3D Printer Enclosure & Indoor Air Quality

Report Summaries or Recommendations

1.

Our recommendations are based on an approach known as the hierarchy of controls, and would be applicable for all brands of 3D printers and filaments. This approach groups actions by their likely effectiveness in reducing or removing hazards. In most cases, the preferred approach is to eliminate hazardous materials or processes and install engineering controls to reduce exposure or shield employees.

Characterizing 3D Printing Emissions and Controls in an Office Environment.

2.

Ventilation is an important engineering control to help control/reduce emissions from 3D printers. Examples of ventilation controls could include single unit local exhaust ventilation system, snorkel fume extractors, or for situations where multiple printers are used, operating 3D printers on enclosed ventilated racks that exhaust to the outdoors may be appropriate. These ventilation approaches may reduce energy costs compared to general dilution ventilation. Because the majority of 3D printer emissions are nanoparticles, another option would be to exhaust the air from printers through a room air cleaner equipped with high-efficiency particulate air (HEPA) filtration.

More research is needed to identify additional low emitting filaments for use in 3D printers so that filament selections can be made based on low emission rate in addition to other filament properties. Low emitting filaments will reduce energy costs associated with ventilation and filtration controls and may be particularly important for workplaces in leased facilities or other settings where ventilation modifications are not feasible or allowable.

Integrate local exhaust duct  connections and/or particulate filtration into the design of individual 3D printers to reduce ultrafine particle emissions into the indoor work environment.

Evaluation of 3-D Printer Emissions and Personal Exposures at a Manufacturing Workplace.
Photo by NIOSH

We evaluated whether a custom-built ventilated enclosure could reduce particle and chemical emissions in the Print Room. This enclosure system was highly effective in reducing both particle number and TVOC concentrations in the Print Room. As noted at the beginning of the Results section of this report, there are no occupational exposure limits for particle number concentration or TVOC levels. As such, it is unknown at this time whether the measured levels present a health hazard and whether the reported reductions in contaminant levels are necessary. However, if improved ventilation is desired, one possible consideration would be to route the exhaust from the NIOSH custom enclosure to a fan on the roof at 700 cubic feet per minute to discharge the particle and volatile emissions from the 3-D printing process to the outdoors away from outdoor air intakes. This option would create the need for make-up air to be supplied inside the room but outside of the NIOSH custom enclosure. Also, similar capture effectiveness could be achieved at a lower air flow rate by sealing air gaps around the NIOSH custom enclosure.

Evaluation of 3-D Printer Emissions and Personal Exposures at a Manufacturing Workplace.

3.

Results of our experiments indicate that TVOC emission rates from this 3-D printer were influenced by a printer malfunction, filament type, and to a lesser extent, by filament color. TVOC emission rates were not influenced by the number of printer nozzles used or the manufacturer’s provided cover. Of interest is the observation that 14 different VOCs were identified during 3-D printing that were not present during laser printing. Further, carbonyl reaction products were likely formed from emissions. of the 3-D printer, including 4-oxopentanal. 3-D printed objects continued to off-gas styrene, indicating potential for continued exposure after the print job is completed. Ultrafine particles generated by the 3-D printer using ABS and a laser printer contained chromium, a known toxicant. Our results indicate that both printer-and consumable-related factors influenced the release of chemical contaminants from a FDM3-D printer and that understanding these factors can help to better design exposure assessment and control strategies.

Characterization of chemical contaminants generated by a desktop fused deposition modeling 3-dimensional Printer.

4.

Desktop 3D printers might emit high numbers of ultrafine and fine particles during operation. Emissions are influenced by the consumables, including filament type and color, as well as by the printer design characteristics. Exposure to high concentrations of UFP particles emitted from laser printers has been associated with increased risk in mortality frequency, but whether such risks apply to emissions from 3D printers is yet to be elucidated. Based upon our data, evidence indicates that it is prudent to recommend the following precautions to reduce exposures in non-industrial workplaces as well as public locations such as in libraries or universities and private homes: (1) Always use the manufacturer’s supplied controls (full enclosure appears more effective at controlling UFP emissions than a cover); (2) use the printer in a well-ventilated place, and/or directly ventilate the printer; (3) maintain a distance from the printer to minimize breathing in emitted particles and choose a low emitting printer and filament when possible; (4) if the printer nozzle jams, turn off the printer and allow it to ventilate before removing the cover; and (5) utilize the industrial hygiene hierarchy of controls to mitigate exposures (from most to least preferable): engineering > administrative > protective equipment (e.g., respirators).

Emission of particulate matter from a desktop three-dimensional (3D) printer.

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