Posted By Brian McMillan Not actually legislation but a good source of nreference can be found at http://www.teachernet.go..._safety_guide%5B1%5D.pdf This guidance is echoed in many local and fire authorities licencing documentation. We used a company that cleaned curtains in situ and then treated curtains with a liquid that gives a satisfactory level of flame retardency. The certificate lasts for five years at which time furtehr treatment is required.