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Author Oxygen levels
pwhole

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Joined: 22/02/2011
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Oxygen levels
Posted: 01/10/2020 14:39:34
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I was with staffordshirechina some way into Hillcarr Sough when the O2 levels went down to very, very low, and I felt fine, but I can't remember if we had a CO2 meter - but that must have been one of those instances where it wasn't all replaced by CO2, or I guess we wouldn't be here now.

The 0.03 level for CO2 in fresh air is correct - there's really not much. CO2 supplementation is also used in indoor horticultural businesses for this reason (both legal and not so legal) - plants can take up to 1.5% quite happily, and will grow approximately 25% larger in the regular time frame, and can tolerate increased temperatures, with the supplemental CO2. Which means they can be closer to the lights, increasing yield further. So market growers can increase bulk quite dramatically, though it doesn't speed things up necessarily - that's genetic.

Obviously you don't want staff present if this technique is being used. I'm sure there's plenty of Vietnamese guys stumbling around dodgy grow-warehouses totally unaware, with a tank permanently hissing it out. At least it's not flammable. Also I can't imagine the producers are complaining. Nitrous Oxide sales have gone through the roof over the last twenty years but I doubt they're up in arms at the shareholders meetings.
IP: 81.174.241.13 Edited: 01/10/2020 14:39:53 by pwhole
staffordshirechina

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Oxygen levels
Posted: 01/10/2020 14:48:43
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pwhole wrote:

I was with staffordshirechina some way into Hillcarr Sough when the O2 levels went down to very, very low, and I felt fine, but I can't remember if we had a CO2 meter - but that must have been one of those instances where it wasn't all replaced by CO2, or I guess we wouldn't be here now.


No, you are correct, the meter I was using that day was only the usual 4 gas.
I only had use of the five gas one at work. At around £1500 it is too expensive for general use. Obviously if you work in an iron mine somebody else is paying!
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Down and beyond

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Oxygen levels
Posted: 01/10/2020 15:41:06
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It is a major shame their is not a co2 sensor you can buy that’s acceptable for use underground I no they do them for in underground car parks etc , i don’t think they would work properly in a mine probably beep all day long

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Wormster

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Oxygen levels
Posted: 01/10/2020 16:43:34
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A couple of pints from what little I remember from my time in Gas detection manufacture:

1 - a 1% fall in oxygen will equate to a bout 3% rise in Carbon Dioxide.

2 - if you are going to obtain a quad gas detector might I suggest that a CROWCON one is the one to choose.
(historically my folks set up the company back in the 70's.)
(ok,ok, I know that they're a bit like Stella Artios - reasuringly expensive, but they have the longest experience with monitoring gasses in most environments!)

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ChrisJC

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Oxygen levels
Posted: 02/10/2020 08:22:49
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Thanks Wormster. I've not come across Crowcon before, but this one looks suitable as it has 5 gas dectors, which should be enough:
https://www.crowcon.com/products/portables/gas-pro/
O2, CO, CO2, H2S and NO2.

Chris.
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sinker

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Oxygen levels
Posted: 02/10/2020 08:57:32
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ChrisJC wrote:

Thanks Wormster. I've not come across Crowcon before, but this one looks suitable as it has 5 gas dectors, which should be enough:
https://www.crowcon.com/products/portables/gas-pro/
O2, CO, CO2, H2S and NO2.

Chris.


No offense Wormster, the Crowcon is ideal for industrial / factory / petro-chem type stuff (basically clean) but for mining, underground and wet / muddy / damp conditions the MSA Altair is a better tool; much more durable and less susceptible to damp and muck ingress.



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ChrisJC

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Oxygen levels
Posted: 02/10/2020 14:32:23
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sinker wrote:


No offense Wormster, the Crowcon is ideal for industrial / factory / petro-chem type stuff (basically clean) but for mining, underground and wet / muddy / damp conditions the MSA Altair is a better tool; much more durable and less susceptible to damp and muck ingress.



Why do you say that Sinker? Crowcon claim IP65 and IP67 (which is odd, surely it can only be one of them!)

If it turned out to be IP67, would that be sufficient?

Chris.
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sinker

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Oxygen levels
Posted: 02/10/2020 16:36:14
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ChrisJC wrote:

sinker wrote:


No offense Wormster, the Crowcon is ideal for industrial / factory / petro-chem type stuff (basically clean) but for mining, underground and wet / muddy / damp conditions the MSA Altair is a better tool; much more durable and less susceptible to damp and muck ingress.



Why do you say that Sinker? Crowcon claim IP65 and IP67 (which is odd, surely it can only be one of them!)

