Acceptable CO levels on boat??

[Polishicebreaker]

I’m guessing zero. 
 

our CO alarm/monitor generally reads around 10-15 ppm .  Alarm doesn’t go off. 

No stove on.  Just a Small morco around 4 years old- flu seems clear!? 
 

Any thoughts?? 
 

cheers 

Edited November 13, 2020 by Polishicebreaker

[Alan de Enfield]

6 minutes ago, Polishicebreaker said:

Any thoughts?? 

Get the Morco properly serviced (should be done annually)

[Chewbacka]

23 minutes ago, Polishicebreaker said:

I’m guessing zero. 
 

our CO alarm/monitor generally reads around 10-15 ppm .  Alarm doesn’t go off. 

No stove on.  Just a Small morco around 4 years old- flu seems clear!? 
 

Any thoughts?? 
 

cheers 

You might find this helpful, though I would add the US workplace limit for 8 hours exposure is 35ppm.

https://www.safefiredirect.co.uk/Page/16/Carbon-Monoxide-Detectors-Frequently-Asked-Questions.aspx

 

Though you don’t mention it a gas ring on a hob can produce CO.  
Do you have adequate ventilation?

[Phil.]

31 minutes ago, Polishicebreaker said:

I’m guessing zero. 
 

our CO alarm/monitor generally reads around 10-15 ppm .  Alarm doesn’t go off. 

No stove on.  Just a Small morco around 4 years old- flu seems clear!? 
 

Any thoughts?? 
 

cheers 

If that reading is a peak reading when you press a button, then probably nothing to be concerned about. If it is a constant reading then it needs to be addressed as whilst a very low reading, CO has an accumulative effect in the body.

[Jen-in-Wellies]

Does anyone smoke on board? Another possible source if there is. It will be much worse in their lungs and blood stream!

[Momac]

Batteries ?

[Polishicebreaker]

Thanks for your replies. 
 

reading is for maximum level  in the previous 24hrs. 
 

we have a house sized cooker and cook a lot so that may well be the cause. 
could perhaps use more vents too
 

it would be useful to know what an average reading would be. Maybe I could get another testing device. 

[Alan de Enfield]

1 minute ago, Polishicebreaker said:

it would be useful to know what an average reading would be. Maybe I could get another testing device. 

My average is zero, except for when I had a battery internal short and the reading went to 'millions' (exaggeration) in the middle of the night, and, the battery being so hot I couldn't touch it.

All windows and doors open , wafting tea-towels about and couldn't get the alarm to 'shut-up'.

[Jen-in-Wellies]

If it is a peak of 15ppm over 24 hours, then personally, I wouldn't worry. There are various exposure limits, average and peak over various time scales set by various bodies around the planet.  A good summary of this is here. Lower concentrations for a long time are bad. High concentrations for a short time are bad as you die quickly. If you are in the cabin for long periods, overnight, or locked down during the day for most of 24 hours, then knowing the average too is good, but if you are feeling no symptoms, then I wouldn't worry excessively.

Jen

Edited November 14, 2020 by Jen-in-Wellies

[1st ade]

17 minutes ago, Alan de Enfield said:

My average is zero

Being pedantic - I'm not sure if an average of zero is possible. Since the instantaneous readding can't be negative the only way to zero average is if every single reading is also zero?

[Machpoint005]

Strictly speaking, a mean of zero is impossible, but it's quite likely that the median and the mode will both be zero. However, in those circumstances the mean will be very low, and it might well be zero "as near as makes no difference". 

 

The mean over a short measurement period could easily be zero.

[Jen-in-Wellies]

36 minutes ago, 1st ade said:

Being pedantic - I'm not sure if an average of zero is possible. Since the instantaneous readding can't be negative the only way to zero average is if every single reading is also zero?

 

4 minutes ago, Machpoint005 said:

Strictly speaking, a mean of zero is impossible, but it's quite likely that the median and the mode will both be zero. However, in those circumstances the mean will be very low, and it might well be zero "as near as makes no difference". 

 

The mean over a short measurement period could easily be zero.

Anti-matter CO? ?

[Martin R]

Just reading this and can high charge currents on the leisure batteries trigger such a CO alarm.

I only ask as recently i had mine sound in my engine room, this was after connecting to shore power after several weeks disconnected and the batteries requiring a heavy charge.

[Jen-in-Wellies]

1 minute ago, Martin R said:

Just reading this and can high charge currents on the leisure batteries trigger such a CO alarm.

I only ask as recently i had mine sound in my engine room, this was after connecting to shore power after several weeks disconnected and the batteries requiring a heavy charge.

Yes. CO alarms can get confused by H₂ outgassing from batteries. Good suggestion.

[Sea Dog]

1 hour ago, 1st ade said:

Being pedantic - I'm not sure if an average of zero is possible. Since the instantaneous readding can't be negative the only way to zero average is if every single reading is also zero?

Well, I don't know what my average is then, but the readout on both of my CO alarms with this display function is also habitually zero. Anything other than that would have me looking for a source/cause rather than trying to determine an "acceptable" level. 

[nbfiresprite]

Some aerosols are also detected by Co alarms, depending on the propellant used and the content. For example canned whipped cream uses nitrous oxide as the propellant. Dimethyl ether is used in hair sprays.

Edited November 14, 2020 by nbfiresprite

[Alan de Enfield]

Just now, Sea Dog said:

Well, I don't know what my average is then, but the readout on both of my CO alarms with this display function is also habitually zero. Anything other than that would have me looking for a source/cause rather than trying to determine an "acceptable" level. 

That was what I was (rather clumsily) trying to say.

I don't sit and watch it continuously, but when I have glanced, it is always a zero.

I do rather rely on the alarm, which I now know does work and wakes me up.

 

[Sea Dog]

3 minutes ago, Alan de Enfield said:

 

I do rather rely on the alarm, which I now know does work and wakes me up.

For which we are thankful!

 

[ditchcrawler]

1 hour ago, Polishicebreaker said:

Thanks for your replies. 
 

reading is for maximum level  in the previous 24hrs. 
 

we have a house sized cooker and cook a lot so that may well be the cause. 
could perhaps use more vents too
 

it would be useful to know what an average reading would be. Maybe I could get another testing device. 

I have 2 CO alarms on our boat, not that I would know if one was correct if they read differently

[nb Innisfree]

We used to get low level indications now and then, eventually realised it only happened if wind was blowing from stern to bow. Observing the outside I could see smoke from chimney was curling downwards and occasionally touching a brass roof vent, taller chimney cured it. 

[Scholar Gypsy]

Mine  (fireangel) always reads zero - well whenever I look at it.

This thread reminds me it is time for the annual test - ie getting out the jos sticks and putting the machine into test mode, so it goes off without me having to poison myself. 

Edited November 14, 2020 by Scholar Gypsy

[Martin R]

I use the Nest Protect system, alerts me on the phone and shouts very loudly inside the boat?

[ditchcrawler]

4 hours ago, Martin R said:

I use the Nest Protect system, alerts me on the phone and shouts very loudly inside the boat?

How many detectors do you have ?

[Martin R]

Two. One in the main saloon and the other in the Engine room/ boatmans cabin.

 

The Nest is also a smoke detector.

[flogget]

The gas detector  for out fire dept is set  for carbon monoxide  at around 50 parts per million.. anything more than that will send it into alarm .  So would considered safe without breathing apparatus , presuming  no other alarm was triggered.

 

To add though, this would be after some type of incident so presumably levels would drop further  and I believe for safe long term exposure should be way lower than this , around 10 (ish)