I wonder how many times you have drilled through it without knowing? scary stuff

Thats the real problem.

I would agree with unistrut across but the original statement was.

I also said i had Considered unistrut

How long is this corridor and how high is the ceiling jef?

3 floors, long corridors, but to many fire doors (37 pairs) for firebeams

The way we do it with the councils up here is sticky back trunking, marshal tuflex call master boxes and some no nails. Put your trunking up, get it in place and then go around with your perm marker and dot your fixing holes. Get your asbestos contractors in. (theirs is in house) and they do they rest. Saves so much hassle and the cost isn't too great if explained properly to the client. We have just done a job similar to one you describe using this method. It has the least amount of intrusion and at least you can then get some third party accreditation on it. Surely worth it if your the RP.

Saying that if it's still to expensive, uninstructed 30mil of the ceiling with standoffs either side will also do the trick, paint it afterwords to matching the ceiling and after a while they will forget its there.

Basicaly this is where we are at.

3 floors, long corridors, but to many fire doors (37 pairs) for firebeams

Well that was one thing i was going to suggest. Or caterniry and steel conduit attached to the catinery.

Basicaly this is where we are at.

Depends on what the client wants then. Some of our headteachers/architects don't give a monkeys. Could use string for all they care. Others have their head switched on and agree for the extra. I prefer trunking but either will keep you true of the standard.

Basicaly this is where we are at.

Are we? How are you going to fix the cables in accordance with BS5839?

Are we? How are you going to fix the cables in accordance with BS5839?

I think P-clips inside the trunking was mentioned?

I think P-clips inside the trunking was mentioned?

But what about the dust?

the trunking is on the wall

But what about the dust?

As said if the asbestos contractor is making the hole/painting/rawl plugging then you have a nice clean fixing to go in to.

That saved me reading all those troublesome posts