FIRE PROTECTION · 2018-04-02 · fire protection performance metrics for fire detection psychological variables that may affect fire alarm design underwriters laboratories contributions

FIRE PROTECTIONFIRE PROTECTION

PERFORMANCE METRICSFOR FIRE DETECTION

PSYCHOLOGICAL VARIABLES THAT MAYAFFECT FIRE ALARMDESIGN

UNDERWRITERS LABORATORIES CONTRIBUTIONS FOR FIRE ALARM SYSTEMS

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33

PROVIDING PRACTICE-ORIENTED INFORMATION TO FPEs AND ALL IED PROFESSIONALS

SUMMER 2001 Issue No. 11

ALSO:

INTEGRATING FIREALARM SYSTEMS WITHBUILDING AUTOMATIONAND CONTROL SYSTEMS

5

IntelligentFire Detection

IntelligentFire Detection

page 15

21

Fire Protection Engineering 1

3 VIEWPOINTAn Added Level of SafetyBrad Keyes, Safety Manager, Rockford Health System

5 INTEGRATING FIRE ALARM SYSTEMS WITH BUILDINGAUTOMATION AND CONTROL SYSTEMSThe popularity of BACnet systems are growing around the world and are wellsuited for integrating fire alarm systems with building automation systems.Steven T. Bushby

21 PERFORMANCE METRICS FOR FIRE DETECTIONMore progress is needed toward credible metrics for accurately predicting theperformance of heat and smoke detectors.John M. Cholin, P.E., and Chris Marrion, P.E.

33 UNDERWRITERS LABORATORIES CONTRIBUTIONS FOR FIREALARM SYSTEMSThis article describes the certification activity performed by UnderwritersLaboratories that contributes to the predictable operation of a fire alarm system.John L. Parssinen, P.E., Paul E. Patty, P.E., and Larry Shudak, P.E.

42 PSYCHOLOGICAL VARIABLES THAT MAY AFFECT FIREALARM DESIGNThere are a number of behavioral and psychological principles that, whenidentified, enable fire protection engineers to more effectively design, specify,and install fire alarm systems.Dr. John. L. Bryan

50 CAREERS/CLASSIFIEDS

52 SFPE RESOURCES

56 FROM THE TECHNICAL DIRECTORA Responsibility to OurselvesMorgan J. Hurley, P.E.

Cover: Bill Frymire/Masterfile

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contents S U M M E R 2 0 0 1

15COVER STORYINTELLIGENT FIRE ALARM SYSTEMSUnwanted fire alarms can seriously undermine the effectiveness of installedalarm systems, pressing the need for more intelligent alarm systems.Jeffrey S. Tubbs, P.E.

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Copyright © 2001, 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 Board

Carl F. Baldassarra, P.E., Schirmer Engineering Corporation

Don Bathurst, P.E.

Russell P. Fleming, P.E., National Fire Sprinkler Association

Douglas P. Forsman, Firescope Mid-America

Morgan J. Hurley, P.E., Society of Fire Protection Engineers

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

Jane I. Lataille, P.E.

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 Building Officials

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COVER DESIGN

Dave Bosak, Custom Media Group, Penton Media, Inc.

By Brad Keyes

Rockford Memorial Hospital islocated in Rockford, Illinois, andserves northern Illinois and

southern Wisconsin with a 50,000 m2

(500,000 ft2), 490-bed facility. Likemany hospitals, the campus has beenbuilt incrementally over a number ofyears with the earliest portion con-structed in 1951. Along with majorbuilding additions, numerous internalremodelings have taken place to meetthe changing needs of healthcare. Eachchange and addition was designed andbuilt to meet the requirements ofbuildings and life safety codes in forceat the time. Over the years the codeshave evolved, and as a result, RockfordMemorial has tried to keep currentwith these changing requirements.

In July of 1993, a Health CareFinancing Administration (HCFA) surveyfound numerous deficiencies with vari-ous aspects of the building’s life safetyfeatures. At the time, the fire detectionsystem included a combination of firealarm panels, which were located inthree different areas of the hospital.While the hospital had a working manual fire alarm system, the level ofsmoke detection was not consistent.One wing had detection in rooms,while another had detection only in thehallways; other areas had no detectionat all. After the HCFA survey, a FireSafety Evaluation Survey (FSES) wasconducted to evaluate the existing firesafety features. As a result, it was decid-ed to install a new automatic fire detec-tion system to gain additional points onthe FSES for smoke detection in corri-dors and habitable spaces in the entirefacility. Along with the addition of anew fire alarm system, it was alsodecided to complete the installation ofthe water-based sprinkler system for theentire facility. This would provide addi-tional points on the FSES and grant thehospital exceptions to certain coderequirements.

These two major projects begansimultaneously in December of 1993

and had to be completed by March1995. This did not allow much time todesign, implement, and commissioneach phase of the project. After consid-ering several options, the hospitalchose a fire alarm system which incor-porated the latest generation of equip-ment available on the market.

For construction purposes, the build-ing was divided into workable sections,by nursing units or department.Cooperation between staff and contrac-tors was extraordinary. As each unitwas completed, the systems were acti-vated and placed into operation. Thiscreated challenges in keeping recordsand documents current, as work pro-gressed rapidly. At times, there were sixdifferent crews installing sprinklers andthree different crews installing the firealarm system.

In February 1999, the HCFA visitedRockford Memorial for another valida-tion survey. The survey revealed incon-sistencies with testing and recordkeep-ing procedures. For example, the firealarm service contractor was inconsis-tent with testing frequencies, providingqualified technicians, and responding tothe needs of the hospital. Since the firealarm system is an integral part of thelife safety features, the FacilitiesManagement department decided totake control of all testing and serviceon the fire alarm system. Technicianswere trained by the fire alarm manufac-turer, and all testing and service arenow conducted by Rockford Memorial’sown staff. This has proven to be amajor improvement as the hospital canbetter control all activity on the firealarm system.

Recent improvements to the firealarm system include the addition of anetworking computer allowing expand-ed communication between the fourpanels and remote operation terminals.This is a significant enhancement astechnological improvements made inthe hospital put increasing demands onthe fire alarm system. A remote monitorwas installed in the hospital’s Securitydispatch office which displays the loca-

tion of every alarm initiated with analphanumeric description. Alarm infor-mation is quickly transmitted to thehospital’s fire response team via two-way radios. Other improvements includeexpander circuit cards to allow over500 additional initiating devices to meetthe needs of recent building additions.

Not everything concerning the instal-lation went as well as the hospitalwould have liked. With a fire detectionproject this large, some problems andmistakes did occur. The most embar-rassing one was the day the fire alarmmanufacturer brought a contingent offacility managers from other hospitalsto see the ongoing installation of thenew fire alarm system. Unbeknownst toRockford Memorial’s facility manager,who was greeting the contingent at thefront entrance, an installer accidentallywired line voltage into the initiating cir-cuit on one panel and blew out all thefirmware and control circuit boards. Bythe time the proud facility managerbrought the visitors to the fire panelroom, he found all the internal boardsand power supplies from one panelscattered across the floor with workersfrantically trying to rectify the situation.

One key issue the hospital wouldchange is the decision to install the firealarm wiring using plenum-rated twist-ed pair cable, instead of installing thewire in conduit. While this decisionsaved time and money at the point ofinstallation, it has been the source ofmany ground fault troubles, due in partto the numerous tradesmen workingabove the ceilings and inadvertentlydamaging the cable.

All things considered, the RockfordMemorial Facilities Management depart-ment is pleased with their new firealarm system. They have a system thatis user-friendly, and they maintainexcellent as-built documents and draw-ings. With their own staff conductingtesting and repairs, they feel they havecomplete control over the system.

Brad Keyes is with the Rockford HealthSystem.

SUMMER 2001 Fire Protection Engineering 3

An Added Level of Safety

viewpoint

By Steven T. Bushby

INTRODUCTION

Integrating fire alarm systems with buildingautomation systems can result in manyeconomic and operational benefits. Such

integration requires communication standardsand careful design practices. BACnet™ is aninternationally recognized communicationprotocol standard specifically designed forintegrating building automation and controlsystems. Thousands of BACnet systems canbe found around the world, and its populari-ty is growing. Newly proposed additions toBACnet make it very well suited for integrat-ing fire alarm systems with building automa-tion systems.


INTEGRATING

Fire Alarm Systems with Building Automation and Control Systems

6 Fire Protection Engineering NUMBER 11

Maintaining the integrity of fire alarmsystems when they are integrated withother building systems requires morethan just communication standards.Best design practices, appropriate test-ing procedures, and modernized build-ing are also needed.

The technology of building automa-tion and control systems has advancedrapidly over the past fifteen years.Today’s technology provides buildingowners and designers with a richassortment of options and flexibility.Powerful personal computer worksta-tions and intelligent distributed con-trollers that process complex algorithmsquickly and efficiently characterizestate-of-the-art building automation andcontrol systems. These advances havetaken place across a variety of buildingservices including heating, ventilating,and air conditioning (HVAC) controlsystems, lighting control systems, accesscontrol systems, and fire alarm systems.

In spite of these advances, buildingowners have been frustrated by theinability to bid projects competitivelyand to integrate innovative productsmade by different manufacturers in waysthat best suit the unique needs of theirfacility. The main obstacle has beenincompatible proprietary communicationprotocols. The adoption of BACnet1 asthe standard communication protocol forintegrating building control products haschanged the industry and opened thedoor to new innovation in building con-trol technology and true integration ofpreviously isolated building systems.

In the United States, the NationalElectrical Manufacturer’s Association(NEMA) Signaling, Protection, andCommunication Section (3SB) hasendorsed the use of BACnet as the pre-ferred way to integrate fire alarm sys-tems with other building control sys-tems. The National Fire ProtectionAssociation (NFPA) is in the process ofrevising NFPA 722 to address designissues related to integrating fire alarmsystems with other building systems.First-generation BACnet fire alarm sys-tem products are already available inthe marketplace in the United Statesand in Europe. These are clear indica-tions of interest in integrating fire alarmsystems with other building systemsand in using the BACnet protocol as ameans to accomplish that goal.

A BACNET OVERVIEW

BACnet is a standard communicationprotocol developed by the AmericanSociety of Heating Refrigerating, andAir-Conditioning Engineers (ASHRAE).It has been adopted as a prestandardby the European Community3,4 and hasbeen proposed as an ISO standard.Today there are over 70 companieswith registered BACnet vendor identi-fiers. These companies are located inNorth America, Europe, Asia, andAustralia. Commercial BACnet productofferings range from gateways thatconnect proprietary systems to com-plete product lines that use BACnet asthe primary or sole means of commu-

nication. There are thousands ofinstalled systems ranging in complexityfrom a single gateway to very largeoffice buildings with top-to-bottomnative BACnet systems, to campus orcity- wide systems linking multiplebuildings. BACnet products includeHVAC controls, lighting controls,access controls, and fire detection systems.

Fundamentally, BACnet, like anycommunication protocol, is a set ofrules that provide a way to exchangeinformation. BACnet was designed andoptimized specifically to meet theneeds of building automation and con-trol applications, and to convey thedata needed by these applicationsincluding, but not limited to, hardwarebinary input and output values; hard-ware analog input and output values;software binary and analog values;schedule information; alarm and eventinformation; files; and control logic.BACnet does not define the internalconfiguration, data structures, or controllogic of the controllers.

BACnet is designed to be scalablefrom very small, low-cost devices tovery large complex systems that mayinvolve thousands of devices and multi-ple buildings located anywhere in theworld. It achieves this by combining anobject-oriented representation of theinformation to be exchanged, flexiblechoices for local area network (LAN)technology, an ability to interconnectlocal area networks, and an ability touse Internet protocols (IP) to link build-

Figure 1. BACnet Protocol Architecture

BACnet Application Layer

BACnet Network Layer

BACnet LayersEquilaventOSI Layers

Application

Network

Data Link

Physical

ISO 8802-2 (IEEE 802.2)Type 1

ISO 8802-3(IEEE 802.3) ARCNET

MS/TP

EIA - 485

PTP

EIA - 232

LonTalk


ings over wide area networks. Thestructure of the BACnet protocol and itsrelationship to the Open SystemsInterconnection (OSI) – Basic ReferenceModel5 is shown in Figure 1.

BACnet represents the informationand functionality of any device bydefining collections of related informa-tion called “objects,” each of which hasa set of properties that further charac-terize it. For example, an analog inputis represented by a BACnet AnalogInput object that has a set of propertiesthat include its present value, sensortype, location, alarm limits, and others.Some properties are required and oth-ers are optional. A device is represent-ed by an appropriate collection of net-work-visible objects. Once the informa-tion and functionality of a device arerepresented on the network in terms ofstandard objects and properties, mes-sages can be defined to access andmanipulate this information in a stan-dard way. This combination of standardobjects and standard messages toaccess and manipulate their propertiesmakes up the BACnet application layer.

Once the information to beexchanged and message structures are

defined, it is necessary to provide away to transfer the information fromone place to another. BACnet providesa choice of five LAN technologies tomeet this need. Several choices are pro-vided because different building controlapplications must meet different costand performance constraints. A singlenetwork technology cannot meet theneeds of all applications. A LAN isdefined by a combination of the datalink and physical layers of the OSImodel. The LAN options available inBACnet are shown in Figure 1.

