Abstract
Proper maintenance and energy saving must be considered to environment-consciously run building services during their lifecycles. Proper maintenance leads to the effective use of natural resources, in particular. Maintenability relates to reliability very much. Reliability has been originally highlighted in the high-speed transportation system like airplane and bullet train from the safety point of view. Now that many complex and high-performance buildings requiring security like internet data center and biomedical facility increase, reliability of building services should be paid much attention. Proper maintenance has been seldom employed due to the lack of necessary reliability data and reliability knowledge. There are several maintenance guidelines showing how frequently the maintenance should be done for building services or its components. But the guidelines are seldom based on both enough reliability data and acceptable explanations. This paper tries to correct the ambiguous guidelines and illustrates a reliability study for fire tube boiler by mainly applying Cumulative Hazard Analysis with actual operational data in about ten years. The analysis was carried out on the boiler's 19 components by taking into account of the manufacturers' maintenance guidelines. As a result their MTBFs (Mean Time Between Failures) were estimated spanning from 1.0 to 5.0 years. The Weibull distribution shape parameters with Cumulative Hazard Analysis were from 0.61 to 2.68. The blow-through fan for burner was a sole component being planned time-based maintenance. Since the shape parameters of air volume control damper, water supply pump, water supply pipe and water level detector showed they had initial failures, it is of necessity to think about their design and construction methods.
