BS 7457:1994

This British Standard specifies the property requirements, composition, and the production parameters of suitable rigid polyurethane foam (PUR) systems, which are dispensed on site, to fill the cavities of maximum width 150 mm of suitably constructed external walls of maximum continuous cavity height 12 m which have masonry or concrete inner and outer leaves, thereby providing additional thermal insulation to such walls and simultaneously, especially in the case of damaged wall ties improving their structural integrity.