The effectiveness of personal protective equipment made of metallized materials when exposed to extreme levels of infrared radiation

Abstract

Introduction. The results of the study of the nature of the formation of the thermal state in workers under the influence of extreme levels of the heating microclimate with multifactorial exposure against the background of heavy physical labour, justify the need to develop and experimentally evaluate a set of preventive measures. Such measures need to prevent chronic overheating, with the mandatory use by workers of modern effective personal protective equipment from infrared radiation. 
 The purpose of the study – the study of the effectiveness of personal protective equipment made of metallized materials in real production conditions, for the prevention of chronic overheating from exposure to extreme levels of infrared radiation with multifactorial exposure against the background of heavy physical labour. 
 Materials and methods. To assess the possibility of using personal protective equipment in the conditions of modern forging and pressing production, there were taken protective clothing sets made of the material OXA-440, consisting of a cotton-asbestos lining and a metallized material with an aluminum surface. In the manufacture of prototypes of workwear, the topography and the estimated area of the irradiated area of the body surface, and the moisture and air tightness of metallized materials, were taken into account. The effectiveness of personal protective equipment was evaluated with taking into account the indicators of the thermal state of the workers of the main occupations who used two sets of the specified protective clothing alternately. The thermal state of the body was studied in accordance with the guidelines of the MUK 4.3.1895-04 and the provisions of the standard GOST R ISO 9886-2008. Studies on the hygienic assessment of workwear were carried out in the cold and warm periods of the year. A questionnaire survey was conducted to subjectively assess the usability, design and protective properties of workwear made of metallized material.
 Results. The main sources of thermal radiation in the studied production are incandescent to a temperature of over 1200°C with metal forgings of various lengths and various profile configurations, which largely determine the variability in the degree of radiation intensity of the radiant energy flow at the workplaces of blacksmiths and heaters. The formed thermal state of the workers of the specified occupational groups, dressed in standard cotton workwear, during the performance of the main work operations during the first half of the working shift in the cold and warm periods of the year, is estimated as the maximum permissible, requiring a limit of working time – no more than one hour per working shift. The use of workwear made of metallized materials in the cold period of the year led to a slight improvement in the thermal condition, which allowed to prolong the time spent at the workplace to 2 hours. When using the original design of a protective suit made of a metallized material characterized by moisture – and air-tight properties and covering a large area of the body surface during the warm period of the year, no improvement in the thermal condition of the workers was observed. According to the questionnaire survey, good reflective and mechanical properties of the test material were revealed. The expressed wishes and suggestions of the workers in the areas of improving the design of workwear suggest the development of new design samples of special protective clothing made of this metallized material, taking into account these comments.
 Limitations. The chosen research method determines the limitation on the possibility of its use in relation to a specific production, characterized by the multifactorial nature of the production environment against the background of heavy physical labour and extreme levels of infrared radiation determined by the specifics of the technological process. 
 The obtained research results objectify the subject of further research – the development and evaluation of the effectiveness of new design samples of special protective clothing made of metallized materials.
 Conclusion. The results of the conducted studies have shown good reflective and mechanical properties of the new metallized materials. During the questionnaire survey, the workers expressed their wishes and suggestions for improving the design of workwear sets, which must be taken into account when creating new design samples of special protective clothing, for their subsequent use as the main means of protection when working under conditions of exposure to extreme levels of industrial infrared radiation.