As a dry cleaner and carpet cleaner, we do hundreds of curtain flame retarding per year. As I was aware any public building, hall , churches , schools or landlord for furnished houses, shops etc nightclub & pubs.
We are aware that some curtains have to be able to accept the flame retardent coating.
Some material state that they are able to withstand 5 or some even 50 cleans
As for the ridiculously expensive, we are one hell of a lot cheaper than most ridiculously expensive carpet cleaners like Jason L. lol
idealrob