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Need new fire countermeasures for the laser-cutters #335

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amcewen opened this Issue Aug 17, 2016 · 20 comments

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amcewen commented Aug 17, 2016

There was an acrylic fire in Gerald now - after the cut had finished, so presumably the protective film on the acrylic underneath had caught fire out-of-sight and then set fire to the rest of the sheet of acrylic.

Laura deployed the fire blanket, but that had little effect, and some acrylic had dropped through the bed and set fire to the scraps below. So we used the CO2 fire extinguisher to put out the fire under the bed and then also the fire still running quite nicely underneath the fire blanket(!?!)

So, CO2 extinguisher seems to be better than fire blanket.

We need to get a second fire extinguisher to replace the fire blanket, and get the current fire extinguisher re-charged.

There's still some CO2 in the current extinguisher, so it's still available while we get the new one, but everyone should pay even more attention than usual, in order to catch fires before they take hold as much as possible.

Thanks to Laura's prompt action, there wasn't any damage to Gerald. I cleaned his mirrors and lens in case there was any smoke on them, and he's still in service.

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amcewen Aug 17, 2016

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There's still some CO2 in the fire extinguisher next to Gerald's computer BUT BE CAREFUL IF YOU PICK IT UP AS THERE'S NO PIN IN THE HANDLE, so if you squeeze the red handles together you'll squirt VERY COLD CO2 out of the end. I've positioned it with the nozzle facing away from anyone who might get hold of it to mitigate the risk from that. (And we'll get it recharged and with a new pin in as soon as possible).

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amcewen commented Aug 17, 2016

There's still some CO2 in the fire extinguisher next to Gerald's computer BUT BE CAREFUL IF YOU PICK IT UP AS THERE'S NO PIN IN THE HANDLE, so if you squeeze the red handles together you'll squirt VERY COLD CO2 out of the end. I've positioned it with the nozzle facing away from anyone who might get hold of it to mitigate the risk from that. (And we'll get it recharged and with a new pin in as soon as possible).

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johnmckerrell Aug 17, 2016

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This suggests we'll get 10s of discharge time so I doubt there's much left:

http://fire-extinguisher-information.co.uk/discharge-time.htm

On 17 Aug 2016, at 13:42, Adrian McEwen notifications@github.com wrote:

There's still some CO2 in the fire extinguisher next to Gerald's computer BUT BE CAREFUL IF YOU PICK IT UP AS THERE'S NO PIN IN THE HANDLE, so if you squeeze the red handles together you'll squirt VERY COLD CO2 out of the end. I've positioned it with the nozzle facing away from anyone who might get hold of it to mitigate the risk from that. (And we'll get it recharged and with a new pin in as soon as possible).


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johnmckerrell commented Aug 17, 2016

This suggests we'll get 10s of discharge time so I doubt there's much left:

http://fire-extinguisher-information.co.uk/discharge-time.htm

On 17 Aug 2016, at 13:42, Adrian McEwen notifications@github.com wrote:

There's still some CO2 in the fire extinguisher next to Gerald's computer BUT BE CAREFUL IF YOU PICK IT UP AS THERE'S NO PIN IN THE HANDLE, so if you squeeze the red handles together you'll squirt VERY COLD CO2 out of the end. I've positioned it with the nozzle facing away from anyone who might get hold of it to mitigate the risk from that. (And we'll get it recharged and with a new pin in as soon as possible).


You are receiving this because you are subscribed to this thread.
Reply to this email directly, view it on GitHub #335 (comment), or mute the thread https://github.com/notifications/unsubscribe-auth/AABqa_SWV5HQJ120mKUTk5qqmTeDcts8ks5qgwHMgaJpZM4JmZpq.

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amcewen Aug 23, 2016

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The new CO2 extinguisher has arrived and is next to Sophia's computer (although @DoESsean hasn't posted a link here to where he ordered it from for future reference... :-).

We still need to get the half-empty one recharged. @DoESsean found that H. Roberts & Son on Regent Street can refill that, for ~half the cost of a new one (£15.50+vat). Does anyone with transport want to offer to take it along and get it refilled? Obviously DoES will reimburse the cost.

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amcewen commented Aug 23, 2016

The new CO2 extinguisher has arrived and is next to Sophia's computer (although @DoESsean hasn't posted a link here to where he ordered it from for future reference... :-).

We still need to get the half-empty one recharged. @DoESsean found that H. Roberts & Son on Regent Street can refill that, for ~half the cost of a new one (£15.50+vat). Does anyone with transport want to offer to take it along and get it refilled? Obviously DoES will reimburse the cost.