The first option is ISO 8802-3, betterknown as “Ethernet.” It is the fastestoption and is typically used to connectworkstations and high-end fielddevices. The second option is ARCNET,which comes in modestly high speedsor in slower, lower-cost versions.BACnet defines the MS/TP (master-slave/token-passing) network designedto run over twisted-pair wiring.Echelon’s proprietary LonTalk* networkcan also be used. The Ethernet, ARC-NET, and LonTalk options all support avariety of physical media. BACnet alsodefines a dial-up or “point-to-point”protocol called PTP for use over phone

lines or hardwired EIA-232 connections. A key point is that BACnet messages

are the same no matter which LAN isused. This makes it possible to easilycombine LAN technologies into a singlesystem. The purpose of the networklayer is to provide a way to make suchinterconnections. It is common in largesystems to combine high-speed (andhigh-cost) networks with lower-speed(and lower-cost) networks in a singlesystem. Such a system is shown inFigure 2. Figure 2 also illustrates thatBACnet has wide area networkingcapability that is implemented using IP.

In principle, BACnet messages canbe transported by any network technol-ogy. This means that technologies thathave not even been invented yet canbe used in the future to convey BACnetmessages, and they can be integratedinto today’s systems in the same waythat multiple existing network technolo-gies can be combined today. This lackof dependence on today’s technology isa very important feature of BACnet.

The object-oriented structure alsoprovides a way to add new applicationfunctionality to BACnet by definingnew objects and/or new application

Internet

Unitary Controllers

Low-Speed LANs High-Speed LANs

Field Panel

Field Panel

Field Panel

Field Panel

Field Panel

Field Panel

Workstation Workstation

Router

Router

Ethernet Ethernet

Unitary ControllersLow-Speed LANs

Figure 2. A Hierarchical Building Control System Structure


services. This is being done to addfunctionality needed for fire alarm sys-tems. Two new BACnet objects, LifeSafety Point and Life Safety Zone, havebeen developed. The Life Safety Pointobject represents the features of anindividual detection or enunciationdevice. The Life Safety Zone object rep-resents the status of a collection or“zone” of life safety devices. Whenthese objects detect an alarm, the alarmstatus latches until a reset command isexecuted. A new application servicehas also been developed that providesa way to reset latched alarms and tosilence annunciating devices. All theseadditions were developed with assis-tance from the fire alarm industry andhave been approved by the BACnetcommittee. They are currently undergo-ing a public review process and areexpected to be approved as part of theBACnet standard.6

More detailed information aboutBACnet concepts and structure may befound elsewhere.7 There is also tutorialinformation and an extensive bibliogra-phy available on a Web page main-tained by the BACnet committee(www.BACnet.org).

WHY INTEGRATE FIRE ALARMSYSTEMS WITH OTHER BUILDINGSYSTEMS?

There are many reasons for integrat-ing fire alarm systems with other build-ing automation and control systems.Examples include smoke control, single-seat access to building information, easi-er maintenance, sharing sensor data,obtaining information about the locationof people during an emergency, andproviding infrastructure for new tech-nology to improve performance andsafety.

Fire detection systems have beenintegrated with door locks and withHVAC fan and damper controls forsmoke management for several years,

but these systems have relied on relayscontrolled by the fire alarm system tooverride the normal controls. This kindof integration has primarily involvedconstant-volume HVAC systems andrequired only on/off control of fansand dampers to be moved to fullyopen or fully closed positions.

Many modern HVAC systems are farmore complex. Variable air volume sys-tems are used to reduce energy con-sumption. These systems require sophis-ticated control algorithms to operateeither a continuously variable-speed fanor inlet guide vanes to control the staticpressure in the supply air duct. Variable-air volume boxes control the airflowfrom the supply duct into individualrooms by modulating dampers. Thecontrol algorithms for these systems arecomplicated and require interlocks andsafeties to prevent overstressing duct-work in the event that dampers do notopen when fans are turned on. Smokemanagement is much more complicatedwith these systems and outside of thecapability of most fire alarm systems.What is needed is a way for the firealarm system to command the HVACcontrol system to enter a smoke controlmode and let the HVAC controllersmanage the equipment.

New sensors are being developedthat can recognize various contaminantsin the air that can represent a fire signa-ture or a hazardous contaminant thatposes a life safety threat. In an integrat-ed system, these sensors could be usedby the HVAC control system to controlventilation rates with no adverse impacton their life safety functions. Multipleuses for the same information willmake it more cost-effective to imple-ment new sensor technology.

In some buildings, access control sys-tems monitor the location of buildingoccupants. Providing access to thisinformation to the life safety systemscould be very helpful in an emergency.Emergency response personnel wouldknow where to look for occupants whoneed to be evacuated. They could alsoreduce the risk to themselves by avoid-ing dangerous areas where no peopleare present.

Research is now underway at theNational Institute of Standards andTechnology (NIST) to develop a newgeneration of smart fire alarm panelsthat can make use of sensor data froman integrated system to calculate heat

release rates in a fire. Using this infor-mation, a fire model in the panel canpredict how the fire will grow andspread. Emergency response personnelcan use these predictions to plan a strat-egy for fighting the fire. It could evenbe transmitted by the building systemsto fire stations or fire trucks so thatplanning can begin before emergencypersonnel reach the site. This could sig-nificantly improve response time, savinglives and reducing property loss.

For all of these reasons and probablyothers, integrating fire alarm systemswith other building systems makes a lotof sense. The technology is already beingdriven in that direction by market forces.

OTHER INTEGRATION ISSUES

Several important integration issuesmust be addressed if these potentialbenefits are to be realized. The primaryconcerns are ensuring the integrity offire alarm systems in emergencies andisolating them from interference causedby failures of other building systems,meeting code and UnderwritersLaboratory (UL) listing requirements, and regulating and tracking humanresponses to alarms and trouble conditions.

Maintaining the integrity of the firealarm system and protecting it fromfailures in other building systems areprimarily a matter of system designpractice. Today this is being handled byusing a gateway to isolate the fire alarmsystem from outside interference. Allcomponents of the fire alarm systemreside on one side of the gateway andcommunicate using proprietary proto-cols in the same way that they didbefore BACnet. The BACnet gatewayprovides a way for other building sys-tems to get information from the firealarm system but protects it from inter-ference from outside. This provides thenecessary protection, but it also limitsthe integration possibilities.

An alternative approach is to developbest design practices for constructingnetworks of integrated systems. Byappropriate selection of network tech-nology and appropriate use of routersand bridges to filter traffic, interferenceproblems and concerns about guaran-teed access to network bandwidth inan emergency can be effectively elimi-nated. Business network systems com-monly use these techniques today, and


there is no reason why they cannot beapplied to building automation systems.

Having fire alarm systems tested byUL and listed for their intended purposeis an expensive and time-consumingpractice. It is unrealistic to expect man-ufacturers of other building automationdevices to absorb this expense whentheir products are not directly involvedin detecting or responding to a fire justbecause they can communicate with

listed fire-detection devices. The testingand listing procedures need to beupdated to recognize this reality. Bycombining good design practices withtests that ensure the integrity of the firealarm system under conditions that canoccur if the design practices are fol-lowed, safety concerns can be satisfiedwithout sacrificing the benefits of inte-gration. In some locations, buildingcodes may need to be modified so that

they are based on performance criteriainstead of prescriptive requirements.

In fire alarm systems, it is very impor-tant to ensure that only authorized per-sonnel can silence alarms, reset alarms,and perform other operations that sig-nificantly affect the performance or sta-tus of the system. Traditionally this hasbeen accomplished by having dedicatedfire system workstations that providethe operator with capabilities that areassigned when the operator logs in. Inan integrated system, there may bemany workstations with the ability tosend messages to fire alarm systemcomponents. Fire alarm panels need tobe protected from accidental or inten-tional disruption from other devices orworkstations in the building. BACnetprovides mechanisms for authenticatingmessages but they are not widelyimplemented. This is another designissue that needs to be addressed.

INTERNATIONAL STANDARDSACTIVITIES

As stated before, BACnet has beenadopted as a standard in the UnitedStates and as a prestandard in theEuropean Community. The Internation-al Organization for Standardization(ISO) Technical Committee 205 is delib-erating the adoption of BACnet as aworld standard. This is being done aspart of the activities of Working Group3, Building Control System Design. Theparticipants in this activity include rep-resentatives from the United States,Europe, Japan, and Australia. BACnet isnow at the “committee draft” (CD) stageand is expected to advance to the “draftinternational standard” (DIS) stage soon.The ISO activities are being coordinatedwith the ongoing maintenance ofBACnet in the United States. The inten-tion is to incorporate into the U.S. stan-dard any additional features needed toobtain international acceptance of theprotocol. It is also expected that anyadditions that come from the continu-ous maintenance process in the U.S.will be incorporated into the ISO stan-dard. An effort is being made to coordi-nate BACnet testing and certificationprograms in Europe and the U.S. Thereis a strong international consensus thatit is in everyone’s interest to be able tofreely market BACnet products any-where in the world. A common stan-


dard and reciprocal certification recogni-tion are critical if this is to happen.

There are a variety of important rea-sons for integrating fire alarm systemswith building automation systems.These include smoke control, single-seat access to building information, eas-ier maintenance, sharing sensor data,obtaining information about the loca-tion of people during an emergency,and providing infrastructure for newtechnology to improve performanceand safety. A standard communicationprotocol is a critical infrastructure com-ponent to make this integration possi-ble. BACnet is such a protocol, and it isgaining popularity around the world.

More than just communication stan-dards need attention. Systems must bedesigned and maintained in ways thatwill assure the integrity of the firealarm system even when other compo-nents of the building automation sys-tem fail. It is also necessary to designthe system so that bandwidth is avail-able to the fire alarm system when anemergency arises. Best practice designguidelines can meet these needs. ULtesting and listing procedures need tobe updated to address open integratedsystems. In some cases, building codesmay need to be revised to perfor-mance-based approaches.

Market forces are already pulling theindustry in the direction of integratedsystems. As new technology is devel-oped that adds capabilities because ofthe integration, the pressure to integratesystems will grow. The end result willbe buildings that are easier to operateand are safer for the occupants.

Steven Bushby is with the NationalInstitute of Standards and Technology.

* Certain trade names and company productsare mentioned in the text in order to specify ade-quately the equipment used. In no case doessuch identification imply recommendation orendorsement, nor does it imply that the productsare necessarily the best for the purpose.

REFERENCES

1 ASHRAE 135. BACnet –A Data Communication Protocol for Building Automation andControl Networks. American Society ofHeating Refrigerating, and Air-ConditioningEngineers, Atlanta, Georgia.

2 NFPA 72. National Fire Alarm Code.

National Fire Protection Association,Quincy, Massachusetts, 1999.

3 ENV 1805-1: European Committee forStandardization.

4 ENV 13321: European Committee forStandardization.

5 ISO 7498, Information Processing Systems– Open Systems Interconnection – BasicReference Model, InternationalOrganization for Standardization, 1984.

6 Addendum c to ASHRAE 135, First PublicReview Draft, 2000. American Society ofHeating, Refrigerating, and Air-Conditioning Engineers, Atlanta, Georgia.

7 Bushby, S. T., “BACnet,™ a standardcommunication infrastructure for intelli-gent buildings,” Automation in Con-struction 6 (1997). Elsevier, pp. 529-540.

For an online version of this article, goto www.sfpe.org.


IntelligentFire Alarm

Systems

IntelligentFire Alarm

SystemsBy Jeffrey S. Tubbs, P.E.

INTRODUCTION

The fire protection community faces growing needs forreliable fire-detection systems that give the earliestpossible warning of fire. These needs draw attention

to problems associated with false or unwanted fire alarms.Unwanted fire alarms can seriously undermine the effective-ness of installed alarm systems, interrupt business, and, atworst, may cause occupants to ignore the fire alarm systemduring an actual fire.

Historically, fire alarm manufacturers have addressedunwanted alarms through two approaches:

• Decreasing detector sensitivity. Maintenance personnelare able to set individual detectors to be less sensitiveafter the devices are installed to alleviate false alarms.Typically, detector sensitivity is only decreased; the sensi-tivity is rarely increased to improve detection capability.

• Using alarm verification. Alarm verification essentiallyintroduces a detection delay time. When the detectorreports an alarm condition, the fire alarm system waitsfor a specified programmed delay time (typically, a 30-second delay) to confirm that the detector continues toreport an alarm condition. If the detector is in alarm afterthe delay time, the alarm sequence is actuated.


Although decreasing detector sensi-tivity and using alarm verification canreduce the potential for unwantedalarms, occupant notification may alsobe delayed

Intelligent fire alarm systems havebeen developed to address unwantedalarms while maintaining the desiredlevel of detector sensitivity. Althoughthe capabilities of intelligent systemsvary between manufacturers, intelligentsystems can provide a number of bene-fits, including faster occupant notifica-tion, increased detector sensitivity, anddecreased potential for unwantedalarms. Also, intelligent systems canprovide users with notification of need-ed detector maintenance.

INTELLIGENT VS. CONVENTIONALDEVICES

Artificial intelligence has become abuzzword in many fields involvingtechnical products. Intelligent systemshave been used in virtually every tech-nical field involving a wide range ofindustries, from systems designed forthe space shuttle to many computergames. The term “artificial intelligence”is typically associated with systems thathave the ability to reason or learn.

A number of new fire alarm productshave become available, many of whichare labeled as components of intelligentfire alarm systems. While intelligent firealarm systems are not as advanced andsophisticated as what is typicallythought of as artificial intelligence, theydo incorporate some of the simplelogic techniques incorporated in suchsystems.

