Modern Work Protection with the Shotcrete Construction Method under Overpressure.
NIOSH 1990 Sep:525-528
A review was presented of the use of shotcreting to construct urban traffic tunnels in the Federal Republic of Germany. High dust levels involved in shotcreting, rock excavating and conveying operations have been noted to result in poor air and visibility conditions. The work has often been conducted in long, largely narrow and closed spaces. Studies have been conducted to provide information on whether harmful mineral dusts under overpressure constituted a greater health hazard than atmospheric pressure. Several animal experiments have been conducted and in the preliminary trials it was determined that the inhalation of dust containing quartz (14808607) at an overpressure of 1.5 bar for a period of 6 months resulted in increased typical quartz induced lesions of mediastinal lymph nodes. Additional studies were then sought using primates under conditions similar to those prevailing at construction sites. The shotcrete dust has been deemed a health hazard for two primary reasons. First, the dust has been observed to often contain fine mineral dusts containing in some cases considerable amounts of quartz, which were added with the sand, the accelerating agents and the filler, and due to their high alkalinity with a pH value around 13, all accelerating agents must be regarded as caustic substances.
Construction-industry; Construction-workers; Respiratory-system-disorders; Mineral-dusts; Occupational-hazards; Tunneling; Lung-function; Dust-exposure; Tunnel-workers;
DHHS (NIOSH) Publication No. 90-108
Asthma and Chronic Obstructive Pulmonary Disease; Disease and Injury; Respiratory-system-disorders;
Proceedings of the VIIth International Pneumoconioses Conference