Fire Safety Questions  

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christopherjohnmuller
(@christopherjohnmuller)
New Member

Hi I’m new to the 3D printing world (have done a ton of research) I purchased a prusa mk3 and was very excited to begin my journey. However, my wife is scared to death that this thing is going to burn our house down (to the point where she doesn’t want me printing in the house) 

my questions are:

how fire safe is the prusa mk3?

have there been known fires that people have had with these units?

is there any way to build A fire safe enclosure?

what are people’s safety recommendations?

thank you very much to anyone who responds it is greatly appreciated 

chris 

 

Posted : 29/08/2020 4:40 pm
MartyS
(@martys)
Trusted Member

It's pretty rare for a 3D printer to catch fire, but it has happened.

Home appliances burn down lots of houses every year, space heaters, toasters, toaster ovens, etc...  Do you have any of those in your house?

Be careful and follow the typical safety tips that would apply to any appliance that gets hot.  

 

Posted : 10/09/2020 3:44 pm
bobstro
(@bobstro)
Illustrious Member

3D printers have certainly been known to start fires. The Prusa printers are better than many of the low-cost competitors in terms of build quality and components used. The Prusa firmware has the safety checks (thermal runaway) features enabled. None of these are 100% fool proof of course.

  • Regardless of what 3D printer you use, you want to regularly check cabling and connectors for scorching, abrasion or fraying. There are more moving parts in a 3D printer than many appliances, and the wires that connect them need to be checked periodically.
  • Always use the 3D printer in an area with smoke detector coverage.
  • Consider adding a smart outlet that will shut off power to the 3D printer if the smoke detector is activated.
  • Don't leave the 3D printer running when away from home (esp. if pets or loved ones are still at home).
  • Use common sense for storage of supplies and cleaning materials. Store highly flammable supplies away from the 3D printer.
  • Consider an enclosure (hard or soft) made with fire-retardant materials.
  • Keep and maintain a suitable fire extinguisher.

Most of this falls under good practice for any device. You can't make a 3D printer (or any other mains-powered device) 100% guaranteed not to cause a fire. You can reduce the odds of it doing so, and your ability to detect any problems quickly. I don't consider a 3D printer any more dangerous than a space heater given that it stays in one place and is not likely to be tipped over by pets or family.

All of this changes if you're using a cheaper 3D printer. You get peace-of-mind from buying a Prusa with known quality and support.

 

My notes and disclaimers on 3D printing and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan...
Posted : 10/09/2020 4:22 pm
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jasonstone.designs
(@jasonstone-designs)
Active Member

This is my set up. My enclosure includes a fire grenade. You can buy these on Amazon and eBay.

It's basically a firework with a long fuse wrapped around the circumference. It's covered with a flammable wrapper. The concept is such: If there's a fire inside the enclosure the wrapper ignites . . . which ignites the fuse . . . which sets off the main charge . . . which instead of pretty sparkly stuff is filled with fire retardant.  The combo of the blast/fire retardant puts out the fire.

There's a Youtube video of a guy putting out campfires and holding them in his hand and setting them off.

Makes me feel a little better while the printer is running while I'm asleep or at work.

[img] [/img]

[img] [/img]

 

 

This post was modified 8 months ago by jasonstone.designs
Posted : 10/09/2020 6:00 pm
jsw
 jsw
(@jsw)
Noble Member

I asked this question a while back.

Supposedly there was one known case of a Prusa printer catching fire, but it had been modified by the user.  Prusa, however, was said to have taken it very seriously.

I just added an enclosure and one of my soon-to-do projects is to place a smoke detector in the enclosure and wire it into a latching relay that will kill the power to the box if it should go off.

For now, the home office where I have the printer has a smoke detector, and all of the detectors in the house are interconnected such that if one goes off, all of them sound, very loudly.  There is also a fire extinguisher in the garage down the hall, and in the kitchen cabinet a bit farther away.  If there is an actual fire, I want an extinguisher where I can get to it in a safe location and not where the fire is.

One thing that was brought up in that thread, which I was actually embarrassed about, is this, which I have corrected.

This post was modified 8 months ago by jsw
Posted : 10/09/2020 11:03 pm
JoanTabb
(@joantabb)
Moderator

If an explosive goes off in an enclosed space, what happens to the  enclosing parts? 

Black powder and Smokeless powder both burn quite nicely if ignited in the open. (Unconstrained)

Both respond violently if ignited in a confined space. (Constrained)

Admittedly the enclosure is not as confining as a gun barrel or cartridge case , but rapidly expanding gasses inside a plastic walled enclosure may have 'exciting' results...    possibilities ranging from popping the door open, to fragmentation... (I suspect, any less than popping the door open, is unlikely)

the demonstration blasts, that I have seen,  seem quite powerful in the open... 

