The requirements for precast hollow core slabs made from reinforced or prestressed normal weight concrete, are given in: BS EN 1168: Precast concrete products – Hollow core slabs.

Prestressed elements are limited to a maximum depth of 450mm and a maximum width of 1.2m. Reinforced elements are limited to a maximum depth of 300mm and the maximum width without transverse reinforcement to 1.2m. They may be designed with or without a structural topping.