Two regimes meet here and they are often confused. The Fire Safety Order governs non-domestic premises and the common parts of blocks. Separate housing rules govern alarms inside rented homes in England, with their own requirements per storey. A landlord letting a flat in a block is answering both, for different parts of the building.
Rented homes in England
The requirement is for a smoke alarm on each storey used as living accommodation, and a carbon monoxide alarm in any room used as living accommodation containing a fixed combustion appliance other than a gas cooker. Alarms must be checked and found in working order on the first day of a new tenancy, and repaired or replaced when a tenant reports a fault. Those obligations are on the landlord, whatever the tenancy type.
Where alarms actually go
Circulation spaces are the priority: the hallway and the landing, because that is where smoke from any room reaches first and where somebody escaping has to pass. Then rooms with the higher risks. Kitchens get heat alarms rather than smoke alarms. Ceiling mounted and away from corners, vents and light fittings, which is a positioning detail people get wrong and which dramatically changes how quickly an alarm responds.
HMOs, which ask for more
A house in multiple occupation is a higher risk because occupants do not know each other, may be asleep at different times and may not hear an alarm in another part of the house. Licensing conditions and local authority standards typically require an interlinked system across the property, with the grade and category following from the property's size and layout rather than from a national list.
Testing, and who does it
Weekly with the test button is the standard advice, and in a let property that is normally the tenant's routine while the duty to provide working alarms stays with the landlord. Record the check at the start of a tenancy, because that is the check the regulations name and the one you would have to evidence.
Blocks of flats
Inside the flat, the housing rules apply. In the common parts, the Fire Safety Order does, and what is required there follows the building's fire strategy: many purpose built blocks with a stay put strategy deliberately have no common alarm, because a common alarm would produce exactly the simultaneous evacuation the strategy is designed to avoid. That is a design decision, not an omission.
Questions people ask about interlinked alarms
Where are smoke alarms required in a rented home?
On each storey used as living accommodation, with a carbon monoxide alarm in any room used as living accommodation containing a fixed combustion appliance other than a gas cooker.
Who tests the alarms in a let property?
The landlord must check them and find them in working order on the first day of the tenancy. Routine weekly testing is normally the tenant's, and the landlord must repair or replace reported faults.
What do HMO smoke alarm requirements add?
Typically an interlinked system across the property, with the grade and category set by the size and layout and by the local authority's licensing standards.
Why do some blocks of flats have no alarm in the common parts?
Because a stay put strategy relies on fire being contained in the flat of origin, and a common alarm would trigger the simultaneous evacuation that strategy is designed to avoid.