Thanks davincey,
the following guidance comes from the Technical Standards for compliance with the Scottish Building Standards but I'm sure the English / Welsh standards will be similar. If the residents fall into the category of 'Very Slow Evacuation' (an this is the norm for disabled people) the maximum travel distance to a 'protected' route is 18 metres (more than one direction of travel). If the category can be assessed as 'slow evacuation' the travel distance improves to 32 metres (more than one direction). Therefore these Technical Standards suggest the corridor may need fire separation, not to protect evacuees from a fire in the corridor, but to protect them as they get away from a fire in the occupied rooms. Passive protection from properly installed fire doors would be greatly enhanced if the lounge and offices opening into the corridor were also included in the automatic system coverage area.