I'd be far more concerned that the flats only have a sounder off the common system inside and not a heat detector off it as well near the door to the common areas (as a minimum). If it has a common alarm & thus presumably a simultaneous evacuation policy then that is usually something not to the standard for stay put (compartmentation, lack of suitable common area smoke control, etc) so it's usually vital to sound the alarm whilst the fire is still contained & not yet fully developed in the flat of origin - the detection being a back up in case the occupiers of the flat of fire origin are out when the fire starts or forget to activate a call point.

Flats are not usually provided with call points (access and testing once a year for the detector is bad enough without adding a call point) however this doesn't mean they might never be appropriate - whilst there is a 'typical' minimum specification for an alarm system for simultaneous evacuation in flats it's down to the situation in a particular building as to what is needed and sometimes it's more - I've seen common systems take the place of the flats self contained LD2 system (using conventional zones with hush buttons or the addressable common loop with suitable C&E) or even, albeit rare, a common L1 system covering virtually every area & room, common or flat, in a building, due to the particular scenerio

Hi,
I have a very small building conversion 2 storeys + basement.
The basement is accessed from external stairs only and is used for bike storage and utilities.
The ground floor has 3no. 1 bed apartments with independent direct external access to each.
The first floor has with 3no. 1bed maisonette apartments - each with a second floor at a height above ground of approximately 5.4m.
The maisonettes have an 'entrance lobby' separated from a kitchen and lounge at entrance level - but with entrance lobby stairs open to a first floor open plan bedroom at upper level.
Client is keen not to encroach on the stairs / bedroom with walls in an attempt to keep feature roof trusses exposed.
Normal practice would be to enclose the stairs to leave a protected lobby where you might have several bedrooms - but in this instance it is only 1 bedroom.

The building is very small and a common landing at first floor level discharges direct via a single flight of stairs to the ground level final exit.
The stairs are within 4.5m of the apartment entrances and the landing has an opening vent which could be automatic if required.
Again, normal practice is to have a lobbied stair but the ABD & BS examples all illustrate apartments on each level (above and below) so requirement for stair lobby protection is understandable - less so if the apartments are all on a single level.

Appreciate any thoughts on possible solutions with enhanced detection or venting?

Regards,

I have seen a study somewhere that showed a debilitating effect on mental agility as sound levels increase. Can?t find it but it wasn?t directly related to FA devices. However, I have experienced a kind of brain numbing effect when the banshee-type sounder operated during FA testing and I wasn?t wearing ear defenders.
Better to have more sounders and a more even distribution of sound levels.

BS 5839-1 states sound pressure levels should not "not greater than 120 dB(A) at any normally accessible point"

Many current 24V sounders are usually in the 85-95dB @ 1m range. The Banshee Excel, like some, can (depending on which of the 32 tones is used) be up to 110dB but the DIL switches include volume settings where you can reduce the dB by 10dB or 20dB id required.

Excessive sound was an issue when 240V fire alarm systems were common using motor driven sirens blasting out 127dB (you'd often see single sirens covering whole floors where you might have 2-4 or more now)

Well - I think it would be daft to have a compartment wall between the kitchen and the restaurant. But there are means of escape considerations in ADB.