Why would a building inspector insist we installed a AOV Smoke ventilation system in a 3 floor building with 2 x 1 bedroom flats on the first floor and 1 x 2 bedroom flat on the second floor.  Ground floor is commercial.

We have been renovating the flats and have upgraded insulation / fire alarm systems / new FD30S fire doors / new windows / new electrics / new plumbing etc.  They have agreed that there is no material change of use but insisted on an AOV Smoke Vent in an existing building located in a conservation area.

I understand about AOV smoke ventilation in new builds or buildings with change of use - but didn't think that this would apply to an existing building.

Why would they insist on this and are there any alternatives?

The layout of the existing stairs and the planning implications (conservation area) are becoming a nightmare

Can anyone give us advice on this?

Ask the building inspector for hi reasons.

This is what he has said:
 

Whilst I accept in principle the project does not constitute a material change of use, given the extent of the alterations the communal escape provisions and flat layouts needs to be fully compliant with ADB. This will also help ensure compliance with the RRFSO but of course a fire risk assessment and maintenance procedures will still need to be carried out. The fire service can be contacted for further details about your legal obligations under the RRFSO.

The alterations he is referring to is that we have reconfigured the layout of the flats - but the building is 1930's steel portal building with brick infill.  We have removed internal stud walls and reconfigured the layout (not structural work).

First floor - was 2 x 1 bedroom flats and it is still 2 x 1 bedroom flats
Second floor - was 1 x 3 bedroom flat and has been reconfigured to 1 x 2 bedroom flat

Is your fire alarm system set up for a simultaneous evacuation procedure with a common alarm that extends into the flats?

Unfortunately too many BCO's think Approved Document B is a mandatory document - it is not (It even says this: "There may be other ways to comply with the requirements than those described in an approved document. If those responsible for meeting the requirements prefer to meet a requirement in some other way than described in an approved document, they should seek to agree this with the relevant building control body at an early stage".)

There are plenty of flat conversions in older buildings where smoke control and a stay put policy are not viable to fit where simultaneous evacuation is used and the functional requirements of Building Regulations are met and completion issued.

Perhaps they are only a Class 2 Building Inspector under the new Building Control regime & only able/willing to stick to ADB - if you are departing from ADB significantly (which you can do) you may need a Class 3 or above even though it's a low rise building.

Thanks for this information Anthony B - that's very interesting.  

Yes our fire alarm system set up is for simultaneous evacuation procedure with a common alarm that extends into the flats - so everything is linked.

I'll have a good look at the rest of your response and see if we can look at alternatives.

Again, thank you for your help