1. Catchfan

• 3.4.1         Requirements

The design intention of the catchfans is to catch small pieces of building debris that passes through the protective screen and net, and the catchfans are not designed to collect large pieces of building debris which should have been collected by the protective screen or net. A small piece of debris could be disastrous after gaining enough kinetic energy through falling great heights. Thus, a catchfan shall be installed at a vertical distance of not more than 10 m below the working floor. A catchfan shall have a horizontal extension of 1.5 m from the exterior face of the scaffolding. The typical angle of inclination shall be 20^o to 45^o from the horizontal plane. Catchfans shall be used only as precautionary measures and shall not be used as temporary support for any anticipated loads.

Both bamboo catchfans and metal catchfans are acceptable provided that they are properly installed. Under the present craftsman’s techniques, bamboo catchfans can be applied to either bamboo scaffolds or metal scaffolds, but metal catchfans are allowed to be mounted on metal scaffolds only.