ASHRAE HVAC APPLICATIONS SI CH 39-2015 OPERATION AND MAINTENANCE MANAGEMENT.pdf

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1、39.1CHAPTER 39OPERATION AND MAINTENANCE MANAGEMENTOperation and Maintenance as Part of Building Life-Cycle Costs 39.1Elements of Successful Programs . 39.2Automated Fault Detection and Diagnosis (AFDD). 39.5Documentation 39.7Staffing 39.8Managing Changes in Buildings. 39.9FFECTIVE operation and main

2、tenance is essential for cost-Eeffective provision of the built environment that humankindenjoys today. To derive the greatest return on existing building stock,and to ensure future generations will continue to enjoy these bene-fits, the built environment must be sustainable. A significant compo-nen

3、t of the sustainable facility is the way the structure and itssystems are operated and preserved for the long term. This chapterpresents several strategies, methods, procedures, and techniques foroperation and maintenance management programs that minimizeasset failure and preserve system function to

4、 deliver their intendedpurpose.Evolving building system complexity and increasing operatingcosts demand that equipment and systems providing thermal com-fort and beneficial indoor air quality be properly maintained toachieve energy efficiency and building owners reliability require-ments. These fact

5、ors clearly imply that a highly organized, system-atic approach for properly and effectively functioning buildingassets is necessary to achieve a successful maintenance program.Maintenance management is the formal effort required to plan,design, and implement a maintenance program tailored to the sp

6、e-cific needs of the facility.Traditionally, considerable focus has been devoted to minimizingfirst costs (i.e., capital investment) of construction. However,choices made regarding operation and maintenance (O Yates 2001).1. OPERATION AND MAINTENANCE AS PART OF BUILDING LIFE-CYCLE COSTSOperation and

7、 maintenance are major contributors to the totalcost of ownership over the life of a facility. It is useful to comparemaintenance costs to the total costs of facility ownership. The majorcategories of the life-cycle cost of facility ownership include designand construction; operations and maintenanc

8、e; acquisition, renewal,and disposal; and employee salaries and benefits. Figure 1 representsthe major categories of facility life-cycle costs as pillars supportinga building. Within each category, examples of the typical elementsthat make up the foundation of the category are shown.Several studies

9、e.g., Romm (1994); Yates (2001) state that thecosts of operations and maintenance exceed the costs of design andconstruction. For example, Yates finds that “operational resourcecosts account for approximately five times construction costs overthe 60 year life of a building.” Accurately quantifying t

10、he life-cyclecost of building components through a statistically significant sam-ple is difficult see, e.g., Whitestone (2012), given the availability ofdata, the timeline required to collect the data, and the varying lives ofbuildings.Figure 2 (NIBS 1998) categorizes life-cycle costs to includedesi

11、gn and construction, operations and maintenance, and em-ployee salaries and benefits. Other studies find similar values: overa 30-year period, design and construction costs account for about2% of the life-cycle cost, whereas operations and maintenance costsare about 6% and personnel salaries are 92%

12、 (Romm 1994). Figure3 (BOMA 2008) further defines operations and maintenance costsfor a typical office building and shows that operations and mainte-nance costs most directly related to HVAC (i.e., maintenance andrepair and utilities) make up over 50% of the operations costs for abuilding.The prepar

13、ation of this chapter is assigned to TC 7.3, Operation and Main-tenance Management. Significant content on fault detection and diagnosticswas provided by TC 7.5, Smart Building Systems.Fig. 1 Three Pillars of Typical Life-Cycle Cost with Cost ElementsFig. 2 Life-Cycle Cost Elements: Business Costs f

14、or Nonresidential Buildings, Including Salaries and Benefits to Occupants(Adapted from NIBS 1998)39.2 2015 ASHRAE HandbookHVAC Applications (SI)An alternative approach comparing the cost of design and con-struction to the cost of operation and maintenance over the buildinglife cycle is to consider t

15、he current replacement value (CRV) as apercentage of the cost of construction of the building. CRV is cal-culated considering the cost of maintenance and repair (M Breuker etal. 2000; Comstock et al. 2002; House et al. 2001a, 2003; Jacobs etal. 2003; Katipamula et al. 1999; Proctor 2004; Rossi 2004;

