Inner rooms

[steve walker]

What does the forum think about "inner rooms"?

I know that the occupants need to have early warning of a fire in the access room and this can usually be accomplished by SD, vision panels or a (500mm?) gap between the wall and the ceiling.

With SD do you think that it is acceptable to have inner, inner (etc) rooms if SD covers all the access rooms and the travel distance is acceptable?

[johndoe]

It depends on the risk in the room as well not just afd or TD.

[AnthonyB]

We've always not accepted inner inner rooms (except where the inner inner room is so small it's more of a cupboard and is not occupied) regardless of protection, but I suppose in theory based on risk of ignition, spread, rate of smokelogging and precuations such as AFD limited travel distance, VP, etc it could be justifiable in certain circumstances under the new non prescriptive regieme.
However as most places we find this the situation hasn't been covered in the FRA and precautions are inadequate we go for removal of one of the rooms

[messy]

I am surprised by some of my colleagues reactions to inner inner rooms. If you try to mention the phrase you get interupted half way through with a firm "No".

This is one area where the non prescriptive approach may be a definate advantage as each case needs to be taken on it's own merits/risks.

To have a blanket ban on the concept (as some I/Os have adopted) is ridiculous. With reasonable TD, AFD, a low risk occupancy and low fire loading, I can't see the problem.

[steve walker]

Thanks for the thoughts.

I am happy to consider inner inner rooms and will support them if escape appears acceptable. For inner rooms I usually recommend SD over the other methods of early warning. A person working on a computer with their back to a small vision panel is unlikely to notice a developing fire. A domestic type detector/alarm (mains + battery) might be suitable in a building with a silent staff alarm.