Would you please advise on positioning of Fire Exit Sign please. We have the usual sign over door but are considering putting it a little higher over the door, leaving space to see through the door at the top via a half-moon glass window above the door. Would this be acceptable please?

Check out the full details which can be found in BS 5499 part 4 2013.

Escape route signs should be sited conspicuously within the normal field of vision.

To assist evacuees with the prediction of the location of successive signs, the following principles should be applied:

1. Signs above doors or open spaces should be mounted between 2m and 2.5m from floor level, measured to the base of the sign and be sited as close to the centreline of the escape route as practicable;

2. Signs sited on walls should be mounted between 1.7m and 2m, from floor level measured to the base of the sign;

NOTE 1 this mounting height is intended to ensure that signs can be readily seen, e.g. over the heads of people.

3. Mounting heights greater than 2.5m may be used, e.g. in large open spaces or for operational reasons , but such signs should be both conspicuous and legible;

NOTE 2 this mounting height is intended to ensure the signs are within the immediate field of vision and therefore larger signs might be necessary;

4. Signs should be sited at the same height throughout the escape route, so far as is reasonably practicable.

But isn't there a risk of smoke preventing the sign for being visible? Considering the fact that smoke rises up, should there not be evacuation signs nearby the floor?

If you are still in an area when the smoke layer has formed sufficiently to obscure the signage then something has gone badly wrong with other fire safety provisions!

Floor mounted signage does have a place and a variety of products exist for this.

If there is no height above the door for a sign due to low ceiling heights can the sign be placed next to the door on the wall at 2m?

If the sign is indicating to use this door, it sounds you do not have an option however I would ensure the upwards point arrow is next to the door, next to the pictogram, next to the lettering.