I'm applying the LACORS guidance to an existing conversion of a house to flats.
Converted 1982 to provide a single flat at ground, 1st & 2nd floors. All have lobby <9m travel from rooms FD30 self closing doors to all rooms other than bathroom including flat entrance. Dormer window open-able as a vent (albeit from top landing) to the stair.
Basement not in use (but considering further flat conversion) but has it's own external stairway and doesn't really affect the upper floors.
No real fire risk to the common stair, no current fire warning anywhere.
LACORS looks at Grade D-LD3 to each flat, but also a Grade A-LD2 to the common stair as passive protection is only 30 minutes to walls and floors, but this conversion is to the 60 minutes standard that is in current Building Regs and has the paperwork from 1982 to prove it and has had no structural stuff since to defeat this.
I'm asking for the D-LD3 as well as door upgrades (rebate only, no smoke and seals) but am in two minds about the communal system as the compartmentation is far higher than LACORS and that of Document B for stay put and I don't want to over provide as the landlord is willing but on a budget, plus I don't like over provision for the sake of it anyway.
Anyone got an opinion - if it was straightforward 30 minute compartmentation or less then i have no problem putting in the big system, but this one is a bit different.