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.
Dynamic test method for full body harnesses exploited in cold climates
In this paper, a method of testing the dynamic strength of full body harnesses is proposed. The possibility of conducting the method in laboratory conditions is determined by testing the method while maintaining the specified conditions of low temperatures. The main attention is paid to the effect of the set temperature on the full body harnesses, when dynamic shock loads occur in user operation mode. The advantage of the developed method of dynamic testing of full body harnesses is the simplicity in bringing the test sample to the climatic parameters of operation by pre-conditioning. This makes it possible to implement dynamic testing under specified climatic conditions within mass laboratories in the chain of conformity confirmation. Pre-conditioning allows you to conduct research on the influence of climate factors on various characteristics of safety harnesses. The interaction of the binding elements with each other, previously reduced to the specified temperature parameters, is also studied. It is necessary to pay special attention to the resulting impact loads during dynamic tests, and their relationship when conditioning products at different temperature.
Prevention of Barite Sag in Oil-Based Drilling Fluids Using a Mixture of Barite and Ilmenite as Weighting Material
Drilling high-pressure high-temperature (HPHT) wells requires a special fluid formulation that is capable of controlling the high pressure and is stable under the high downhole temperature. Barite-weighted fluids are common for such purpose because of the good properties of barite, its low cost, and its availability. However, solids settlement is a major problem encountered with this type of fluids, especially at elevated downhole temperatures. This phenomenon is known as barite sag, and it is encountered in vertical and directional wells under static or dynamic conditions leading to serious well control issues. This study aims to evaluate the use of barite-ilmenite mixture as a weighting agent to prevent solids sag in oil-based muds at elevated temperatures. Sag test was conducted under static conditions (vertical and inclined) at 350 °F and under dynamic conditions at 120 °F to determine the optimum ilmenite concentration. Afterward, a complete evaluation of the drilling fluid was performed by monitoring density, electrical stability, rheological and viscoelastic properties, and filtration performance to study the impact of adding ilmenite on drilling fluid performance. The results of this study showed that adding ilmenite reduces sag tendency, and only 40 wt.% ilmenite (from the total weighting material) was adequate to eliminate barite sag under both static and dynamic conditions with a sag factor of around 0.51. Adding ilmenite enhanced the rheological and viscoelastic properties and the suspension of solid particles in the drilling fluid, which confirmed sag test results. Adding ilmenite slightly increased the density of the drilling fluid, with a slight decrease in the electrical stability within the acceptable range of field applications. Moreover, a minor improvement in the filtration performance of the drilling fluid and filter cake sealing properties was observed with the combined weighting agent. The findings of this study provide a practical solution to the barite sag issue in oil-based fluids using a combination of barite and ilmenite powder as a weighting agent to drill HPHT oil and gas wells safely and efficiently with such type of fluids.