If it turned out to be IP67, would that be sufficient?

Chris.


The body may be IP67 (or 65; haven't checked) while the MSA Altair is definitely IP67 but in both cases that's only the main body, not the vent / screen / filter to the sensors. They are only moisture proof obviously as if water can't get in then neither can gas.... Wink


So the comparison I was making is the resistance of the sensor openings to moisture and muck. I have seen loads of detectors fail and be ruined by moisture ingress into the (unrated sensor filters) but never into the IR-rated body.





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Morlock

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Oxygen levels
Posted: 02/10/2020 17:02:12
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Agree, once one lowers the remote sampling tube (or the whole unit) into a warm and misty industrial tank or other damp confined space the unit is u/s in seconds. IP: 86.183.245.144
Wormster

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Oxygen levels
Posted: 03/10/2020 11:20:57
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ChrisJC wrote:



Why do you say that Sinker? Crowcon claim IP65 and IP67 (which is odd, surely it can only be one of them!)

If it turned out to be IP67, would that be sufficient?

Chris.


As I recall all of the detectors we made were IP65 rating, but that may have changed over time.

(The triple and quad detectors came about after market requests from the water industry (why carry 3 separate detectors?))

Perhaps the combined rating is because the "guts" are at the IP67 rating all nicley sealed with O rings etc. and the detectors are IP65 rating becaus they are open to the elements.

Granted its always going to be the pellistors and fuel cells in the instrument thst are going to take the brunt of abuse as they have to be open to the elements in order to work.

I will ask an ex-employee who I work with if she knows......


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Steve Holding

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Oxygen levels
Posted: 07/10/2020 10:40:02
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I am particularly interested in carbon dioxide in mines - but have yet to splash out on purchasing a CO2 meter (and cover the on-going calibration costs).

I was able to borrow a CO2 meter in September and carried out measurements in Scaleburn Vein of Rampgill, Nenthead, compared against a disposable type O2 meter. The lowest O2 encountered was 17.5% and this gave a 1.29% measured CO2. This CO2 being half the O2 deficiency was maintained throughout measurements along this level. As a memorable location - at the Horse Gin in was 19.0% O2 and 0.88% CO2. I think this relationship most common but would like to check more.

One location in Rampgill (Rampgill Cross Vein) did give CO2 about 0.45% with less that 0.9% O2 deficiency.

Other locations at Nenthead that week also gave the CO2 being half the O2 deficiency but the atmospheric pressure was generally high and air quality underground generally good.
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Down and beyond

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Oxygen levels
Posted: 07/10/2020 10:48:48
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Interesting Thankyou very much for your input , I don’t personally believe that it is always like that as when I was in a iron mine and it dropped to 14.1% that would be roughly 7% co2 which should mean I shouldn’t be here according to the link I posted but nitrogen could of been a factor in that , this is the reason I think a 5x is best for mines with these issues , or just don’t go in them Laugh

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ChrisJC

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Posted: 07/10/2020 10:52:56
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Interesting measurements Steve. I hope that by NAMHO next year I will have some equipment and will have tried it out in a few places, so we can compare notes.

Chris.
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Steve Holding

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Posted: 07/10/2020 11:26:24
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I should have noted that my expectation was CO2 being a maximum of half the oxygen deficiency. I have been in many situations with measured <17% O2 without really being uncomfortable. Having noted this, I was surprised to find any significant CO2 levels in Rampgill.

I hope to be in a mine level, in Shropshire, this evening where there has normally been low O2 but this should be the first time that I am aware of a CO2 measurement.
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Down and beyond

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Posted: 07/10/2020 11:57:17
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Very interesting! I look forward to seeing your updates on your progress , as I am also interested

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Morlock

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Oxygen levels
Posted: 07/10/2020 14:42:47
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NCB ventilation manual lists CO2 effects down to 9%.



(click image to open full size image in new window)
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Down and beyond

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Posted: 07/10/2020 15:09:46
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Nice bit of information what does page 3 refer to is it just black damp or more about co2

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Morlock

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Posted: 07/10/2020 15:15:53
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See image , page 1 of thread. IP: 86.162.208.50
Down and beyond

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Posted: 07/10/2020 15:17:38
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Thumbs Up

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Wormster

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Posted: 07/10/2020 15:26:03
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With regard of the Crowcon units I did some asking around and it was as I suspected IP67 for the circuitry and IP65 for the detectors. Apparently Thames Water sewer men liked the old 84TR because it would sink (stainless steel case) where as the new quads float (plastic case and a better IP) and have to be chased down the flow when dropped.

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