My Portable CO Monitor/Tester Field Experiences .

[DandyDon]

Carrying a portable CO monitor from Carbon Monoxide Detection - Pocket CO on my next dive trip included some learning curve of course, and I wanted to share these thoughts…

$139 - wish my Nitrox tester had been that cheap,
but I think this is as important.
​

I’d thought that as cheap as user-replaceable batteries were that I’d simply leave it active all the time for my Yucatan trip and see what developed. It was interesting, but in reviewing my experiences with the manufacture reps - I guess that I did expect a little too much of this marvelous little gadget. It does have some limitations altho none that would prevent it from serving its intended purposes of checking tank air before diving and hotel room air before and during sleep.

(1) Leaving it on and exposed in relative humidity greater than 85% tends to overload the sensor. Having it run in the crowded Cozumel airport van with even higher humidity than outside is still a good idea considering all, but then giving the monitor plenty of rest time in a lower humidity room with AC running until needed for tank testing would probly be best. Too much humidity or exposure to organic vapors - like downtown San Miguel or worse on Playa del Carmen - can give higher than true readings, but AC room time will generally clear this up. Our PDC room was over a restaurant tho and never did clear completely there, which was worrisome but part of the reason for having a traveling monitor/tester

(2) Putting the monitor in a clear bag and filling with tank air works well and if the monitor is clear when the air is added, then two minutes on a safety-stop timer is all that should be needed for a dependable reading. Two problems I did incur…

(a) Leaving the monitor exposed on the way to pick up tanks on the Tulum hiway left it tainted for the tank air test, especially with the smell of smoke in the air at the fill shack - but even tho this facility is patronized by cave and tri-mix divers, the air smell made me want to test even more. The two minute reading was 14 ppm but it came down to 10 in three minutes and continued to drop. Testing additional tanks then should be accomplished with two minute readings.

(b) I didn’t like the idea of using ziplock bags as a standard bag is easier to hold onto a tank neck when cracking the valve slightly to slowly fill the bag. The bags I took were a little light weight for the job tho; next time I’ll take one gallon oven cooking bags.​

(3) Do not bleed air directly into the monitor! From the manual that really should actually be read before using: “Pocket CO is a diffusion-based instrument, meaning it detects CO present in still air. To obtain accurate readings, do not place Pocket CO in the direct path of fast moving air (e.g. directly in front of a heating or cooling vent). Also, do not blow directly into the instrument with your mouth. For best results, place Pocket CO close to your breathing space. If air from a moving gas needs to be checked for CO, place Pocket CO several inches away from the source. Alternately, place Pocket CO in an empty plastic bag and then fill the bag with this air.“

(4) As instructed by the manual, the air ports on the monitor need to unblocked. For my uses, I preferred…

(a) Traveling in planes and vans, clipped to my shirt color, face down, ports on three sides exposed.

(b) In the room, face down in a dry area with other electronics or hanging from its clip on something like hanging clothes - not a window curtain would could lead to sun heating.

(c) In the bag, face down for the first two minutes.​

​

Otherwise, for typical travel to hot, humid dive destinations in the tropics, often with marginal air quality controls - I think I’ll carry it in a Pelican box or airtight cigarette box with maybe a moisture muncher and a activated carbon pack if I acquire excessive exposure. I think the main thing is to have a 0 reading before testing tank air, then watch for any increase.

(5) If you don’t smoke, fine; if you do, you can expect that to affect readings and again more time in clean air would be needed to return the monitor to a clean position.

Summary....

The 12 hour mode is preferable in the hotel room or plane after study of the manual this mode gives Dosimetry and TWA Warnings - see manual for explanation. Hehe, and if the alarm goes off on a plane, don’t be shy about alerting the crew as reduced air pressure will lower readings somewhat.

Someone here said he tested his new monitor by holding it to his car’s exhaust. Don’t! That’s a bit much. If you want to see it react, take it somewhere where smoking is allowed. I remember a smoking lounge at the Atlanta airport before Delta stopped serving my home airport; that room would probly set off the beeping alarm!

