| 摘要 |
This invention provides fall protection systems, in metal building construction, and methods of installing such systems. A given such system comprises a suspension fabric, supported by a grid-work of longitudinal and lateral support bands. At least one of the lateral support bands is a relatively softer steel having greater elongation properties, while having lower yield and tensile strengths. The balanced properties better distribute the force of a falling object to the respective members of the fall protection system so as to limit the force which must be tolerated by the suspension fabric, such that the system can catch and hold a dropped test load, or a worker falling onto such system, without catastrophic failure of the suspension fabric. |
| 主权项 |
1. A fall protection system in a building roof structure, such building roof structure including structural roof elements which include at least first and second rafters, a space between said first and second rafters defining a first distance between said first and second rafters, each said rafter having a length, a top, and opposing first and second ends, said roof structure further comprising an eave, having a length, and extending between the first ends of said first and second rafters, a ridge, having a length, and extending between the second ends of said first and second rafters, and a second distance between said eave and said ridge, said eave and said ridge being disposed on, extending transverse to, and being connected to, the tops of said first and second rafters, and a plurality of intermediate purlins extending between said first and second rafters and spaced from each other between said eave and said ridge, said intermediate purlins being disposed on, and extending transverse to, the tops of said first and second rafters, said fall protection system comprising:
(a) a first set of longitudinal support bands extending from said first rafter to said second rafter and being connected to said building structural roof elements, said first set of longitudinal support bands being spaced along the lengths of said first and second rafters; (b) a second set of lateral support bands extending from said eave toward said ridge and under said intermediate purlins, said bands of said second set of support bands having first and second end portions which are spaced along the lengths of said eave and said ridge; and (c) a suspension fabric overlying, and being supported by, said first and second sets of support bands, and being attached to said building structural roof elements,said first and second sets of support bands collectively defining a grid-work of crossing bands,a first band of said second set of lateral support bands, next adjacent said first rafter, having at least one of
(i) a yield strength of 45 ksi to 85 ksi, or (ii) a tensile strength of 60 ksi to 90 ksi, or (iii) an elongation of 12 percent to 40 percent. |
