Ultrasound is widely used in the metalworking industry, mechanical engineering, and metallurgy. The applied ultrasound frequency is from 20 kHz to 1 MHz, and the power is up to several kilowatts (Moyano et al., 2022). Ultrasound has a harmful effect on the human body. Workers with ultrasonic devices often experience functional disorders of the nervous system, changes in pressure, blood composition, and properties — frequent complaints of headaches, fatigue, and loss of auditory sensitivity (Moyano et al., 2022). Ultrasound can act on a person both through the air and through a liquid or solid (contact effect on the hands). Sound pressure levels in the frequency 11-20 kHz should not exceed 75-110 dB, respectively, and the total sound pressure level in the frequency range of 20-100 kHz should not exceed 110 dB.
Table 1: Mechanical hazard assessment before implementation of controls
Protection from the action of ultrasound during air irradiation can be provided:
- by using higher operating frequencies in the equipment, for which the permissible sound pressure levels are higher
- by making ultrasonic emitting equipment soundproof
- by arranging screens, including transparent ones, between the equipment and the working
- placement of ultrasonic units in special rooms, enclosures, or booths, if the above measures cannot achieve the desired effect
Protection against the action of ultrasound during contact irradiation consists in the complete exclusion of direct contact of workers with the tool, liquid, and products since such exposure is the most harmful. The matrix (Table 1) provides a hazard assessment prior to the establishment of controls. Red indicates high hazard, yellow indicates medium, and green indicates low. The hazard matrix after implementing the proposed remedies is presented below (Table 2).
Table 2: Mechanical hazard assessment after implementation of controls
Hazards such as the hazard of falling can be classified as a group of so-called ‘cross-cutting hazards.’ It means that this is inherent in all jobs in any enterprise. Not one employee is insured against a possible fall in the process of moving, not only at work but also at home. Another thing is that the probability and severity of this hazard for each specific workplace will differ significantly. Falls from heights are the number one hazard factor in fatal accidents in construction (Navon & Kolton, 2007). Table 3 presents a hazard assessment matrix for falls during construction activities, taking into account the severity of the consequences and the likelihood of their occurrence. Red indicates high hazard, yellow indicates medium, and green indicates low.
Table 3: Fall hazard assessment before implementation of controls
Measures aimed at reducing this hazard, depending on the conditions of each particular enterprise, will be:
- barriers when working at height
- identify dangerous areas early
- use a helmet, sturdy shoes with anti-slip soles, and seat belts
- equip the place of work with warning labels
- take into account weather conditions
Given the proposed fall hazard controls, hazard can be assessed using the following matrix (Table 4):
Table 4: Fall hazard assessment after implementation of controls
References
Moyano, D. B., Paraiso, D. A., & González-Lezcano, R. A. (2022). Possible effects on health of ultrasound exposure, risk factors in the work environment and Occupational Safety Review. Healthcare, 10(3), 423.
Navon, R., & Kolton, O. (2007). Algorithms for automated monitoring and control of fall hazards. Journal of Computing in Civil Engineering, 21(1), 21–28.