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1、 SYSTEM VIEW OF LEAN CONSTRUCTIONAPPLICATION OPPORTUNITIES Flvio A. Picchi Doctor in Engineering, Consultant, and Director of Lean Institute Brasil. R. Vergueiro, 3645 cj. 906 - So Paulo - CEP 04101-300, Brazil, +55-11-5579-9613, FAX +55-11-570-9613, piccon.br.ABSTRACTConstruction has been one of th
2、e first sectors to discuss Lean Thinking in an environment different from that where it was developed. Lean Thinking is a broad concept and construction is a highly diversified and complex sector, so the opportunities for application are very wide. This paper will discuss these opportunities in a sy
3、stematic framework, useful for identifying interactions among applications developed so far as well as gaps for future studies.This framework will be constructed crossing Lean Thinking core elements and construction main flows. Due to differences between construction and manufacturing, lean tools di
4、rect application is not suitable in most cases. Lean principles deployed to a detailed conceptual level, named core elements, is argued to be a better basis for the discussion of potential applications in different environments, as construction. According to lean concept, construction is understood
5、in this paper as a connection of five main flows. The discussion of each core element for each flow points up opportunities of application.KEY WORDSLean construction, applications, system view.INTRODUCTION Lean Thinking is a concept based on the Toyota Production System (TPS), consequently developed
6、 in a manufacturing environment, more specifically in the automotive industry. Since Womack, Jones, and Roos (1990) announced this concept as a new production paradigm, several industries have dedicated great attention to the possibilities of applications to their environments. Construction is a ver
7、y complex sector, with many differences from manufacturing. Since Koskelas pioneer report (Koskela, 1992), several researchers and industry practitioners have sought concept interpretation (e.g. Howell and Koskela, 2000; Howell, 1999, Ballard and Howell, 1998) and practical application. A large numb
8、er of discussions and cases can be found in the International Group for Lean Construction (IGLC) Conference papers Available in Alarcon (1997) and at IGLC site: http:/cic.vtt.fi/lean/conferences.htm., dealing with different issues, such as design, suppliers, job site, etc.A system view understanding
9、 of concepts and experiences accumulated so far is the harder challenge for companies from any industry, in the lean transformation. Lean Thinking is a complex combination of philosophy, system and techniques, and a misunderstanding of this combination, for example focusing on isolated techniques (o
10、r tools), is one of the most common reason for poor partial implementations with few results. This paper presents a proposal of a framework that aims to enable a systematic discussion of opportunities of lean thinking application to the construction sector. The system view provided by this discussio
11、n is useful for understanding the complex links that exist among lean concepts, techniques, and cases applied to the construction so far, as well as for the identification of gaps and future priorities.PROPOSED FRAMEWORK FOR A SYSTEM VIEWThe first dimension: lean thinking complexity representationWa
12、ste elimination is the basis of Lean Thinking, as stated in the TPS definition referred by Liker (1997, p.7): a manufacturing philosophy that shortens the time line between the customer order and shipment by eliminating waste. For this purpose, several techniques (or tools) have been developed, dire
13、ctly related to Lean Thinking. The term techniques (or tools) is generally used for routines, standardized for training and communication, such as Kanban, Total Productive Maintenance (TPM), 5S, Poka-yoke, etc These and other techniques are described in the literature, e.g.: Shingo (1989), Monden (1
14、998), Schomberger (1982), Suzaki (1987). These techniques are the most visible components, and sometimes are misunderstood, being confused with the whole system. Shingo (1989, p. 67) says that most people answer that “TPS is Kanban, but in his opinion TPS is just 5% Kanban, (that is a means of achie
15、ving Just In Time), 15% production system, and 80% waste elimination.The understanding of the philosophy and system that are behind these techniques is fundamental: Lean manufacturing includes a set of techniques that comprise a system that derives from a philosophy (Shook, 1997, pg 45). We can say
16、that techniques are more related to operational aspects, system to integration aspects, and philosophy to conceptual aspects (Table 1). In truth, the separation of technique/system/philosophy is not simple. Every technique (Kanban, for example), when taught, is integrated to the system (e.g. the JIT
