Grade D alarm system in single let property

[Guest pete]

Fireangel have advised me that for grade D system, I only need one mains wired alarm and all other can be battery operated. I thought they all needed to be mains wired but they are adamant that this is the case. I informed them:

It's for a single let rental . Kitchen lounge bathroom and 2 beds. 

 

They referred me to:

https://www.fireangel.co.uk/british-standard-bs-5839-6-2019/

 

Grade D1. A system of one or more mains powered detectors, each with a tamper‑ ...

 

Also will one smoke in hall, one in lounge and one heat detector in kitchen suffice for ld2? 

Any help much appreciated. 

 

 

[AnthonyB]

Utter nonsense.

Grade D is mains with battery back up, D1 being tamperproof back up, D2 user replaceable back up. All devices are the same power source and interlinkable.

A battery only system is Grade F and only really suitable for legacy single dwellings and flats and over time would be phased out as new, builds, conversions and rewires see Grade D installed as minimum.

You don't mix Grades other than a HMO or conversion to flats where you may have a Grade A common system and Grade D to individual flats/bedsits

Grade D:LD2 is a system comprising interlinked mains powered with back up smoke & heat alarms with smoke to Alarms in hallways and landings (circulation spaces & escape routes) plus high risk rooms (at least heat to kitchen and smoke to principle habitable room, i.e. living room)

The only situation I could see mixed in place is where the statutory requirement is Grade D:LD3 (new builds, re-wires, etc although LD2 is more common now) and additional voluntary protection is provided to other areas and to save money and ease installation Grade F is used - however unless interlinked the added value is grossly reduced (Grade F are more likely to be removed, flat battery or no battery hence the move towards Grade D)

[Guest Guest Pete]

Thankyou so much Anthony, yes it didn't make sense to me. Glad to have asked you. 

Thanks again!