[Greenbuilding] Stale Air

John Straube jfstraube at gmail.com
Mon Dec 13 08:58:37 CST 2010


Oh and CO kills you at rather low levels.
Sent from my BlackBerry®

-----Original Message-----
From: Keith Winston <keith at earthsunenergy.com>
Sender: greenbuilding-bounces at lists.bioenergylists.org
Date: Mon, 13 Dec 2010 00:25:03 
To: <greenbuilding at lists.bioenergylists.org>
Subject: Re: [Greenbuilding] Stale Air

Um, apples and oranges here, no? John is talking about CO2, and Stephen 
responded concerning CO. One is a natural result of breathing, and the 
other generally occurs indoors in significant quantities when a 
combustion appliance is maladjusted. There is no reliable correlation 
between the two.

Keith




On 12/12/2010 10:31 PM, JOHN SALMEN wrote:
> Sorry Stephen – I know you know all that stuff, I liked the question
> and was thinking out loud and still thinking out loud. One of the
> interesting things for me is that when someone is cyanotic or hypoxic
> in a medical situation it is pretty apparent. Basically co2 drives our
> breathing as we eliminate it. Chronic high(er) levels of co2 in our
> built environment may be an issue. It would never be the case that
> there was not sufficient oxygen – more that the body becomes less able
> to utilize the oxygen as it becomes less able to eliminate co2 or other
> mixtures of gases. So we end up with chronic problems.
>
> That is one thought and then a companion thought is that co2 is used as
> an indicator – if it is present at higher levels then other gases are
> so is a broad measuring tool for IAQ and these gases interact. I think
> we are allowed approximately double the exterior co2 level for indoor
> environments. Perhaps that is too high for an aging or health
> compromised population.
>
> Increasingly I think ventilation rates are too low (and people spend
> too much time indoors but ironically not that much time in their
> houses). Are we heating and ventilating houses far too much when are
> unoccupied and then ventilating sufficiently for when they are? How
> well is demand controlled ventilation actually working?
>
> Thanks for the question – has me scratching my head as well.
>
> John
>
>_JOHN SALMEN ENVIRONMENTAL DESIGN_
>
> /4465 UPHILL RD//,. DUNCAN, B.C. CANADA, V9L 6M7/
>
> /PH 250 748 7672 FAX 250 748 7612 CELL 250 246 8541/
>
> /terrain at shaw.ca/
>
> -----------------------------------------------------------------------
>
> *From:*Stephen Collette [mailto:stephen at yourhealthyhouse.ca]
> *Sent:* December 12, 2010 4:44 PM
> *To:* JOHN SALMEN
> *Cc:* Greenbuilding at bioenergylists.org
> *Subject:* Stale Air
>
> Thanks for your thoughts John. I am wondering how useful the
> measurement of CO2 in homes is. I have a CO meter and pull it out on
> occasion and to my memory have not found anything with it in a home.
> Typically with a couple of people or small family in a single family
> dwelling, I wonder whether they alone could ever get the levels up to
> something dangerous? Now blended families or extended families all
> living under one roof, I think that may be possible.
>
> I'm not disagreeing with you at all, what you are saying is what I talk
> about too, but again, is it actually valid? I don't know, and hence the
> head scratching.
>
> Grateful for your time thinking about this.
>
> Stephen
>
> Stephen Collette BBEC, LEED AP, BSSO
>
> */Your Healthy House/*-Indoor Environmental Testing & Building Consulting
>
> http://www.yourhealthyhouse.ca
>
> stephen at yourhealthyhouse.ca <mailto:stephen at yourhealthyhouse.ca>
>
> 705.652.5159
>
>> Hi,
>>
>> There are a lot of adjectives for air – stale, stagnant, dead, fetid…
>>
>> Air basically means for us oxygen as a requirement – so stale air
>> could simply be oxygen poor air.
>>
>> .
>>
>> With ashrae I guess there is adequate ventilation and inadequate
>> ventilation and stale would be an excess of unventilated air
>> (stale??). Ashrae uses co2 concentrations as the indicator for
>> adequate ventilation so there definition is ppm for various uses.
>>
>> In emergency first aid I measure ventilation rates, blood oxygen
>> levels as well of level of consciousness – all of which could reveal
>> an emergency condition in students in a classroom at the end of a day
>> subject to averaged ventilation and subsequent ‘stale’ air. Tidal
>> volume (breath) is about 500ml with about 14% oxygen and 4.4% co2
>> exhaled – outside air is about 21% oxygen and .04% co2.
>>
>> So a significant amount of c02 is released on each breath in
>> comparison to the intake – so we could say that ‘stale air’ is any
>> air exhaled.
>>
>> Fun question.
>>
>> John
>>
>>
>>
>>
>
>
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