The ceiling system D152-4AK.de consists of a substructure made of sheet steel profiles CD 60/27 as base and support profiles (double profile grid) or supporting profiles (simple profile grid) and a planking of Knauf 4AK Horizonboard gypsum boards. The 4AK board had a four-sided flattened edge formation, resulting in a perfect surface with high crack resistance. Knauf Horizon ceiling or wall systems with a Horizonboard GKF cladding are therefore the ideal system solution with high demands on the optics. The ceiling system can be executed with or without fire protection in various paneling qualities. This fire protection is available in the qualities F30, F60 and F90.