Environmental and Safety Rules in Sandblasting Facilities

What is Sandblasting?

In combating corrosion, certain procedures exist to extend the service life of metal surfaces and enable coating of the desired quality. Surface quality depends to a large extent on surface preparation prior to coating. The most common and effective method used to eliminate the effects of corrosion is coating the surface with a material resistant to external factors. Surface preparation prior to these coatings is the foundation of coating quality. Sandblasting is a method applied to provide the roughness necessary for paint adhesion to the surface, remove mill scale from the material surface, homogenize the surface, and clean rust, scale, oil and paint residues from the metal surface. As an application, sandblasting is the process of propelling granules against the surface with high-pressure air. During this impact, the granule abrades the surface at the micron level while simultaneously cleaning it. Special high-pressure sandblasting vessels are used for sandblasting application. The desired degree of surface roughness depends on the type, size, shape of the abrasive granule used and the application pressure. Sandblasting operations must be carried out in special facilities suitable for sandblasting application, and these facilities must be established in accordance with Environmental Health Standards and Occupational Safety regulations.

Environmental Health Standards for Sandblasting Facilities

For sandblasting facilities to obtain operating permits, they must be designed in accordance with environmental regulations. The objective of Environmental Regulations is to prevent harm to the environment from facility operations, ensure emission limit values, control air quality and monitor mass flow rates. Emission: Refers to air pollutants released into the atmosphere from a facility as a result of fuel and similar combustion, synthesis, decomposition, evaporation and similar processes, material accumulation, separation, transportation and other mechanical operations. In sandblasting facilities, dust emission values specified in the industrial air pollution control regulation must be met. To obtain emission permits, dust must be sent to a dust collection unit and discharged through a stack after passing through a filter as required by regulation. Stack height above the roof is important for meeting emission values and regulatory requirements. Stack heights are mandatory provisions that must be met to obtain the necessary permits. The dust emission limit value specified in the regulation is 20 mg/Nm³. The dust generated during sandblasting operations is quite dense. Proper filtration is of great importance both in terms of occupational safety rules due to personnel health, workplace efficiency of the factory and environmental ministry standards. Special filter units are used to meet emission values. Dusty air is delivered to the filter through air ducts designed with appropriate diameter and thickness. Air passing through the filter is discharged outside through a stack by means of a fan. In filter design and fan selection, criteria such as facility volume, number of sandblasting operators working in the facility and location of dust collection points must be considered.

Safety Measures and Personnel Health in Sandblasting Facilities

Sandblasting operations in enclosed areas must be carried out in facilities with adequate lighting systems, safety measures in place and sufficient space left for operations. Lighting: In sandblasting facilities, appropriate lighting values should be selected to ensure operation quality and provide the operator with proper viewing angle. Performing sandblasting operations in areas that are darker than necessary not only affects surface quality but also poses a hazard to operator safety.

Equipment Used and Protective Measures; High-Pressure Sandblasting Vessel

Sandblasting vessels used for sandblasting application operate at high pressure. At the nozzle outlet, average pressure is approximately 7.5 bar. Vessels to be used must have undergone hydrostatic testing, have documented test results and possess a conformity certificate to the EU Pressure Equipment Directive. Granules sprayed at high pressure pose serious hazards with improper use. To prevent potential accidents, the sandblasting vessel must have an automatic control system rather than a manual hand control. In cases such as the operator falling for any reason or the nozzle slipping from his hand, the system automatically stops sandblasting, thus preventing injuries.

Sandblasting Hose:

Sandblasting is performed with special hoses that resist high pressure. Hoses to be used in sandblasting must comply with TS 5928 EN ISO 3861 standards and be certified. Sandblasting hoses must be secured with a safety rope.

Sandblasting Nozzle:

Sandblasting nozzles are manufactured from various special materials that are blast resistant. Nozzle quality and standards compliance are of great importance to prevent work accidents.

Operator Mask and Clothing:

Sandblasting operators must use protective masks and clothing specially manufactured for sandblasting. This prevents granules coming from inside the high-pressure sandblasting vessel from harming the operator. The sandblasting mask must have documented compliance with EN 14594 standards.

Clean Air Unit:

One of the important factors threatening personnel health in sandblasting facilities is dust in the air. In addition to the filtration system in sandblasting facilities, operators must use a clean air supply unit while present in the facility. Clean air units are generally fed from a compressor. The clean air unit passes air coming from the compressor through an activated carbon filter and delivers clean air to the operator's mask. Çiğdem Arslan Project Director Sandblasting and Painting Systems Alfatechnic Makina San. ve Dış Tic. Ltd. Şti.