Audibility - Huge single family home

[David Rooney]

Huge single family "stately home" Grade 1 Listed, 3 storeys and at least a dozen bedrooms.

We are assuming a minimum Grade A LD2 but this may move to Grade A LD1.

Due the audibility relaxations of Part 6 we only need to achieve 85dB at each bedroom door. With regard to the rest of the mansion there is no specified minimum, it simply needs to be "audible".

If we now introduce two "live in" staff flats in the basement we did consider a detector simply inside each door connecting the flats to the main house but are suggesting full AFD within the flats (LD2) mainly due to the Listed status and lack of guarantee of any meaningful compartmentation.

Is this reasonable?

However, regarding alarm levels.... although these people will be familiar with the place and almost part of the family am I right in thinking we are required to achieve 75db in their bedrooms  ??

Also, am I right in thinking we still do not have to increase audibility throughout the house even though these are paid employees that will be looking after the place essentially on their own 11 months of the year??

Thanks

[kurnal]

Dave just a bit puzzled why if you are assuming Grade A LD1 or LD2 throughout the building this would not also apply to the flats in the basement as a matter of course?
The staff in the flats may well be considered to be domestic servants keeping them outside of the scope of RR(FS)Order.  There is no real reason to justify why they will require 75db and a part 1 alarm system to wake them if other people sleeping in the building will be adequately served by a part 6 system and to provide a mixed system brings its own disadvantages. The crux is the standard of the conversion to install flats in the basement which should be carried out under the supervision of the Building Regulations. The fire alarm system and coverage of detection will then be determined by the risk of a fire anywhere in the building being detected sufficiently early to ensure persons are not trapped. But if it's done right a comprehensive Part 6 Grade A system should be the order of the day. 

[David Rooney]

Top man .... I was thinking along those lines but wondered if there was an implied duty of care (like a hotel staff accommodation block) that you should be obliged to wake them (at 75db) if there was a fire in the main house.

They do have their own exits to air so that's not an issue.

Thanks K ....