Trying to get a definitive answer for a report on several hundred fire doors which all have signs (Fire Door Keep Locked) and so on that are 42mm in diameter (blue area) these where pre attached to metal door sets when installed 10 years ago.

BS5499-5 states 60mm, which is superseded by BS EN ISO 7010 which states 70mm and I'm being told by "professionals" it is 80mm.

Who is right?

Thanks

Usually they are either 100mmx100mm square or 80mm diameter based on what is sold ex-stock by suppliers and I've never seen smaller.

Letter heights on signs used to be set in fire certificates, but now it's usually based on viewing distances and the signage British Standards. If the standard says 70mm considering the 'point blank range' viewing distance the smallest size in guidance would apply - although 80mm is the smallest sign I've ever seen for sale - the ones on sound like specials or made on a label printer.

If the signs were already on the door, and they were compliant at the time they were put on the door then there would be no expectation to update them.  However, I suspect that they were not compliant (42mm 10 years ago!).  The off the shelf size appears to be 76mm Dia

Thanks guys, think we will add more, they are so cheap anyway.