Intelligent fire alarm systems wereinitially another name for addressablesystems. Addressable systems provide aunique address for each detectiondevice, providing a increased level ofinformation to the user. Today’s intelli-gent systems do more.

Currently, intelligent fire alarm sys-tems incorporate detectors that usedecision-making algorithms to deter-mine alarm conditions. Some employmultisensor approaches, while othersuse multidetector approaches or profilecomparisons. In most cases, measure-ments, such as smoke concentrationand temperature, are received by oneor more sensors. This information is

then analyzed by specific algorithms todetermine if these measurements indi-cate that a fire condition may be pre-sent.

Some intelligent detection devicesmake all the alarm decisions, while oth-ers report conditions to the alarm sys-tem control equipment which makesthe alarm decision. Conversely, conven-tional fire alarm detectors use setthresholds in a single sensor to deter-mine alarm conditions. Thus, conven-tional devices are rigidly designed tosignal alarm conditions only after a spe-cific level has been reached.

INTELLIGENT DEVICES

Fire alarm devices labeled as intelli-gent are usually thought of as analog-type detectors.1 Analog-type detectorsprovide continuous, real-time measure-ments of air properties within a detec-tion chamber which is, in turn, affectedby the surrounding air. These detectorscan have set thresholds such as con-ventional detectors to initiate an alarmsequence based upon these measure-ments. In addition, many intelligentdetectors use algorithms to process lev-els lower than those threshold valuesset to indicate an alarm. These aredefined here as prealarm signals. Pre-alarm signals can be compared with anumber of analog signals from otherdetectors and sensors within the space,compared with previous signalsreceived from the affected detector orcompared with predetermined fire pro-files obtained through fire tests. Thesetechniques allow an increase in detec-tor sensitivity, while decreasing thepotential for false alarm potential.

To be listed or approved, intelligentdetectors must meet the criteria forconventional detectors. As such, whenan intelligent detector reaches thealarm threshold specified for conven-tional detectors, it must initiate analarm signal.

A discussion of some of the decision-making algorithms used in intelligentfire alarm systems follows.

AUTOMATIC SENSITIVITYCOMPENSATION

Dust, dirt, humidity, age, and otherenvironmental factors affect smoke

detector sensitivity. These factors shiftthe base reading of detectors closer toor further from an alarm threshold,depending upon the type of contamina-tion and type of sensor. As this basereading is shifted, higher or lower con-centrations of smoke are required forconventional detectors to reach the pre-set alarm threshold. This makes smokedetectors more susceptible to unwantedalarms or delayed activation over time.

Many analog detectors are designedwith automatic sensitivity compensa-tion. While detectors incorporatingautomatic sensitivity compensation, or“drift” compensation, may or may notbe classified as intelligent detectors perthe definition suggested within NEMATraining Manual on Fire AlarmSystems,1 “drift” compensation is includ-ed within some intelligent detectionand is discussed here to provide back-ground.

Since the detectors have a continu-ous range of sensitivities, the alarmthreshold can be shifted higher orlower, based on the analog prealarmsignal. If the sensitivity increases as thedetector becomes dirty, the alarmthreshold is shifted upward within thedetector’s range of sensitivity, compen-sating for the increased analog read-ings. When, over time, the analog sig-nal is shifted close to the upper sensi-tivity limit, the detector provides amaintenance signal, notifying the userof service requirements before unwant-ed alarms occur. This allows the detec-tor to compensate for contaminationand environmental factors while allow-ing for optimum detector sensitivity.

PRESET SENSITIVITYADJUSTMENT

Detectors with preset sensitivityadjustments operate similar to thosewith automatic sensitivity compensa-tion. This design adjusts the sensitivityaccording to preset conditions. Somespaces may routinely require anincrease or decrease in detector sensi-tivity. For instance, a highly protectedspace may require a higher level ofprotection during off-hours or a nightclub may require a decrease in detectorsensitivity during normal business hoursto compensate for occupant smoking.This allows optimum sensitivities to be


used for each predictably changingbackground condition within a givenspace.

PROFILE COMPARISON

Fires tend to have unique smoke andheat profiles based upon specific fuelsburning. For instance, fires in plasticmaterials tend to produce more smokethan fires in flammable liquids. Somefire alarm manufacturers have devel-oped proprietary databases with detailscharacterizing products of combustionfor a large range of fuels. These data-bases include measurements of time-dependent properties, such as photo-electric detector readings, ionizationdetector readings, and temperaturereadings. Data have been groupedaccording to fuel packages and specifictraits have been determined for eachtype of fuel package.

Although individual fire alarm manu-facturers use different methods, analogmeasurements from individual detectorsare compared with predetermined val-ues obtained in fire tests. This allowsdetectors to filter out conditions thatare not typically associated with fires.The comparison algorithm is based onthe predetermined values obtainedfrom testing. Therefore, large spikes inproperties such as obscuration noticedwhen insects enter smoke chambers orlarge spikes in ionization values due toradio frequency interference can berecognized and ignored.

Since alarm verification allows detec-tors to use a time delay to confirmalarm conditions, the detector can usethe alarm verification delay time to ana-lyze the prealarm signal. If the pre-alarm value is consistent with condi-tions typically associated with fire con-ditions, the alarm is verified, and analarm is reported immediately. Sinceunwanted alarm conditions are filteredout, detector sensitivities can be signifi-cantly lowered, allowing early detectionof fires.

Various manufacturers use differentmethods with this approach. Somegroup the test results from variousenvironments such as offices, ware-houses, or hospitals, while others usea single-representative approach tocompare recorded readings to actualreadings.

MULTISENSOR COMPARISON

Detectors using multisensor compar-isons operate similar to single-sensorcomparison detectors described earlier.However, several methods of detectionare used. Combinations of ionization,photoelectric, and heat detectors areincorporated into a single detectiondevice. This device can then compareinformation from several differentsources. This approach may enhancethe ability to filter out unwanted condi-tions and allows for increased sensitivi-ties. For instance, a quick rise in obscu-ration, without any associated rise intemperature, can be filtered out.Another benefit may be that thesedetectors use algorithms to process theanalog values from all of the sensors.The conditions for reporting an alarmcan then be based upon a combinationof inputs from each sensing element,which further increases reliability byenhancing stability, sensitivity, or both.

MULTIDETECTOR COMPARISON

As smoke flows across a ceiling, ittends to affect more than a singledetector. Multidetector comparisonsmake use of this trend. Affected detec-tors analyze adjacent detector prealarmconditions. Alarms are initiated whenthe prealarm conditions of adjacentdetectors indicate a similar rise in theassociated value. Similar to the detec-tors that compare profiles, these detec-tors can compare multiple locations andeliminate local spikes caused by aninsect or radio frequency interference.This allows decreased alarm thresholds,faster detection times, and greater sys-tem stability.

OTHER FEATURES

Powerful system processors allowadditional features, such as:

• Automatic Addressing: detectorsautomatically determine an inde-pendent address and integrate itinto the system.

• Setting of Prealarms: one or moreprealarms can be set.

• Detector Memory: detectors canstore a variety of informationincluding the rate of environmentalcompensation, last maintenance

date, and analog signal for lastalarm.

• Intelligent Notification: notificationdevices can be given discreteaddresses to allow a single circuitto cover multiple independentnotification zones. This also allowsindividual notification device test-ing.

Intelligent fire alarm systems can pro-vide additional information to the con-trol equipment and ultimately to theuser. Each building layout and environ-ment is unique, and application ofthese systems should be carefully eval-uated to provide the best approach.Since analog detectors can compareconditions with known values and pro-vide increased information, this tech-nology provides many enhancements totoday’s systems.

Intelligent detectors will likelybecome the typical or standard detectorfor many applications. This will be due,in part, to the cost of these detectorsbecoming comparable to that of typicaldetectors. Currently, several intelligentdevices are only slightly more costlythan that of standard devices. As thecost of intelligent technology decreases,more and more of these devices will beused in fire alarm systems.

Finally, it is important to note that alldetectors, whether combination and/orintelligent, require maintenance to beeffective. Even with all of the new tech-nology, maintenance programs fordetectors and fire alarm systems shouldbe viewed as one of the most impor-tant aspects of fire alarm systems.

Jeffrey Tubbs was formerly with RolfJensen & Associates.

REFERENCES

1 Training Manual On Fire Alarm Systems,National Electrical ManufacturersAssociation, Washington, DC, 1992.



By John M. Cholin, P.E., andChris Marrion, P.E.

OVERVIEW

The concept of a smoke detectoris over 75 years old. In E.Meili’s book “My Life With

Cerberus,”1 Meili states that H.Geinacher reported in the Bulletin ofthe Swiss Association of ElectricalEngineering in 1922 of experiments heperformed using an ionization cham-ber and how they could be applied toanalyzing smoke concentrations. Thenext documented indication of a simi-lar-type device was from French patentapplications dated 1937/1938 byMalsallez and Breitman1 describing afire detector based on using ionizationchambers.

Over 25 years ago, Custer andBright published their seminal publica-tion, Fire Detection: State of the Art.2 Inthis document, they conclude:

“Several areas of the detection pic-

ture, however, need improvement inorder to provide data which will alloweffective engineering judgements to bemade in selecting the appropriatedetector for specific applications...

Changes need to be made in the test-ing and approval procedures to pro-vide engineering data for approveddetectors. Data should be providedwhich accurately describe the perfor-mance of approved units over a widerange of smoke sources, air velocities,rates of heat evolution, and installa-tion configurations. These data canpermit better engineering of detectionsystems with respect to the expected fireexposure and response time criteria. Bylimiting approval testing to a narrowrange of fire signatures, ambient con-ditions and installation configuration,or testing against a standard devicesuch as an automatic sprinkler head,many detectors which have desirablecharacteristics for specific applicationsmay be excluded from the marketplacewhile others which may have undesir-able properties, such as insensitivity to

certain fire signatures, may be accept-ed. This can result in detector failuresdue to lack of engineering data con-cerning the capabilities of a listed orapproved unit.”

Over 20 years ago, Heskestad andDelachatsios stated in their landmarkresearch:

“There is a need to tie the spacing ofdetectors, heat as well as smoke, torealistic fire situations, recognizingeffects of fire-growth rate, ceilingheight, combustible material (in thecase of smoke detectors), and ceilingconfiguration. The spacing should besuch that a threshold fire size, Qd

(kW,Btu/s), is not exceeded at detec-tion.”3

As seen, it has been almost 80 yearssince the initial development of smokedetectors and at least 20 years sincetwo significant publications in the fireprotection industry identified the needfor developing performance metricsfor detectors. Yet given all this time,

PerformanceMetrics

for FireDetection


and the identified need, the fire pro-tection industry has made virtually noprogress toward a credible metric foraccurately predicting the performanceof either heat or smoke detectors.

The engineering community hasaccepted the concept of performance-based fire engineering design for thebuilt environment. The SFPEEngineering Guide to Performance-Based Fire Protection Analysis andDesign of Buildings outlines the frame-work and the design methodology forperformance-based design. The LifeSafety Code,® NFPA 101-2000, and theICC Performance Code adopt the per-formance-based design method as rep-resenting an acceptable means to pro-vide equivalent life safety throughalternative designs. Now that the con-cept of performance-based design forthe fire protective systems has beenaccepted, how can its promise be ful-filled? How can a performance-baseddesign or analysis be conducted effec-tively when the response of heat orsmoke detectors to even the simplestof fire scenarios cannot be predictedwith any reasonable degree of engi-neering precision or confidence? Sincemany fire safety aspects (includingoccupant notification, notification ofthe responding fire service, activationof special suppression systems, initia-tion of smoke management systems,release of door holders and otherdevices to complete the compartmenta-tion, etc.) rely on determining whensmoke or heat detectors will respond,an accurate assessment of detector per-formance is necessary. Yet fire detec-tion systems are relied upon for all ofthese critical fire safety functions withno credible means of accurately pre-dicting when, if ever, these functionswill be initiated.

It is interesting to note that the leastcommonly used type of fire detectionhas performance metrics and, hence,the best design tools. A NationallyRecognized Testing Laboratory (NRTL)listing radiant energy-sensing detectorsin the U.S. has a long-standing, estab-lished practice of providing a perfor-mance metric for flame detectors. Thisperformance metric has permitted per-formance-based design in confor-mance with NFPA 72, the NationalFire Alarm Code,4 and its predecessordocument NFPA 72E-1990 Standard on

Initiating Devices.5 Indeed, perfor-mance-based design has been therequired method of designing flameand spark/ember detection systemssince 1990. Unfortunately, over 10years after performance-based designutilizing detector performance metricswas first incorporated into NFPA 72,the designer still has no such methodand metric for heat detectors andsmoke detectors, the most commonlyused types of detection.

HEAT DETECTOR PERFORMANCEMETRICS

The fundamental premise underlyingperformance-based design is that, ifthe information regarding the compart-ment, ambient conditions, detectionsystem characteristics, and hazards areadequately defined, engineering toolscan be used to predict how a fire candevelop once ignited. These sameengineering tools can be used to pre-dict conditions in the compartment offire origin at a location relative to thefire plume and some specified timesubsequent to ignition. This wouldthen enable one to predict the intensi-ty of the fire signature at a hypotheti-cal detector location as a function ofthe fire size and growth rate, androom configuration. Ostensibly, thispermits the engineer to predict detec-tor response.

