Ventilation question

Discussion in 'BigBox General Chat' started by Henry feldman, Nov 27, 2015.

  1. Henry feldman

    Henry feldman Well-Known Member

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    So after reading on the hazards of some of the filaments I am planning ventilation on my home BigBox (when I get one at work, clinical engineering will take care of that). My house happens to be new enough to have a whole house free-air exchange system (required by code) and it runs the exhaust duct through my workshop by chance. I was planning on putting an acrylic box over the printer when printing and can exhaust the fumes into that duct with a flap so air only goes one way.

    That being said, my question for experts is whether when using the heated bed for ABS and other heat-requiring filaments, how do you balance pulling fumes out vs. cooling down the build box or creating some weird thermal gradient?

    I suppose I could put in a heat-exchanger, but that is getting extreme...
     
  2. Sanjay

    Sanjay Administrator
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    Basically, from the research out there (which is from good solid sources), it seems that fumes and particles given off by printers exist, but are at extremely low levels and are thus not harmful. Enclosing a printer while printing ABS might be nice to stop the smell which can be a bit annoying at times but isn't safety critical. This paper http://www.eastman.com/Literature_Center/S/SPMBS1615.pdf is very informative.

    It appears from the evidence that the emissions from printing are much lower and less harmful than other household tasks such as cooking, aerosols etc, and are well below accepted safety levels.
     
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  3. Michael Brooke

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    I agree with Sanjay; ABS fumes are annoying but not toxic. I have been to several manufacturing facilities in the USA that do ABS injection molding, the fumes are strong, but they pass all of their safety audits and meet government regulations.
     
  4. Henry feldman

    Henry feldman Well-Known Member

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    Not sure that the latest studies are baring that out, and for a more rigorous study here.
     
  5. Sanjay

    Sanjay Administrator
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    Henry,

    Thanks for the link to the other paper, informative.

    However from my reading of both of the papers, they both have very similar and consistent results, in terms of particle numbers emitted and particle size, as well as different materials emitting different levels of particles. Surprisingly similar and consistent in fact, although it is hard to exactly read the data and match it up between the two papers. Certainly both measurements yielded particle number and size results within the same order of magnitude.

    The papers you linked give more information about the potential detrimental effects, but the paper you linked to is a little scaremongering linking to papers involving exposing rats/mice to decomposition products of polymers that are known to be highly toxic such as PVC and PTFE, at exposure levels two orders of magnitude higher than recommended exposure levels.

    The decomposition products of ABS/PLA/PETg materials are substantially less harmful than those of PVC and PTFE. Furthermore the levels of these products produced when printing are again, several orders of magnitude lower than even the "concern" levels issued by the FDA. Only the Eastman paper actually compares emission levels to established safety levels to get a handle on how close to harmful levels the measured levels are.

    While it must be taken into consideration that Eastman has a commercial interest in being able to say that 3D printing is safe in the home, it is relevant that both papers show very similar levels of emission, and that these levels of emission are both far lower than the levels established to be of concern.

    TL;DR, evidence is consistent between the two papers, measured levels are far lower than concerning levels.
     
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  6. Henry feldman

    Henry feldman Well-Known Member

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    There is definitely scare mongering in a lot of this, just like that recent article that used direct exposure of the compounds to fetal tissue to demonstrate mutation, but so what I'm not bathing in the stuff. That being said, nano particles can build up and if not evacuated certainly can cause issues (as a doctor I see these exposures from other industries present with pneumonitidies). Even benign things can cause weird problems when inhaled in micro particle form (the most famous was COP induced by butter flavor popcorn topping in workers at popcorn plants). If you print a lot in a non-ventilated room, probably suboptimal. If you print a bunch and have a baby/young child around, probably sub optimal. I'm putting in ventilation anyway as the laser cutter will need it (now that can throw nasty stuff), and also one huge advantage of the BB is that it prints up to 400C giving access to exotic things like PEEK [so excited] which seems like it should have some sort of ventilation; not sure if I would do it without, but might if it was in living space, rather than the workshop.
     
  7. mike01hu

    mike01hu Well-Known Member

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    I was wondering if the use of the active carbon filtration in a kitchen hob extractor unit would be an option for those who have concerns and use the printer in a home environment; these too are relatively cheap and have the active filter installed. I have used one housed on the top of a plywood cabinet for use in a soldering environment when lead based solders and certain fluxes were being used. Laminar flow was assisted by having a drop-down half-height acrylic front cover.
     
  8. Henry feldman

    Henry feldman Well-Known Member

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    I have the Hakko flux filter with activated charcoal. Works really well.
     
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