersJames W. Nolan Company (emeritus)Joslyn Clark Controls, Inc.Koffel Associates, Inc.

Marsh Risk ConsultingMountainStar EnterprisesNational Electrical Manufacturers AssociationNational Fire Protection AssociationNational Fire Sprinkler AssociationNuclear Energy InstitutePoole Fire Protection Engineering, Inc.The Protectowire Co., Inc.The Reliable Automatic Sprinkler Co., Inc.Reliable Fire Equipment CompanyRisk Technologies, LLCRolf Jensen & AssociatesSafeway, Inc.Schirmer Engineering CorporationSiemens, Cerberus DivisionSimplex Time Recorder CompanyS.S. Dannaway Associates, Inc.Starwood Hotels and ResortsTVA Fire and Life Safety, Inc.Tyco Laboratories Asia Pacific Pty., Ltd.Underwriters Laboratories, Inc.Vanderweil EngineersVan Rickley & AssociatesVision Systems, Inc.Wheelock, Inc.W.R. Grace Company

C O R P O R AT E 1 0 0 The SFPE Corporate 100 Programwas founded in 1976 to strengthen the relationship between industry and thefire protection engineering community. Membership in the program recog-nizes those who support the objectives of SFPE and have a genuine concernfor the safety of life and property from fire.


A wire loop is constructed withenough wire so that the loop justtouches the top of Mt. Everest whenthe loop’s center coincides with that ofthe earth’s center (i.e., it wraps all theway around the earth). You are placedat the top of Everest and asked to cutthe wire and insert a 10-meter section.

Assuming that the radius of the loopis 20,000 km, how far above the top ofthe mountain will this large wire looprise?

Thanks to Derrick M. Tjernlund, P.E.,for providing this issue’s brainteaser.

Unlike in other countries, where pro-fessional registration is typically man-aged nationally, licensure in the UnitedStates is on a state-by-state basis (aswith the article on page 14, the term“state” is used broadly here). For engi-neers who practice in many states, thisrequires that they become licensed ineach state. Fortunately, states usuallyallow comity of licensure, which meansthat someone who is licensed in onestate can become licensed in other stateswithout going through the same processas someone who is not licensed at all.

However, there are differencesbetween how states license engineers.For example, some states may differ asto the number of years of experiencethat they require before consideringsomeone eligible for professional regis-tration, or may allow for a (large) num-ber of years of experience to substitutefor successful completion of the P.E.exam.

In California, registered engineers fallinto two categories: “practice” and “title.”“Practice” engineers are the only engi-neers that may perform engineering incertain disciplines. In California, the onlyengineering disciplines that are classifiedas “practice” are civil (including the sub-specialties of structural and geotechnical),mechanical, and electrical. Therefore, thepractice of engineering within these disci-plines is limited by regulation to engi-neers registered within those disciplines.

Other engineering disciplines areclassified as “title.” Regulations inCalifornia only allow people who areregistered in one of the title disciplinesto use the title of that discipline. Sincefire protection engineering is a “title”discipline in California, only peoplewho are registered in fire protectionengineering may call themselves “fireprotection engineers.”

Therefore, unlike civil, mechanical, orelectrical engineering, engineers of otherdisciplines are not strictly forbiddenfrom practicing fire protection engineer-ing. However, as a matter of profession-al ethics and regulations in California,engineers may only practice in areas inwhich they are competent by education,

training, and experience.The California state legislature is

presently reviewing the laws that governthe regulation of engineering. Changesthat are presently being consideredinclude:

• Creating definition in state statutorylaw for “mechanical engineering”and “electrical engineering.”

• Evaluating which engineering disci-plines currently classified as a “TitleEngineer” should be changed to a“Practice,” retained or eliminated.

Obviously, changes in both of theseareas could impact the fire protectionengineering profession. A definition of“mechanical engineering” could be creat-ed that would include smoke control orfire suppression system design. Similarly,electrical engineering could be definedto include fire alarm system design.

In fact, early definitions that were pro-posed could have been interpreted toinclude these fire protection engineeringfunctions. Since the practice of mechani-cal and electrical engineering is limited toengineers registered in those disciplines,the effects on public safety could havebeen adverse. Fire protection engineershave the greatest knowledge and experi-ence in the design of smoke control, firesuppression, and alarm systems, and theycould have been prohibited from prepar-ing designs of these systems.

Fortunately, the proposed definitionsfor “mechanical engineering” and “elec-trical engineering” have been revised,which will not affect the licensed FPE’sdesign of fire protection systems.Additionally, a study has been commis-sioned to “determine whether certaintitle acts should be eliminated or con-verted to practice acts...”. While this lan-guage sounds ominous because of theword “eliminated,” this will create anopportunity for fire protection engineer-ing to receive increased recognition.

The favorable outcomes to date in thechanges described above are due to theactivism of several SFPE volunteers andthe California Legislative Council forProfessional Engineers. TimothyCallahan, P.E., deserves special recogni-tion among this group.

Professional Licensure in California

from the technical director

Morgan J. Hurley, P.E.Technical DirectorSociety of Fire Protection Engineers


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