Good Afternoon, 

BS 5839 Part 6 confirms the requirements for alarm systems/detection in flats converted pre 1991. Can I assume that the guidance doesn't concern flats converted after this date as the assumption is that the evacuation policy is Stay Put? 

I understand that building regs 1991 would have required 60m compartmentation after 1991, hence the Stay Put policy. 

A type 1 FRA is limited as to the assessment of the structure of the flats, so even if a flat was converted after 1991, could an alarm system be necessary? 

Thanks 

Whilst many conversions post '91 are to ADB for stay put there are also a fair number that aren't for a variety of reasons - whilst it's more likely to be stay put and not require a common alarm the risk assessment shouldn't assume this and should check the structure, layout and smoke control provisions are adequate.

I've assessed modern conversions in old buildings that haven't been able to have the right layout and smoke control for stay put due to the age of the building & listing so were designed and equipped for full evacuation.