I am not aware of anyone actually discharging an automatic fire extinguisher like this, in an enclosed space. 

I would love to see what happens...   does anyone have a video? 

regards Joan

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK...
Posted : 11/09/2020 2:15 am
MartyS
(@martys)
Trusted Member
Posted by: @joantabb

If an explosive goes off in an enclosed space, what happens to the  enclosing parts? 

 I was just thinking the same thing, could be bad for anyone in the room if the enclosure shatters and bits go flying.

I would take a page from old black powder mills, don't attach the top on the enclosure, just have it resting on the frame, then the top blows off if the fire extinguisher bomb goes off.

Posted : 11/09/2020 2:27 am
jasonstone.designs
(@jasonstone-designs)
Active Member
Posted by: @joantabb

If an explosive goes off in an enclosed space, what happens to the  enclosing parts? 

Black powder and Smokeless powder both burn quite nicely if ignited in the open. (Unconstrained)

Both respond violently if ignited in a confined space. (Constrained)

Admittedly the enclosure is not as confining as a gun barrel or cartridge case , but rapidly expanding gasses inside a plastic walled enclosure may have 'exciting' results...    possibilities ranging from popping the door open, to fragmentation... (I suspect, any less than popping the door open, is unlikely)

the demonstration blasts, that I have seen,  seem quite powerful in the open... 

I am not aware of anyone actually discharging an automatic fire extinguisher like this, in an enclosed space. 

I would love to see what happens...   does anyone have a video? 

regards Joan

What happens if the fire ball goes off inside the enclosure will probably be the LAST thing I'd be worried about . . . if there is ACTUALLY a fire when I'm not present.  I'd be more thankful that potentially spreading flames were stopped. Besides, if this thing goes off the presumption is that the printer was already toast at that point.)

My nephew, who is a firefighter, was the one who suggested it; though admittedly as a "better than nothing" option.

Just look up "fire ball" on Youtube.

There's actually several variants of this concept. The most common is a tin can that hangs over your stovetop to put out grease fires. It's the same idea, but with a smaller "charge" that pops the bottom and drops baking soda into the flame. They used to sell them at my local ACE Hardware.

Posted : 11/09/2020 3:16 am
Mete
 Mete
(@mete)
Active Member

@bobstro

I am looking for a good way to do this "Consider adding a smart outlet that will shut off power to the 3D printer if the smoke detector is activated.". Any recommendations ? I guess it is not a necessity (or better to have online than nothing), but it would be nice to have an offline solution (not using wifi etc.).

Posted : 25/09/2020 5:01 pm
jsw
 jsw
(@jsw)
Noble Member

What I plan to do, from a KISS point of view with few failure points, I have this huge honking DPDT power relay left over from another project.  Let the NC contacts power the strip into the box with the printer and such, and the NO contacts power the coil, to latch it in the energized position.  Smoke alarm and/or high temperature will drive the coil, which will then latch it in a printer-power-off mode until it is manually reset.

Posted : 25/09/2020 6:05 pm
JDubs
(@jdubs)
Eminent Member

Personally, I think it's brilliant. Ball goes off, puts out the fire, and also blasts the wooden enclosure (firewood) away from the fire.

 

Of course, I'm really too new to start talking that sort of trash in here, but all of that exposed pine seemed to be as much of a fire hazard as anything else.

-------------------------------------------------------------------------------------------------------------------
In theory, there is no difference between theory and practice. In practice, there is. -Yogi Berra...
Posted : 28/09/2020 2:05 am
Mete
 Mete
(@mete)
Active Member

As I was looking for ready to use/commercial devices rather than DIY, I decided to use homematic IP smoke sensor, pluggable switch and their offline controller (ccu3). This still uses RF but not WiFi, and very easy to turn the switch off when smoke sensor alarms or basically do any type of logic. It is a bit too expensive (because of the controller) and probably overkill to use only on this problem but I plan to use it for other things so I was OK with the costs.

Posted : 06/10/2020 4:38 pm
Tim
 Tim
(@tim-2)
Illustrious Member

Interesting that in a discussion of what folk have done to minimize fire risk I see a photo of a printer right next to a large bottle of alcohol, right next to a can of alcohol. Regardless of any suppression, I doubt that plastic bottle will survive long enough for the suppression to help.

Safety is a mind set.

