Management systems are tools used to help ensure the existence, organization, and application of the standards and methods needed to achieve safe and environmentally friendly engineering, operations, and maintenance and to control accepted or unavoidable risks. Many "ready-made" and prescriptive models, such as those of Intl. Standards Organization and the European Community＇s (EC＇s) Ecomanagement and Audit Scheme (the EC＇s voluntary system model for environmental management), may suit the needs of individual companies. Other companies may prefer to work from basic "good-management" principles and create their own models. In either case, the system cannot stand alone or apart; it must work within the context of the overall business objectives and needs of the company and within the limits set by any relevant national legislation.