Thanks - just for a bit of background, I'd read some of the MAIB reports of NB fire-related deaths on board. There's the obvious lessons to be learnt from them as to how to prevent or lessen the risk of a fire starting, but chancing on the fire-retardant products made me wonder whether it was worth the cost/effort slow down the spread of fire in the event of one occurring, to give yourself and anyone else on board time to escape. If you've already installed fire and smoke detectors as belt and braces, would such a further measure make any significant difference, I wondered.
1. I was careful to use the term 'fire-retardant.
2. Would have been as an alternative to 'standard' varnish. Hadn't looked into how it holds up over time.
5. How widepread the use of it was what I was wanting to find out, but your last sentence is interesting in conjunction with 4. - perhaps it's not used in domestic applications because of dangerous by-products? I can only find this:
But anyway, conclusion is as you say, that most people wouldn't bother.