失效模式與效應分析應用於單元式帷幕牆施工風險之探討

Abstract

帷幕牆系統發展越來越複雜與精細，台北101之外牆玻璃帷幕，從系統設計、結構及地震與風力計算、選定材料、工廠加工組裝、乃至於現場吊裝等，全部施工過程必須符合設計需求，達到相關氣密及水密之規範要求，在生產或組裝過程發生問題都會對該專案工期及成本產生重大影響，而這都需要帷幕牆施工團隊於事前的縝密規劃，所以對於帷幕牆製造及安裝過程中相關潛在缺失能否及早發現問題與缺失進而進行防制措施，以及相關缺失如何改善以避免系統失效而產生損失。藉由失效模式與效應分析 (Failure Model and Effects Analysis，FMEA)之量化分析模式，進行評估施工中缺失改善之優先順序，以達到預防及改善施工問題之發生。 經由專家顧問問卷與資料彙整，制定成242項失效模式與原因(包括：工廠製造階段、工地吊裝階段等共計2階段、13個項次、242項)，並據以擬定單元式帷幕牆之失效模式與效應分析表。依據FMEA風險優先數計算與分析，先行制訂風險優先指數>125或嚴重度>7(等級Ⅲ以上)之項目應列為加強管控項目以為重點查核、解決、改善處理對象。經風險指數分類與分析結果等級Ⅲ以上為加強管控項目共有76項，分別為等級Ⅰ計有12項，等級Ⅱ計有14項，等級Ⅲ計有50項，另等級Ⅳ及Ⅴ計有166項可依既有品質管制之管制方法與查核頻率進行管理。 242項失效模式中，風險優先法評點計算出76項加強管制項目，其中以材料進場檢驗所佔項次最多，顯見施工前與施工過程必須確認材料品質必須符合規範，才能達到帷幕牆耐久的需求。 在FMEA應用上，於規劃或製程施工前利用失效模式與效應分析法來進行施工階段作業上之潛在缺失檢討，並制定防治與改善措施，將有效降低缺失發生機率，從案例中可明確顯示風險優先數之降低。

The development of curtain wall systems is getting more complex and exquisite. Take the facade of the Taipei 101, the tallest building in the world, for example. All the system designs, structural calculations for earthquake and wind load, material selections and the fabrication/assembly at shop and election at site should meet the design requirements of certain water- tightness and air-tightness during the process of construction. Any problems occurred during the process of production or assembly will cause a serious impact to the schedule and cost of the project. Therefore, it is necessary that the whole team of curtain wall works maps out meticulously and previously to identify potential defects and take necessary measurements to prevent such defects during the process of curtain wall construction. By means of quantitative analysis model of Failure Model and Effects Analysis (FMEA), this study aims to evaluate the priority of defect amendment for the curtain wall construction to prevent and solve problems. 242 items of failure and cause, including two stages (production and construction stages), 13 categories and 242 items are summarized through questionnaires and data collections from experts and consultants in curtain wall field. Thus, failure mode and effects analysis for unitized curtain wall are prepared. According to the calculations and analysis of risk priority number of FMEA, items with risk priority number > 125 or acuity > 7 (Level III and above) are rated as enhanced ones for primary auditing, problem-shooting, and improvement. The result of classification and analysis via danger index is that totally 76 items are rated Level III above, which are 12 items of Level I, 14 items of Level II and 50 items of Level III; the other 166 items of Level IV and Level V could be managed in accordance with existing method and auditing frequency for better quality control. Among the 76 enhanced items out of 242 items of failure model, there are material inspection upon arrival share the highest portions. This is obvious that it’s curial that the material should meet the specification requirement prior to production and construction in order to satisfy façade performance. In the application of FMEA, using the Failure Model and Effects Analysis to identify potential defects at the stage of planning and pre-construction stages to set up control and improvement measurements will effectively reduce probability of occurrence of defects. The reduction of risk priority number is apparent from the case studies.