On Thursday, May 23, 2013 8:06:16 AM UTC+1, Dennis wrote:
On Wed, 22 May 2013 23:05:06 +0100, Neil wrote:





Concentrations above about 900 - 1000ppm will make it difficulty for

people to concentrate so generally we start to open dampers or speed

fans up at levels of 800ppm, depending on the building use.





It's interesting how often Lawrence, CO², and difficulty in thinking

and grasping the tenets of basic English,

appear in the same post