Guys and Girls,
Anyone here has experience scanning an active sewer-manhole?
The manhole i am going to scan is 50 m deep.
I have got a big concern of how safe the laser scanner to be used in a confined space, plus it's a sewer manhole that contains "natural" methan gas..if you know what i mean
I'm afraid it will cause ignition.,
Your feedback guys..
Manhole scanning with FARO 330
- rpuspa
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- Orangeduke
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Re: Manhole scanning with FARO 330
Well, the only scanner I'm aware of that is certified for use in explosive environments is one of the Z&F scanners. But, maybe it's not as bad as you think. Hire a sensor to measure the levels of potential explosive gas to see if it is indeed a explosive environment.
Maybe the bigger problem is how are you going to register the scans together? Will you be able to get some targets down there because it can be difficult to get a cloud to cloud Reg to work in a tunnel.
Gregg
Maybe the bigger problem is how are you going to register the scans together? Will you be able to get some targets down there because it can be difficult to get a cloud to cloud Reg to work in a tunnel.
Gregg
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Re: Manhole scanning with FARO 330
Hi Rahmatyas,
Are you making a confined space entry to scan this manhole?
If so I hope you are experienced at this or are getting/have the proper training and your crew are experienced because this is one of the most dangerous activities a surveyor can be asked to perform.
Even having the sewer flushed with fresh air for hours before entry you can disturb lots of trapped gasses with your feet if the sewer is silted up, plus gas can get disturbed elsewhere in a sewer line and can move in a cloud along the line, and its not just creating an explosive atmosphere you have to worry about, asphyxiation from reduced oxygen, fire from too much oxygen and toxicity from other gasses are all part of the fun.
I've done a good bit of scanning with subsurface features, manholes, shafts, mines, tunnels, karst features etc. and avoid actually going into them if at all possible.
We use an inverted tripod to lower the scanner (HDS 6000 or Focus3D) into the feature and work remotely from the surface. This only up to 20m as there are limitations to the current mechanism.
Deeper than that we use a C-ALS by MDL, however this is not what most laser scanning surveyors with phase scanners would think of as a 'survey grade' instrument - TOF 50mm laser - designed for mining/measuring inaccessible features via boreholes. However like everything MDL build it is a tank and can take some serious beating.
The x330 is not intrinsically safe, in fact I believe (and other users here please correct me if I'm wrong) there is only one intrinsically safe scanner available to the market - The Z&F 5006EX, there are only about 10 of these on the planet, 9 of these are owned by PetroChem companies and they are about 250k (strl) to buy. As mentioned in previous posts here the EX rating certificate is based on European standards only and may not be complaint in other jurisdictions.
(You'd think that if it wasn't going to cause a fire in the EU it wouldn't cause a fire in the US either)
So, avoid going in if at all possible.
Work up a proper methodology and do a good risk assessment with someone who has lots of experience in confined space entry (It may be a case that your going into a client who has a crew working down there regularly so take your ques from them, local knowledge is nearly always best)
Get trained up and don't take risks and, if at all possible....... get some other bugger to do it.
Are you making a confined space entry to scan this manhole?
If so I hope you are experienced at this or are getting/have the proper training and your crew are experienced because this is one of the most dangerous activities a surveyor can be asked to perform.
Even having the sewer flushed with fresh air for hours before entry you can disturb lots of trapped gasses with your feet if the sewer is silted up, plus gas can get disturbed elsewhere in a sewer line and can move in a cloud along the line, and its not just creating an explosive atmosphere you have to worry about, asphyxiation from reduced oxygen, fire from too much oxygen and toxicity from other gasses are all part of the fun.
I've done a good bit of scanning with subsurface features, manholes, shafts, mines, tunnels, karst features etc. and avoid actually going into them if at all possible.
We use an inverted tripod to lower the scanner (HDS 6000 or Focus3D) into the feature and work remotely from the surface. This only up to 20m as there are limitations to the current mechanism.
