The A/E is responsible for designing and implementing facilities and systems to meet the security needs unique to each industry and building. The security manager, on the other hand, must work with the A/E from the start to ensure that the design is tailored to individual facility requirements. The ultimate goal of the design process is to provide exactly the right amount of access control to the facility. To ensure a functional system, the security manager and A/E should take the following steps very early in the design process: (1) determine which assets are most critical to the operation; (2) define the number of unique access levels to be provided; (3) arrange the building to accommodate the "onion theory;" and, (4) define the types of screening to be performed at each access level. The following steps separate the development of requirements and the finished design: requirements definition, conceptual design, preliminary design, and final design. The integration of security and access control methods with building systems and components must be an evolutionary process.