It is always wise to get more than one opinion...
Posted : 06/10/2020 6:12 pm
jsw
 jsw
(@jsw)
Noble Member
  I see a photo of a printer right next to a large bottle of alcohol, right next to a can of alcohol.

That was me, and those have been relocated.

Posted : 06/10/2020 6:16 pm
bobstro
(@bobstro)
Illustrious Member

MatterHackers sells the BlazeCut series for automotive. It's a tubular arrangement as opposed to the cartoony cannonball bomb format, but the same basic idea. When heated, it releases a fire suppression agent. Not explosive though, and it's meant to use in confined (under the hood) spaces though not a sealed enclosure. At $160, I've considered it as a passive backup.

My notes and disclaimers on 3D printing and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan...
Posted : 06/10/2020 8:36 pm
tlveik
(@tlveik)
Active Member

The problem that I see with devices like the fire-ball is that they don't remove the power source.  So re-ignition is possible.  I'm going to use a smoke detector triggered system that disconnects the power and keeps it shut off.

Posted : 07/10/2020 2:26 am
JDubs
(@jdubs)
Eminent Member
Posted by: @mete

@bobstro

I am looking for a good way to do this "Consider adding a smart outlet that will shut off power to the 3D printer if the smoke detector is activated.". Any recommendations ? I guess it is not a necessity (or better to have online than nothing), but it would be nice to have an offline solution (not using wifi etc.).

I'll add my name to the list of people who are looking for something like this. Has anyone set something up themselves? Have any product recommendations? Or am I destined to dig through the dusty back corners of my brain to remember how to design the relay circuit?

 

In other news, this thread has inspired me, and the flammable storage cabinet I ordered will apparently be delivered tomorrow.

This post was modified 7 months ago 2 times by JDubs
-------------------------------------------------------------------------------------------------------------------
In theory, there is no difference between theory and practice. In practice, there is. -Yogi Berra...
Posted : 07/10/2020 4:34 am
Mete
 Mete
(@mete)
Active Member

@james-watriss

I have just decided and installed homematic IP products after looking for options. There are usually WiFi based "smart" products that works through cloud, so in order to have even a small logic program it has to communicate with the cloud (so there is a need for internet) which I do not want. There are wired products but they need obviously some wiring which I do not want to do particularly for the power lines.

So I decided to use homematic IP wireless smoke sensor and power plug switch. They use RF but not WiFi, and it is possible to have an offline controller so there is no need for internet for system to work (but it is almost 3x more expensive than normal controller). There are also open-source alternatives (running on rpi) for the controller (but then you also need the RF electronics sold as an rpi hat). As far as I can see, there is a large community (forums etc.) but the content is mostly in German.

After investing this, since I can connect more devices, I installed another power plug switch which switches on when printer is switched on (or I guess it is possible to check if it is actually printing based on power consumption as measured by the power plug switch) to switch on the lights inside enclosure and an external fan etc.

(in case there is a question mark, I have no relationship with the company manufacturing homematic products, I actually have heard them first time while doing this search on internet)

An ideal and simpler product which I would actually buy would be a smoke detector that has a cable (to signal alarm) going to a power plug switch which turns off when alarm is detected. So no RF/wireless, no controller, very hard to fail I guess. I could not find any such product yet.

This post was modified 7 months ago by Mete
Posted : 07/10/2020 8:11 am
Tim
 Tim
(@tim-2)
Illustrious Member

There was a thread somewhere that had a link to a smoke/fire detector that can control a relay directly. The user had done some convoluted wiring to make his system work the way he wanted, but it didn't need to be that hard.

 

Here's one possible method - use a Kidde smoke alarm and one of their relay modules:
https://www.kidde.com/home-safety/en/us/products/fire-safety/safety-accessories/auxiliary-devices/sm120x/

 

 

 

It is always wise to get more than one opinion...
Posted : 07/10/2020 8:33 am
jasonstone.designs
(@jasonstone-designs)
Active Member
Posted by: @james-watriss

Personally, I think it's brilliant. Ball goes off, puts out the fire, and also blasts the wooden enclosure (firewood) away from the fire.

 

Of course, I'm really too new to start talking that sort of trash in here, but all of that exposed pine seemed to be as much of a fire hazard as anything else.

The charge isn't THAT big. 🙂 There's a video of a guy on YouTube setting them off in his hand (he's wearing safety glasses at least). Maybe the plexiglass sheet windows I have taped on there might get blown off. But there isn't going to be enough force to blow the whole thing apart. The purpose is to quickly coat everything in the fire retardant. 

 

Posted : 07/10/2020 1:40 pm
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