Hi all, new member but been prepping for a while. I have a 10 x 20 underground steel shelter. We have a Carbon Monoxide and explosive gas detector in it that is constantly reading about 200ppm for CO. When I turn on the fans and vent the shelter, it drops to safe levels in about 30 mins. I have nothing combusting in the shelter (it's all electric powered, AC and DC) so not sure I really have a CO problem. I can`t come up with another realistic gas that could cause a false positive either. Any one have experience with false CO readings in underground shelters or have a guess what could trigger it? I have tried 3 different brands,of detectors and they all show similar readings.
CO monitor constantly alarming in Shelter
- Thread starter SirBacon
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Do you have any aquifers or abundance of ground water there?
Dissolved carbon monoxide (CO) is present in ground water produced from a variety of aquifer systems at concentrations ranging from 0.2 to 20 nanomoles per liter (0.0056 to 0.56 microg/L).
Dissolved carbon monoxide (CO) is present in ground water produced from a variety of aquifer systems at concentrations ranging from 0.2 to 20 nanomoles per liter (0.0056 to 0.56 microg/L).
what's your floor material? hard earth or concrete?
some places here have some problems with radon gas,sipping from the ground,though it's been quiet about that for many many years now,prolly solved with air con I think.
some places here have some problems with radon gas,sipping from the ground,though it's been quiet about that for many many years now,prolly solved with air con I think.
It's a giant steel box buried in the ground and encased in 1 ft of concrete. There shouldn't be any point of air entry other then the ventilation leading above ground. Not sure of ability for these gasses to pass through the steel, but will research quick. The surrounding earth is clay. No aquifers, and the levels seem consistent year round independent of water levels.
What's the humidity?
I'll check on levels but it typically gets humid when in use. Humidity is either brought in with the outside air, or from the people in it. I only run the ventilation when in it, and try to dry it out after usage. I have a small dehumidifier to help dry it out.
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- Mar 29, 2013
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I pulled the batteries out of all my detectors.got tired of them going off at 3 in the morning.
Move the sensor to a new location, also, what paint if any that was used to paint the inside?
One other thing, do you have a waste holding tank that has been used for the shelter?
Has a grey water tank that pumps to my home's septic tank. Composting toilet that hasn't had any waste in it yet. We have had the sensor in several locations. Do these sensors need to be "reset"? I hadn't thought of that, but now I want to put them in fresh air for a while. Maybe being in a sealed environment for a month at a time is causing build up on the sensor.
How high is the water table their?
Put a plant in there with a small UV plant light.
I'm under the impression he should use a different tester and check before doing anything
I've used multiple testers from different companies and in different locations. The water table is below the shelter, but not real far below. Floor of the shelter is approx 10' below grade, water table is about 12'. Not that it matters, but frost line is about 32".
I thought plants used CO2? Also, this is the shelter, different layout and options, but the materials are the same. Survival Shelter Upgrade Model 10x20 | Rising S Company
Yes a plant uses CO2, but it also removes CO, benzene, formaldehyde and nitrogen oxide from the air.
only during the day, at night its the other way round
Formaldehyde is used or once used in carpets, furniture, certain glues and paints to inhibit bacterial and fungal growth!
If I get a chance I'll try to get some pics to post. Maybe you can see something I'm missing. It is set up for propane, but I don't have it hooked up. It also has an alcohol burning stovetop, but it hasn't been used yet. I designed the floorplan myself, and am pretty proud of it. Open to other feedback unrelated to this problem as well if you see anything.
I would put in a plant aquarium. Research the best plants. The soil can also be an air scrubber.
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Except it gives back CO2 instead of CO.
I know some mentioned this earlier but I live in an area where Radon gas can be a problem in basement and below ground level enclosures. I do not know the answer, but could your monitors be sensing Radon. If so, you need to figure out how to vent it out.
CO detectors/monitors don't detect radon
I ask my son who ask his friend a fire investigator said that over 80% callouts on CO detectors going off are the results of humidity levels, cheap batteries and age of the detector.
He said a lot of CO detectors have a warning alert that the unit needs replacing, most of off the shelf brands have a 5 year limit when it starts beeping and progressively gets worse. Also a detector in a closed room with very little air movement will in time give false alerts. He suggested going to home depot getting a Kidde CO detector and setting up next to the one giving the alert and see if the new one is giving the alert.
He said a lot of CO detectors have a warning alert that the unit needs replacing, most of off the shelf brands have a 5 year limit when it starts beeping and progressively gets worse. Also a detector in a closed room with very little air movement will in time give false alerts. He suggested going to home depot getting a Kidde CO detector and setting up next to the one giving the alert and see if the new one is giving the alert.
I've used kidde, along with several others. They were all new, and started alarming within days of being put in. I could believe it is a combo of humidity and a unventilated space. I did buy extras I keep in a sealed plastic box as well, in case I am down there for an extended period. They are also explosive gas detector for when I get propane hooked up. Considering getting an oxygen level monitor as well. I have used the shelter a few times when we have had tornado sirens, and I've always been nervous having my family there as I wait for the CO reading to drop. Once I get it down close to 40ppm, I get a little more comfortable. With the ventilation on, it will eventually get to 0.
