Health & Safety Information

Health and Safety Guidance for Using Silica Based Products

Crystalline silica is a natural substance found in stone, rocks, sand and clay, as well as products like bricks, tiles, concrete and some plastic composites.

The minerals Quartz, Cristobalite and Tridymite are crystalline forms of Silica that are found naturally around the world. Quartz is in most rocks, but most particularly in sandstone and granite. Some of these natural minerals can be blended to make refractory products such as investment casting powder.

Respirable silica dust particles are typically less than around 5 micrometers in size. Compare this to the full stop at the end of the sentence, which is around 200–300 micrometers in diameter, and the finest sand on that beach, which is about 50–70 micrometers. Individual silica dust particles are
so small that they are invisible to the naked eye in normal light – so you can have relatively high airborne concentrations without being aware that the dust is being inhaled.

Silica dust is generally only harmful when it’s inhaled deep into your lungs (Respirable dust), where oxygen is taken up into the blood. Sitting on a sandy beach won’t, in theory, cause any respiratory harm because any sand particles breathed in will generally be much too big to go beyond your nose
or upper airways (Inhalable dust). As a very fine airborne dust, respirable silica can be dangerous.

Investment powder contains fine silica, and those exposed to the product must be adequately protected from the harmful dust.

Long-term exposure to silica dust without adequate protection, caused by tasks such as; handling or using materials containing Respirable Crystalline Silica (RCS), or even just sweeping up after a task; can cause silicosis (an irreversible chronic respiratory illness).