Again, the manual really should actually be read before using just like your dive computer or camera manual - and I am one of those who learned the hard way the importance of such when I tried to bluff by just playing with the electronic gadgets. Two specific parts to keep in mind…

3.10 Additional Usage Information:

Sudden Temperature Changes: Pocket CO may briefly display readings of CO slightly above 0 ppm when experiencing a sudden change in temperature. Some examples are: moving from a warm building into cold outside air, a sudden gust of frigid air on the instrument (e.g. next to an A/C vent), or placement onto a cold stone surface. This reading will settle back down to the actual concentration of CO within a few minutes, as Pocket CO’s temperature compensation circuit comes into equilibrium with the new temperature.

Prolonged Exposure to Organic Vapors and Smoke: If Pocket CO has experienced prolonged exposure to organic vapors, such as fumes from paints, solvents, or alcohol, a small amount of sensor drift above 0 ppm may occur (even when no CO is present). This same effect can also be caused by excess exposure to smoke. If this is observed, relocate your Pocket CO to an area with fresh air, until the reading returns to 0 ppm. Depending on the length of the exposure, this may take from minutes to days. If the reading does not return to 0 ppm within 5 days in a fresh-air environment, contact KWJ Engineering for further instructions. If Pocket CO must frequently be used in an environment with organic vapors, it is recommended that it be stored in an air-tight container along with some activated carbon. A Pocket CO storage container can be purchased from KWJ Engineering.

For other questions, or sales information, you may call the manufacturer customer service line at (877) 794-4296, 7:00 a.m. to 5:00 p.m. Pacific Time, or contact them by email: pocket_support@kwjengineering.com

 

[learningdiver]

Hello Dan;

I am intrigued with your field testing. Just wondering when you saw 14ppm if you were surprised or not. Did you think it was the meter? Is that why you waited a extra minute, or were you thinking I'm not going diving today?ilot:

Cheers

LD

 

[DandyDon]

Hello Dan;

I am intrigued with your field testing. Just wondering when you saw 14ppm if you were surprised or not. Did you think it was the meter? Is that why you waited a extra minute, or were you thinking I'm not going diving today?ilot:

Cheers

LD

Haha, I was considering both ideas - so waited.

This fill station was the largest and most impressive looking one I've ever seen. I knew I was in a learning situation and would have to be pretty confident to reject air from it, so what's another minute or two?

 

[Seanpaul]

Thanks for your information DandyDon! I meant to tell you I received mine in just a few days of placing the order and also exchanged emails with Oliver a couple times. I did test mine on the car exhaust as well, on a humid day here. Got a reading of 462 but it was great since all the beeps, alarms and buzzing worked as described! I will be testing some tanks in Jamaica on Friday so appreciate the tip on the larger oven bag! Have you really settled in your mind yet at what level will you not take the dive? I would have thought 10ppm was still too high. This is the only thing in my mind which isn't clear yet. Thanks again!

 

[DandyDon]

Thanks for your information DandyDon! I meant to tell you I received mine in just a few days of placing the order and also exchanged emails with Oliver a couple times. I did test mine on the car exhaust as well, on a humid day here. Got a reading of 462 but it was great since all the beeps, alarms and buzzing worked as described! I will be testing some tanks in Jamaica on Friday so appreciate the tip on the larger oven bag! Have you really settled in your mind yet at what level will you not take the dive? I would have thought 10ppm was still too high. This is the only thing in my mind which isn't clear yet. Thanks again!

Yeah, don't do the car exhaust test again. It can take days to get over something like that. Jamaica is certainly a destination I'd want to test all tanks, as rules are only guidelines in the Caribbean generally but with the reputation of that island - extra cautions on land or in water are not a bad idea. I don't mean to alarm here, but suggest prudence.

If your CO monitor reads 0 on start up but your reading increases in a bag test, you do have air contamination. Anything over 10 ppm is going to be 5 times as concentrated at 130 ft, then hit your harder on ascent - so I see no reason to risk anything over 10 ppm if you've taken care of the monitor. That's the main point I wanted to offer in post #1 here.

I'm going to edit the idea of a moisture muncher in post #1 as that may not be a god idea. The suggested range is 15-85% I think, still learning some here...

 

[SkipperJohn]

How important is this? How frequent are issues and what is the result of issues? I don't mean to hijack your post here but all this talk of bad air has me worried. I told a colleague of mine that I went diving for the first time and he told me a story of a relative who passed several days after his first dive. The autopsy showed it was likely the air in his tank.

