From 25 April 2006, a first European intersectorial agreement has been signed concerning the Alveolar Crystalline Silica (ACS). It concerns the health protection of the employees by observation of good practices within the framework of the manipulation of the crystalline silica and the products that contain it. This social agreement is of application from January 2007 and concerns the extractive industries and the users of crystalline silica.
In the case of the crystalline silica, that can be found in three main forms (quartz, cristobalite and tridymite), it is the alveolar fraction (< 9.3 µm) of the dust that causes problems due to its health effects. Belgium adopts an upper limit of 0.1 mg/m³ for the quartz and 0.05 mg/m³ for the two other crystalline forms (cristobalite et tridymite). The sampling period on the working posts is normally of 8 hours. As a result, the quantities obtained are very little if one considers an air aspiration debit corresponding to the average respiratory debit of a person. As such, the precision of weighting must be in the order of µg.
This project that has been the object of a Walloon Region Guidance of two years, continues on own resources. The CRIC-OCCN and the CTP join their knowledge to measure the exposition rates to ACS in the Small and Medium Enterprises (SME). Shortly, the CTP performs in this project the sampling while the CRIC-OCCN takes care of the measurements to determine the quantity of ACS in the samples obtained by the CTP.