This concept was the basis forAppendix C – Engineering Guide forAutomatic Fire Detection Spacing toNFPA 72E-1984, Standard onAutomatic Fire Detectors.5 This appen-dix utilized the correlations developedby Heskestad and Delachatsios3 to pro-duce a set of tables that specified heatdetector spacing as a function ofdesign fire size, fire growth rate, detec-tor location relative to the fire, ceilingheight, and detector response parame-ters including operating temperatureand thermal response. The thermalresponse of a heat detector was esti-mated by using a correlation to thetest methodology for determiningResponse Time Index (RTI) for sprin-klers. This correlation is outlined inSection B-3-2.5.1 of NFPA 72-1999, theNational Fire Alarm Code.4

Unfortunately, as Schifiliti and Pucci6

have pointed out, this correlationintroduces an error of unquantified

magnitude due to the different ceilingjet velocities encountered at fire sizesnormally associated with heat detectorresponse versus the fire size requiredfor sprinkler response. Heat transferbetween a fluid and a heat sink is afunction of fluid flow velocity.7

Consequently, when a simple coeffi-cient of heat transfer is to be deter-mined for any heat transfer device,sprinkler, or heat detector, it must bemeasured at flow velocities close tothose for which the device is beingdesigned. The test methodology fordetermining RTI utilizes a flow velocityof 1.5 m./sec. (5.0 ft./sec.), consider-ably larger than the ceiling jet velocityone would expect to observe at a heatdetector location during a fire thatwould normally be anticipated as thedesign basis for a heat detection sys-tem. The magnitude of the error intro-duced by using the test methodologyfor RTI has not been quantified andmay be large enough to invalidate adesign. Without conducting furtherresearch, however, it is difficult to tell.

Since heat detectors are not, as partof their listing examination, subjected tothe test to determine RTI, a correlationtable was included into the Appendix C– Engineering Guide for Automatic FireDetection Spacing to NFPA 72E-1984,Standard on Automatic Fire Detectors.5

However, this correlation is of limitedprecision as the exact same heat detec-tor may obtain a different “listed spac-ing” from the various NRTLs due to theslightly different test conditions thatmay be found at each NRTL. Listedspacing is a lumped parameter com-prised of numerous independent vari-ables, many of which are determinedby the test and not the detector undertest. Consequently, a correlationbetween listed spacing and RTI is tenu-ous at best. Thus, RTI may be of quitelimited use in the context of being ableto accurately predict the response ofheat detectors.

Listed spacing was originally intend-ed as a means of comparing onedetector to another and not as a designtool. Since listed spacing is a lumpedparameter that encompasses detectorcharacteristics, fire characteristics, testroom characteristics, and test condi-tions into a single value, the designerhas no method of separating out theeffect of any one parameter from the


lumped parameter for design purposes.Consequently, the lumped parameterof listed spacing is of very limited use-fulness in the context of performance-based design. It does not appear thatany published study exists that sup-ports the notion that heat detectorsinstalled pursuant to their listed spac-ing actually provide the expected per-formance in terms of fire size at alarminitiation. This therefore leaves theengineer without the proper tools toaccurately predict when the detectorwill respond to a given fire scenariowith a high degree of certainty.

To confidently and accurately designa heat-detection system in a perfor-mance-based design environment, thedesigner must know the operatingtemperature (Tr) and the ThermalResponse Coefficient (TRC) of thedetector. Without both of these met-rics, the designer is forced to estimateresponse by using a correlationbetween the listed spacing of thedetector and RTI. Since there areunknown inaccuracies in the listedspacing to RTI correlation, the design-er must perform their design calcula-tions using a range of RTI values andanalyze the sensitivity of the design toinaccuracies in the correlation. Theresult is a design of questionable cred-ibility and hence large safety factors.Such a design rarely lives up to thefull potential of performance-baseddesign as an engineering concept.

A SOLUTION

In view of the need for a heatdetector performance metric, theTechnical Committee on InitiatingDevices for the National Fire AlarmCode (NFAC) adopted language in the1999 edition mandating the determina-tion and publication of the ThermalResponse Coefficient, a performancemetric analogous to RTI, for a heatdetector as part of its listing. Thisrequirement was established with aneffective date of June 2002 to providesufficient time for the development ofthe test methodology and the determi-nation of the TRC for currently listeddetectors. With a properly developedmethod for determining TRC, thedesign of fire detection systems usingheat detectors could be based on theprincipals of fire dynamics rather than

listed spacing, yielding designs whoseperformance could be predicted moreaccurately. The strategy was to publisha TRC that had the same form as RTI.This would enable the fire protectionengineer to use existing performanceprediction correlations and fire models,originally developed for sprinklers, topredict the performance of detectionsystems using heat detectors.

Unfortunately, as of this writing,despite the fact that two research pro-posals were presented to the manufac-turers of heat detectors and UL overtwo years ago, there has yet to beagreement on how to fund theresearch to develop the test methodol-ogy. In addition, recent proposals toNFPA 72 have been made to retractthis requirement from the code.Consequently, the engineering commu-nity is still left with no validated per-formance metric for heat detectors.

SMOKE DETECTORPERFORMANCE METRICS

As if the situation with heat detec-tors is not sufficiently challenging, thesituation does not get better when itcomes to performance metrics forsmoke detectors. Optical density orobscuration is usually used as a mea-sure of smoke concentration. Thismeasure was apparently adopted dueto the presumed objective for smokedetection: to provide occupant notifi-cation while there was still sufficientvisibility to allow escape of the occu-pants prior to the onset of untenableconditions. Unfortunately, the opticalproperties of smoke vary substantiallywith variations in a number of parame-ters including fuel, fire ventilation,smoke temperature, and smoke age. Amore detailed analysis of smoke alsoleads to other measurable parameterssuch as particle size distribution, massconcentration, particle number concen-tration, and smoke color that deter-mine the gross, macroscopic opticalproperties of smoke. The dynamics ofsmoke production, aging, and move-ment have been and continue to be anarea of ongoing research.8

In the U.S., the sensitivity of smokedetectors is stipulated as the percentper foot obscuration at which thedetector renders an alarm in the UL268 Smoke Box.9 This is also a lumped

parameter. The test for determiningthis value relies on a carefully con-trolled air flow, temperature, relativehumidity, fuel (a cotton lamp wickobtained from a specific source), andtest box. Consequently, the sensitivitystipulated on the detector that isderived from the UL 268 Smoke Box isonly valid in the smoke box. Noresearch has been found that substan-tiates the use of the marked sensitivityon the smoke detector as an engineer-ing basis for the design of a smokedetection system; unless, of course, thedesign objective is to detect a smolder-ing lamp wick located inside a UL 268Smoke Box. Yet designers routinelyuse the sensitivity marked on thedetector in conjunction with a firemodel to leap to the conclusion that asmoke-detection system will respondat a given smoke obscuration level.

The closest thing to a performancemetric for smoke detectors available todesigners using U.S. products is theperformance implied by the full-scaleroom fire tests that are conducted aspart of the listing evaluation by UL. UL conducts three room fire tests withthe detector under test located 5.3 m(17.5 ft) from the fire plume center-line,implying a spacing of 7.6 m (25 ft.).These fires are summarized in Table 1.

The maximum obscuration levelstabulated in Table 1 represent the min-imum acceptance criteria for smokedetectors that are marked with the 1%to 4% obscuration sensitivity found onthe detector label. Note that for thepaper fire in an actual room test, theobscuration level can be up to 37times that which is listed on the detec-tor before it is required to alarm. Thesmoke used in the smoke box is alight gray in color, ideally suited fordetectors that rely on reflected light fordetection, whereas the smoke pro-duced by the test fires is far from opti-mal. Nevertheless, the disparity in thecriteria for the room fire tests and themarked “sensitivity” gives rise to con-cern that there might be significantdelays in smoke detector responseunder real fire conditions.

The size of the test fires is notexplicitly stipulated in the UL test stan-dard. Consequently, if a designer wereinclined to use this test data as a basisfor a performance prediction, theymust infer the fire size from the


descriptions in the standard and thenscale up to their design fire. Whilepossible, this process has the potentialfor producing errors in accurately pre-dicting response.

Also, there is no “listed spacing” fora smoke detector resulting from the UL listing evaluation. Instead, the man-ufacturer is left to “recommend” aspacing for its detector. In spite of thefact that the implied spacing derivedfrom the UL Full-Scale Room Fire Testis 7.6 m (25 ft), most manufacturersand NFPA 72 recommend a spacing of9.1 m (30 ft), with no reference todesign goals/objectives or the designfire for which this spacing is deemedappropriate.

Finally, while UL at one time includ-ed a Black Smoke Test in UL Standard

268 to determine the differentialbetween the response of a detector toblack smoke compared to its responseto the light gray smoke produced bythe cotton lamp wicking, there is nocurrent evaluation for the impact ofsmoke color on the response of thesmoke detector listed by UL Since mostspot-type photoelectric smoke detectorsoperate on a reflected light principal,smoke color can have a profoundeffect on the ultimate response of thedetector to real-life fires. Table 2 illus-trates the variation in response to grayand black smoke.

This difference in response is theartifact of a number of variables,including smoke concentration mea-surements and reflectance propertiesof smoke. The smoke concentration is

derived from the attenuation of a pro-jected light beam while, for instance,spot-type photoelectric smoke detectorresponse is derived from the intensityof reflected light. Optically absorbentsmokes produce high attenuations butpoor reflectance, while light graysmoke is deemed to be equallyabsorbent and reflectant. This diver-gence between the smoke measure-ment and smoke detection methodscontributes to inconsistency of the testresults. However, the smoke yield ofthe fires in question also contributes tothe divergence in the test results. Thisfact is inescapable: the same detectorscan respond at different obscurationlevels to different fuels, different com-bustion modes, and different types ofsmoke.

Examples of this wide variation inresponse were shown by Heskestadand Delachatsios3 in full-scale teststhey performed almost 25 years ago.Some of their results are summarizedin Table 3.

Note the large variations of opticaldensity at response that can vary by afactor as large as 200. These variationsare due not only to the variations inthe detector technology but also thevariation in smoke concentration andcolor. This underscores the importanceof having a means to accurately pre-dict smoke detector response that canbe correlated to the detector as well asthe characteristics of the smoke, ifsmoke detectors are to be relied uponfor critical fire safety functions.

The above should not be construedas a criticism of UL or its test standard,UL 268. UL 268 was designed to pro-vide a uniform test of product allowinga purchaser to be assured that theproduct was generally acceptable for aspecific purpose. It has never been theintent of UL 268 to provide a perfor-mance metric for use in the design ofsystems. However, as the needs of soci-ety change, the testing standards uponwhich that society relies must alsochange. If society’s need for fire-safebuilt environments are to be addressedthrough performance-based design,then the testing standards must evolveto serve that emerging need.

Having no credible performanceprediction methodology from either UL or the manufacturers, one is tempt-ed to look to fire plume and ceiling jet

Test Fuel Max. %/m (%/ft)Obs.

Max. ResponseTime

Smoke Color Variance (Max/Min)Acceptable Response Range

A Paper 78 (37) 4 minutes

B Wood 46 (17) 4 minutes

C Toluene/Heptane

Material Ionization

102 Dur m-1(ft-1)

ScatteringRelative

Smoke Color

37 (13) 4 minutes

WoodCottonPolyurethanePVC

1.6 (0.5)0.16 (0.05) 16 (5.0) 33 (10.0)

4.9 (1.5) 0.26 (0.8) 16 (5.0) 33 (10.0)

LightLightDarkDark

Variation 200:1 12.5:1

1.6 %/m (0.5 %/ft) to 12.5 %/m (4.0 %/ft)1.6 %/m (0.5 %/ft) to 29.2 %/m (10.0 %/ft)

Grey SmokeBlack Smoke

7.818.25

Material Ionization

Temperature Rise C ( F)

Scattering

WoodCottonPolyurethanePVC

14 (25)1.7 (3)

7.2 (13)7.2 (13)

42 (75)28 (50)7.2 (13)7.2 (13)

Average 7.5 (14) 21 (38)

Table 1. Summary of the UL Full-Scale Room Fire Tests in UL 268

Table 3. Values for Optical Density at Response (for flaming fires only)6

Table 2. UL 268 Smoke Detector Test Acceptance Criteria for Different Colored Smoke9

Table 4. Temperature Rise for Detector Response6


which the illusion of a correlation wasembraced underscores the urgency ofthe need for a performance-predictivetool for smoke detectors. Sadly, thepracticing engineer has very limited per-formance estimation methods at theirdisposal when designing fire-detectionsystems utilizing smoke detection.

A SOLUTION

To confidently and more accuratelydesign systems using smoke detectors,the designer needs two metrics. Thefirst is the inherent sensitivity of thedetector. There is some disagreementregarding the actual form of this met-ric. Some propose a metric basedupon the optical characteristic of thesmoke, while others propose the useof mass per unit volume of air andcorrelations to correct for the opticalcharacteristics.

