This will be less of a requirement for homes, but for publicly accessible buildings or buildings with many employees, where requirements are placed on functional safety, a risk assessment will have to be done.
Figure 57: Risk class I: not acceptable; II: undesired, medium; III: acceptable, low; IV: insignificant.
In the above table possible errors are allocated to integrated home system functions. The risk class is then examined for people and objects. If however certain actions are taken, you can improve the risk class.
In the cases where no risk assessment has to be done, it is still sensible to provide manual operation at a few important exits. If the integrated home system fails, the user can still control some lighting, roll-down shutters and heating. Certain integrated home systems have output modules that have a manual control facility. When they do not, we can fit a modular bypass switch on strategic output circuits.
Figure 58: This output module has a toggle switch for automatic or manual operation. In the manual state, the individual outputs can be switched with pushbuttons. (Illustration source: Hager)