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From: Rosalie B. (no email)
Date: Wed Oct 03 2001 - 12:22:41 EDT
On Wed, 3 Oct 2001 09:07:21 -0500, you wrote:
>WRONG!
>
>ALL combustion produces CO if the combustion is less than perfect.
>
>Diesel combustion is good, but its not perfect.
>
>Diesels are LESS dangerous than gas engines in this regard for two reasons:
>
>1. They produce a lot less (about 1/10th) CO as a component of their
> exhaust, assuming no catalytic converter on the gas engine. Gas
> engines with operating ("hot") catalytic converters actually produce
> LESS CO (most of the time anyway) than diesels.
>
>2. Their exhaust tends to stink. Therefore, you're more likely to
> smell the fumes before you get nailed by the CO.
>
>The second obviously doesn't mean anything if you're sleeping!
>
>It does NOT take much to cause trouble, and it also doesn't take much to
>KILL you.
>
>9 ppm is the "red tag" level for many fire departments (where they will shut
>off and lock out furnaces, etc!) It is also the 8 hour recommended
>exposure limit.
>
Just as a point of curiosity - who recommends this 8 hour limit? OSHA did
recommend 35 ppm for 8 hours and NIOSH also did the same, with a 200 ppm
ceiling. I've never heard 9ppm but maybe I wasn't paying attention because
those limits were not enforceable..
I usually get a headache around 20-25 ppm. I have sampled warehouse
forklift drivers who were working in 70 ppm. And people who work in blast
furnaces often get socked for several seconds with big blasts of CO much
greater than 200 ppm.
I also feel (entirely without any scientific basis to back it up) that
smokers are likely to be a little more resistant to CO poisoning because
they have low levels in their blood all the time. There is a back
calculation you can do (called the Coberg or Cobern equation or something
like that - hey I'm retired now) where you can take the blood oxyhemaglobin
level and the length of time that the person was out of the hazardous
atmosphere and supply a formula that will tell you approximately how much
CO was there. You have to add 8-10% to the starting level of CO for
smokers.
>30ppm is the "lower display setpoint" on most CO detectors with displays.
>70ppm is the "lower alarm limit" for home CO detectors, with a minimum
> exposure time of 1 hour.
>100ppm is the "evacuation limit" for many fire departments (if they find
> this, they force everyone out of your building)
>500ppm lethal level to humans over a period of several hours
>1000ppm lethal level to humans over a SHORT period of time (few minutes
> to an hour)
1200 ppm is the IDLH level (immediately dangerous to life and health) which
is defined as no more than half an hour.
>
>1000 - 5000 ppm - CO range produced by a DIESEL engine in "good tune"; that
> is, one with clean fuel, properly fueled (not overfueled, etc) and
> not producing visible smoke. Even at the lower level it is lethal
> within hours in healthy persons; within minutes to someone with
> compromised respiration or circulatory systems)
>
>10,000 - 100,000 ppm - CO range produced by a GAS engine without a
> catalytic converter (boat engines.) The lower level is lethal
> within a few minutes; the upper within a few breaths (suck
> directly on an open exhaust and you're done.)
And if you let your car idle for a few minutes (less than 5) in a closed
garage (say - as happened to the father of a friend, you come into the
garage and shut the garage door by remote and something is on the radio
that you are listening to, like a ball game and you want to hear the rest
of it and don't want to turn the ignition off and leave the radio on for
fear of running down the batteries) then you may never be able to turn off
the ignition because you are dead.
>DO NOT sleep in any space where combustion products COULD enter unless you
>have a functioning CO detector in that space or in all the potential paths
>for air to enter that space.
>
>I have three CO detectors on my boat, one of each type. One is AC powered
>in the salon, one is DC powered in the master cabin, and the third is
>BATTERY powered in the guest cabin.
>
>The master cabin unit is a marine-rated unit, the other two are
>"residential" CO detectors.
>
>I've never had any of the three alarm, but I prefer to be safe from this
>hazard and a little poorer than to save a couple hundred bucks and be dead.
grandma Rosalie
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