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Air quality concerns during heating

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Emma emmsclaire

Air quality concerns during heating

28/01/2018 at 06:40

Hi! I wanted to start a topic to discuss air quality concerns from heating plastic. Obviously most people have been just using the machines in an open area and hoping for the best. However, I know that we as a community should gather all the information we can about gaseous byproducts from the injecting, compression, extrusion process. If there are any experts on here (@marcelozp ?) please chime in! I’ll be doing my research and will report back with any literature I can find.

Other air quality posts:

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09/02/2018 at 21:19

Yes, please, I’m very interested in this as well!

20/02/2018 at 11:29

Depending on the types of plastics used, and given that the plastic is cleaned properly, it should be relatively safe, for instance if you look at the chemical formula for HDPE, there is not any harmful chemicals like Chlorine (found in PVC) or Flourine.
That said there is the chance of byproducts of the manufacturing process, but in general HDPE,PS and PP are fairly harmless

02/05/2018 at 17:23

Hi, sorry, I just came here today.

In fact lots of polymers are relatively safe (and I guess you will process not too much material) if you have a window near it will be ok.

My only concern is about PVC, in fact, I do not recommend anyone without expertise to try to process PVC at home. Focus on the others types of polymer!

14/12/2018 at 03:34

I’m back and working on an industrial hygiene manual and an open source ventilation system for the entire precious plastic community to use. I’ve got a Slack and a Google Drive if you want to participate in the project!

Topics I’m going to cover:
What gases, vapors, fumes, particulates precious plastic workshops produce
Health effects of those
Industrial Hygiene pyramid: 1) engineered controls 2) workplace controls 3) PPE
Design for a ventilation system
Model of ventilation system working
Test of ventilation system
Proven design and plans including where to buy parts online and cost
PPE protections: respirator use and safety, safety glasses, etc etc

Message me on here if you want to participate.

14/12/2018 at 05:49

@emmsclaire. Some real technical data would be great for this topic. Most polymer companies act like the big cigarette companies and don’t want to admit to the lethality of polymers. In the meantime, just go get one of these dust extraction systems, some more fittings from your local hardware store for venting your clothes dryer and vent the fumes out of your workshop thru the roof or propped door.  Central Machinery® 31810 13 Gallon Industrial Portable Dust Collector13 gal. 1 HP Heavy Duty High Flow Dust Collector  https://www.harborfreight.com/13-gallon-industrial-portable-dust-collector-31810.html

14/12/2018 at 20:10

hey there !

I am also interested in this topic.

where can i find the fumes that are being released when heating PMMA sheet ? (it also have the LDPE coating on it ?
what temperature is considered to be heating and not burning it?

I was thinking around 150 Celsius

does anyone have some helpful information about it ? I searched quite a lot and didn’t get what i was searching for

Many thanks,

16/12/2018 at 05:11

@sheffieldcompany That’s exactly what I’m going to be doing. I’ve started:

1) Identifying and acquiring current scientific literature on the thermal degradation of: PP, PET, LDPE, HDPE, PS. I will not study PVC because we already know it is not recyclable by our equipment (DON’T EVER RECYCLE PVC EVERYONE – it produces hydrochloric acid that will kill you) Reference for PVC producing HCl ->> http://ec.europa.eu/environment/waste/studies/pvc/mech_recylce.pdf on pg 71.
2) Once I know what gases are likely to be produced during the recycling of PP, PET, LDPE, HDPE, & PS I will make a list of them all
3) I will conduct a study using gas detection tubes to see what gases from the list in step 2 are present, using my extruder, in a closed environment.
4) I can use that information to then design an effective ventilation system for precious plastic machines specifically. If anyone is interested, Local Exhaust Ventilation is the method I’ll likely use because that is typical in the plastics industry. Here is a video about Local Exhaust Ventilation ->> https://youtu.be/Ky8y2jDk6i8
5) I’ll build it and test it using gas detection tubes and smoke tubes (test if air is leaking from the ventilation system that shouldn’t be)
6) Make any tweaks and share the plans for everyone to build and use

Anyone who knows polymer engineers, people who have dealt with ventilation or anything like this send them my way! I’ve got a background in hazardous materials and environmental sampling.

16/12/2018 at 05:14

Also a dust collector definitely won’t do the trick – dust isn’t the concern. Oxygenated hydrocarbons, aromatic hydrocarbons, aliphatic hydrocarbons, CO, and CO2 are primarily what is released when polymers like polypropylene are broken down, in addition to any contaminants that are incinerated.

