Best Practice Guide 4, latest issue, says C3.

So does common sense.

Regs aren’t retrospective, if it’s a new installation then yes needs SPD, as you are carrying out an Eicr I would code it C3 and leave it to the client to decide.

Lol. Like the clients an expert. 

What data is available to advocate spd's

Answer.. none.

Just engineering mumbo jumbo from so called experts offering no statistical observed empirical data.

Bit like climate change but I didn't say that.

The daft thing being if there was no main supply to the detectors it would be fully compliant as battery only is fully compliant in a rental , be it a minimum requirement.

Gary

Careful reading of Chapter 65 might lead one to conclude that there is no requirement to consider recommendation for improvement. Unless the issue would give rise to danger, there is no requirement to mention it and therefore a Code 3 could be dispensed with. 
I wonder if I just stuck an appendix in at the back of my reports listing out some of the common code 3 issues and directed the client’s attention to it, or, perhaps, just inserted a link to Best Practice Guide 4……mmm, ….always the rebel, or so my headmaster told my parents!
Then again, my dad’s warning that rebels usually find their way to the gallows is still worth heeding!

The daft thing being if there was no main supply to the detectors it would be fully compliant as battery only is fully compliant in a rental , be it a minimum requirement.

Although in that case the smoke detectors would be immune to damaging surges on the mains - as there would be no path to conduct the surge to the detector.

   - Andy.

Agreed.  I don't know how we have managed all these years. 

Like smoke detectors have been blowing off the ceilings with all those transients.

Load of nonsense SPD,s

Yet we're forced to install them. A recent NICEIC shock and awe essay in the recent publication shows no scientific reason for employing spds just a narrative from manufacturers with vested interests.

I think that engineering has departed the IET

Recently found these https://www.expresselectrical.net/fire-safety/domestic-smoke-and-fire-alarms/interlinked-smoke-and-fire-alarms/hispec-smoke-fire-alarms?limit=25&gclid=Cj0KCQiAofieBhDXARIsAHTTldqBazq0KrMCctKXizrystXxuB1evMBNNiHnKnojbdPXd3N4HJkmC_EaAlrMEALw_wcB

Interlinked 10 year sealed battery smokes and heats. I would have thought ideal for rentals, and no SPD required, nor mweic(s). I guess a fire alarm certificate might be needed if a new installation, if the system is designed, but if you are following the installation instructions in the placement of the detectors, and/or possibly replacing existing ones, they could save time and money.

So tech is catching up.