17、 production system) and several conceptual aspects, or philosophy, are emphasized (pulled production, total quality, etc.).Table 1 Lean Thinking: Philosophy, system, and techniquesLevelAspectsFocusAspectsAdaptation demandedPhilosophyConceptualPermanent goalsConceptual Operational Less MoreSystemCoor
18、dination aspectsHow techniques are integrated, coherently with philosophyTechniquesOperationalHow to put the philosophy in practiceThe philosophy behind systems and techniques is the most important element. It is very difficult to be described since it is composed by objectives and concepts not alwa
19、ys explicit. In TPS the subtle philosophy is transmitted day-by-day to employees and is present in all operational techniques.Besides a conceptual basis provided by philosophy, a company needs practical application templates, in the operational level, to design its systems and select techniques. The
20、 direct application of techniques developed in an industry to a different sector is limited, due to specific characteristics of each industry (as stated by Koskela and Vrijhoef 2000). In this case, more adaptation is demanded in the operational extreme (techniques) and less in the conceptual extreme
21、 (philosophy). In the framework proposed we subordinate the techniques understanding, selection, and adaptation to a deployed concept analysis. We named this deployed concepts as “lean core elements,” discussed below.The second dimension: construction sector complexity representationConstruction is
22、a very complex sector, with strong fragmentation. In the product cycle several companies are involved, such as owners, designers, general contractor, sub-contractors, suppliers. Lean thinking proposes that the enterprise should be analysed through their flows (from order to cash, from raw materials
23、to delivery, etc.), and not through departments.The construction project can be understood as a virtual, multi-company and temporary organization. The application of lean thinking application opportunities, if limited to each company involved, will not focus on the major potential of waste reduction
24、, considering the whole flows within the project. For this reason, the construction main flows, discussed below, are the second dimension of the proposed framework.Crossing lean core elements and construction flowsWe propose as a framework for a systematic analysis of lean thinking opportunities Opp
25、ortunities for application or just opportunities are referred in this work as possible applications of lean concepts or techniques to the construction sector , with interesting expected results. for the construction sector a matrix, crossing the lean core elements and the construction flows, as disc
26、ussed above and detailed in the following sections.This frameworks objective is to provide a system view to help construction sector agents to design their system and select, adapt or create techniques coherent with lean philosophy. Identifying techniques and showing how they are integrated in the “
27、lean core elements x flows” framework is a way to give meaning and context to these techniques.LEAN CORE ELEMENTSThe inexplicit way lean philosophy, system and techniques have been developed and transmitted in Toyota becomes a difficulty for other companies and industries to understand its core elem
28、ents and try to implement them. Several authors, from outside, have studied the system, providing descriptions more focused on the system and its techniques, such as .: Shingo (1989), Monden (1998), Schomberger (1982), Suzaki (1987)The most recent efforts to understand the core elements are provided
29、 by Womack and Jones (1996), Spear and Bowen (1999) and Fujimoto (1999).Womack and Joness 5 principlesWomack and Jones (1996) organize the fundaments of Lean Thinking in five principles: Value: specify and enhance value Value Stream: identify the value stream and remove waste Flow: make the product
30、flow Pull: let the customer pull Perfection: manage toward perfectionActually, these principles go beyond the Production System practiced up to now by Toyota, emphasizing for example aspects in the principles Value and Value Stream towards a vision of a wide application in the whole and extended com
31、pany.Spear and Bowens 4 rulesSpear and Bowen (1999) state that the tacit knowledge that underlines TPS can be captured in four basic rules: Work: shall be highly specified as to content, sequence, timing, outcome; Connections: all communications must be direct and unambiguous; Pathways: for every pr
32、oduct and service must be simple and direct; Improvements: must be made using a scientific method at the lowest level in the organization.The authors discuss how these rules are in the basis of the TPS, and how they create an environment with high delegation level that enables decentralized and cont
33、inuous change without creating chaos.Fujimotoss 3 capabilitiesFujimoto (1999) analyzes the TPS from an evolutionary point of view and identify three levels of capabilities that explain its sustained high performance and continuous improvement: Routinized manufacturing capability related to the stand
