# Conceptual model

## Elementary components level

`floodam.building`

relies on a decomposition of a building in elementary components. For each elementary component, the damage process is modelled as follows:

- Before a flood, the elementary component is assumed to be in a normal state (i.e. non altered). An elementary component that is in a normal state is not necessarily new. As a result, its replacement value can depend on its level of dilapidation.
- When a flood occurs, the elementary component can be altered (i.e. it can switch to an altered state, for instance moist, dirty, damaged, destroyed, depending on the water depth and submersion duration). This step reflects the elementary component sensitivity to flooding, which has been defined based on expert knowledge.
- To go back to normal state, it is necessary to take one or several actions.
- The sum of the costs of these actions is considered to be the damage to the elementary component.

For each elementary component, the damage process is modelled for all possible combinations of flood parameters (water depth and submersion duration in `floodam.building`

v1.0.0). Thus, the domain of definition of the elementary damage functions produced by `floodam.building`

is the set of all possible combinations of flood parameters. In other words, for each elementary component:

\[d_{e} = f(h, d)\]

where:

- \(d_{e}\) is the level of damage suffered by the elementary component;
- \(h\) is the water depth in centimetres, which is comprised between \(-\infty\) and \(+\infty\);
- \(d\) is the flood duration in hours, which is comprised between \(-\infty\) and \(+\infty\)

## Building level

Buildings are described precisely in terms of geometry, composition, and contents, which enables `floodam.building`

to make an inventory of the elementary components and to locate them within a building. More specifically, for each elementary component that is present in a building, `floodam.building`

identifies the storey and room in which it is located, but also the height at which it is located, relative to the ground. Combining this inventory with elementary damage functions leads to a damage function at the building level, which can be adjusted by information on potential flood protective devices. Damage functions at the building level can be either absolute (directly in €) or relative to a summary statistic of the corresponding building (surface, value of contents for instance.)