supply and fixing of armstrong suspended ceiling with ultima micro look tiles. , providing & fixing of armstrong suspended ceiling system with ultima microlook tiles. the tiles should have lifelong guarantee with humidity resistance of 99%, light reflectance 90%, nrc = 0.70, thermal conductivity k-0.052-0.057 w/mk, colour white, fire performance uk class 0/class 1 (bs 476 pt-6 & 7) in module size of 600mm x 600mm x 19mm laid on armstrong silhouette reveal profile grid system with 15mm white flanges incorporating a 36mm or 6mm central recess. silhouette main runners & cross tees to have mitered ends and birds mouth notches to provide mitered cruciform junctions. installation: to comprise main runner spaced at 1200mm centres securely fixed to the structural soffit by approved hangers at 1200mm maximum centre & not more than 150mm from spliced joints. the last hanger at the end of each main runner should not be greater than 600mm from the adjacent wall. 1200mm long cross tees to be interlocked between main runners at 600mm centres to from 1200 x 600mm module. cut cross tees longer than 600mm require independent support. 600 x 600mm modules to be formed by fitting 600mm long cross tees centrally between the 1200mm cross tees. the 1200mm cross tees to have central birds mouth notches to facilitate fitting of 600mm cross tees armstrong wall angles in white colour to be secured to walls at 450mm maximum centres.