Safety Precautions for Abrasive Blasting

 

Cleaning operations using abrasive blasting can present risks for workers’ health and safety, specifically in portable air blasting or blast room (booth) applications. There is a large amount of dust created through abrasive blasting from the substrate and abrasive.[12] Although many abrasives used in blasting rooms are not hazardous in themselves, (steel shot and grit, cast iron, aluminum oxide, garnet, plastic abrasive and glass bead), other abrasives (silica sand, copper slag, nickel slag, and staurolite) have varying degrees of hazard (typically free silica or heavy metals). However, in all cases their use can present serious danger to operators, such as burns due to projections (with skin or eye lesions), falls due to walking on round shot scattered on the ground, exposure to hazardous dusts, heat exhaustion, creation of an explosive atmosphere, and exposure to excessive noise. Blasting rooms and portable blaster’s equipment have been adapted to these dangers. Blasting lead-based paint can fill the air with lead particles which can be harmful to the nervous system.[13]

Mineral: Silica sand can be used as a type of mineral abrasive. It tends to break up quickly, creating large quantities of dust, exposing the operator to the potential development of silicosis, a debilitating lung disease. To counter this hazard, silica sand for blasting is often coated with resins to control the dust. Using silica as an abrasive is not allowed in GermanyUnited KingdomSweden, or Belgium for this reason.[11] Silica is a common abrasive in countries where it is not banned.[12]

In the US the Occupational Safety and Health Administration (OSHA) mandates engineered solutions to potential hazards, however silica sand continues to be allowed even though most commonly used blast helmets are not sufficiently effective at protecting the blast operator if ambient levels of dust exceed allowable limits. Adequate levels of respiratory protection for blast operations in the United States is approved by the National Institute for Occupational Safety and Health (NIOSH).

Typical safety equipment for operators includes:

  • Positive pressure blast hood or helmet – The hood or helmet includes a head suspension system to allow the device to move with the operator’s head, a view window with replaceable lens or lens protection and an air-feed hose.
  • Grade‑D air supply (or self-contained oil-less air pump) – The air feed hose is typically attached to a grade‑D pressurized air supply. Grade‑D air is mandated by OSHA to protect the worker from hazardous gases. It includes a pressure regulator, air filtration and a carbon monoxide monitor/alarm. An alternative method is a self-contained, oil-less air pump to feed pressurized air to the blast hood/helmet. An oil-less air pump does not require an air filter or carbon monoxide monitor/alarm, because the pressurized air is coming from a source that cannot generate carbon monoxide.
  • Hearing protection – ear muffs or ear plugs
  • Body protection – Body protection varies by application but usually consists of gloves and overalls or a leather coat and chaps. Professionals would wear a cordura/canvas blast suit (unless blasting with steel abrasives, then they would use a leather suit).

In the past, when sandblasting was performed as an open-air job, the worker was exposed to risk of injury from the flying material and lung damage from inhaling the dust. The silica dust produced in the sandblasting process would cause silicosis after sustained inhalation of the dust. In 1918, the first sandblasting enclosure was built, which protected the worker with a viewing screen, revolved around the workpiece, and used an exhaust fan to draw dust away from the worker’s face.[14] Silicosis is still a risk when the operator is not completely isolated from the sandblasting apparatus.[12]

Sandblasting also may present secondary risks, such as falls from scaffolding or confinement in a small space.[12] Carbon monoxide poisoning is another potential risk, from the use of small gasoline-powered engines in abrasive blasting.[15]

Several countries and territories now regulate sandblasting such that it may only be performed in a controlled environment using ventilation, protective clothing and breathing air supply.

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