1、826 ASHRAE TransactionsABSTRACTAssessing and reducing vulnerability of building occu-pants to intentional indoor airborne releases of chemical andbiological agents has acquired some importance in the pasttwo decades. This paper reports on the evaluation and compar-ison of a set of available tools (d
2、escribed in the companionpaper) that have been developed for practical and pragmaticuse by building security professionals, consulting engineers,building owners, and maintenance personnel to evaluate thevulnerability of a building and determine the effect of imple-menting specific countermeasures. T
3、hese tools have beenapplied to a few carefully selected buildings so that theirresponses can be evaluated both in terms of the risk assessmentaspect as well as a portion dealing with evaluation of resiliencymeasures. The ease in using the tools, the quantity and spec-ificity of the suggestions they
4、provide, and the extent to whichthe responses differ between tools are issues that have beeninvestigated and are presented in this paper. Also articulatedare suggestions for future modifications to these tools in orderto make them more user-friendly while enhancing their capa-bilities (such as being
5、 able to tailor the tools to a specific build-ing rather than to a generic type, compute risk explicitly,compute the consequences of the event, etc.).BACKGROUNDPart I of this paper (Reddy et al. 2011) presents findingsof a scoping study undertaken to review existing literature,available protocols, a
6、nd analysis tools meant to first evaluatecurrent state of risk of building occupants from chemical andbiological (CB) threats, and then suggest mitigation measuresto reduce vulnerability (Bahnfleth et al. 2008). The literatureexamined was specific to indoor airborne threats and dealtwith technologie
7、s and design practices for enhancing resil-iency via ways of securing the buildings heating, ventilating,and air-conditioning (HVAC) systems. Gaps in the open liter-ature were also discussed. The CB threat and metrics to quan-tify them were identified and reviewed, and it was found thatthough a numb
8、er of reasonable performance measures havebeen proposed by various organizations and researchers, allhave limitations, and no consensus standard has as yetemerged. In terms of recommended technologies and designpractices for enhancing resiliency, there are a fair number ofdocuments that provide guid
9、ance (largely repetitive), but theirrecommendations are mainly heuristic and are rarelysupported by quantitative data. Only a few studies have quan-titatively, via simulations and/or field trials, analyzed theeffectiveness of the resiliency measures advocated. The scop-ing study also identified and
10、discussed gaps in the variousanalysis methods, tools, and simulation programs meant toevaluate building security and to mitigate against these threats.Though several of the evaluation guidelines have appeared inthe published literature for years, not a single paper/report wasfound that evaluates the
11、se in terms of practical applicabilityand relevance against one another or in absolute terms. Thispaper reports on findings of a study undertaken to address thisdeficiency.TOOLS TO BE EVALUATEDThe following five tools were identified and described insome detail by Reddy et al. (2011) as useful to pr
12、acticing engi-neers and field professionals to obtain practical and pragmaticrisk assessment and guidance on how to enhance resistance oftheir facilities to indoor airborne threats: Analysis Tools and Guidance Documents for Evaluating and Reducing Vulnerability of Buildings to Airborne ThreatsPart 2
13、: Comparison of ToolsT. Agami Reddy, PhD, PE Steven SnyderFellow ASHRAE Associate Member ASHRAEJustin Bem William Bahnfleth, PhD, PEStudent Member ASHRAE Fellow ASHRAET. Agami Reddy is SRP Professor of Energy and Environment in the School of Architecture and Landscape Architecture and a professor in
14、 the Schoolof Sustainability and Steven Snyder is a graduate student and research assistant in the School of Architecture and Landscape Architecture, Arizona StateUniversity, Tempe, AZ. Justin Bem is a mechanical engineer with James Posey Associates Inc., Baltimore, MD. William Bahnfleth is director
15、 of theIndoor Environment Center and a professor in the Department of Architectural Engineering, The Pennsylvania State University, University Park, PA.LV-11-0162011. American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. (www.ashrae.org). Published in ASHRAE Transactions, V
16、olume 117, Part 1. For personal use only. Additional reproduction, distribution, or transmission in either print or digital form is not permitted without ASHRAES prior written permission.2011 ASHRAE 8271. The HVAC Building Vulnerability Assessment Tool(BVAT), developed by the Rhode Island Department
17、 ofHealth (RIDH 2004) 2. The Building Assessment Checklist (BAC), developedby the Los Angeles County Department of Public Health(Fielding et al. 2006)3. The Building Vulnerability Assessment and MitigationProgram (BVAMP), developed by the Lawrence Berke-ley National Laboratory (LBNL 2005) 4. The Che
