Silica occurs as a natural component of many materials used or encountered in construction activities. Crystalline silica is present in substantial quantities in sand, sandstone and granite, and often forms a significant proportion of clay, shale and slate. It can also be found in chalk, limestone and other rock and soil, though this is unusual. Products such as concrete and mortar also contain crystalline silica.
The health hazards of silica come from breathing in the dust. Activities which can expose workers to the dust include:
The use of power tools to cut or dress stone will lead to high exposures throughout the work. For other activities, exposure will often depend upon how confined theworking space is, the presence or absence of ventilation and how near the worker’s breathing zone is to the source of the dust.
Activities which may expose workers to silica are subject to the Control of Substances Hazardous to Health Regulations 2002 (COSHH) which require the health risk to be assessed and then prevented or controlled. In most cases, when it is reasonable to expect dust levels to be significant, you should consider the need for atmospheric sampling of respirable dust and respirable silica in accordance with MDHS 101.
Silica has been assigned a maximum exposure limit (MEL) of 0.3 mg/m3, expressed as an 8-hour time weighted average (TWA). This means that exposure to respirable crystalline silica should be reduced so far as is reasonably practicable and, in any case, below the MEL.
As a general rule, levels greater than 0.1 mg/m3 can be regarded as significant. In cases of doubt it should usually be assumed that levels will be significant unless sampling from very similar work has shown otherwise.
Our consultants are here to help you and can develop and implement monitoring strategies to ensure maximum exposure limits are not exceeded with respect to silica dust present in the workplace or arising from your working activities. Our team we will advise on appropriate measures to be taken to reduce the risk of exposure to crystalline silica and ensure you comply with the Control of Substances Hazardous to Health regulations.
For more information on crystalline silica dust exposure testing or if you simply require a competitive quote please call us on 0870 7019170 or complete our online contact form and a member of our team will respond to your query promptly.