Occupational Noise Exposure to Masonry Saw Cutting Materials

Abstract

Despite a widespread recognition of the impacts of noise on hearing and other aspects of health, noise exposure in industry remains a significant problem, especially in the construction industry where noise exposure levels of workers are high, especially due to the use of manual equipment and machines used in constructions sites. The masonry saw is a portable power tool widely used in construction in small cuts and finishes for floors, tiles, bricks and woods. It stands out for versatility, lightness and its ergonomics. As part of efforts to identify sources of noise pollution from construction, a noise exposure is developed here for the occupational assessment from masonry saws, which are electric cutters that are commonly used in the industry. Different building materials commonly used in Brazil are used with the masonry saw in their conditions of loading and operation. The proposed methodology evaluates the noise generated during cutting with equipment in accordance with ISO 3744:2010 which specifies methods of measuring sound pressure levels on a surface enveloping the noise source in an environment that approximates an acoustic free field over a reflecting plane and the standard ISO 9612:2009 which specifies an engineering method for measuring workers' exposure to noise in a working environment and calculating the noise exposure level. The cutting of different building materials was louder than the disengaged saw. The highest observed sound pressure level was 106.9 dB(A) at operator ear and 99.1 dB(A) at 2 meters from the source. The smallest difference observed between the cutting and disengaged saw was 7.8 dB(A). Noise generated by the saw was quantitatively assessed. An occupational analysis illustrates that the sound levels generated in operations exceeded the tolerances permitted without protection. The subject is relevant to anticipating risks in the workplace in activities with the masonry saw cutting various building materials. Noise excess removal in the workplace is not just a legal responsibility of the companies, as it is also involved with the market interests of an organization. The safer and healthier a workplace is, the fewer probabilities of absenteeism, accidents and low performance, and consequently, cost savings will be achieved. This study also contributes to the analysis of occupational noise generation, considering the difficulties in obtaining previously reported values of the sound spectrum of masonry saws.

Acoustical absorptive properties of meltblown nonwovens for textile machinery

“…To measure the acoustical properties of the fabric materials, the impedance tube method (ASTM C 384-98) and the acoustical chamber method were used. 25,26…”

“…The chamber is insulated by a top cover. 25 The mean sound absorption coefficient values at frequencies of 250, 500, 1000, 1600 and 3500 Hz were used to calculate the sample’s NRC. 26

Figure 2.Schematic drawing of the setup for measuring the sound transmission loss.

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“…To measure the acoustical properties of the fabric materials, the impedance tube method (ASTM C 384-98) and the acoustical chamber method were used. 25,26 Although these methods do not represent the real transmission loss in a diffuse sound field, they are quite useful for testing small material prototypes. 26 The developed sound insulation measuring apparatus is based on the acoustical chamber method and is illustrated schematically in Figure 2.…”