Figure 2. Response ofionization smokedetector plotted for a)mass concentrationversus b) numberconcentration for mono-disperse DOP aerosol.11

0 20 40 60 80 100 120 140 160 180 200Mass concentration (mg/m3)

Dete

ctor

out

put -

Bac

kgro

und

(vol

ts)

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

Dete

ctor

out

put -

Bac

kgro

und

(vol

ts)

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

0 5 10 15 20 25Number concentration (103/cm3)

20% DOP 65 m�

20% DOP 0.53 m�

6.3% DOP 0.5 m�

2.1% DOP 0.22 m�

0.67% DOP 0.15 m�0.3% DOP 0.14 m�

55% DOP 0.90 m�

100% DOP 1.05 m�

Line indicates changein particle size

Figure 1. Response ofphotoelectric smokedetector plotted for a)mass concentrationversus b) numberconcentration for mono-disperse DOP aerosol.11

Dete

ctor

out

put -

Bac

kgro

und

(vol

ts)

1.8

1.6

1.4

1.2

1.0

0.8

0.6

0.4

0.2

0.00 20 40 60 80 100 120 140 160 180 200

Mass concentration (mg/m3)

Dete

ctor

out

put -

Bac

kgro

und

(vol

ts)

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

0 5 10 15Number concentration (105/cm3)

8.3% DOP0.5 m�

20% DOP0.75 m�

100% DOP1.2 m�

2.1% DOP0.26 m�

20%DOP0.75 m�

8.3%DOP0.50 m�

2.1% DOP0.20 m�

0.67% DOP0.17 m�

0.10% DOP0.79 m�

0.013% DOP0.043 m�

dynamics for a method. Heskestad andDelachatsios offered the notion that,for a given fire and detector, the tem-perature rise at the detector andsmoke concentration could be deemedto be a constant.3 In fairness to theseresearchers, it should be noted thatthey contemplated the development ofa series of temperature rise versusresponse correlations over a range offuels for each smoke detector as partof its listing evaluation. To illustratetheir hypothesis, they selected a tem-perature rise correlation of 13°C(20°F). Unfortunately, readers of thisresearch incorrectly concluded thatsuch a correlation actually existed,assumed one number as representativefor all detectors and all fuels, and thenbegan using it as the basis for design.The truth is that no such correlationexists. Schifiliti and Pucci6 have shownthat there is not a basis for using a

13°C (20°F) temperature correlation asthe basis for an actual design. Table 4shows the temperature rise at alarmfor the range of fires used byHeskestad and Delachatsios. Clearly,this data does not support the notionof a single correlation for all fires.

Furthermore, even if there was a reli-able correlation between temperaturerise and smoke concentration, the tem-perature rise would be a different valuefor each pairing of fuel and detector.Despite the fact that the “13°C tempera-ture correlation” does not exist, manydesigns have been based upon theassumption that it does. Engineers stillcling to the idea because it gave theman ability to predict smoke detector acti-vation based upon the plume and ceil-ing jet produced by the fire. Clearly, thisis what the design community needs inorder to execute a performance-baseddesign. Indeed, the enthusiasm with


In 1980, Mulholland wrote,11

“The two most important aerosol properties affecting theperformance of these detectors are the concentration of thesmoke aerosol and the particle size.”This statement was taken from his work with the National

Bureau of Standards – again almost 20 years ago. His state-ment is based on the relationships observed for these charac-teristics, as indicated in part in the Figures 1 and 2.

From the figures, it is clear that Mulholland’s researchdemonstrated a significant correlation between detectorresponse, mass concentration, and number concentration.Clearly, additional research is necessary to provide sufficientdata to develop a basis for a design correlation. Nevertheless, Mulholland’s findings look quite promising. It certainly justi-fies the notion that, given a few years and a concertedresearch effort, reasonable test methods could be developedthat would provide a performance metric that can be used topredict response to a given design fire under a range of envi-ronmental conditions.

Research is needed to determine the most effective form ofthe smoke detector performance metrics as well as the meansof determining their numerical values for real smoke detectors.For example, is it more practical to quantify detector sensitivityas a function of optical density, or is it more practical to char-

acterize it as a function of aerosol mass per unit volume andcorrelate for optical properties? Without research, the potentialefficacy of these two approaches remains unresolved.Currently, the concept of two metrics, one quantifying detec-tor sensitivity to the smoke aerosol and a second quantifyingthe smoke entry time delay, still seems to make the mostsense. Ultimately, the objective is to have one or more perfor-mance metrics that can be used in the context of currentlyavailable fire modeling tools to predict smoke detectorresponse within a range of situational conditions.

A proposal requiring the publication of smoke detectorperformance metrics in the form of a Sensitivity Factor and aSmoke Entry Factor has been submitted to the TechnicalCommittee on Initiating Devices for the 2002 edition ofNFPA 72, the National Fire Alarm Code. This proposal hasbeen offered to create the necessary sense of immediacy togalvanize the manufacturing community into funding theresearch. Ostensibly, a code requirement would producethe necessary economic incentive for action. However, thereality is that this proposal will not survive without the sup-port of the engineering community.

John Cholin is with JM Cholin Consultants, Inc. ChrisMarrion is with Arup Fire.

REFERENCES

1 Meili, E., My Life with Cerberus – Successes and Setbacks, printedZurichseee Druckerei Stafa, 1990.

2 Custer, R. L. P. & Bright, R. G., “Fire Detection: The State of theArt,” NBS Technical Note 839, National Bureau of Standards, June1974.

3 Heskestad, G. & Delachatsios, M.A., “Environments of FireDetectors, Phase I: Effect of Fire Size, Ceiling Height and Material,”NBS-GCR-77-95, National Bureau of Standards, Washington, DC,July 1977.

4 NFPA 72-1999, National Fire Alarm Code, National Fire ProtectionAssociation, Quincy, MA, 1999.

5 NFPA 72E-1984, Standard on Automatic Fire Detectors, NationalFire Protection Association, Quincy, MA, 1984.

6 Schifiliti, R. P. & Pucci, W.E.,”Fire Detection Modeling: State of theArt,” Fire detection Institute, Bloomfield, CT, 1996.

7 White, F. M., Heat Transfer, Addison Wesley Publishing Company,Inc., 1984.

8 Mulholland, G. “Smoke Production and Properties,” The SFPEHandbook of Fire Protection Engineering, 2nd Ed., National FireProtection Association, Quincy, MA, 1995.

9 UL/ANSI 268, Smoke Detectors for Fire Protective Signaling,Underwriters Laboratories, Northbrook, IL, 1996.

10 Heskestad, G. & Delichatsios, M. A. “Environments of FireDetectors, Phase 1: Effect of Fire Size, Ceiling Height andMaterial,” Measurements vol. I (NBS-GCR-77-86), Analysis vol. II(NBS-GCR-77-95). National Technical Information Service (NTIS),Springfield, VA 22151.

11 Mulholland, G. & Liu, Response of Smoke Detectors toMonodisperse Aerosols, Journal of Research of the NationalBureau of Standards, Volume 85, No. 3, May-June 1980.

For an online version of this article, go to www.sfpe.org.

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FIREALARM

SYSTEMSBy John L. Parssinen, P.E.,Paul E. Patty, P.E, andLarry Shudak, P.E.

Factors that assure that fire alarm systemsfunction effectively include: (1) initialdevice design, (2) third-party certification,

(3) analysis of the protected area, (4) testing, and(5) maintenance of the system. This articledescribes the certification activity performed byUnderwriters Laboratories (UL) that contributes tothe predictable operation of a fire alarm system.UL’s certification includes review of installationinstructions, product construction analysis, perfor-mance tests for compliance with requirements inStandards for Safety, follow-up surveillance toconfirm that products when shipped match theproducts tested during the initial product investi-gation, and certification of the installed fire alarmsystem.


Underwriters LaboratoriesContributions for


STANDARD TYPE OF EQUIPMENT UL LISTING OR SERVICE CATEGORY

UL 268 – Smoke Detectors for Fire-Protective Smoke Detectors UROXSignaling Systems Smoke Detectors for Releasing Service SYSW

Smoke Detector Accessories URRQ

Smoke Detectors for Special Application URXG

UL 268A – Smoke Detectors for Duct Application Duct-Type Smoke Detectors UROX

UL 38 – Manual Signaling Boxes for Use with Noncoded Boxes UNIU

Fire-Protective Signaling Systems Coded Boxes UMUV

UL 228 – Door Closures-Holders, With or Releasing Devices for Door Holders GTISWithout Integral Smoke Detectors

UL 346 – Waterflow Indicators for Fire-Protective Extinguishing System Attachments USQTSignaling Systems

UL 521 – Heat Detectors for Protective Heat Detectors UQGSSignaling Systems Heat Detectors for Release SZGU

Device Service

Heat Detectors for Special UTHVApplication

UL 464 – Audible Signal Devices Audible Appliances ULSZ

UL 1971 – Signaling Devices for the Hearing-Impaired Visual Signal Appliances for UUKCthe Hearing-Impaired

UL 1638 – Visual Signaling Appliances – Visual Signaling Appliances UVAVPrivate Mode Emergency and General Utility Signaling

UL 1480 – Speakers for Fire-Protective Speakers UUMWSignaling Systems

UL 864 – Control Units for Fire-Protective Control Units UOJZSignaling Systems Control Unit Accessories UOXX

Releasing Device Control Units SYZV

Control Units and Accessories, Marine UXWK

Releasing Device Equipment SZNT

Releasing Device Accessories SYSW

Emergency Communication and UOQYRelocation Equipment

UL 1711 – Amplifiers for Fire-Protective Amplifiers UUMWSignaling Systems

UL 1481 – Power Supplies for Fire-Protective Signaling Power Supplies UTRZSystems

Table 1. UL Standards Relating to Fire Alarm Equipment


INSTALLATION INSTRUCTIONS

The initial activity of UL’s investiga-tion of devices intended for use in firealarm systems is the review of themanufacturer’s installation instructions.These instructions, which cover boththe intended application of the productand how the product is to be used tomeet that application, are primarilyreviewed for consistency with theNational Fire Alarm Code, NFPA 72. ULadditionally reviews the instructions foroperational claims and uses the docu-ment as the basis for electrically load-ing and interconnecting the productduring the evaluation. Because of thesignificance of the document in relatingUL’s testing to the actual use of theproduct, the drawing number and revi-sion level of the installation instruc-tions/wiring diagram are required to beincluded in the product marking forreference by both the installer andinspection authority.

PRODUCT CONSTRUCTION

The second component is an analy-sis of the product’s construction. Thisinvolves a review to confirm the prod-uct is constructed so that it will bepractical and sufficiently durable for itsintended installation and use.Generally, all electrical parts of a prod-uct shall be enclosed to provide pro-tection of internal components andprevent contact with uninsulated liveparts. Enclosures must have thestrength and rigidity necessary to resistthe abuses to which the product islikely to be subjected during intendeduse without increasing the risk of fire,electrical shock, and/or injury to per-sons. All current carrying parts must besufficiently rated for the application,and the product must provide main-tained spacings between uninsulatedlive parts and the enclosure or deadmetal parts, and between uninsulatedlive parts of opposite polarity.

PERFORMANCE TESTS

The third component is performanceevaluation that is based on the Standardfor Safety for the specific product. Thestandards in Table 1 are used in theevaluation of fire alarm equipment.

The performance tests in the applic-able UL Standard are used to helpdetermine the reliable performance ofthe product. The evaluation generallyincludes a series of tests as follows:

1. Environmental tests to test forfalse alarms (variable temperatureand humidity for control, detec-tion, and notification equipment;corrosion for both detection andnotification products; and acceler-ated aging, stability, and velocitysensitivity for detection units);

2. Mechanical abuse tests to evaluatethe stability of the mechanicalassembly and circuit connections(jarring for all equipment; vibra-tion for both detection and notifi-cation products; and drop/impactfor portable equipment); and

3. Various electrical tests (endurance,variable input voltage, transients,abnormal, and component tem-perature for all equipment; andstatic discharge for detectionproducts).

As part of the aforementioned tests,the acceptable operation of the productis verified before and, depending uponthe conditioning, either during orimmediately after each test. Thisinvolves examining control equipmentfor minimum required operation, evalu-ating amplifiers for acceptable harmon-ic distortion and frequency responselevels, verification of stable sensitivityfor detection products, and maintainingrated audible and visual outputs, asapplicable, for notification appliances.

Additionally, the above tests are con-ducted to determine that no falsealarms occur and to confirm the condi-tioning does not have an adverse affecton the threshold response for smokedetectors when adjusted to maximumsensitivity settings. This procedure alsoestablishes the upper sensitivity limit ofthe production window. During thesmoldering smoke test, no alarm mayoccur before 0.5 percent per footobscuration.

Smoke detection initiating devicesare subjected to wood, paper, gas, andplastic fire tests as well as a smolderingsmoke test while calibrated to theirleast favorable production sensitivity.Heat detectors are subjected to full-scale fire tests while mounted on theirrated spacing.Un

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The evaluation of compatibility ofinterconnected equipment is critical inconfirming an effective fire alarm sys-tem. The compatibility evaluation mayinvolve:

1. The confirmation of the requiredoperation of interconnected con-trol equipment such as fire alarmcontrol units and related acces-sories, networked fire alarm con-trol units, all products on signaling

line circuits, and interoperability ofprotected premises and receivingequipment. This testing is conduct-ed with maximum and/or mini-mum number of devices (or elec-trical load simulation where possi-ble) and maximum and/or mini-mum line losses;

2. Confirming voltage and currentoutput levels of the fire alarm con-trol units and accessories consis-

tent with the input ratings for thenotification appliances and detec-tion devices referenced in theinstallation instructions/ wiring dia-gram for the control equipment;and

3. Verification of operability of two-wire smoke detectors with anycontrol equipment.

In 1989, UL issued new requirementsfor the evaluation of compatibility offire alarm control equipment and two-wire smoke detectors. As part of thisprogram, UL verifies various electricalspecifications provided by the manu-facturers through laboratory tests, anda comparison of the specifications isconducted to confirm that the operat-ing parameters of each product arebeing met.

