Not sure if you can help but I need a quick question answering for work. What is the maximum gap allowed between and intumescent strip and a door keep?

Three millimeters plus or minus one millimeter between the door edge and the frame. The intumescent strip should be fitted into a groove cut in the door edge or the door frame and be flush. However if smoke seals are required they should seal the gap between the door and frame, to prevent cold smoke from passing through.

when measuring gaps between doors is it measured from the smoke seal to the frame? I. E. Putting a 3 mm packer in if it holds in place it passes?

There should be no gap for a smoke seal otherwise it fails to perform it's job of stopping cold smoke passage prior to the activation of the intumescent seal underneath.

Hi all, I have fitted a rubber fin intumescent strip (10x4mm) to a communal fire door. The strip has been rebated into a 10x4mm groove and sits flush. When I try to close the door the rubber fin stops the door from closing. Am I ok to rebate 1mm more?  as I feel this would allow the door to close and the fin to make contact all the way down the frame. 
thank you for any help you can offer.

Rob