 

[DandyDon]

It's probly not common, but hard to say since most air providers in the tropics do not do much to prevent or monitor. The problem is that it can only take one bad hit to be dead and the coroner will write is off simply as drowning as they don't test tanks and bodies for CO or - even if they did, it's bad for business to let such get out. In less serious cases one might only feel ill on a trip and but I've known many who missed days of diving to similar feelings and I have to wonder how many may have been close calls with CO?

You're a Skipper; how many stories do you know about onboard CO fumes? Too many? I mentioned on related thread today that even the little 5"x3" Kiddie detectors at Wal-mart, etc in the cabin would be a good idea but I never noticed one in any I've slept in. I know that the Engineers on some of those boats do a helluva job making things work sometimes - sometimes just barely, and I have to wonder about the margins of error survived?

Those $30 units don't alert until 70 ppm tho, and even the digital ones don't give readings until 35 ppm - see quote from another thread below. At 100 ft down, breathing 4 atmospheres pressurized air, the effect of 15 to 25 ppm becomes 60 to 100 - which is why the scuba industry has a 10 ppm max. It gets more complicated here as the eventual effect is that the poisoning hits hardest on ascent with changes in Partial Pressure, so yeah - 10 ppm is a good to max to hold. I was happy to have found a detector for less than $150 that is accurate in the 5 to 15 ppm range (but will read higher in worse cases) yet had to learn from a few handling errors on this trip.

None of the home CO detectors are appropriate for dive breathing air applications. By law they are not allowed to display visually until a CO level of 35 ppm is reached nor audibly until a concentration of 70 ppm has existed for four hours. If you have a home CO monitor without digital display there will be no warning if the CO level is sitting at 69 ppm.

The manufacturer reps have been very helpful and have mentioned the possibility of a special model adapted more for scuba diver needs. I'm quite happy with this one for tank air testing as well as hotel rooms and travel on planes, liveaboard boats, buses. Want piece of mind? Get the $140 monitor, a few oven bags, test your own - just don't carry it all over town in 90+% humidity like I did as the testing will take longer. I'll carry mine in a waterproof cigarette box after arriving on trips.

 

[InTheDrink]

I got mine last week as did my buddy. Great little device. Works very well; I've tested a tank from LDS air (6ppm/0ppm, think some user error involved), my smokers breath (62ppm and rising), ambient room (0 ppm) or 6ppm if I've had a cigarette indoors (which of course I don't usually .

DandyDon, you mentioned keeping it face down.... curious as to why as it appears that a sensor is slap bang in the front (in the middle of the grey the circle where it says Pocket CO).

Anyhow, I'll post any readings I or my buddy gets from various locations.

John

 

[DandyDon]

I got mine last week as did my buddy. Great little device. Works very well; I've tested a tank from LDS air (6ppm/0ppm, think some user error involved), my smokers breath (62ppm and rising), ambient room (0 ppm) or 6ppm if I've had a cigarette indoors (which of course I don't usually .

Yeah, I wouldn't blow smoke directly onto it. It's natural to want to see it react but you can overwhelm the sensor. In your PM you said you had difficulties with the "freezer bag" being too small & too stiff? Terms vary between the two countries as we know so I'll try to describe what I have used.
> The clear freezer bags I tried were lightweight enough that they soon leaked in use;
> The "oven bag" I use now is 16"x17.5" and just a little heavier altho still very flexible. I drop the analyzer in, turn it on, fill it half full from a cracked tank, wait two full minutes, and if there is any reading wait another minute or two to see if it changes - up or down, with 4 minutes being all seemingly needed in the event of any contamination.
> When anticipating tank testing, I keep it in a airtight container to prevent the sensor being tainted by contaminants in the air or relative humidity over 85%. It's not uncommon for surrounding air to have 10 ppm CO or more and while not damage to most, you want to ensure that the compressor filtered that out when filling the tanks...!

DandyDon, you mentioned keeping it face down.... curious as to why as it appears that a sensor is slap bang in the front (in the middle of the grey the circle where it says Pocket CO).

You'll see on page 5 of your manual that that is the buzzer, and the gas entry holes are on the side and back, which you want to keep unblocked when testing...

 

[InTheDrink]

RTFM, eh?

I did read *some* of it. I'll place it in the bathroom, that'll ensure it gets read cover to cover

Thx for the clarification.

John