18、mical/Biological Building Protection Tool(CBT), developed by the United Technologies ResearchCenter (UTRC 2004) 5. The document/software program, FEMA 452, developedby the Federal Emergency Management Agency (FEMA2005)METHODOLOGY The second objective of this paper is to report on ourobservations and
19、 conclusions in evaluating the above-described tools in terms of applying them to actual buildings.This section will describe our methodology for making suchan assessment and state the criteria involved. 1. Identify tools. The methodology for evaluating guidanceand risk assessment tools must first s
20、tart by identifyingthose that are developed to a stage where they are actuallytools that can be used in an actual and specific situation,as against general analysis procedures or methodologiesor case study examples. The subset of tools to be evalu-ated has already been identified, and they have been
21、stated in the section above.2. Evaluation criteria. The following criteria were identi-fied as appropriate to evaluate the selected tools: What information is needed and whom from thefacilities staff is best able to provide this informa-tion? Would the services of specialists be required toobtain it
22、? How difficult is it to get the necessary informationneeded by the tools? How long does it take to insert the necessary infor-mation in each tool? How do they describe a buildings vulnerability? What types of categories or distinct subsystems areused? How logical are they? What type of guidance do
23、they provide and what isits quality? How comprehensive and building-specific are therisk evaluations? How do the recommendations generated by the toolscompare with one another? How sensitive are the recommendations to changesin the inputs? How user-friendly and intuitive are the tools in theirinputs
24、? How opaque/transparent are the tools in how theydetermine or assess risk and propose mitigationmeasures? How sound are the suggested enhancements toreduce vulnerability?3. Risk assessment questionnaire. The first step in evaluatingthese tools was to become familiar with each of them interms of how
25、 their checklist or questionnaires weregrouped, and which specific questions were asked. Sincethere was a great deal of overlap in questions among thesetools, we felt the need to develop a single, concise checklistcontaining all the questions needed for all tools, and whichcould be administered only
26、 once to the building owner/manager. Having such a compact vulnerability question-naire greatly simplifies the process of obtaining buildinginformation, and is more appealing to facility managersfilling out such a questionnaire. The questions relating toairborne contaminant attacks were extracted fr
27、om eachtool and compiled into one comprehensive questionnaire.Next, all redundant questions were eliminated to create acompact vulnerability questionnaire that is geared specifi-cally toward airborne contaminant attacks (this question-naire can be found in Bahnfleth et al. 2008). 4. Identification o
28、f representative buildings. A final andimportant step in the evaluation procedure was to identifya few buildings to which the questionnaires could beapplied. The scope was limited to noncritical buildings,i.e., buildings for which security from terrorist incidentsis not normally a design considerati
29、on, and so no specialprotective measures are incorporated in their designs.Then, a logical choice is to select buildings that fall underthe office and hotel categories. The former comprises byfar the largest portion of building stock, while the lattercan be viewed as one where a large number of occu
30、pantscould be adversely affected. RESULTS OF EVALUATING THE TOOLSRepresentative BuildingsBuildings on university campuses are subject to a height-ened risk of attack compared to most buildings because of theirhigh visibility and open access. Four buildings were selectedwhose characteristics are repr
31、esentative of a large portion ofbuilding stock that would qualify as noncritical importancelevel (see Table 1): two each from two university campuses,one in an urban setting and another in a semi-rural universitytown setting. One building is a typical residence hall on theurban campus. Residence hal
32、ls usually have fairly simpleHVAC systems and repeated floor plans. They also have a highoccupancy of students, making them a significant target for apotential attack. Two buildings are typical office/classroombuildings, while the fourth one is a large auditorium. These828 ASHRAE Transactionsfour bu
33、ildings were chosen because they are all typical build-ings that make good case studies since they would apply to alarge portion of existing buildings that qualify as noncriticalbuildings. The director of plant maintenance in the FacilitiesManagement Department at the urban university campus, andthe
