This sounds like the beginnings of a an elaborate/scientific office prank with the boss's thermostat... =)
In all seriousness, I believe the effect of ambient temperatures are pretty established. Here's a brief article in layman's terms and a pretty graph:
http://productivity-science.com/blogen/post/What-temperature-is-best-for-your-productivity.aspx
Here's a research paper cited in the previous link with more info:
http://escholarship.org/uc/item/45g4n3rv#page-8
I'm not certain whether there is anything in the realm of IEQ/CO2 monitoring that establishes a clear causal effect on task productivity similar to the above.
Here's a paper that attempts to connect the dots between ventilation rates (2 levels) and annual sick-leave accrual for office workers: http://www.google.com/url?sa=t&rct=j&q=milton%20risk%20of%20sick%20leave%20associated%20with%20outdoor%20air%20supply%20rate%2C%20humidification%2C%20and%20occupant%20complaints&source=web&cd=3&ved=0CFoQFjAC&url=http%3A%2F%2Fwww.e-co.uk.com%2FRecirc-Milton2000.pdf&ei=xCbRT5ujBeWL2AXWw4WxDw&usg=AFQjCNFBvi_nWYBGbwn_f6NV3hxRHn7MtA
The "dollars lost" economical argument extrapolated in the conclusions looks dramatic, but even if we accept CO2 concentrations are tied directly to sick leave hours... that's not quite the same thing as a direct productivity effect (i.e. my co-worker breathing heavily is preventing me from doing my work).
If you were to combine the above studies into a single model I suppose you reasonably establish a linear CO2-concentration-factor curve to apply against an ambient temperature curve to come up with a combined productivity effect. I might sooner look further for something akin to the temperature study however.
Classification: UNCLASSIFIED
Caveats: NONE
Monitoring CO2 concentrations isn't necessarily about CO2. Sensing CO2 is only an indicator for all the other chemicals in the air.
People put off methane, wear perfume, expel formaldehyde, sweat and a whole lot of disgusting stuff.
Buildings often try to maintain 800ppm of CO2. OSHA allows exposure of 5,000ppm of CO2 for 8 hours. The reason it is common to maintain a CO2 level which is 1/6th of the OSHA approved limits is because it isn't necessarily CO2 we are trying to control. It is all the other smells...
This is also why it may be difficult to find a graph showing performance vs C02 levels (see bottom). The study showed at 2500ppm no measurable difference in performance was detected.
And lastly, Why monitor CO2? The sensors are cheap and accurate.
Without having read the documents Nick is referring to...
Recall that CO2 is a surrogate indicator of air quality. It was never
intended to indicate that the atmosphere was unhealthy, just that it might
be unhealthy.
. the original research done by ASHRAE varied outdoor air
ventilation rates in a test studio which was occupied by real people.
. The people were surveyed at random times for their perception of
comfort. (Since the temperature and humidity did not vary, "comfort" was
more akin to perception of "freshness" of the air.)
. Survey results were analyzed for correlation with ventilation
rates that existed at the time corresponding to the survey
. There was a correlation between ventilation rate and comfort
. The correlation was presented as ppm of CO2 assuming:
o a specific background / outdoor air concentration (350ppm, I think)
o sedentary people were the only generators of CO2
So, it seems to me that it's a BIG stretch to try to correlate productivity
with CO2.
This sounds like the beginnings of a an elaborate/scientific office prank with the boss's thermostat... =)
In all seriousness, I believe the effect of ambient temperatures are pretty established. Here's a brief article in layman's terms and a pretty graph:
http://productivity-science.com/blogen/post/What-temperature-is-best-for-your-productivity.aspx
Here's a research paper cited in the previous link with more info:
http://escholarship.org/uc/item/45g4n3rv#page-8
I'm not certain whether there is anything in the realm of IEQ/CO2 monitoring that establishes a clear causal effect on task productivity similar to the above.
Here's a paper that attempts to connect the dots between ventilation rates (2 levels) and annual sick-leave accrual for office workers: http://www.google.com/url?sa=t&rct=j&q=milton%20risk%20of%20sick%20leave%20associated%20with%20outdoor%20air%20supply%20rate%2C%20humidification%2C%20and%20occupant%20complaints&source=web&cd=3&ved=0CFoQFjAC&url=http%3A%2F%2Fwww.e-co.uk.com%2FRecirc-Milton2000.pdf&ei=xCbRT5ujBeWL2AXWw4WxDw&usg=AFQjCNFBvi_nWYBGbwn_f6NV3hxRHn7MtA
The "dollars lost" economical argument extrapolated in the conclusions looks dramatic, but even if we accept CO2 concentrations are tied directly to sick leave hours... that's not quite the same thing as a direct productivity effect (i.e. my co-worker breathing heavily is preventing me from doing my work).
If you were to combine the above studies into a single model I suppose you reasonably establish a linear CO2-concentration-factor curve to apply against an ambient temperature curve to come up with a combined productivity effect. I might sooner look further for something akin to the temperature study however.
NICK CATON, P.E.
Classification: UNCLASSIFIED
Caveats: NONE
Monitoring CO2 concentrations isn't necessarily about CO2. Sensing CO2 is only an indicator for all the other chemicals in the air.
People put off methane, wear perfume, expel formaldehyde, sweat and a whole lot of disgusting stuff.
Buildings often try to maintain 800ppm of CO2. OSHA allows exposure of 5,000ppm of CO2 for 8 hours. The reason it is common to maintain a CO2 level which is 1/6th of the OSHA approved limits is because it isn't necessarily CO2 we are trying to control. It is all the other smells...
This is also why it may be difficult to find a graph showing performance vs C02 levels (see bottom). The study showed at 2500ppm no measurable difference in performance was detected.
And lastly, Why monitor CO2? The sensors are cheap and accurate.
http://www.energy.wsu.edu/Documents/CO2inbuildings.pdf
http://www.cal-iaq.org/phocadownload/2011_satish_ia.pdf
Without having read the documents Nick is referring to...
Recall that CO2 is a surrogate indicator of air quality. It was never
intended to indicate that the atmosphere was unhealthy, just that it might
be unhealthy.
. the original research done by ASHRAE varied outdoor air
ventilation rates in a test studio which was occupied by real people.
. The people were surveyed at random times for their perception of
comfort. (Since the temperature and humidity did not vary, "comfort" was
more akin to perception of "freshness" of the air.)
. Survey results were analyzed for correlation with ventilation
rates that existed at the time corresponding to the survey
. There was a correlation between ventilation rate and comfort
. The correlation was presented as ppm of CO2 assuming:
o a specific background / outdoor air concentration (350ppm, I think)
o sedentary people were the only generators of CO2
So, it seems to me that it's a BIG stretch to try to correlate productivity
with CO2.
James V. Dirkes II, P.E., BEMP , LEED AP