Deeper than that we use a C-ALS by MDL, however this is not what most laser scanning surveyors with phase scanners would think of as a 'survey grade' instrument - TOF 50mm laser - designed for mining/measuring inaccessible features via boreholes. However like everything MDL build it is a tank and can take some serious beating.
The x330 is not intrinsically safe, in fact I believe (and other users here please correct me if I'm wrong) there is only one intrinsically safe scanner available to the market - The Z&F 5006EX, there are only about 10 of these on the planet, 9 of these are owned by PetroChem companies and they are about 250k (strl) to buy. As mentioned in previous posts here the EX rating certificate is based on European standards only and may not be complaint in other jurisdictions.
(You'd think that if it wasn't going to cause a fire in the EU it wouldn't cause a fire in the US either)
So, avoid going in if at all possible.
Work up a proper methodology and do a good risk assessment with someone who has lots of experience in confined space entry (It may be a case that your going into a client who has a crew working down there regularly so take your ques from them, local knowledge is nearly always best)
Get trained up and don't take risks and, if at all possible....... get some other bugger to do it.
- rpuspa
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Re: Manhole scanning with FARO 330
Guys,
Successfully done with high precaution. We were well equipped with gas level detector and highly ventilated during the scanning process (thanks for the above comment). Good planning and communication is the key, we even had a rehearsal before the d-day.
So., we entered the shaft using man cage, and wearing overall suit. We even managed to place the scanner on the specific place as we planned, but not the target. Due to restricted time and movement, we couldn't place any target. luckily the manhole was full of objects that latter on I can used as tie point.
On similar case/condition, I highly recommended to operate the laser scanning remotely , I used my android tablet as controller.
The most terrifying moment was the time when I have to place the scan from the moving platform to the beam the giant mixer is active at the bottom !!!, and there was a time when the man cage almost knocked the scanner down.
Successfully done with high precaution. We were well equipped with gas level detector and highly ventilated during the scanning process (thanks for the above comment). Good planning and communication is the key, we even had a rehearsal before the d-day.
So., we entered the shaft using man cage, and wearing overall suit. We even managed to place the scanner on the specific place as we planned, but not the target. Due to restricted time and movement, we couldn't place any target. luckily the manhole was full of objects that latter on I can used as tie point.
On similar case/condition, I highly recommended to operate the laser scanning remotely , I used my android tablet as controller.
The most terrifying moment was the time when I have to place the scan from the moving platform to the beam the giant mixer is active at the bottom !!!, and there was a time when the man cage almost knocked the scanner down.
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Re: Manhole scanning with FARO 330
Wow That looks and sounds incredibly scary! Good job, glad to see there were no accidents. Did you perform any scans from that platform or were they all from the beams? I would imagine that platform was in a constant state of motion. Also, how close were you to the mixer at the bottom?
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Re: Manhole scanning with FARO 330
Ventilation and monitoring is key. Methane will combust between 5-15% mixture with oxygen. I think we don't allow entry over 2%. There is other nasty chit down there as well... top to bottom...
(top) Methane, Carbon Monoxide, Hydrogen Sulfide, Propane, Gasoline, sewer water (bottom)
Glad it went well...
(top) Methane, Carbon Monoxide, Hydrogen Sulfide, Propane, Gasoline, sewer water (bottom)
Glad it went well...
- rpuspa
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Re: Manhole scanning with FARO 330
It was scary, nerves wrecking.jcoco3 wrote:Wow That looks and sounds incredibly scary! Good job, glad to see there were no accidents. Did you perform any scans from that platform or were they all from the beams? I would imagine that platform was in a constant state of motion. Also, how close were you to the mixer at the bottom?
No Scan performed from the man-cage, The platform was so unstable and for efficiency we didn't take tripod with us. Yes, the man cage kept moving around, so we need to get a good grip and hold on to the beam to make it steady before placing the scan, good thing the operator was very helpful.
At our lowest level, the giant mixer was about ~3 m below.
And here is the result (cloud to cloud registration)
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