Component and facility layout plays an important role in the design and usability of many engineering products and systems as mechanical design, facility layout, process plan, management and architecture including ship compartment layout. In real-world applications, all designer's requirements can not be formulated as simple mathematical expressions. The accessibility to components is one of these requirements which can not easily be taken into account in the layout optimization process. Firstly, this accessibility deals with the required vacant space located around the component and used to guarantee the correct mechanism of the component. This space is described, in this paper, as a virtual component with particular attributes. Moreover, the accessibility requirement means that each component has to be attainable from the container's entry. In order to consider it in the layout optimization process, designers usually use their expertise to modify the layout problem description and satisfy a priori all the accessibility specifications. This paper proposes an alternative approach based on the integration of the accessibility to components in the layout problem formulation. The accessibility is considered as a design constraint or an objective of the optimization problem. This method is applied on a two dimensional real-world problem which deals with the layout optimization of components inside a shelter. Some research leads are also described in order to use this approach for the three dimensional layout problems.