Risk Analysis of Unitized Curtain Wall System?Application of Failure Mode and Effects Analysis

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.