| 摘要: | 墜落是我國勞工重大職業災害之主要原因，勞工經常在高處平台操作移動式機具與設施作業，稍有不慎即有墜落死亡之虞。作業場所在條件許可下，墜落災害防止之規劃應朝向避免存在高處作業之本質安全要求。當以工程控制無法達到時，安全網及安全母索之安裝即為解決墜落職災立竿見影的設施之一。 為了更進一步了解不同規格安全網的特性，來確認安全網的安全性，本研究先對工地現場設置安全網狀況進行現況設置調查，試驗之設計以常用之尼龍材質繩索，以三種繩徑(3mm、5mm、7mm)、三種網目大小(10cm、15cm、20cm)及曝曬條件等變數編織成1.2m×2m大小之安全網進行抗張強度的靜態試驗。試驗時，先以假人負載於安全網上，再以油壓機靜態方式施加垂直外力，記錄外力與網底垂墜變形量、網目形狀變化以探討其防墜性能。本研究共完成一般安全網18組及曝曬後安全網18組試驗，其結果分析顯示安全網繩徑越細，承受重力垂墜變形越大；安全網網目越大時承受重力垂墜變形越大；安全網材質經過日曬之後抗張力的變化，發現安全網經過曝曬後,材質變脆(楊氏係數增大)且抗拉強度有衰減的現象。
Falling from a high place has been one of the most serious occupational hazards for laborers in Taiwan, since laborers often operate mobile equipments at high places. Without considerate protection, falling from high places often bring about the termination of a life. If none of the previous working environments are provided, the installations of safety nets or lifelines are then regarded as the most efficient approaches to prevent falling hazards. This research aimed to examine the performance of those safety nets commonly used at work places, based on which to construct installation guidelines as references for this field.In order to understand the performance of various safety nets, the researcher conducted the study at a real workplace. The static testing design was adopted to examine the tensile strength of nylon safety nets of different conditions: three different rope width (3mm, 5mm, 7mm), three different mesh width (10cm, 15cm, 20cm), and solarization of the net. Each net was designed equal-sized, with 1.2m in width and 2m in length. During each test, a dummy was firstly carried by a safety net. Then a vertical press was added from a hydraulic machine. The falling protection performance of each safety net was examined with the records of the vertical press, the deformation degree of the net bottom after falling, and the deformation of the mesh shapes. This research has completed testing on 18 safety nets without solarization and on 18 safety nets with solarization. The results showed that the smaller the rope width, the higher degree the deformation of the net became. The bigger the mesh width, the higher degree the deformation of the net became. Also, the embrittlement of the rope material after solarization has decreased the tensile strength of the safety nets. |
