Fire alarms for blocks of flats in London

Very often it is entirely correct. Purpose-built blocks of flats in the United Kingdom were traditionally designed around a stay-put strategy, which depends on each flat being a fire-resisting compartment that holds a fire long enough for the fire service to arrive and deal with it. In a building designed that way, a communal alarm that empties the block for a fire in one kitchen would put more people in the stairs than it takes out of danger, so the absence of one is a design decision rather than a gap. What matters is whether the compartmentation the strategy depends on is still intact, and that is a question for your fire risk assessment rather than for an alarm contractor.

Usually because something the stay-put strategy relies on has been found wanting. Breached compartmentation, a problem with the external wall construction, missing or failed flat entrance doors, or an escape route that no longer performs as designed will all push an assessor towards recommending simultaneous evacuation, either permanently or as an interim measure until the underlying defect is put right. When the evacuation strategy changes, the building needs a way of telling everybody to leave at once, and that is where a communal system comes in. The assessment drives that decision. We install to what it specifies.

For the common parts it is whoever has control of them, which in practice is usually the freeholder, the management company, or the managing agent acting for them. Where a residents management company or right-to-manage company holds the responsibility, the directors carry it, and that surprises a lot of people who joined an RMC board expecting an administrative role. The duty covers the corridors, stairs, plant rooms, bin stores and the structure and external walls, and it is not something you can contract away by appointing an agent.

They do different jobs and are operated by different people. A fire alarm detects fire and warns occupants. An evacuation alert system, covered by BS 8629, has no detection at all: it is a set of controls the fire and rescue service operates from a panel at the entrance to sound alerts floor by floor, so they can move people out selectively when they judge it necessary. In England these are expected in new blocks of flats above 18 metres. If somebody offers you one as a substitute for a fire alarm, or the reverse, they have misunderstood both.

In England, if the building is over 11 metres in height and contains two or more sets of domestic premises, then yes. The Fire Safety (England) Regulations 2022 came into force on 23 January 2023 and require quarterly checks of fire doors in the common parts and best-endeavours annual checks of flat entrance doors. Note that the interval comes from those Regulations and not from the Fire Safety Order, which sets no interval at all. Conflating the two is the most common error written about this subject.

Yes, and it is worth understanding that they are covered by two different standards. The communal system in the common parts is designed to BS 5839-1, the same standard as a commercial building, because the common parts are non-domestic premises. The systems inside individual flats are designed to BS 5839-6, the domestic standard, which is where grades and LD categories come from. A block often needs both, specified together so that they behave sensibly at the boundary between them.