17/12/2018 at 09:51

Only the person that made the plastic knows for sure whats was in that batch of plastic.Items not meant to ever be eaten get mixed into our food supply daily, sometimes, even on accident.Anyone that tells you drinking water from a plastic cup is safe means to say, it is safe depending on what the plastic was made from.And whats in the water….Never remold kitchenware from recycled plastic.. It’s just not worth the risk. In many parts of the world people burn trash, melting plastic can’t be as bad as that, so just use caution.

And likewise, only God knows what has been poured in the plastic bottle after it was empty but before you decided to melt it, Its kinda pointless to try to figure out what a bucket full of of shredded plastic pieces once contained… Just wear gloves and hold your breath and run away if the fumes seem toxic….Run Forrest Run

17/12/2018 at 12:32

I am working on the V4 sheet press design and I’m melting 10kg of plastic at a time with chances of burning and while using release agents and polluted plastics. Currently, we don’t know how toxic everything is but I play it safe and bought a Gas mask with an ABEK1P2 filter, it filters a broad range of gases and both dry and wet particles.
I think you can never know exactly what you are inhaling since the plastics are unknown and polluted and contained chemicals when used as containers.
Better safe than sorry.
But I think the smaller machines can be granted some lea way since they don’t burn the plastics and process way less.

for the sheet-press we now built a tent around it from which we suck the air out and pump it through a filter.

21/12/2018 at 00:43

I have this complete article in PDF if anyone wants it. It is just talking about PET but it could be interesting for someone.
It is from my teachers at the university. They also told me that for the temperatures and the plastics we usually use it could be enough with an active carbon filter. Because we are not producing real fumes, just another type of particles. Which ones that are really difficult to identify because depend a lot of the additives (difficult to know which ones have each plastic). Also the amount of this particles is very low.

27/12/2018 at 12:22

Hey @emmsclaire. The first time I discovered Precious Plastic, I immediately feel triggered to run health and safety assessment to each machine for better improvement. I think i really want to know if i can help anything regarding IH assessment/ measurement in order to put the best reccomendation for the machine. (The LEV!)

I’m an occupational health and safety student, i might as well want to discuss further research with my prof regarding HSE analysis for the PP machines. Currently i’m approaching my local community to see if there’s actual accident finding (both health and safety aspects). I also have summarized people’s confusions about safety in this forum (i’ll share them later)–> my initial data to make sure I must do this.
There’s so much to learn and discover but i’m so excited.


05/03/2019 at 11:11

Hi everyone,
I am searching a place for Precious Plastic machines. I am in discussion with a great place but they are not equiped with a ventilation system at all. They have visitors, and I would like to get visitors too. So I should be totally safe and should be able to prove it. Do you have idea of material I could add/buy to complete the machine? I will begin with the extrusion one as only warming machine.
Thanks in advance for your help.
Kind regards,

06/03/2019 at 21:31

@annel Unfortunately, the PP V-4 activities have not reported on any project looking at the safety and fumes issue. In the meantime, I would consider building an enclosure/fume collector around the extrusion machine and use fans/flexible ducting to get it to a nearby window. An insert in the window should make for a visually acceptable setup. If you make it with a couple of well placed access doors you should be able to fill the hopper and attach molds with the fume extraction functioning.
If there is a laser cutting/engraving shop nearby that cuts plastic, go see what they set up. It is a similar problem.
Good luck, please post what your solution ends up being

31/05/2019 at 01:56

Air quality should be a concern while shredding, not just while heating. In the last couple of years, research has found plastic microfibres are not just restricted to the oceans, but are also present in the air (https://www.sciencedirect.com/science/article/pii/S2468584417300119) and water, bottled or filtered, and even in beer (https://www.theguardian.com/environment/2017/sep/06/plastic-fibres-found-tap-water-around-world-study-reveals).

We know very little about it, except that the microfibres are small enough to pass through regular filtration systems. Most of the plastic in the air is thought to come from the textile industry (synthetic fabrics made from plastic), but I am concerned about plastic dust that might be generated in the process of recycling plastic, however well-intentioned our efforts may be. What do others think?

08/06/2019 at 01:39


Microplastics are plastic particles that started as larger pieces of plastic and broke down on their way to or in the ocean, not tiny particles of plastic created on land that go to the ocean. Microfibers start small due to being released during washing. By reducing the amount of plastic that makes its way to the ocean through recycling, we should be reducing the amount of plastic in the ocean.

It’s a lower priority for me to build a dust collection system for the shredder, but I will be sure to include that in the ventilation documentation.

