Back from my travels- lots of new postings since I last looked at this most interesting of cases. Heres my view on it so far for what its worth
1- Change of use from residential 1b to residential 2b does represent a material change of use and to keep within the law it is right to submit an application.Many dont bother- but if you dont you are in breach of the Building Regulations and this could be enforced within 12 months of the change taking effect, you could be served with a notice equiring changes to be made.
2- As far as the Building Regs is concerned, they would normally just look at the present use and work from this rather than what happened 10 years ago
3- Once you have made an application with a building control authority, either local government or approved inspector their protocols do not allow you to switch horses halfway through the race, this is to prevent people trying one after the other till they find someone prepared to accept their scheme.
4- The building inspector does not have to work to ADB- its usually down to the applicant to identify the design strategy adopted. ADB annex does list other documents references as well, the DCLG guidance has no status as far as the buiding Regs is concerned but it would be very interesting in an existing building to take diagram 50 of the Sleeping guide as the design strategy - after all building Regulations B1- B5 are Functional requirements and the sleeping accommodation guidance is being taken as best practice in enforcement cases!
5- Avoid at all costs any determination or appeal to the Secretary of State, these arguments are always decided on purely technical argument and nearly always find against the apellant. Does ADB recommend a lobby in this case? Yes. Have you provided one? No Have you provided an alternative system using pressure differentials to protect the stairs ? No. Appeal dismissed. The secretary of state wont be in the least interested whether lobbies would in this case have any benefit whatsoever, just whether they are there or not.
6- In practical terms you need to resume dialogue with the inspector. Present an alternative offer to him as I suggested in an earlier posting and give him space to ask for a little more. I would speak to the senior fire safety officer for the area- ask him for advice, get him on board and show him your proposals and compare it to the DCLG guide. Despite what the building inspector says the fire officer cannot reasonably turn down a proposal that fully conformes to the Govermnent guide.
7-I would suggest multi sensor detection to an L1 standard to give the earliest warning of any type of fire. And all fire doors to the stair to a pucker standard with (if necessary) new frames. FD30S doorsets. If he still holds out for a lobby I would then offer swing free self closers. Would you prefer two doors likely to be wedged open or one pucker dink fire door you can rely on?
8- You were looking at sprinklers but were unable to find an installer or had a problem with the mains I believe. Before burying this as a solution I would get a quote from someone like aqua mist of Wakefield, which is a low pressure water mist system. Heres their web site
http://www.aqua-mist.co.uk/you could also try one of the many sprinkler suppliers listed here
http://www.bafsa.org.uk/mission.php Hope this helps and keep us in touch with progress