34、 senior mechanical engineer in the Office of the PhysicalPlant at the semi-rural campus were interviewed to obtain theanswers to the questions asked by each assessment tool. Thedirector of plant maintenance and the senior mechanical engi-neer answered all the questions in the compact questionnairefo
35、r the four buildings being assessed. With these answers, eachtool can be applied to all of the buildings. Evaluation in Terms of Overall CapabilityTable 2 provides a summary of the characteristics of thetools: the tool format (MicrosoftWord document, softwareprogram, etc.), the category breakdown of
36、 each tools ques-tionnaire, the number of questions, and the number of ques-tions that are related to the HVAC system and airborne agentattacks. From this table, it can be seen that each tool is some-what unique in structuring the questionnaire for assessing abuildings vulnerability toward airborne
37、attacks. Our judgment and opinions of how the various toolscompare against each other in terms of the various character-istics described earlier to evaluate the tools are assembled inTable 1. Description of Buildings EvaluatedType of Building Dormitory Office/ Classroom Office/Classroom AuditoriumLo
38、cation Urban campus Urban campus Semi-rural campus Semi-rural campusGross floor area 108,535 ft229,444 ft231,1000 ft245,000 ft2Number of floors 7 43 floors + mechanical room in basementTotal occupancy 3003040 office personnel, 30050 students in classNormal occupancy of 140 + up to 170 floating stude
39、nts and professionals2595 seats + ticket office + ushers+ concession workersHVAC system Water-source heat pump in each suite, centralized ventilation, AHU with heat recovery Rooftop-packaged units with VAV and gas heatVAV chilled-water AHU with hot-water heating coilsMultiple VAV and CAV chilled-wat
40、er AHUs with hot-water heating coilsOther information 46 person per suite Mixed office-classroom Table 2. Format and Categories of Evaluated ToolsTool Tool Format Categories # Questions# Questions on HVAC/IAQBVAT- Rhode IslandMS Word Types of air ventilation/conditioning, air-handling units, air int
41、akes, recirculation modes, mechanical rooms, filtration specs, system O however, FEMArequires that the user provide the weights for the variousthreats. Except for CBT, all the remaining four tools providegeneric guidance. CBT provides a color-coded metric of riskbroken up into separate subcategories
42、, and also performs acost analysis on the filtration/pressurization process.Table 4 provides an overall classification of each tool interms of the guidance/recommendations it provides and interms of the vulnerability (threat) evaluation it conducts. Avalue of “0” means that the tool omits this featu
43、re, a value of“1” means that the tool provides a general or low-level guid-ance/threat evaluation, and a value of “2” means that the toolprovides a guidance/threat evaluation that is still heuristic butsomewhat building specific. As can be seen from this table,BVAT, BAC, and BVAMP do not provide any
44、 means ofmeasuring building vulnerability or risk. By using these toolsand answering the questions given, the building assessor mayget an idea of where vulnerabilities are, but the tool itself doesnot provide a measure. FEMA and CBT each provides a meansTable 3. Comparison of Evaluated Tools Tool Ti
45、me Required/Ease of Use Type of User InputBasis of Evaluation of Building VulnerabilityUnique FeaturesBVATRhode Island*Little time required to complete checklist. Simple to use, self-explanatory. May need qualified assessors to answer some questions.Mostly yes/no with some short answer questions No
46、visual/numerical output, but user acquires a sense of building vulnerability by answering questions and reading recommendations.BACLos Angeles*Ditto OK/not OK Inputs Ditto BVAMPLBNLDitto Yes/no Inputs DittoQuestions asked are dependant on answer to previous questions. Program eliminates questions th
47、at do not apply after a certain answer has been provided.FEMA*Complex database capable of storing a large amount of information. Significant time required to answer all questions and fill out all matrices. Time required to read FEMA document. Need qualified assessors to answer some questions. Descri
48、ptive input in the users own words.User selects weights from given tables, which provide a quantitative index of risk that is color-coded.Database format (image and information storage), ability to link databases, risk matrices, ability to organize and prioritize noted vulnerabilities.CBTUTRCUser-fr
49、iendly program, relatively self explanatory. Little time required to answer questions. Some time required to evaluate recommendations and explore other features. May need qualified assessors to answer some questions. Drop-down menu of preset answers (in hierarchy of security level) to each question. Weighted matrix calculated depending on answers showing vulnerability that is color-coded. Automatically produced color-coded matrix, air filtration/pressurizationcost analysis. *General guidance to each question, independent of answer.830 ASHRAE Transactionsof measuring buil
