Evaluation of a Horizontal Lifeline System Used during Installation of Residential Roofs

摘要

Residential roofing is considered as one of the most risky occupations. Usually, workers use roof anchors for fall protection during roof installation. This method is time consuming and hinders their tasks. Instead of roof anchors, a building contractor has developed a horizontal lifeline system (HLLS) consisting of two 4.9-m long posts made up of three aluminum hollow structural sections of size 51x152x6.4mm welded together and a horizontal lifeline (HLL) wire rope of 9.5mm diameter. The posts are assembled to end trusses and hoisted in place by a crane and the HLL is installed at 1.524m above the ridge. The HLLS is heavy and has never been tested on on-site braced trusses as the host structure. This paper presents the results of a study to evaluate and optimize the HLLS and to verify the strength of on-site braced trusses as the host structure of the HLLS. Tests results show that the HLLS and the on-site braced trusses have passed all fall tests and can be used as fall protection during roof installation. The HLLS has to be installed with a crane during roof installation and it is not easy to be used on an existing roof. (C) 2016 American Society of Civil Engineers.