They are starting to be something that really gets my back up.
They work fine in test situations but im pretty much sure you can speak to FFs and they will say that in a live fire that they do not activate as they are supposed to, thus leaving gaps, thus not improving the resistance.
As far as I can see there is no legal requirement for them and yet it seems to be one of the most commonly requested things with threat of prosecution if not installed!
Piglet:
The OP was specifically querying cold smoke seals, not intumescent seals (which is what I think you’re talking about)? Cold smoke seals will work very well
if properly fitted and maintained but, in my experience, they very rarely are. I would, personally speaking, be amazed if this had ever caused a fatality, but I have no hard data to back that opinion up.
You’re right inasmuch as there is no specific ‘legal requirement’ for either fire or smoke seals on doorsets. Generally speaking, though, both cold smoke seals & intumescent seals are necessary parts of an installation designed to meet the safety performance specifications defined in the relevant National Guidance (British Standards, AD-B, Scottish Technical Standards or whatever), so they cannot be simply ignored, whatever ones’ personal opinion or their efficacy is. As generally accepted good industry practice any Court would be likely to regard those documents as the ‘benchmark’ of acceptability & compliance with the Law.