[snip]
>
>Please pay attention to Andy Persily's comments about CO2. It's used an
>indicator, not a pollutant at the levels being discussed for control in
>office buildings. There has been research on using CO2 as a control strategy
>in homes but my recollection is the levels rarely get high enough to trigger
>the system.
>
Yes, yes, and yes. Persily is the best! Note that the Candians report
measuring upwards of 2500 ppm in bedrooms at night with the door closed.
More than plausible. Hazardous? Not likely an indicator of anything serious.
In fact, 2500 ppm CO2 was the concentration differnce between indoor CO2 and
outdoor CO2 on which the 5 cfm/p ventilation rate in the 1981 version of the
ASHRAE standard was based. Got changed to 15 cfm/p in 1989 version because
people were abusing the smoking versus non-smoking distinction - 20 cfm/p
was required in 1981 where smoking was permitted in offices and such.
Some of you may have seen an article in the recent issue of Indoor
Environment Review on a new CO2 standard from ASTM Subcommittee D22.05. The
article is full of errors, misquotes, and more. I have written a letter to
the editor to try to clarify. If you are interested in my letter, request a
copy and I will email it to you.
Hal
Hal Levin <hlevin@cruzio.com>
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