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Shearing layers is a concept coined by architect Frank Duffy which was later elaborated by Stewart Brand in his book ''How Buildings Learn: What Happens After They’re Built'' (Brand, 1994), and refers to buildings as composed of several layers of change. The concept has been adopted by a number of technology vendors to also describe the different layers of systems within an organisation (see variations) ==Description== The Shearing layers concept views buildings as a set of components that evolve in different timescales; Frank Duffy summarized this view in his phrase: “Our basic argument is that there isn't any such thing as a building. A building properly conceived is several layers of longevity of built components” (quoted in (Brand, 1994)). The layers are (quoted from Brand, 1994): ;Site: This is the geographical setting, the urban location, and the legally defined lot, whose boundaries and context outlast generations of ephemeral buildings. "Site is eternal." Duffy agrees. ;Structure: The foundation and load-bearing elements are perilous and expensive to change, so people don't. These are the building. Structural life ranges from thirty to three hundred years (but few buildings make it past sixty for other reasons). ;Skin: Exterior surfaces now change every twenty years or so, to keep up with fashion or technology, or for wholesale repair. Recent focus on energy costs has led to re-engineered skins that are air-tight and better-insulated. ;Services: These are the working guts of a building: communications wiring, electrical wiring, plumbing, fire sprinkler systems, HVAC (heating, ventilating, and air conditioning), and moving parts like elevators and escalators. They wear out or obsolesce every seven to fifteen years. Many buildings are demolished early if their outdated systems are too deeply embedded to replace easily. ;Space Plan: The Interior layout—where walls, ceilings, floors, and doors go. Turbulent commercial space can change every three years or so; exceptionally quiet homes might wait thirty years. ;Stuff: Chairs, desks, phones, pictures; kitchen appliances, lamps, hairbrushes; all the things that twitch around daily to monthly. Furniture is called ''mobile'' in Italian for good reason. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Shearing layers」の詳細全文を読む スポンサード リンク
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