FOLLOW-UP SERVICE

A fourth component contributing toan effective fire alarm system is UL’sFollow-Up Service (FUS) for the com-ponents of the system. This programconsists of periodic visits by speciallytrained Field Representatives to eachmanufacturing location of the firealarm system component. During thesevisits, the Field Representatives exam-ine the construction of the product,verify that required production linetesting has been performed, andreview items such as marking andinstallation instructions.

UL Standards for the product covernot only the required minimum perfor-mance the product must demonstrateduring the UL investigation, but alsospecify requirements for product con-struction and minimum marking andinstruction requirements. As a part ofthe UL initial product investigation, anFUS Procedure is prepared. This proce-dure is for the use of UL’s FieldRepresentatives during their visits tothe factory. It contains product-specificinstructions for the FieldRepresentative’s use during the visit, adescription of the specific UL Marks tobe applied to the product, and adescription of the product.

Using a combination of product pho-tographs, written product description,and manufacturer’s prints, all of whichare included in the FUS Procedure,UL’s Field Representative will verifythat the product being manufactured is


the same as was tested during the ini-tial product investigation. The FieldRepresentative verifies that any produc-tion line testing, as specified by thespecific UL Standard covering the prod-uct, is being performed. Should theField Representative note any discrep-ancies in product construction duringthe visit, the variation is noted and, ifdeemed significant, use of the UL Markmay be withheld until UL has evaluat-

ed the variation. The FUS programassures that the product is equivalentto the product that was evaluated dur-ing the initial product investigation.

ALARM SYSTEM CERTIFICATION

Another component that contributesto an effective fire alarm systeminvolves a method to identify alarmsystems that have been properly

installed, tested, monitored, and main-tained in accordance with applicableinstallation codes and standards. Thestandard used by UL to evaluate thealarm system certification is UL 827,Central Station Alarm Services [UUFX].This service is identified as UL’s AlarmSystem Certificate Service.

The certification process begins byqualifying the alarm service company.A company can be qualified afterNICET-Certified members of UL’s alarmsystems auditing group review exam-ples of the company’s work. UL typi-cally charges between $1,800 to $3,900for this one-time, initial qualification,depending upon the level of serviceprovided by the alarm service compa-ny. UL then charges the alarm servicecompany an annual fee that currentlyranges between $1,270 to $1,920, plus$30 for each active certificate. Therecan be additional costs incurred by thealarm service company if an installedsystem is found to require upgrades tobring it into compliance with thecodes. These equipment and installa-tion costs can vary depending uponthe degree of modifications necessary.

If it is determined that a companycan install these systems in accordancewith the applicable codes and standards,the company is authorized to issue cer-tificates to cover the systems that theyinstall. The certificate is a document thatidentifies the type of alarm system, theprotected property location, the alarmservicing company, and a description ofthe system equipment. Each certificateincludes both the issue and expirationdates and a serial number. The alarmcompany retains a copy of the certifi-cate, while inspection authorities canverify specific certificates either onlineat UL’s Web site (www.ul.com/alarmsys-tems) or via printed documentationavailable from UL.

Once an alarm service company hasbeen qualified to issue certificates, acertain number of their certificatedinstallations are audited annually by ULto verify that they continue to complywith the applicable standards andcodes.

The authors are with UnderwritersLaboratories.



Life Safety Code provides two exceptions to the activation ofthe “general evacuation alarm signal” throughout the building.One of these exceptions provides buildings with physicalenvironments which make total evacuation of the occupantsimpractical, e.g., many high-rise buildings. The second ofthese exceptions provides for the occupancies in which theoccupants are incapable of “self-protection” and evacuationwithout the assistance of staff personnel is not feasible, suchas occurs in healthcare or detention and correction facilities.

The Life Safety Code permits automatically transmitted or“live voice” evacuation instructions. This provision for the utili-zation of recorded or “live voice” communications with theexceptions to the general evacuation notification were firstintroduced in the 1981 edition of the Life Safety Code.

INITIAL DESIGN AND UTILIZATION OF VOICE ALARM SYSTEMS

One of the first evaluations of the design criteria for a voicealarm system was established and reported by McCormick asearly as 1964. This design criteria consisted of the followingcritical elements for an effective vocal alarm system.3

1. Audible (heard above background noise)2. Quick-acting (capable of evoking a quick reaction)3. Alerting4. Discriminable (easy to differentiate from other signals)5. Informative6. Compatible (consistent with others in use)7. Nonmasking (not prone to interfere with other functions

by drowning out other audio signals)8. Nondistracting (not startling)9. Nondamaging (not prone to cause irreversible damage to

hearing)One of the early listings of the characteristics of a voice

alarm system was developed at the International Conference

PSYCHOLOGICAL VARIABLESTHAT MAY AFFECT

By Dr. John L. Bryan

Beginning with the 1996 edition, the National Fire AlarmCode® specified a distinctive “evacuation signal” thatused a three-phase temporal pattern signal in all new

fire alarm systems. The specification for the three-phase tempo-ral pattern can be seen in Figure 1.

The three-phase temporal pattern (ANSI S3.41) AudibleEmergency Evacuation Signal is intended to be used whereimmediate evacuation is intended. Where relocation of occu-pants or defense in place is intended, the National Fire AlarmCode contains requirements for an “emergency voice/alarmcommunications service,” which provides for verbal communi-cation to the occupants to facilitate the selective evacuation orprotection procedures.

The Life Safety Code, NFPA 1011 specifies when a fire alarmsystem is required and the features of the system that may varyfrom the requirements of the National Fire Alarm Code.2 The

National Fire Alarm Code® is a registered trademark of the National Fire Protection Association, Inc.,Quincy, MA 02269.

FIREALARMDesign


on Fire Safety in High-Rise Buildings in 1971.4, 5 These charac-teristics were reported to have consisted of the following ninefactors:6

1. A voice alarm system can give precise instruction undervarying emergency conditions (fire, bomb threat, etc.).

2. Instructions can vary for different zones of the building.3. Recorded alerting sounds can capture attention of the

people and alert them to emergencies at hand by precon-ditioning.

4. Prerecorded messages can be used for preplanned condi-tions.

5. Prerecorded voice announcements can be used automati-cally to respond to manual or automatic fire alarms.

6. The voice system can be used to modify or update infor-mation.

7. Number and type of speakers are dependent on the situ-ation of the area covered.

8. A voice alarm system may be combined with amusic/paging system. If so, the music system can beturned off, and the emergency announcement system canoperate at predesignated volume levels.

9. Manual voice directions can override or cancel automaticvoice transmission.One of the first “vocal alarm systems” was designed by

Keating and Loftus in the Seattle Federal Building in 1974. Thecritical design variables of this system consisted of the follow-ing features:7

The alerting tone consisted of a 1000 Hz, pure sine wavetone (the then-authorized FCC warning signal). The human earis reported to be most sensitive in the 500-3000 Hz range.7

The voice qualities of the communicator were varied with afemale voice to initiate the announcement and a male voice toprovide the emergency communication.

The actual wording of the messages provided the followingthree essential elements:

1. Tell the occupants exactly what has happened.2. Tell the occupants what they are to do.3. Tell the occupants why they should do it.

STUDIES AND OBSERVATIONS OF OCCUPANTS’RESPONSE TO ALARMS

There have been both experimental and observational stud-ies involving practice evacuations and fire incidents. Thesestudies have involved both systems using evacuation signalsand voice notification systems over the past thirty years. Thefollowing summaries of study reports are illustrative of the pub-lished observational and experimental research studies relativeto the responses of building occupants to the various types ofalarm signals or voice messages:

1. Seattle Federal Building, Seattle, WA, 1974.6

Keating and Loftus conducted two practice evacuationsinvolving 205 participants consisting of adults, both visitorsand employees. The alarm system consisted of a voice notifi-cation to the floors involved with the relocation and the floorsreceiving the relocated personnel. The report indicated theoccupants on the floors being relocated had vacated thesefloors within 1.5 minutes of the alerting tone initiating thevoice announcements. This report indicated the following gen-eral observation of the relocating occupants in response to thevoice announcements:6

“Personnel unhesitatingly went to the stairwells to evacuate,no one attempted to use the captured elevators, nor was thereany pushing, running, or other panicky behavior observed.”

2. World Trade Center, New York, NY, 1975.8

Lathrop has reported on a voice alarm system involved in afire incident in the South Tower on April 17 at approximately9:04 a.m. The fire involved a trash cart in a storage area on thefifth floor, adjacent to an open stairway door. This configurationwith the thermal column from the cart fire enabled smoke topenetrate the ninth through the twenty-second floors. Theoccupants on these floors moved into the core corridors of thefloors as previously conducted during the practice evacuations.At approximately 9:10 a.m., a voice announcement from theTower Communications Center monitoring these areas advisedthe occupants to remain calm and to return to their respectiveoffice areas. In spite of this announcement, the occupantsremained in the corridor areas and became more concernedabout the visible and irritating smoke condition. The TowerCommunications Center then announced an evacuation mes-sage at approximately 9:16 a.m. It should be noted that thevalidity of any announcement will be questioned by occupantsif the announcement is in conflict with direct physical aware-

(a) Temporal pattern parameters. On

Off

Key:Phase (a) signal is on for 0.5 sec 10%Phase (b) signal is off for 0.5 sec 10%Phase (c) signal is on for 0.5 sec 10% [(c) = (a) + 2(b)]Total cycle lasts for 4 sec 10%

(a) (b) (a) (b) (a)

Cycle Time (sec)

Time (sec)

(c) (a)

(b) Temporal pattern imposed on audible notification appliances that otherwise emit a continuous signal while energized.

(c) Temporal pattern imposed on a single-stroke bell or chime.

On

Off

On

Off

0 2 4 6 8 10

Time (sec)0 2 4 6 8 10

Figures A-3-8.4.1.2 a to c

Figure 1. Figures A-3-8.4.1.2 a to cFigures are reprinted with permission from NFPA 72 National Fire AlarmCode® Copyright © 1999, National Fire Protection Association, Quincy,MA 02269. This reprinted material is not the complete and officialposition of the National Fire Protection Association on the referencedsubject, which is represented only by the standard in its entirety.


ness cues evident to the occupants.Thus, in this situation, the physical pres-ence and discomfort from the smokeresulted in the occupants disregardingthe information presented by the voiceannouncement.

3. Conference Room, London, UK, 1987.9, 10

Pigott has described an experimen-tal study in a basement conferenceroom in an office building with tworandomly selected groups, consistingof ten adults, five males and fivefemales. The adults were seated attwo tables, six at one table and fourat the other, with the seating selectedby the participants. They were givenquestionnaires to fill out prior tobeing called for interviews on marketresearch. The participants were givenbiscuits and coffee while filling outthe questionnaires.

The first group was subjected to acontinuous sounding alarm bell. Afterthe bell had operated, the ten subjectsdiscussed among themselves the mean-ing of the bell. The first subject to leavethe room left after a period of threeminutes, with the remaining nine per-sons leaving after eleven minutes. Thesecond group of ten subjects had theidentical refreshments and question-naire. This group was subjected to avoice alarm announcement initiated afterthree seconds of the ringing bell statedin the following manner:10

“Attention. This is an intelligent firewarning system. There is a fire aboveyou on the ground floor. Evacuatenow.”The second group subjected to the

above voice announcement all left theconference room within thirty seconds.It should be noted, as in many practiceevacuations, the ten subjects in eachgroup all left the basement level of thebuilding by the way they entered, dis-regarding a corridor door marked as a“Fire Exit.”

4. Lecture Theatre, Portsmouth, UK. 1989.11

Michiharu and Sime studied two prac-tice evacuations with biology and phar-macy students in the age range of 18-19years. Two different lecture theatreswere utilized, one with the fire exit andthe entrance/exit at the rear of the the-atre, and one with the fire exit at thefront of the theatre and the entrance/exit

at the rear of the theatre. The fire alarmnotification was by a continuous bell.The first evacuation practice involved thetheatre with the entrance/exit and thefire exit at the rear of the theatre. Thisevacuation involved a total of 56 individ-uals with 31 persons (55 percent) leavingby the entrance/exit and 25 (45 percent)leaving by the fire exit. Upon hearing thebell alarm, the lecturer, after a period of13 seconds, indicated the following:11

“We’d better all run for exits.”The second evacuation practice

involved the theatre with the entrance/exit at the rear and the fire exit at thefront of the theatre. This evacuationinvolved a total of 77 individuals, andthey all evacuated through the fire exitdue to the directions of the lecturer.The lecturer issued the exiting direc-tions after a few moments of hesitation,upon hearing the alarm bell in the fol-lowing manner:11

“I gather it sounds like a fire alarm,have to go that way.”The authors of this study indicate the

importance of instructions from a validand reliable source in influencing thebehavior of the occupants as follows:11

“The fact that everyone in the R lecturetheatre left by the fire exit, as a resultof the lecturer’s instruction, demon-strates how crucially important evacu-ation instructions from an authorita-tive and credible source can be.”

5. Underground Station, Newcastle, UK, 1991.12

Proulx and Sime conducted five prac-tice evacuations in the Monumentunderground transit station These evac-

uations involved approximately 304 par-ticipants, consisting of adults, children,and infants. The study utilized sevenobservers in the station, the 12 closedcircuit television cameras in the station,and 133 questionnaires completed byadult participants. The practice evacua-tions were all conducted at approxi-mately noon time on a weekday, and 5seconds after Train 124 arrived in thestation. Five different alerting scenarioswere utilized in the practice evacua-tions, consisting of the alarm bell, staffdirections, and public address systemannouncements.12

Evacuation 1: The alarm bell wasrung; there was no staff in the stationand no public address (PA) used.

