The first step is to install the crossbeams. The 3m high crossbeams are placed vertically on the floor by lifting lorry and fixed to the parapet by 4 nos. of Hilti HST M20 anchor bolts. Crossbeams are placed 1m apart, total 19 crossbeams will be installed for each of the catchfan location. Horizontal members are installed to the crossbeams for every 600mm height. Horizontal members and crossbeams are connected together by couplers to fix their positions. Once the crossbeams are fixed, catchfan layer can then be installed. Metal tubes with 4m in length are used as the vertical members of the base layer of the catchfan and they are fixed to the crossbeams 1m apart, additional metal tubes are fixed on top of the crossbeams and connected to the vertical members to form a triangular shape structure in section view.