This part of PD 6682 gives guidance on the use of BS EN 13055-1 in the UK. BS EN 13055-1 which specifies the properties of lightweight aggregates and lightweight filler aggregates obtained by processing natural, manufactured, by-product or recycled materials and mixtures of these aggregates for use in concrete, mortar and grout in buildings, roads and civil engineering works. BS EN 13055-1 covers lightweight aggregates of mineral origin having particle densities not exceeding 2 000 kg/m3 (2.00 Mg/m3) or loose bulk densities not exceeding 1 200 kg/m3 (1.20 Mg/m3), including: natural aggregates; aggregates manufactured from natural materials and/or from by-products of industrial processes; by-products of industrial processes; recycled aggregates.