How Important are Reliability and Maintainability?

Reference is often made in this type of literature to the spectacular reliability of many nineteenth-century engineering feats. Telford and Brunell indeed left a heritage of longstanding edifices such as the Menai and Clifton bridges. Fame is secured by their continued existence but little is remembered of the failures of their age. If, however, we concentrate on the success and seek to identify which characteristics of design or construction have given them a life span and freedom from failure far in excess of many twentieth-century products then two important considerations arise.