Sandblasting is one of the most widely used (and perhaps abused) terms in the surface preparation industry. In many cases, sandblasting is used as a catch-all term for any process that involves shaping, preparing, or cleaning surfaces using abrasive propelled by a blast of compressed air to create the necessary pressure.
Sandblasting in its true term is the use of silica sand as the abrasive material, silica sand is classified by having >1% free silica and is prohibited for use by the HSE in the UK as the dust generated may contain respirable crystalline silica (RCS). Breathing this dust can cause serious lung diseases like silicosis, chronic obstructive pulmonary disease (COPD) and even lung cancer.
Silica Sand & ‘Silica-Free’ Sand
The use of allegedly ‘silica-free’ substitutes has frequently raised the question of what qualifies as ‘silica-free’. In considering this, it should be appreciated that crystalline silica is a very commonly occurring substance in both the natural (rocks and soil) and artificial (mainly construction materials) environments. It is found in many extracted mineral substances as a main or trace component and may also arise from contamination at later stages of treatment and processing. Consequently many of these may not be entirely silica-free. The COSHH regulations do not define a concentration at which a substance is regarded as silica free, so it has been necessary, in practice, to apply a pragmatic limit of 1%. If a substance contains 1% or more of free silica, it is subject to the prohibition.
This limit has not been scientifically established. However, where a substance contains less than 1% free silica it is more than likely that the general COSHH respirable airborne dust level of 4mg/m3(see COSHH reg.2(d)(ii), definition of ‘substance hazardous to health’,) will be exceeded well before the MEL for respirable crystalline silica is even approached. Therefore, compliance with the general dust limit would mean that there is unlikely to be any risk to health from exposure to silica arising from the use of such substances.
Alternatives To Sandblasting
Fortunately there are other types of blast cleaning that don’t require the use of silica sand, now categorised under the term grit blasting or abrasive blasting. The grit blasting method is the same as sandblasting, the difference being the abrasive selected. KUE Group provide safe alternative abrasives such as garnet, aluminium oxide, glass beads and chilled iron to name but a few with no compromise on quality. A quick guide to abrasive blasting media can be found on our website.
Effective Blast Cleaning Solutions
At KUE Group we specialise in blast cleaning, coating and lining industrial components including Tank Containers, Process Pipework, Vessels, Turbine Components etc. using alternatives to sandblasting with silica sand and choosing the most efficient abrasive for each task. As leaders in the steel surface preparation industry, we enforce strict safety, health, environmental and quality standards endorsed by compliance with relevant ISO and BS OHSAS certification.
References:
- HSE Operational Guidance OC 273/18 (The Control of Substances Hazardous to Health regulations blasting using silica sand)
- HSE Guidance Note CN7 Abrasive Blasting
