Carbon monoxide alarm query

Cardo

Cardo

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www.yacht-tinkerbell.co.uk
With all the CO stuff cropping its ugly head up once again, I thought I'd check my CO alarms. I have two, one in the saloon, and one in the aft cabin. These are the places where we have Eberspacher outlets.

The alarms are the Kidde type that were linked a couple of years ago, about £20 with the PPM read out and supposedly last 10 years.

I've checked them both out and they both show a "Peak level" of around 20 PPM. Unfortunately, I have no idea when this occurred, and the alarm hasn't gone off, certainly not when I've been aboard. As a precaution, I've reset both units. The one in the cabin has reset its peak level to 0, however the unit in the saloon is now showing 16. However, that's only if I press the peak level button. The normal readout shows 0.

Pressing test seems to work, with the alarm going off and all that.

Any thoughts?
 
You could contact Kiddie customer support people http://www.kiddesafetyeurope.co.uk/Pages/FAQ.aspx to talk it through.

However most certified CO alarms test the sensors when the test button is pressed, not just a simple battery power test.

Assuming the alarm is working correctly, then there is a suggestion that you have a background level of CO. My Kiddie CO alarm has never risen above zero.

There is a possibility that hydrogen from batteries gassing off under charge, and not being ventilated out of the boat, may be being detected as some CO sensors can sometimes pick this up.

However if you have a low-level CO atmosphere, it may not be fatal, but health studies are now showing that long term exposure to lower level CO concentrations can still affect health.

The other point to think about is that if CO is already escaping into the cabin, albeit at lower levels as a norm, what will it take for the source to start producing higher levels. Also, if another source of CO was to happen, you already have a background level of 20ppm, so any more may be critically dangerous.

So in addition to talking to Kiddie, you may also wish to check for potential problems or sources, here's a few pointers http://www.boatsafetyscheme.org/stay-safe/carbon-monoxide-%28co%29/co-know-the-danger-signs/, you may also want to check out the advice on early symptoms.

The key thing is; don't let it ride, check out the issues while they are hopefully still small.

Hope everything turns out OK - Rob
 
Cardo said:
With all the CO stuff cropping its ugly head up once again, I thought I'd check my CO alarms. I have two, one in the saloon, and one in the aft cabin. These are the places where we have Eberspacher outlets.

The alarms are the Kidde type that were linked a couple of years ago, about £20 with the PPM read out and supposedly last 10 years.

I've checked them both out and they both show a "Peak level" of around 20 PPM. Unfortunately, I have no idea when this occurred, and the alarm hasn't gone off, certainly not when I've been aboard. As a precaution, I've reset both units. The one in the cabin has reset its peak level to 0, however the unit in the saloon is now showing 16. However, that's only if I press the peak level button. The normal readout shows 0.

Pressing test seems to work, with the alarm going off and all that.

Any thoughts?
Click to expand...

From memory the alarm goes off when it hits 30. Bit weird the way they always show 0 on the display and then flip to the actual reading when you select peak. I guess it's to avoid freaking people out.

Our Kidde unit over our boiler died the other day - a couple of years before it expired. Just said Err. Either that means Error or it was pausing before saying something profound. Mind you, when I bought it I tested it by putting it near an open fire which slightly melted the case. A better way to test it is by passing it near a car exhaust. Otherwise ours never read anything other than zero even with 'peak' pressed.

So you may have a problem.
 
Cardo said:
I've checked them both out and they both show a "Peak level" of around 20 PPM. Unfortunately, I have no idea when this occurred, and the alarm hasn't gone off, certainly not when I've been aboard.

Any thoughts?
Click to expand...

There are a couple of relevant tables in the MAIB report - unfortunately I can't cut and paste them - so much for their attitude towards disemminating this info, but you can check yourself.

Anyway, according to the standard for domestic CO alarms, the lowest alarm level is 30ppm.

The effect of a 100ppm is a slight headache after 2-3 hours. 400ppm is described as a risk to life after 2-3 hours exposure and is the lowest level in the table that indicates possible fatality.
 
I've just reset the one in the saloon and now it's remaining at 0.

I've tested the Eberspacher by putting one of the alarms near the outlet whilst this has been running at full tilt and it's remained at 0.

The alarm in the saloon is near the batteries. These do have a a vent off the boat, but it's not a 100% sealed compartment, so maybe a little hydrogen is escaping? The batteries are only on float charge, so I wouldn't really expect them to be gassing, though.

I'll keep an eye on things and see what happens.

I'm curious that the alarm would only show an actual figure of PPM if it's more than 30? Seems a bit odd to keep showing a figure of 0, when this may not well be the case.
 
On my last boat I had a charcoal heater (Pansey) and fitted a CO alarm to keep an eye on it.

Never moved above 0 with the burner alight. One chilly day I lit the Origo for a cuppa and the alarm went off within a minute or two.

So in my case it would have been the cooker that killed me not the heater!
 
Good illustration by Sophie19. It is possible that using a pan on a burner, especially if it large and has a lot of cold stuff in it, to cool the burner flames to an extent to cause CO.

Its even possible to achieve levels of hundreds of ppm in some specific circumstances for a short while during the heating of the pan. It may not last long enough, nor be quite high enough to trigger the alarm.

But for example if the Pansy had its narrow flue-pipe restricted with a build up of soot or tar, or the weather conditions cause a back-draught and was it already producing some lower levels of CO. The extra CO caused by the pan/burner combination could build up to alarm level concentrations.

So having the alarm as the back stop is a good idea.
 
Cardo has anyone had a cigarette below?

A typical daily smoker exhales CO at levels anywhere from about 10ppm to 80ppm so I wouldn't be worried by an occasional ambient level of 30 which might have come from your gas cooker? If you light a cig and let the side stream smoke waft onto the monitor you can get levels well over 200.

In my workplace in London in the Autumn during evening rush hour, particularly if it's windless and foggy, we sometimes get ambient levels of 20-30 from car exhausts. These have been reliable validated readings using CO monitors costing £££
 
Regarding cigarettes and CO and not in a boat but at home, before the smoking ban in pub's etc if my wife and I who don't smoke had been out for a drink in a pub, as soon as we arrived home we would set the house CO detector off with presumably CO on our clothes, it never ever went off otherwise.
 
Turns out it's the cooker. I've had the Eberspacher running for a while, and both alarms remained at 0. I just boiled some water for my tea, and the readings shot up. In fact, the one in the saloon went all the way up to 30. Interestingly, the alarm didn't go off (I think it's set to go off at 36?), however it did start showing the figure on the screen.

Looking at the flame, it is rather yellowish. I'll take it apart and give it a good clean.
 
cornell_b said:
does anybody know the proper height these should be mounted....my kero. hurricane lamp tripped mine after 2 hours.
Click to expand...

Try to avoid putting the alarm within 6" of the deckhead. Clean air can be trapped in the corners reducing the effectiveness.

Maybe you need more ventilation with the paraffin lamp.
 
As an update, I removed and cleaned up the hob plate, which had sooted up. It's burning with a much cleaner flame now and the alarms aren't detecting any CO anymore.

I guess this could be a lesson for others. If your hob is burning with a yellowish flame, clean it up! It may well be churning out carbon monoxide! :eek:
 
Cardo said:
As an update, I removed and cleaned up the hob plate, which had sooted up. It's burning with a much cleaner flame now and the alarms aren't detecting any CO anymore.

I guess this could be a lesson for others. If your hob is burning with a yellowish flame, clean it up! It may well be churning out carbon monoxide! :eek:
Click to expand...
it will be anyway, but you now have a better air/fuel mix
 
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