Evacuation 2: Two staff members onPlatform 3 knew a drill was scheduled,gave a PA announcement to “evacuate the station,” and directed evacuation.

Evacuation 3: Each 30 secs. (10 sec.message, 20 sec. interval) PA announce-ment “Please evacuate the stationimmediately.” No staff in the station.

Evacuation 4: Two staff membersassisted evacuation with PA directions topassengers on platform to take trains andthose on concourse to leave by exits.

Evacuation 5: No staff in station.Directed PA was used: “To all passen-gers. There is a suspected fire on the North/South escalator between the con-course and platforms 1 and 2.Passengers on all platforms shouldboard the first available train. Pass-engers at concourse level should leaveby the nearest exit. Do not use the lift.”

Table 1 contains a summary of theresults of these evacuations.

Evacuation

Time to Start to Move

Concourse BottomEscalator

Time to Clearthe Station

Appropriateness ofBehavior

1Bell only

8:15 9:00 Exercise ended 14:47 Delayed or noevacuation

2Staff

2:15 3:00 8:00 Users directed toconcourse

3PA

1:15 7:40 10:30 Users stood at bottomof escalator

4Staff + PA + 1:15 1:30 6:45 Users evacuated

5PA ++

1:30 1:00 5:45 (10:15) Users evacuated bytrains and exits

Table 1. Summary of Times and Movements:12

Note: In Evacuation 5, the indicated time of (10:15) to clear the station was by a woman with two small children and a babyin a push cart.


6. Apartment Buildings, Ottawa,Montreal, North York, Vancouver,Canada, 1993.13

Proulx studied practice evacuationsin four 6- and 7-story apartment build-ings, one evacuation in each building.The total study population consisted of254 participants with adults, seniors,impaired adults, and children. Thealarm/notification systems consisted ofbells. The results of these practice evac-uations indicated the time to initiate theevacuation varied from 30 seconds to24 minutes, with a mean time of 2.5minutes. The most prevalent pre-evacu-ation activities were:13

“Find pet, gather valuables, getdressed, look in corridor, move to bal-cony, find children.”

7. High-Rise Apartment Building,Ottawa, Canada, 1997.14

Proulx studied this fire whichoccurred in a unit on the sixth floor of a25-story apartment building at approxi-mately 4:30 p.m. This study involved theconduct of interviews with occupants ofthe sixth and seventh floors and the dis-tribution of questionnaires to all theother units. A total of 137 questionnaireswere utilized in the study consistingonly of persons that were in the build-ing at the time of the fire. The popula-tion in the building was predominatelyadults with 68 percent over 65 years, 29percent between 21 and 65 years, andonly 3 percent children or teenagers. Atotal of 43 adults consisting of 23 per-cent reported perceptual, physical, ormental impairments. The fire alarm sys-tem consisted of a sounding devicethrough speakers in each unit, with thefire alarm signal being overridden byvoice messages through the speakers.The building manager operates thevoice communication system and madethe following four announcements asindicated in the report:14

The first message was given beforethe arrival of the fire department; itstated: “There is a fire on the sixthfloor. The fire department is on itsway.” After the fire department’s initialassessment of the situation, the chiefin command gave the order to evacu-ate. The resident manager issued themessage: “All occupants should evacu-ate using Stairwells B and C.” Afterencountering occupants coming downStairwell A that was being used for

fire-fighting, another message wasissued: “Occupants should not evacu-ate through Stairwell A.” Finally, manyexhausted, anxious occupants exitedfrom all stairwells into the lobby com-plaining of the crowd and smoke conditions they encountered. The chiefin command decided to change strate-gy, and a last message was issued:“Occupants who have not started toevacuate should remain in theirunits.”

A new alarm system had beeninstalled five months before the fire,and this system was tested monthlywith a voice announcement prior to thetest. The ten occupants who indicatedthey had hearing impairments all indi-cated they were alerted by the firealarm and eight indicated the voiceannouncements were clear. Consideringall the occupants responses, 95 percentindicated the instructions over the voiceannouncements were clear.

In spite of the confusion created bythe contradictory voice instructions “toevacuate” and then “not to evacuate,”the report of this fire incident concludesin the following manner relative to theutilization of the voice announcements:14

“The occupants placed considerabletrust in the information received overthe voice communication system. Thisis evident from the 83 percent of therespondents who attempted evacuationas a result of evacuation instructionsgiven over the voice communicationsystem. It confirms that, in mostinstances, the public is prepared to fol-low voice communication instructions,especially if this means of providinginformation has been accurate in thepast and if the message comes from aperson in which they confide or fromfigures of authority such as the firedepartment.”

SUMMARY

The characteristics of voice alarm sys-tems have been established since the1960s and early 1970s. The effectivenessof these systems has been demonstratedin both practice evacuations6, 9, 10, 12, 15 andactual fire incidents.8, 14 The critical func-tion needed for a fire alarm system is todirect an adaptive behavioral responseof the occupants by providing theessential definitive and directive infor-mation relative to the fire incident to the

occupants. This information cannot beconveyed by a signaling type of system,due to the lack of the communicationcapability to provide the followinginformation to the occupants:7, 14

What has happened. What they are to do.Why they should do it.Ramachandran in his review of the

studies on human behavior in fires inthe United Kingdom formulated the fol-lowing conclusions which emphasizethe importance of providing completeand valid information to the buildingoccupants upon the detection of possi-ble fire cues:16

“Early behavior is characterized byuncertainty, misinterpretation, indeci-siveness, and seeking additional infor-mation for confirmation – the ‘gather-ing phase.’ Such delay can be danger-ous, as actions taken at the earlystages of a fire have the most decisiveeffect on the eventual outcome.” The response to fire alarm bells and

sounders tends to be less than optimum. There is usually skepticism asto whether the noise indicated a firealarm and if so, is the alarm merely asystem test or drill?

In the stress of a fire, people oftenact inappropriately and rarely panic orbehave irrationally. Such behavior, to alarge extent, is due to the fact thatinformation initially available to peopleregarding the possible existence of afire and its size and location is oftenambiguous or inadequate.

Valid information is needed relativeto a perceived fire incident by theoccupants of a building, and both theNational Fire Alarm Code2 and the LifeSafety Code1 permit the utilization ofvoice alarm systems which provide theneeded communication capabilities totransmit this information.Ramachandran in the report on aninformative fire warning system devel-oped a psychological design criteria fora fire alarm system:17

1. The meaning of a fire alarm mustbe obvious and distinct fromother types of alarms.

2. Fire alarms must be reliable andvalid indicators of the presence ofa fire.

3. People need to know the locationof a fire so they can authenticatethe alarm and plan their response.

4. There is a need to provide infor-


mation to building occupants onthe most appropriate response toan alarm, including information onavailable escape routes.

The adaptation of the behavioral andpsychological principles previouslyillustrated should enable fire protectionengineers to more effectively utilize thecommunication and information capa-bilities of voice alarm systems in thedesign, specification, and installation offire alarm systems.

Significant scientific research is alsoneeded to compare the effectiveness ofthe human behavioral response of vari-ous populations to the ANSI S3.41Audible Emergency Evacuation signalas compared with voice alarm systemsand other existing audible signalingsystems.

John Bryan is Professor Emeritus inthe Department of Fire ProtectionEngineering, University of Maryland.

REFERENCES

1 National Fire Protection Association, Codefor Safety to Life from Fire in Buildingsand Structures. NFPA 101, Quincy, MA:National Fire Protection Association, 2000.

2 National Fire Protection Association,National Fire Alarm Code. NFPA 72,Quincy, MA: National Fire ProtectionAssociation, 1999.

3 McCormick, E. J., Human FactorsEngineering. New York: McGraw Hill,1964, 171-172.

4 General Services Administration, Pro-ceedings of the Reconvened InternationalConference on Fire Safety in High-RiseBuildings. Washington, DC, October 1971.

5 Hicks, H. D., “Another Look at DesignGuidelines for Voice Alarm Systems,”NFPA Journal, 88, (January/February1994), 50-52.

6 Keating, J. P., and Loftus, E. F., PeopleCare in Fire Emergencies – PsychologicalAspects. Boston: Society of Fire ProtectionEngineers, Technical Report 75-4, 1975.

7 U. S. Government Printing Office,Human Engineering Guide to EquipmentDesign, Washington, DC, 1972.

8 Lathrop, J. K., “Two Fires DemonstrateEvacuation Problems in High-RiseBuildings,” Fire Journal, 70, (January1976), 65-70.

9 Darlowsmithson, “Blaze=Equinox – YouWant Bells on It?” (VCR Tape), London,1988.

10 Pigott, B. B., “An Administrator’s View ofHuman Behavioural Research from 1975to 1995,” Human Behaviour in Fire:Proceedings of The First InternationalSymposium. Fire Sert Centre, Universityof Ulster, 1998, 31-38.

11 Kimura, M., and Sime, J. D., “Exit ChoiceBehavior During the Evacuation of TwoLecture Theatres,” Fire Safety Science –Proceedings of The Second InternationalSymposium. Washington: HemispherePublishing Corp., 1989, 541-550.

12 Proulx, G., and Sime, J. D., “To PreventPanic in an Underground Emergency:Why Not Tell People the Truth?” FireSafety Science-Proceedings of The ThirdInternational Symposium. London:Elsevier Applied Science, 1991, 843-852.

13 Proulx, G., “The Time Delay to StartEvacuating Upon Hearing a Fire Alarm,”Proceedings of The Human Factors andErgonomics Society. Nashville, 1994, 811-815.

14 Proulx, G., “The Impact of VoiceCommunication Messages During aResidential High-Rise Fire,” HumanBehaviour in Fire: Proceedings of TheFirst International Symposium. Fire SertCentre, University of Ulster, 1998, 265-274.

15 Cable, E. A., Cry Wolf Syndrome:Radical Changes Solve the False AlarmProblem. Department of Veterans Affairs,Albany, NY, 1994.

16 Ramachandran, G., “Human Behavior inFires – A Review of Research in TheUnited Kingdom,” Fire Technology, 46,(May 1990), 149-155.

17 Ramachandran, G., “Informative FireWarning Systems,” Fire Technology, 47,(February 1991), 66-81.

18 Burns, D. J., “The Reality of ReflexTime,” WNYF, 54, 1993, 26-29.

19 Fahy, R. F., and Proulx, G., “CollectiveCommon Sense: A Study of HumanBehavior During The World TradeCenter Evacuation,” NFPA Journal, 87,(March/April 1995), 59-67.


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Entry-level Fire Protection EngineerSummary: The Los Alamos National Laboratory (LANL) Fire Protection Group helps protect one of themost prestigious scientific research and development institutions in the world. This group is seekingan entry-level Fire Protection Engineer. The successful candidate will be part of a team of customer-oriented fire protection professionals who implement and maintain the Laboratory's Fire ProtectionProgram. Responsibilities may include conducting construction inspections, life safety inspections,and loss prevention inspections; recommending fire protection for new facilities; preparing systemspecifications; performing drawing and calculation reviews; witnessing system acceptance tests;preparing Fire Hazard Analyses, etc. There are many different types of fire hazards associated with theLaboratory's many facilities, making this an excellent opportunity for an entry-level engineer to quickly broaden her or his experience.Required Skills: Knowledge of fire protection engineering, building construction, and NFPA codes andstandards. Ability to work as part of a team to accomplish project objectives in addition to interactingeffectively with peers. Ability to perform in an environment where priorities and schedules are constantly changing. Strong self-motivation and goal-oriented management of multiple tasks. Abilityto work on specific projects independently. Effective interpersonal, written, and verbal communica-tion skills. Be available to work various hours in a 24-hour period when necessary. Must have the ability to obtain a “Q” level security clearance.Desired Skills: Experience/knowledge in HPR insurance industry or fire protection/loss prevention programs. Familiarity with Factory Mutual data sheets and Underwriter’s Laboratory listings used in highly protected risk (HPR) facilities. Familiarity with ASTM, UBC and other pertinent codes andstandards applicable to fire protection engineering. Engineering in Training (EIT) courses or professional engineering (PE) registration. Familiarity with fire protection in nuclear facilities. Have anactive UC-DOE “Q” clearance. Education: BS in Fire Protection Engineering (FPE), Engineering degree with relevant fire protectionexperience, or equivalent combination of education and relevant experience.Notes to Applicants: For specific questions about the status of this job, call (505) 665-1823.

To Apply: Submit a comprehensive resumeand cover letter that addresses the specificrequired and desired criteria, referencing“FireProEng016737”, via email [email protected], or via postal service to theResume Service Center, Mailstop MSP286,Los Alamos, NM 87545.

Operated by the University of Californiafor the Department of Energy. AA/EOE


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]

SCHIRMER ENGINEERING

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.

Arup Fire

The F.P. ConnectionAn 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

As part of our global expansion, Arup Fire is seeking to add staff through-out the USA, including Massachusetts, New York, California, Washington,

DC, and Florida. Successful candidates will play a very active role in develop-ing Arup Fire in the USA and will work closely with many of the world’s lead-ing architects and building owners, developing innovative, performance-baseddesign solutions for a wide range of building, industrial, and transport pro-jects.