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amcewen Aug 26, 2016

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Mea culpa. @DoESsean did post a link, but over on issue #298 :-)

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amcewen commented Aug 26, 2016

Mea culpa. @DoESsean did post a link, but over on issue #298 :-)

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cheapjack Sep 8, 2016

Wonder if it's worth getting a fire blanket also? alot of cardboard fires just need patting down so a quick 'blanket throw' could avoid the need for the extinguisher in first instance then we could advise people to use that next if the blanket fails? In most cases doubt it would be needed.

cheapjack commented Sep 8, 2016

Wonder if it's worth getting a fire blanket also? alot of cardboard fires just need patting down so a quick 'blanket throw' could avoid the need for the extinguisher in first instance then we could advise people to use that next if the blanket fails? In most cases doubt it would be needed.

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DoESsean Sep 8, 2016

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It makes some sense, and I would have no qualms about having one as another precaution, but I'm not sure if everyone agrees - when we last bought fire safety equipment, it was decided that a second extinguisher would be of more use than a blanket, so we didn't replace the one that had been used.

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DoESsean commented Sep 8, 2016

It makes some sense, and I would have no qualms about having one as another precaution, but I'm not sure if everyone agrees - when we last bought fire safety equipment, it was decided that a second extinguisher would be of more use than a blanket, so we didn't replace the one that had been used.

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DefProc Sep 8, 2016

After a quick discussion IRL in the office, the blanket has been dropped in favour of just a CO2 extinguisher because when used in anger, the blanket has been thrown over the moving arm, creating more of a fire tent. Which doesn't extinguish anything.

As the CO2 extinguisher has been shown to be more useful in practice, we'll stick with just that for the time being. Although it's still open to review.

DefProc commented Sep 8, 2016

After a quick discussion IRL in the office, the blanket has been dropped in favour of just a CO2 extinguisher because when used in anger, the blanket has been thrown over the moving arm, creating more of a fire tent. Which doesn't extinguish anything.

As the CO2 extinguisher has been shown to be more useful in practice, we'll stick with just that for the time being. Although it's still open to review.

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amcewen Jan 20, 2017

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Does anyone know what happened to the needs-to-be-recharged fire extinguisher? It doesn't seem to be in the workshop any more. Is someone in the process of getting it recharged?

The remaining extinguisher now needs to be recharged too, as there was an acrylic fire in Gerald just now. It was caught before any real damage was done - I've cleaned the lens and replaced the short length of air-assist tube that had melted enough to have a few holes in it.

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amcewen commented Jan 20, 2017

Does anyone know what happened to the needs-to-be-recharged fire extinguisher? It doesn't seem to be in the workshop any more. Is someone in the process of getting it recharged?

The remaining extinguisher now needs to be recharged too, as there was an acrylic fire in Gerald just now. It was caught before any real damage was done - I've cleaned the lens and replaced the short length of air-assist tube that had melted enough to have a few holes in it.

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amcewen May 18, 2017

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Can anyone do a run to Regent Street to get the three extinguishers in the workshop refilled for us? DoES will pay for it, obviously, but we could do with someone with transport who can take them over there.

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amcewen commented May 18, 2017

Can anyone do a run to Regent Street to get the three extinguishers in the workshop refilled for us? DoES will pay for it, obviously, but we could do with someone with transport who can take them over there.

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amcewen Aug 24, 2017

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From organisers meeting, @DoESsean to chase up.

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amcewen commented Aug 24, 2017

From organisers meeting, @DoESsean to chase up.

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johnmckerrell Nov 2, 2017

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I've used the extinguisher next to Gerald today, obviously still had some in but we should refill (or report back here if the previous refill happened!)

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johnmckerrell commented Nov 2, 2017

I've used the extinguisher next to Gerald today, obviously still had some in but we should refill (or report back here if the previous refill happened!)

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DefProc Nov 20, 2017

Did this refill happen? @DoESsean

DefProc commented Nov 20, 2017

Did this refill happen? @DoESsean

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DoESsean Nov 21, 2017

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DoESsean commented Nov 21, 2017

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johnmckerrell Nov 22, 2017

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Just given them a call and they mention that they won't do it there and then, you need to leave the extinguisher(s) with them and they'll call when filled. I'm wondering if it's possible to do on a bike, I forget how heavy they are (and of course they will be heavier when filled!) Obviously if we do this we have to make sure we don't take all leaving no protection back in DoES.

