Carbon Monoxide Alarm

[BuffaloBill]

10 hours ago, tjg1677 said:

I love a good mystery Bill. If you want to either post the circumstances or pm me, this is something I would love to try to get to the bottom of. I have one theory but need a bit more info and evidence before I make an idiot of myself.

err...I thought I had! I'm happy to share this with anyone as it may help others.

What else you want to know beats me 

[Vaughan]

On 6/3/2017 at 5:11 PM, Viking23 said:

This report and inquest of the death of a couple at Wroxham revently has probably been published or referenced on this site before, but just in case, here it is.

https://assets.publishing.service.gov.uk/media/591058f840f0b67b04000002/MAIBInvReport9_2017.pdf

 

I'm sure after reading this, and reading about other similar incidents, you will really understand the importance of a CO alarm, the fumes from other vessels or even dying barbeques emit huge amounts of CO and if placed near an open window of any accommodation could cause game over. 

I have been waiting to read this, and thank you Viking, for posting it. I suggest that everyone, especially in view of some of the comments on this thread, should read it carefully. It is detailed, and most enlightening.

Results are pretty well exactly what we were discussing last year and I emphasise that this was an un-catalysed petrol engine. The risk of this happening with a diesel engine at slow speed in neutral, is still extremely small. Anyone who owns an aft cockpit cruiser with a petrol outboard however, should read the report very carefully indeed, especially where it talks of "station wagon effect". Anyone who has ever driven a Land Rover with the back flap rolled up, will know what that is!

There are some interesting figures, which are the MAIB's and not mine :

Normal, and acceptable, level of CO is 30ppm (parts per million).

The Fireangel CO detector, which they used in their tests, will first go off at 50ppm but not until 60 to 90 minutes after exposure at that level.

100ppm shows no poisoning symptoms over a long time period and is "allowable for several hours".

200ppm is a level to which you should not be exposed and will cause headache in two hours. It does not say it is fatal.

400ppm can be fatal after 4 hours exposure.

It seems the couple who died in Love for Lydia were exposed to almost 2000ppm and would have died in 8 minutes, having been overcome almost at once.

This suggests to me that there is a large amount of "leeway" between your alarm going off, and actual exposure to a risky level of gas, which is encouraging.

Ventilation is also recognised as paramount, and there was no fixed ventilation in this boat, as the RCD only requires this if there are gas appliances on board, and there were none, in this case. This proves to me that fixed ventilation is not just a matter of gas - it is all about having a breathable atmosphere in your boat.

I think some people may also be confusing a CO detector, which has that specific purpose, and a CO2 detector, which is all about ensuring that there is still sufficient oxygen to breathe, in a living space. So you could still sit there in your cabin and suffocate, because you have turned on the cooker for heat, and shut all the windows, but this would not set the CO detector off. Worth thinking about.

BSS examiners, so it says, will now be recommending CO detectors when they make inspections, but it is still not mandatory.

The Fireangel is designed not to activate at 30ppm, until 2 hours of exposure.