Hi there, 

I am trying to work out who is responsible for installing and maintaining fire alarms in the flats and common areas in the flats above my office. There used to be two separate entrances for the flats (extending 4 floors above the office) and the office, but my company added a porch on to the front of the building making it one exit and entrance. Fire alarms now need to be added so that residents are warned of a fire in the office and vice versa. 

Who is the responsible person here? The freeholder of the flats or the business in the ground floor office.  

Whether you have one or two entrances make no difference to requiring a fire alarm in the common parts of the flats if there is commercial premises below and the guidance is Fire safety in purpose-built blocks of flats. Check out appendix 6.28

The Responsible Person is the owner or owners of the building see article 3 of The Regulatory Reform (Fire Safety) Order 2005.