Not necessarily. If a double glazing unit is installed in a critical location where there is pedestrian access to both sides of the unit, then both panes of the unit should meet the recommendations of BS 6262-4. However, in situations where pedestrian access is restricted to one side of the unit, then only the accessible side needs to follow the recommendations.

For example, where a unit is located in a critical location at a storey above ground floor, but with no pedestrian access to the external faces, then the outer pane may not to follow the recommendations of BS 6262-4.

Care should be taken to ensure that any unit with two different panes is installed the correct way round. Also, the unit may need to resist barrier loads in such applications.

[Reference: BS 6262-4: Glazing for buildings - Part 4: Code of practice for safety related to human impact]