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johnmckerrell commented Nov 22, 2017

Just given them a call and they mention that they won't do it there and then, you need to leave the extinguisher(s) with them and they'll call when filled. I'm wondering if it's possible to do on a bike, I forget how heavy they are (and of course they will be heavier when filled!) Obviously if we do this we have to make sure we don't take all leaving no protection back in DoES.

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johnmckerrell Nov 30, 2017

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I performed a test with one of the extinguishers last week. Both of ours weighed 4.6kg even though they'd both been used, they claim to have 2kg of CO2 in. I then discharged one of them completely, it lasted for more than 20s until you could say it wouldn't be effective anymore. At that point it weighed 2.6kg. I also briefly tested the one that was here originally and it did discharge.

I have since taken the emptied extinguisher to be filled (and commissioned) so will pick that up shortly.

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johnmckerrell commented Nov 30, 2017

I performed a test with one of the extinguishers last week. Both of ours weighed 4.6kg even though they'd both been used, they claim to have 2kg of CO2 in. I then discharged one of them completely, it lasted for more than 20s until you could say it wouldn't be effective anymore. At that point it weighed 2.6kg. I also briefly tested the one that was here originally and it did discharge.

I have since taken the emptied extinguisher to be filled (and commissioned) so will pick that up shortly.

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ajlennon Nov 30, 2017

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I'm working with some people on fire prevention and we have an idea for a proximity sensor that switches off the power if a person leaves the vicinity. Is that something interesting? (i.e. might I test that out on some laser cutterers?)

Edit: We're also looking at adding temp/flame/smoke sensor to also cut out power. Maybe we could try that too. I want to auto-deploy halon gas too but that might be over-reach again on my part...

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ajlennon commented Nov 30, 2017

I'm working with some people on fire prevention and we have an idea for a proximity sensor that switches off the power if a person leaves the vicinity. Is that something interesting? (i.e. might I test that out on some laser cutterers?)

Edit: We're also looking at adding temp/flame/smoke sensor to also cut out power. Maybe we could try that too. I want to auto-deploy halon gas too but that might be over-reach again on my part...

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johnmckerrell Dec 1, 2017

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Filled extinguisher is now down the side of Sophia. Interestingly its weight was 4.4kg and the existing one seems to have dropped to just under 4kg. Probably the scale isn't too good at that end of the range as its max allowable is 5kg. Was £15.50+VAT and receipt is on @DoESsean's desk.

Closing this ticket as we now have the countermeasures for the lasers. I'd be interested in @ajlennon 's idea but would expect it needs a warning buzzer, like "RETURN TO THE LASER, YOU HAVE 10 SECONDS TO COMPLY".

Obviously the other extinguisher should really be recommissioned but we also need a full fire assessment done on the new space so I'm happy to wait for that.

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johnmckerrell commented Dec 1, 2017

Filled extinguisher is now down the side of Sophia. Interestingly its weight was 4.4kg and the existing one seems to have dropped to just under 4kg. Probably the scale isn't too good at that end of the range as its max allowable is 5kg. Was £15.50+VAT and receipt is on @DoESsean's desk.

Closing this ticket as we now have the countermeasures for the lasers. I'd be interested in @ajlennon 's idea but would expect it needs a warning buzzer, like "RETURN TO THE LASER, YOU HAVE 10 SECONDS TO COMPLY".

Obviously the other extinguisher should really be recommissioned but we also need a full fire assessment done on the new space so I'm happy to wait for that.

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amcewen Dec 1, 2017

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Just a note on @ajlennon's suggestion, in case someone is reading through this issue in future and implementing it - it would be better to tap into just the laser firing circuit rather than pulling power on the entire laser cutter. There's already a safety cut-off for the flow sensor and lid open sensor which turns off the laser - adding the "not attended" sensing as a thing that turns off the laser to that would work best. That would allow someone to pause the laser mid-job and, for example, go to the toilet, without coming back to a completely ruined job.

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amcewen commented Dec 1, 2017

Just a note on @ajlennon's suggestion, in case someone is reading through this issue in future and implementing it - it would be better to tap into just the laser firing circuit rather than pulling power on the entire laser cutter. There's already a safety cut-off for the flow sensor and lid open sensor which turns off the laser - adding the "not attended" sensing as a thing that turns off the laser to that would work best. That would allow someone to pause the laser mid-job and, for example, go to the toilet, without coming back to a completely ruined job.

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DefProc commented Dec 1, 2017

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