34、ard and accurate way to perform activities in all companys processes; Routinized learning capability routines for problem identification, problem solving and solution retention; Evolutionary learning capability. intentional and opportunistic learning capability of handling system changes in building
35、 the above routine capabilitiesThe author reinterprets manufacturing activities as an information system, and summarizes the production capability of the most effective Japanese automakers as dense and accurate information transmission between flexible (information-redundant) productive resources (F
36、ujimoto, 1999, p.108). The dense aspect is related to productivity, efficiency, and waste elimination. The importance of a regular pace of information transfer is also emphasized. Quality is interpreted as accuracy of information transmission.Deploying principles in core elementsThe three approaches
37、 briefly referred previously give us a better understanding of the lean philosophy and its core concepts. To apply these concepts in different environments (as other industries, including construction) it is interesting to deploy these ideas or principles in detailed concepts, but not reaching the o
38、perational field, provided by techniques. Table 2 presents a proposal of this deployment in core elements, showing related techniques in the right column. The conceptual part of this Table (all columns but the techniques column) is presented as a tree, expanding from objectives and Womack and Jones
39、five values to more detailed concepts, named core elements, presented in two levels of detailing (columns three and four).Spear and Bowens and Fujimotos approaches, although represent different emphasis and perspectives, are considered in Table 2 related to Womack and Jones five principles. Spear an
40、d Bowens rules: work highly specified, pathway and connections and Fujimotos routinized work capability can be related to Womack and Jones Flow and Pull values. Spear and Bowens improvement rule and Fujimotos routinized and evolutionary learning capabilities can be related to Womack and Jones Perfec
41、tion principle.This tree representation is simplified. Some core elements are in truth related to several principles, as well as many techniques are related to different core elements. The aspects depicted in Table 2 are more conceptual to the left (philosophy) and more operational, to the right (te
42、chniques). The system level, not depicted in this Table, would combine techniques, according to the philosophy. The core elements, as the most detailed conceptual level, are in the border between philosophy and techniques, providing a valuable basis for lean systems design, mainly in different envir
43、onments, where some techniques, developed in the original environment, can be inapplicable. We argue that the discussion of Lean Thinking application to environments different than manufacturing is facilitated if focused on the core elements presented in Table 2. For example, the discussion of the t
44、echnique fast set up can be difficulty in industries as construction and services, but the related core element flexibility can be discussed and deeply understood considering the specific characteristics of the desired environment.The core elements presented in Table 2 depict, in an intermediate lev
45、el of detailing, what one should find in a Lean Enterprise, aiming the objectives and principles. Discussing these core elements can help a company to design its systems and selecting, adapting or developing appropriate techniques.Table 2 Lean core elementsObjectivesPrinciplesCore elementsExamples o
46、f related techniquesPermanently improve companys competitiveness by:- eliminating waste- consistently attending clients requirements in variety, quality, quantity, time, priceVALUEEnhanced product / service package valueSolution that enhances value for the clientIdentification of what is value for t
47、he client, services aggregation, business re-structuringProduct variety Modular design, interchangeability, fast set-up, planned variety compatible with production systemTime based competition Production lead time (order to delivery)Small batches, product family factory lay-out, JITProduct developme
48、nt lead timeBlack box system, heavyweight manager, set based design, concurrent engineeringVALUE STREAMHigh value adding in the extended enterpriseValue stream redesign eliminating wasteMapping, combining activities, eliminating non-adding value activities, supporting and promoting suppliers lean implementationSuppliers involvement in production and product development systemsPartnership, supplier training, black box system, JiIt supplyFLOWDense, regular, accurate and reliable flowDense flow , with hight adding value time, clear pathways and communicati
