CO2 sensor

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General


CO2 Standards

To eliminate most complaints, total indoor carbon dioxide should be reduced to a difference of less than 600 ppm above outdoor levels. 
NIOSH considers that indoor air concentrations of carbon dioxide that exceed 1,000 ppm are a marker suggesting inadequate ventilation.[20] 
The UK standards for schools say that carbon dioxide in all teaching and learning spaces, when measured at seated head height and averaged 
over the whole day should not exceed 1,500 ppm. The whole day refers to normal school hours (i.e. 9:00am to 3:30pm) and includes unoccupied 
periods such as lunch breaks. European standards limit carbon dioxide to 3,500 ppm. OSHA limits carbon dioxide concentration in the workplace 
to 5,000 ppm for prolonged periods, and 35,000 ppm for 15 minutes. 
These higher limits are concerned with avoiding loss of consciousness (fainting), 
and do not address impaired cognitive performance and energy, which begin to occur at lower concentrations of carbon dioxide.

Carbon dioxide concentrations increase as a result of human occupancy, but lag in time behind cumulative occupancy and intake of fresh air. 
The lower the air exchange rate, the slower the buildup of carbon dioxide to quasi "steady state" concentrations on which the 
NIOSH and UK guidance are based. 
Therefore, measurements of carbon dioxide for purposes of assessing the adequacy of ventilation need to be made after an extended period 
of steady occupancy and ventilation - in schools at least 2 hours, and in offices at least 3 hours - for concentrations to be a reasonable 
indicator of ventilation adequacy. Portable instruments used to measure carbon dioxide should be calibrated frequently,
and outdoor measurements used for calculations should be made close in time to indoor measurements. 
Corrections for temperature effects on measurements made outdoors may also be necessary.



The effects of increased CO2 levels on adults at good health can be summarized:
    normal outdoor level: 350 - 450 ppm
    acceptable levels: < 600 ppm
    complaints of stiffness and odors: 600 - 1000 ppm
    ASHRAE and OSHA standards: 1000 ppm
    general drowsiness: 1000 - 2500 ppm
    adverse health effects expected: 2500 - 5000 ppm
    maximum allowed concentration within a 8 hour working period: 5000 ppm


Euro-Gasman

  • C1 ultra low power (3.5mW) low range Infrared CO2 Carbon Dioxide sensor, with analogue voltage transmitter, for measurement ranges
  • 0-2000ppm, 0-5000ppm or 0-1% volume CO2


Gassensing COZIR


co2meter

  • COZIR-AMB 2,000ppm CO2 Qty 3 for $299.00


IR sources and sensors


Enocean

MQ135 AIR QUALITY SENSOR

  • Heater voltage 5V, 31 ohm (40mA consumption)










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