Dust Control Regulations for Plastics and FRPs
Plastic and FRP dusts are regulated under OSHA’s General Duty Clause, which requires employers to maintain a workplace “free from recognized hazards.” They are also subject to specific regulations related to their combustion risk. FRPs and some types of plastics may be subject to additional regulation due to the health hazards of chemicals or mineral fibers used in their composition.
- Combustible dusts: Combustion risk is common to all types of plastic and FRP dust. Combustible dusts are regulated under OSHA’s General Duty Clause (Section 5(a)(1)) with additional requirements under the Hazardous Locations (§1910.307), Hazard Communication (§1910.1200) and Housekeeping (§1910.22) standards. In addition, manufacturers dealing with combustible dusts must follow National Fire Protection Association (NFPA) standards for prevention of fires and explosions. Plastic and FRP dust falls under NFPA 654, Standard for the Prevention of Fire and Dust Explosions from the Manufacturing, Processing and Handling of Combustible Particulate Solids. OSHA’s Combustible Dust National Emphasis Program (NEP) outlines policies and procedures for inspecting workplaces that create or handle combustible dusts.
- Nuisance dusts: Many plastic dusts fall under the OSHA definition of “nuisance dusts,” which are regulated under the general particulate matter concentration limit. The general limit for “Particulates Not Otherwise Regulated” (PNOLs) is 15 mg/m3 (8-hour TWA limit) for total particulate and 5 mg/m3 for respirable particulates. Employers must also follow general Housekeeping standards (OSHA 1910.22, Walking-Working Surfaces) to prevent accumulation of dust on surfaces.
- FRP dust: OSHA regulates synthetic mineral fibers used in FRPs (including fiberglass, mineral wool and refractory ceramic fibers) under the general “Inert or Nuisance Dust” standard. However, due to the health concerns related to breathing in mineral fibers, OSHA established a voluntary limit with industry associations in 1999. This limit, which is supported by the National Academy of Sciences, is one breathable glass fiber per cubic centimeter of air over an 8-hour shift.
- Hazardous dusts: OSHA has set specific exposure limits for certain hazardous substances found in some plastics, such as styrene, heavy metals and vinyl chloride. These are expressed as Permissible Exposure Limits (PELs), which are measured and averaged over a worker’s 8-hour shift and specific to each toxic substance present in the dust. Manufacturers are responsible for ensuring that workers are not exposed to hazardous dusts in levels above the PELs. Failure to control dust in areas where workers may be exposed can result in serious fines and legal action.
- Environmental regulations: Some of the substances used in plastic production are also subject to Environmental Protection Agency (EPA) regulation, which may impact how toxic plastic dusts are disposed of.
Dust Control Solutions for Plastics and FRPs
RoboVent offers robust dust collection solutions for collection of plastic dust. We can work with you to design and engineer a dust control system for your specific processes and exposure risks.
Dust control systems for plastic dust must be designed with care due to the combustible nature of the dust. Dust cannot be allowed to accumulate in the workspace or conveyor system, in the ductwork or in the dust collector cabinet itself.
Relevant considerations in dust collection system design for plastics and FRPs include:
- Explosion mitigation: Combustible dusts such as plastic and FRP dust require a deflagration system to reduce the chances of an explosion inside the dust collector and mitigate damage to the facility if an explosion should occur. These systems may include an explosion vent to release built-up pressure in the collector, an isolation valve to prevent pressure waves from propagating back into the facility, and a rotary airlock to keep collected dust safely contained in the hopper.
- Fire suppression: The dust collector should be equipped with an internal fire suppression system for added protection against fires.
- Filters: A static-reducing filter media should be used to reduce the risk of self-ignition inside the dust collector and reduce clinging to the media. If plastics become heated during machining or grinding, molten plastic can accumulate on filters, causing them to cake and leading to early failure. A longer ductwork run can reduce these problems. Thermal processes such as melting and compounding will require different solutions for control of dust, odors and VOCs. If you are using thermal processes, contact us for more information.
- Filter Pulsing: In addition to choosing the right filter media, it is important to have an effective filter pulsing system to pulse off plastic dust clinging to the filters. A robust pulsing system combined with static-reducing filter media will extend the life of the filters.