Subsection 3: Crystalline silica

Where the risk assessment identifies the simultaneous presence of respirable dusts containing crystalline silica and other non-silicogenic respirable dusts, the occupational exposure limit value for the mixture shall be determined by the following formula: Cns/5 + Cq/0.1 + Cc/0.05 + Ct/0.05 less than or equal to 1

In the formula set out in article R. 4412-154, the following definitions apply: 1° Cns, the concentration of non-silicogenic respirable dust in mg/m³, which corresponds to the difference between the total concentration of respirable dust and the sum of the concentrations corresponding to crystalline silica; 2° (Repealed); 3° Cq, the concentration of quartz in mg/m³; 4° Cc, the concentration of cristobalite in mg/m³; 5° Ct, the concentration of tridymite in…