This is an excellent opportunity for qualified fire engineers to develop theircareer within one of the leading international fire engineering consultancies.

Candidates should possess a degree in Fire Protection Engineering or relat-ed discipline, approximately five years of experience in code consulting anddeveloping performance-based strategies in a project design environment, anda PE in Fire Protection Engineering or related field. Risk management, quanti-tative risk assessment, industrial fire engineering, and computer modelingskills will be highly regarded.

Successful candidates will have excellent report writing and interpersonalskills. They should also have an ability to present clear and technically soundfire engineering strategies and have good negotiating skills in order to gainapproval of clients, architects, and authorities for fire engineering designs.

Arup Fire offers competitive salaries and an excellent benefits package.

Please submit your résumé andsalary history to:

Arup Fire901 Market StreetSuite 260San Francisco, CA 94103

http://www.arup.com/

Attention: Jim QuiterTelephone: 415.957.9445Fax: 415.957.9096E-mail: [email protected]

ClassifiedsCareers/

FIRE PROTECTION ENGINEER

New ConstructionSalary: $51,355 - $72,883

Requires a bachelor’s degree in Fire Protection Engineering or aclosely related field. One year Fire Protection Engineering experi-

ence in new construction is required.

Please submit cover letter, résumé, and mini-application. Pleaseinclude in your résumé or cover letter your experience in reviewingmajor building/construction plans, especially in performance engineer-ing, and fire and life safety reports; working with fire codes, buildingcodes, and NFPA standards; evaluating, reviewing, and testing firedetection, fire protection, and life safety systems; and working withengineers, architects, contractors, and government officials.

Mini-applications can be downloaded from our Web site, phoenix.gov;picked up at the Personnel Department Application Office, 135 N. 2ndAvenue, Phoenix, AZ 85003; or mailed to you by calling ourApplication Office at 602.262.6277.

Continuing professional development isbecoming essential in today’s fast-chang-ing fire protection engineering work-

place. To meet the demands of our members,allied professionals, and increasingly, statelicensing boards, the second annual SFPEProfessional Development Week will be heldSeptember 10-14, 2001, at the Mt. WashingtonConference Center, 5801 Smith Avenue,Baltimore, MD 21209.

Featuring a technical symposium on compu-ter applications in fire protection engineeringand nine seminars ranging from the latest tech-nology in performance-based design to fire pro-tection system design, this intensive five-day/four-track week provides you the opportu-nity to sharpen your skills and interact withyour peers. Continuing education units/profes-sional development hours will be granted for allevents.

Each event is priced separately to permit youto select those which best match your currentprofessional development needs. Detailed infor-mation on each course may be found on SFPE’sWeb site, www.sfpe.org, or from headquartersat 301.718.2910.

Continuing Education from the Society of Fire Protection Engineers

September 10-14, 2001


SEMINARSFire Alarm Systems Design – advanced alarmsystem design techniques applied to real-world examples, including equipment selec-tion, systems design and specifications, andperformance-based design concepts

Performance-Based Design and the Codes –applying pbd in the NFPA and ICCPerformance Code environments

How to Study for the FPE/PE Exam – assists withformulating a preparation strategy for the FPEPE exam

The Project Manager’s Notebook – a guide to man-age and sustain a project from marketingthrough design and construction to close out.Includes classroom exercises, a text, and ready-to use spreadsheets for project management

IBC Special Uses and Mixed Occupancies – anoverview and application of code requirementsfor mixed occupancies, hazardous materials,unlimited area occupancies, covered malls, andhigh-rise buildings

Maryland Building Rehabilitation Code Seminar –reviews and integrates the concepts in the newcode and others currently underway nationally

NFPA 5000 Building Code – provides an overviewof the new code and details on height and areatables, structural design, and occupancy-basedcriteria and requirements

Principles of Fire Protection Engineering – for allindividuals interested in gaining or refreshingtheir basic to intermediate knowledge of theprinciples of fire protection engineering. Coversten subjects from combustion and ignition phe-nomenon to egress and exits

Resources

FEATURED EVENTS

3rd Technical Symposium on Computer Applications inFire Protection Engineering – includes a survey andcomparisons of models, validation and evaluationstudies, forensic analysis using fire modeling, andother topics

Short Course on Advanced Computer Fire Modeling –how to select the right model for the job, limita-tions, problem-solving, and case studies

September 10-14, 2001SFPE Professional Development WeekBaltimore, MDInfo: www.sfpe.org

October 4-6, 2001National Conference on Science and the LawMiami, FLInfo: http://nijpcs.org/SL_2001/SLBrochure.htm

November 10-14, 2001NFPA Fall MeetingDallas, TXInfo: www.nfpa.org

December 2-5, 2001Symposium on Thermal Measurements:The Foundation of Fire StandardsDallas, TXInfo: www.astm.org

U P C O M I N G E V E N T S


December 3-6, 20015th Asia-Oceania Symposium on Fire Science & TechnologyNewcastle, AustraliaInfo: http://www.eng.newcastle.edu.au/cg/AOSFST5/welcome.html

March 20-22, 20024th International Conference on Performance-Based Codes and Fire Safety Design MethodsMelbourne, AustraliaInfo: www.sfpe.org

May 19-23, 2002NFPA World Fire Safety Congress and ExpositionMinneapolis, MNInfo: www.nfpa.org

September 17-19, 2002Interflam 2001Edinburgh, UKInfo: http://dialspace.dial.pipex.com/town/park/xzg98/interflamindex.htm

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

NAVAL FACILITIES ENGINEERING COMMAND

The Atlantic Division, Naval Facilities Engineering Command(LANTDIV) is seeking two (2) experienced fire protection engineersfor our Norfolk, Virginia location. LANTDIV is an agile, global engi-neering organization. Our engineering professionals provide con-tingency engineering; shore facilities planning, design and con-struction; and engineering support for base operations and main-tenance to the nation and its military forces. We are a full servicedesign organization consisting of a highly qualified staff of engi-neers and architects capable of solving any technical problemassociated with facilities design and construction. The work con-sists of projects involving widely diverse Department of Defenseand Federal Government facilities, both stateside and overseas.The projects involve fire protection and life safety elements ofbuilding design and construction for new construction, renovation,repair, alteration, and adaptive reuse of existing facilities.

Competative salaries. Excellent benefits packages (i.e.,annual leave, sick leave, health benefits, and retirement).

Signing bonus is negotiable.

Must be a U.S. Citizen

For information and to apply, visit http://www.usajobs.opm.gov/.Reference Series #0804, Announcement Number AN02359.

For additional information, contact Robert J. Tabet at (757) 322-4408 or e-mail [email protected].

The Navy is an equal opportunity employer.


• Advanced Fire Technology, Inc. ...................Page 30• Ansul, Inc. .........................................................Page 8• Bilco.................................................................Page 11• Blazemaster Fire Sprinkler Systems ..............Page 45• Central Sprinkler .............................................Page 49• Commercial Products Group .........................Page 39• Draka USA.......................................................Page 41• Edwards Manufacturing..................................Page 40• Edwards Systems Technology ..............Page 28 & 29• Fike Protection Systems .................................Page 17• Fire Control Instruments, Inc.........................Page 31• Gem Sprinkler Company..........................Back Cover• Great Lakes Chemicals ...................................Page 26• Koffel Associates.............................................Page 32

• Master Control Systems ..................................Page 19• Metraflex..........................................................Page 10• NOTIFIER Fire Systems....Page 4 & Inside Back Cover• Potter Electric Signal Company .......................Page 2• Protection Knowledge Concepts...................Page 14• Protectowire ....................................................Page 38• The RJA Group..............................Inside Front Cover• Reliable Automatic Sprinkler ................Page 23 & 36• Seabury & Smith .............................................Page 55• Siemens............................................................Page 51• SimplexGrinnell .....................................Page 12 & 13• TVA Fire & Life Safety, Inc. ...........................Page 35• Viking Corporation .........................................Page 46• Wheelock, Inc. ................................................Page 20

Index ofAdvertisers

CORPORATE 100

Solution to last issue’s brainteaser

Each letter below stands for only one other letter. Can you crack the code

and figure out what all these fire protection words are?

PRIH = FIRE

MXEXIA = HAZARD

ROFRYRLF = IGNITION

HWGLUTIH = EXPOSURE

AHFURYS = DENSITY

HWYRFOTRUMHI = EXTINGUISHER

AHZXFA = DEMAND

UGIRFVCHI = SPRINKLER

FLEECH = NOZZLE

GILYHJYRLF = PROTECTION

Starting with the letter A, number the letters in thealphabet in order from 1 to 26. Using these values forthe letters, find a word with the product of 69,888.

Thanks to Jane Lataille, P.E., for providing this issue’sbrainteaser.

B R A I N T E A S E R The SFPE Corporate 100 Program wasfounded in 1976 to strengthen the relation-ship between industry and the fire protec-tion engineering community. Membershipin the program recognizes those who sup-port the objectives of SFPE and have agenuine concern for the safety of life andproperty from fire.

BENEFACTORSRolf Jensen & Associates, Inc.

PATRONSCode Consultants, Inc.Edwards Systems TechnologyHughes Associates, Inc.The Reliable Automatic Sprinkler Company

MEMBERSArup FireAutomatic Fire Alarm AssociationBFPE InternationalFactory Mutual Research CorporationFike CorporationGage-Babcock & Associates, Inc.Grinnell Fire Protection SystemsHarrington Group, Inc.HSB Professional Loss ControlHubbell Industrial ControlsJoslyn Clark Controls, Inc.James W. Nolan Company (Emeritus)Industrial Risk InsurersKoffel Associates, Inc.Marsh Risk ConsultingNational Electrical Manufacturers AssociationNational Fire Protection AssociationNational Fire Sprinkler AssociationNuclear Energy InstituteThe Protectowire Co., Inc.Reliable Fire Equipment CompanyRisk Technologies, LLCSchirmer Engineering CorporationSiemens Cerberus DivisionSimplexGrinnellUnderwriters Laboratories, Inc.Wheelock, Inc.W.R. Grace Company

SMALL BUSINESS MEMBERSBourgeois & Associates, Inc.Demers Associates, Inc.Fire Consulting Associates, Inc.MountainStar EnterprisesPoole Fire Protection Engineering, Inc.S.S. Dannaway & Associates, Inc.The Code Consortium, Inc.


During the development ofSFPE’s White Paper on theroles of engineers and techni-

cians,1 a few anecdotes were broughtup that illustrated situations whereengineers did not perform their jobsproperly. Examples included situationswhere engineers delegated engineeringtasks to nonengineers or practiced out-side of their expertise.

As engineers, if we become aware ofa situation where another engineer hasplaced the public at risk, we have aresponsibility to act. The public, ouremployers, and our clients depend onus to make decisions that provide themwith appropriate fire safety. Becausethe public does not have an under-standing of fire protection engineeringprinciples, they are unable to judgewhen we do not fulfill our responsibili-ties. The public depends on us topolice ourselves.

The SFPE Canons of Ethics for FireProtection Engineers2 identifies a hierar-chy for the types of actions that shouldbe taken when a fire protection engi-neer becomes aware of a hazardouscondition: notification of an employer orclient, and if such notification is notproperly acted upon, notification of theappropriate pubic authority.

However, blowing the whistle on acolleague is serious matter, and lesseroptions may be warranted dependingon the circumstances. Prior to notifyingany outside authorities, an engineerwho suspects that another engineeracted improperly should first verify thata breach has indeed occurred. This willtypically involve searching for and ana-lyzing additional information to gaininsight into the context in which deci-sions were made that led to the per-ceived ethical breach.

Whitbeck3 suggests that perceivedethical problems could be approachedin a manner similar to design problems:

• Develop an understating of theunknowns. When a possible ethicalwrongdoing becomes apparent,there will be many unknowns.These unknowns should be identi-fied; however, it may not be neces-

sary to resolve these unknowns,since resolving them may not bepossible at this stage. Any ambigui-ties should be described with mini-mum interpretation.

• Define the ethical issues involvedand consider courses of action. Theethical issues involved should bedefined to the extent possible. Wasit a case of an engineer practicingoutside of their area of expertise? Isit a chronic problem? With a betterunderstanding of the ethical issuesinvolved, possible courses of actionwill become apparent.

• When there are multiple possiblecourses of action, they should bepursued simultaneously. Some pos-sible courses of action may not beavailable indefinitely. Therefore,the evaluation of options should beconducted so that time-sensitiveoptions are not excluded onlybecause they were not consideredin a timely fashion.

• Ethical issues have a dynamic char-acter. As additional information isobtained, it is likely that the under-standing of the ethical issues willchange. If the understanding doeschange, the possible courses ofaction considered must evolve aswell.

As kids, we were taught that it iswrong to “rat out” our peers. However,as adults, society depends on us tobring ethical wrongdoings to light.Failure to do so could result in conse-quences that reflect badly on the entirefire protection engineering profession.

1 “The Engineer and the Technician:Designing Fire Protection Systems,”Society of Fire Protection Engineers, 1998.Available from http://www.sfpe.org/what-isfpe/final_white_paper.html.

2 Available from http://www.sfpe.org/what-isfpe/canon.html.

3 Whitbeck, C., Ethics in EngineeringPractice and Research. CambridgeUniversity Press, New York: 1998.

A Responsibility to Ourselves

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

from the technical director

Documents

FIRE PROTECTION · 2018-04-02 · fire protection performance metrics for fire detection psychological variables that may affect fire alarm design underwriters laboratories contributions