08/06/2019 at 01:50

June 2019 Update on Ventilation:

Over the last several months I have been studying Local Exhaust Ventilation. LEV is an extract ventilation system that takes dusts, mists, gases, vapour or fumesout of the air so that they can’t be breathed in. Properly designed LEV will:■ collect the air that contains the contaminants;■ make sure they are contained and taken away from people;■ clean the air (if necessary) and get rid of the contaminants safely.

I have an extruder so I am building out a LEV for my machine and am part way through developing documents to help you do the same for your machine.

Here are some sneak peaks. Attached is v1 of the LEV for my extruder (shaded front.png and LEV v1.pdf)
Pros: -Theoretically meets OSHA requirements for LEVs. Easy to build. High efficiency due to 30 degree corners and bell mouth hood.
Cons: -Expensive parts that need to be ordered online and can’t be found at a big box store like Home Depot.

Because it is too expensive, I visited Lowes, Home Depot, and a local duct supply store to ask how I can design Precious Plastic a vent system that is cheap and accessible for everyone in the community. I am now reworking the design with different parts that should be accessible at any hardware store that carries ducting.

There are lots of complicated requirements for local exhaust ventilation and HVAC systems. How do you know you are sucking the fumes produced into your system? How do you know if it leaks? Can you recirculate or do you have to exhaust it outside? Where do you exhaust it outside? What if there are crossdrafts in your space? How do you make sure it is working?

I’m working on a Jupyter notebook and a Manual to help you figure those things out for your workshop, including the rules you need to follow. If you want the partially developed documentation, message me.

In additon, to answer the question: “Is my ventilation system working?” I am working on low cost open source sensor boards that hopefully we will be able to use to monitor our workspaces VOC concentration to ensure we are not being exposed. The current technology to measure VOCs are Photoionization Detectors and they are thousands of dollars USD. Chinese manufacturers use very cheap sensors to monitor their factories, but their accuracy has not been verified. We are going to test the sensors against known standards to see how accurately they read. If you have experience with metal oxide or similar sensors, get in touch!

And remember, wear a respirator rated for Organic Vapors (OV) if you don’t have a ventilation system in your shop.

08/06/2019 at 04:18

@emmsclaire , Here is http://onearmy.world/community/forums/topic/portable-desktop-injection-machine/page/3/  what I did for my desktop injection machine. The April 18 post shows the current configuration of the pseudo enclosed area at the top of the injector tube. The March 14 post shows the vent routing out of my garage. I used RV sewer flex hose (walmart) and 2 cpu fans. The flex hose is very convenient. Just using match smoke as a test it appears to pull well.

Have you been able to identify what is in the fumes? Is it all organic compounds? How do you know when the mask is used up?

Thank you for looking at this.

08/06/2019 at 07:46


Nice one – that is the concept of LEV. One thing you can do to improve the efficiency of that set up is to stretch the flexible ducting out as far as possible so there is the smoothest surface possible on the inside.

When plastics undergo heating/thermal degradation they emit volatile organic compounds (VOCs). I’ve attached one journal article about it so you can get an idea. Also I’ve read other papers that say carbon monoxide and carbon dioxide are emitted.

You should replace your respirator cartridges based on the manufacturer’s recommendation (3-6 months). Store the cartridges in a sealed plastic bag to extend their life. Replace them more frequently if you use them heavily.
Here is some info about VOCs health effects. Obviously this is not tailored specifically to plastics: https://www.health.state.mn.us/communities/environment/air/toxins/voc.htm

Once we are able to quantitatively measure what VOCs are produced with precious plastic equipment specifically, then we will be able to say more about what health effects are potential hazards if proper ventilation isn’t applied.

14/06/2019 at 15:11

Hi everyone,

I heat press LDPE and HDPE. So far I was melting it outside but I would like to create space for long run. My workshop has closed ventilation system which I can’t connect to also hole in a wall is not an option as it is a newly build development. I was looking into using active carbon filters and strong kitchen hood. Do you think that would work? I have read somewhere that activated carbon filters can be use to filter the air of plastic fumes but I am not sure if that would be sufficient.
I would appreciate your comments.

14/06/2019 at 15:18

best is to use proper gear near that stuff; i heard a few times from the guys in injection moulding that 3M half respirators are best choice.

14/06/2019 at 21:46

You may want to do both mask and facility venting, especially if you are sharing that part of the building. Sometimes you can find inserts that fit into a window and are intended to accept the vent from a standalone airconditioner. You could hook up your fume hood to that and have it look a little less DIY.

21/06/2019 at 17:24

When all else fails…

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