Health and Emission Hazards of Dusts from Thermal Spray Processes

The thermal spray coating process uses molten materials, which can produce contaminants that threaten worker health and safety. The process creates airborne particles that can be smaller than one micron and can embed deep in lung tissues. Most commonly, metal dust particles enter the respiratory system, but they can also irritate the eyes, mouth, throat, stomach and skin.

The fine dust particles generated during thermal spraying can contain a variety of metals associated with health risks. Some of the materials that are sprayed, like nickel and chromium, are known carcinogens. In fact, most chromium-bearing materials can produce hex chrome particles when exposed to the high energy levels required for thermal spraying. Other metals like zinc, bronze, cobalt, aluminum and copper alloys can cause sickness, fever, allergic reactions, lung fibrosis, skin diseases, or pneumoconiosis. Manufacturers must know the permissible exposure limit (PEL) for all materials they handle to stay compliant with the local (e.g. OSHA) regulations. Dust collectors are the preferred engineering control to maintain a safe PEL and safeguard operators from serious health concerns.

Combustible dust, fire and explosion hazards

Metal particles in the air can create an explosion hazard. Dust collectors prevent combustible metal dust particles from accumulating on floors and other surfaces. However, it is crucial for dust collection systems that handle combustible dusts to be sized correctly for each spray application and according to the recommendations in a dust hazard analysis and NFPA 652 / ATEX guidelines . Dust collectors must also be fitted with the correct explosion protection equipment like explosion vents, flame retardant cartridges, and possibly spark traps. A correctly engineered dust collection system minimizes risks, protects workers and keeps manufacturers in compliance with the local (e.g.OSHA) regulations and NFPA standards / ATEX guidelines. Camfil APC compliance experts are ready to help.

Applications that can create dangerous dust:

  • Flame spray powder or wire
  • Flame spray with plastics
  • High-velocity oxy-fuel (HVOF) and high-velocity air-fuel (HVAF)
  • Cold spray
  • Detonation flame spray
  • Plasma spray / Vacuum plasma spray
  • Electric arc spraying
  • Plasma transferred arc surfacing
  • Laser spray

Resources and Literature:

Thermal Spray Focus Sheet

Application-Specific Extraction Solutions - We Will Be Happy To Advise You!

Dust collector for thermal spray processes - Gold Series X-Flo®

The modular Gold Series X-Flo dust collector (GSX) was engineered to solve tough dust problems with a minimal footprint. It captures dangerous airborne metal dusts before they can be inhaled by operators or build up on shop surfaces. Camfil experts will work with you to understand your specific application requirements. Individual modules accommodate airflows up to 10.000 m³/h each, providing a near-limitless variety of configurations that can be delivered in days instead of weeks. All GSX collectors feature heavy-duty carbon steel construction and thermal cured powder coatings for unparalleled strength and durability

It's crucial to gather the proper information when configuring a dust collector for thermal spray applications. There are many different types of processes and material coatings that will all react differently inside the dust collector. Camfil APC experts are familiar with design considerations like airflow, negative pressure, loading, emission, air-to-cloth ratio, and filtration required to solve the toughest dust problems. Thermal spray applications are generally sized at a conservative air-to-cloth (A/C) ratio with HemiPleat® fire retardant cartridges.

More information about Gold Series X-Flo

Over the years, we tried several types of dust collection equipment on EAW spraying. However, all previous attempts at extended filter life (more than six months) failed until we installed a high efficiency "Farr Gold Series" cartridge collection system manufactured by Farr, Arkansas. At the time of this writing, the Farr Gold Series collector is still performing exceptionally well without a filter change after about a year and a half.

-David Drozd, Pamarco