16、 Seemet al. 1999). Faults included economizers in packaged air condi-tioners and heat pumps not operating properly; low (and high)refrigerant charges; condenser and filter fouling; faulty sensors;electrical problems; chillers with faulty controls, condensers, com-pressors, lubrication, piping, and e

17、vaporators; and air-handlingunits with too little or too much outdoor-air ventilation, poor econ-omizer control, stuck outdoor-air dampers and other problems.Types of AFDD Tools. Portable service tools can evaluate theperformance of packaged and unitary vapor-compression systemsand guide servicing t

18、o address problems. Self-contained, micro-processor-based portable hardware is used during a service visit fordata acquisition and analysis. The sensors for making measure-ments and evaluating system performance may be installed tempo-rarily or permanently. Data are usually collected for a relativel

19、yshort period of time (minutes) while the equipment operates atsteady-state conditions.Local controllers with embedded AFDD include fault detec-tion and diagnostic algorithms as part of the control software code.Embedded AFDD software can access data at the controllers shortsampling interval; becaus

20、e they perform analysis locally on control-lers, embedded AFDD tools can also reduce control network traffic.Computational and memory limits, however, may place practicalrestrictions on the complexity of algorithms embedded in local con-trollers.Central workstation AFDD tools use dedicated software

21、todetect and diagnose HVAC system faults using data from a buildingautomation system or dedicated sensors or sensor networks. Thissoftware usually resides on a computer that is part of a buildingautomation system, or has access to stored data from a BAS. A keystrength of workstation AFDD software is

22、 its ability to detectsystem-level faults arising from interactions among components.Workstation AFDD software may require extensive effort forconfiguration. In particular, mapping points from the building auto-mation system to the AFDD tool can be labor intensive and costly,depending on the number

23、of measurement and control points usedby the AFDD tool.Web-based AFDD software may obtain data from a BAS,independent data acquisition system, or controller-embeddedAFDD software. In this case, wired and/or wireless Internet con-nections using the Internet for data acquisition allows gatheringdata f

24、rom many buildings and supports enterprise-wide reporting.Because AFDD processing is done by software on the web, updat-ing of software is simplified, and all users have access to the latestversion. Web-based systems are emerging for detecting and diag-nosing faults in individual equipment and whole

25、-building energyconsumption (Brambley et al. 2005). A significant challenge forweb-based AFDD is Internet security, which may require addi-tional hardware and software administration.Characteristics of AFDD Systems. Inherent characteristics ofAFDD systems can be adjusted to suit a variety of applica

26、tions andusers.Sensitivity is the lowest fault severity level required to triggerthe correct detection and diagnosis of a fault. This characteristic isvital for monitoring safety-critical systems. For non-safety-criticalapplications (which cover most HVAC equipment), the sensitivitythreshold can be

27、higher so that faults have significant performanceor cost impacts before operators are alerted.False alarm rate is the rate at which an AFDD system reportsfaults when they do not actually exist (i.e., when operation is nor-mal). A high false alarm rate could result in excessive costs fromunnecessary

28、 service inspections or stoppage of equipment opera-tion.The challenge is to establish a balance between adequate AFDDsystem sensitivity and minimizing false alarms. Take care to achievethe right balance, because false alarms can defeat the purpose ofinstalling AFDD. One technique used for critical

29、systems, installingredundant sensors, mitigates excessive false alarms while maintain-ing desired fault sensitivity. Redundant sensors, however, areunusual in HVAC systems because of their additional cost.Additional characteristics that affect the performance and usabil-ity that should be considered

30、 when selecting an AFDD tool (Houseet al. 2001b) includeNumber of sensors and control signals usedAmount of design data usedTraining data requiredUser-selected parametersUsers should seek a balance among these considerations that isappropriate for the intended application.AFDD in Practice. Figure 5

31、shows an example of an operationand maintenance process using AFDD comprising four distinctfunctional processes. The first two steps in this process are faultdetection and, if a fault is detected, fault diagnosis. After diagnosis,the software can analyze the various consequences of the faultsdetecte

32、d. Human operators can then evaluate the results from theautomated fault impact analysis to arrive at an integrated assessmentof overall fault significance (based on operational requirements forsafety, availability, cost, energy use, comfort, health, environmentalimpacts, or effects on other perform

