Where can I find CO bump gas?

[68raggtop]

I bought this:
OxyCheq - 15 PPM CO Bump Test Calibration Gas
Dave
As an additional reminder, when you turn on the analyzer and get something other than zero, make sure that you verify before you cal. I turned mine on and it read 10ppm in the garage one day. I was about to cal it and thought maybe I should go outside and check first. It went to zero. Turns out my son had backed his car out shortly before.

 

[Akimbo]

Why do they call using calibration gas a bump test?

 

[Jax]

Good question!

However, the can of CO gas is expensive, and lasts only about 10 tests. Since car exhaust or a smoker's breath will show it is working, why waste the money?

Then when you are in a clear area (on a busy street is not a good calibration area, nor is the back of the boat in the boat's exhaust), calibrate to zero.

 

[Akimbo]

Does it really matter for CO? Almost any reading above ambient exceeds what you want to splash with.

 

[68raggtop]

Good question!

However, the can of CO gas is expensive, and lasts only about 10 tests. Since car exhaust or a smoker's breath will show it is working, why waste the money?

Then when you are in a clear area (on a busy street is not a good calibration area, nor is the back of the boat in the boat's exhaust), calibrate to zero.

I would suggest that while car exhaust/ breath may register a reading, do you know how much CO it is relative to what your tester indicates? When a sensor is getting old, do you expect the reading to just stop registering? I am using the bump gas to verify that my sensor is still functioning accurately, since it is close to two years old. My point is not that you need to always use a bump gas, but more of how do I know when the sensor going bad as in will it read CO at 1ppm? 5ppm? 10ppm?
When I had the garage reading 10ppm, and verified that it was in fact 10ppm, I opened the garage door and windows to air it out with a fan. A half hour later when I closed it up, it was still reading 1ppm inside and 0 outside. So how do you really know the environment is CO free when your calibrating to zero?

 

[DancinDiver]

I bought this:
OxyCheq - 15 PPM CO Bump Test Calibration Gas
Dave
As an additional reminder, when you turn on the analyzer and get something other than zero, make sure that you verify before you cal. I turned mine on and it read 10ppm in the garage one day. I was about to cal it and thought maybe I should go outside and check first. It went to zero. Turns out my son had backed his car out shortly before.

Thanks, Dave! That's perfect!

As a response to several posters:
1) No, I'm not a smoker
2) If the CO sensor is sensitive enough, it may pick up some CO on an exhale. Many people have stated that this happens for them.
3) By calibrating with a known concentration of CO, I am verifying that the sensor reads accurately at two different points in its sensitivity range (zero, and non-zero). This will give me much more confidence than just seeing a sensor reading zero when it's never read anything BUT zero.

Thanks everyone for the feedback!
- DnD

 

[scagrotto]

That's perfect!

Before you commit to that, you know that the 10L cylinder at the link in post #10 is a cylinder that contains 10L, not a cylinder with a volume of 10L? It's roughly the size of a can of spray paint, so if you try hard you can probably fit it in the house. For some reason, the 17L cylinder that's also available is 2/3 the cost of the 10L cylinder.

 

[Doc Harry]

Calibration Gas - CanarySense.com

 

[Akimbo]

I still can’t figure out why they call it a “bump” test???
Bump Test of Gas Monitors - What, How Often | Safety Equipment FAQ

Can we actually blame OSHA (Occupational Safety and Health Administration in the US) for such a bizarre name?

 

[DandyDon]

kwinter,

The place where we got it had no calibration gas available. I may take you up on your offer, as it I have never seen the sensor register above 1ppm, even while breathing into the sensor full tilt.

I want to be certain it is actually functioning before I trust it to test my tanks. Without a known concentration calibration gas, I can't have that comfortable feeling.

If I don't find anything in the next few days, I'll PM you.

Thanks!
- DnD

If my tester reacts with more than 1ppm from smoker breath, I know it's working. Attempting to measure exactly how accurate it is may be a futile endeavor. There's more computer technology in your cellphone than the early moon landings, and your tester is of similar technology. If it measures 3ppm from a smoker, then shows 15ppm on a tank, you have a problem. If it measures 3ppm from a smoker, then less than 3ppm on a tank, you're fine.

Are you a smoker? If not, why would you be exhaling carbon monoxide. That's quite the trick if you ask me.

Everyone produces a tiny amount of CO which is exhaled. Smokers breathe out more of course.

Why do they call using calibration gas a bump test?

The WD40 type can of CO gas sold for bump testing may not be accurately produced, at least not exact enough for calibration. Customers whine about prices.