The following four steps are considered as standard logical sequential steps to be taken in the projects delivery process.

• Conceptualisation
• Design
• Development
• Implementation

These steps are applied in conjunction with a three-dimensional model in which special focus is placed on the consideration of sustainability issues along three “dimensions” as schematically shown in the following diagram:

ISD Delivery Model

Each of the three dimensions are separately progressed through the steps as indicated on the left of the diagram and integrated with design decisions along the other two dimensions, all contributing towards on overall sustainable implementation.

The considerations within each dimension will briefly be considered: