DCHAS-L Archives, Mar 12 2020 - Re: [DCHAS-L] 3D printer emissions and UL 2904

This is one of the cases we don't depend on the manufacturers' recommendations. Most don't even acknowledge that there is any need for ventilation at all. As an example, the laser cutter makers addressed the problem with charcoal filters, which fail really fast when exposed to smoke and never capture some contaminants. They don't want to admit that ventilation is needed because it will reduce sales. Same with 3D printers.

As someone who sits on a lot of standards committees, you also need to be aware that the manufacturers are the major presences on these committees that set the product ventilation standards. So economics, which are not relevant to health issues, are a major driving force for setting UL, ASHRAE, and most standards.

That might be alright for adults, but if you are dealing with 3D printers in the schools where there are children and high risk individuals, go for 100 % exhaust to the outside. And this is easy and cheap in the long run. All it requires is an enclosure for the printer (some now come with enclosures) which is breached with a flexible duct and slow speed centrifugal fan and vented out of the building almost anywhere convenient that wouldn't return to the building. The 3D emissions are not regulated at this time, so you don't have to go to the roof. Out a nearby window or a wall penetration works.

The speed of the draw needs to be extremely low. All you need to do is keep the enclosure under negative pressure so it leaks in, not out. And this is also important because a rapid air flow would cool the head and affect the quality of the printed object.

You can also branch-duct a whole row of printers to one fan and exhaust.

We have been doing systems like this for 40 years with electric kilns. It may take a bypass box to damp down the flow low enough as it does with the kilns. But for the right industrial engineer, this is child's play. For most HVAC engineers, it is impossible.

Monona Rossol

-----Original Message-----
From: Chainani, Edward Torres <echaina2**At_Symbol_Here**ILLINOIS.EDU>
To: DCHAS-L <DCHAS-L**At_Symbol_Here**PRINCETON.EDU>
Sent: Wed, Mar 11, 2020 3:30 am
Subject: Re: [DCHAS-L] 3D printer emissions and UL 2904

Thank you, Yaritza-I will determine the room volume of the intended location and compare with the model as you suggested.

It is likely that the authors of this UL standard didn't feel the need to address offensive odors, as there is a different standard, on ventilation for acceptable indoor air quality, that addresses that issue (ASHRAE 62.1).

I should have phrased my question this way: "Have any of you started vetting 3D printers based on the results generated according to this standard, as provided by the manufacturer?" I do not intend to be able to perform the test myself, as the methodology requires specialized equipment, and the list of target chemicals is extensive.

Regards,
Ed

On Mar 10, 2020, at 1:39 PM, Yaritza Brinker <YBrinker**At_Symbol_Here**FELE.COM> wrote:

Ed,

I saw this spec coming down the pipeline. We don't use it as it is intended to apply to the smaller consumer type 3D printers used for classroom, office, and home use. Also, it does not address any issues related to offensive odors.

While you could use this standard to test larger units used in industrial type settings/prototype shops, I don't quite see the point on testing those. Aside from the harmful emissions, 3D printers also have offensive odors. Large units can stink up a warehouse. So, these things should always be vented to the outside.

It looks like you can use the UL test data to decide if ventilation is "technically" required. Since the pass/fail criteria is expressed in emitted mass/room volume, I think you would need to look at Appendix B to ensure the model used to calculate the Pass/Fail criteria is applicable to your building. Looking at the residential model, my house is average for my area. However, it is smaller than the national average home used in the model. Thus, if I had a certified unit in my house, the actual exposure would be higher that the spec allows.

I suspect the UL spec will become a requirement for all 3D printers sooner or later. Until then, I'm asking for ventilation on ours.

By the way, I'm talking about plastic printers. 3D metal printers have no business being used without hard-plumbed ventilation regardless of their size.

Yaritza Brinker

260.827.5402

From: ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**PRINCETON.EDU>On Behalf Of Chainani, Edward Torres
Sent: Tuesday, March 10, 2020 1:14 PM
To: DCHAS-L**At_Symbol_Here**PRINCETON.EDU
Subject: [DCHAS-L] 3D printer emissions and UL 2904

** External Email **

Dear DCHAS community:

We don't have formal policies for 3D printers, but whenever I get wind of a new 3D printer being purchased and installed, I have been thinking of ensuring that there is an enclosure with local exhaust ventilation when there are no emissions data available.

Now, there is a newly released UL standard (UL 2904 - a Standard Method for Testing and Assessing Particle and Chemical Emissions from 3D Printers):

https://www.shopulstandards.com/ProductDetail.aspx?UniqueKey=35397
(You can view it online without purchasing it, if you create an account)

A technical brief is found here:
https://chemicalinsights.org//wp-content/uploads/2019/05/3DPrint_Standard_Brief_Version-2.pdf

This standard specifies the testing methodology as well as the maximum allowable concentrations of target chemicals and particles, in office, classroom and residential models. I expect that 3D printers on the market will soon being tested using this new standard. In fact, one 3D printer manufacturer has provided me with the report of their product tested using the new UL standard with results for the various filaments that they supply. I understand that they can't test for everything specified in the standard, but the report provided by the manufacturer shows they tested for ultrafine particles, TVOCs and 23 chemicals, and the results shows emission rates below the UL 2904 criteria for an office. I take this to imply that there will be minimal exposure when this 3D printer is placed in an office with the typical office ventilation.

Have any of you started vetting 3D printers using this standard?

Regards,
Ed

Edward Chainani, Ph.D.
Assistant Director for Safety
The Grainger College of Engineering Office of Safety
University of Illinois Urbana-Champaign
1308 W Green St
Urbana, IL 61801
Phone: (217)244-5594
Email: echaina2**At_Symbol_Here**illinois.edu
Web: http://officeofsafety.engineering.illinois.edu/

"Safety is a dynamic non-event; we have to work very hard so nothing will happen" -James Reason

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