33、ance indicators). Once faultevaluation is completed, the operators determine how to respond(e.g., by taking a corrective action). Together, these four steps canalert operations and maintenance staff to problems, help identify theroot causes of problems so that they can be properly corrected, andhelp

34、 prioritize maintenance activities to ensure that the mostimportant problems are attended to first. This forms the basis forcondition-based maintenance.Benefits of Detecting and Diagnosing SYSTEM and Equipment FaultsSince 1995, many studies of the effects of O Rossi2004). Building owners and operato

35、rs should carefully evaluate thecost and benefits of implementing and using AFDD technology intheir specific situations.Operation and Maintenance Management 39.74. DOCUMENTATIONInformation on the facilities, equipment, and intended operationprocedures is essential for planning and performing mainten

36、anceefficiently, documenting maintenance histories, following up onmaintenance performance, energy reporting, and managementreporting. For these reasons, documentation is a critical element ina successful maintenance program. Prepare operation and mainte-nance documentation as outlined in ASHRAE Gui

37、deline 4.For new construction, establish operation and maintenancedocumentation requirements as part of the project requirements.Deliverables should support the expected maintenance strategy,skills of the maintenance and operations staff, and anticipatedresources to be committed to performing operat

38、ions and mainte-nance. The requirements for maintenance programs developed forexisting facilities are the same; however, the operations and main-tenance staff may be more involved with developing the docu-ments.Operation and Maintenance DocumentsInformation should be compiled into a manual as soon a

39、s itbecomes available. This information can be used to support designand construction activities, commissioning, training of operationand maintenance staff, start-up, and troubleshooting. In addition toproviding the operation and maintenance manual to the constructionteam, set aside an appropriate n

40、umber of manuals for the buildingowners staff after construction turnover. It is critical that all infor-mation required to operate and maintain the systems and equipmentbe compiled before project turnover to the owners staff and beavailable to the entire facilities department.A complete operation a

41、nd maintenance documentation packageincludes an operation and maintenance document directory, emer-gency information, an operating manual, maintenance manual testreports, and construction documents. These documents should beavailable to the entire facilities department.The operation and maintenance

42、document directory provideseasy access to the various sections within the document. The O store maintenance histories and asset inventory informa-tion; communicate building operation and maintenance informa-tion; and generate reports to quantify maintenance productivity. ACMMS is used by facility ma

43、nagers, maintenance technicians,third-party maintenance service providers, and asset managers totrack the status, asset condition, and cost of day-to-day maintenanceactivities. The number and type of modules used within a CMMSis specified by the facility management team, depending on thefacilitys ne

44、eds and the management teams goals. Typical CMMSmodules include work order generator and tracking, work orderrequests, inventory control, planned maintenance, equipment histo-ries, maintenance contracts, and key performance indicator (KPI)reporting.Although a CMMS is not required to manage maintenan

45、ce activ-ities, they are becoming more commonly used (Sapp 2008). Whenimplementing a CMMS in a new or existing facility, or upgrading anexisting one, the needs of the CMMS and the planning process mustbe carefully determined. Although using a CMMS has the potentialto increase the facility management

46、 teams efficiency and serve as ahistorical maintenance archive, more than 50% of implementationsfail (Berger 2009). One reason for failure is inadequate data popu-lation. To overcome this challenge, especially when new buildingsand major renovations are designed and constructed using buildinginforma

47、tion modeling (BIM), open information exchanges can beused. A supplement in the ASHRAE Handbook Online version ofthis chapter provides a brief overview of what open informationexchange standards are, followed by a descriptive list of current anddeveloping open information exchange standards. Selecti

48、ng theright software does not guarantee that using a CMMS will improvemaintenance productivity; it is important to evaluate, document, andalign facility management processes with how the CMMS will beused. When implementing or upgrading a CMMS, schedule three tosix months to design new processes and

49、develop a set of systemrequirements, using a participatory approach that includes all stake-holders (Berger 2009).5. STAFFINGDetermining the correct number of staff when implementing amaintenance program is a complex exercise. Multiple factors mustbe considered in order to have sufficient maintenance staff availableto do the work. Such factors include but are not limited to skill levelof maintenance staff, complexity and criticality of the equipmentand systems to be maintained, the rigor of the maintenance program,source of the maintenance staff, available maintenance programfun