The Effect of the Use of Full Body Harnesses on Their Protective Properties
A full body harness is a component of personal systems protecting against falls from a height. To ensure users’ safety, the harness must retain its protective properties during its whole service period. All the elements of a harness (webbings, threads, metal buckles, etc.) are exposed to destructive factors. Harnesses stored and used for a few years were tested. The paper discusses the most frequent types of damage and their effect on the essential resistance parameters. The effect of atmospheric conditions, sunlight, mechanical damage and dust on the parameters of webbings was tested. Conclusions on the main causes of the loss of the protective properties of harnesses are drawn; periodic checks of the physical conditions and guidelines for estimating acceptable service time are recommended.
Effect of safety harness design on the pressures exerted on the user’s body in the state of its suspension
The presented studies concern the pressure of safety harnesses on the user’s body in a state of its suspension. An anthropomorphic dummy was used for simulation of human behaviour in suspension. The test objects included four models of harnesses of different designs, equipped with attachment elements placed at the back and front of the human body. Pressure mapping sensors of 56 × 56 mm2 surface area and two-dimensional (2D) pressure mapping apparatus were used for the measurements. The parameters characterizing the pressures of the harness belts on the dummy surface were defined. The obtained results demonstrated in which position the pressures exerted on the dummy are the greatest and that they depend mainly on the design of the safety harnesses and their attachment point. The most sensitive points of action of the harness on the user’s body have been identified. Guidelines for the construction of the safety harnesses have been formulated.
Ground Fault Protection for Electric Utility Generating Station Medium Voltage Auxiliary Power Systems
Most generating station designs have medium voltage auxiliary power systems with low resistance grounded neutrals.1 In order to provide even higher reliability, the auxiliary power distribution system configurations supply increasingly redundant process equipment.