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Bad air quality in rooms (e.g. offices) can lead to tiredness, lack of concentration and illness (Sick Building Syndrome SBS) and is caused, in many cases, by insufficient ventilation. Maximum labour safety concentration (lower toxic limit): 5,000 ppm The CO 2 concentration in demand controlled ventilating (DCV) systems is used to regulate the supply of fresh air. Stationary CO 2 transmitters are used and should be checked on a regular basis using hand-held measuring instruments. 5,000 ppm 242
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242
CO2 measurement technology
Indoor air quality
CO2 concentration (ppm)
Perc
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peop
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CO2 concentration is used as anindicator when assessing indoor airquality. If the CO2 concentration inindoor air is too high (limit value:1000 ppm), the air feels “stuffy andstale”.
Bad air quality in rooms (e.g.offices) can lead to tiredness, lackof concentration and illness (SickBuilding Syndrome SBS) and iscaused, in many cases, byinsufficient ventilation.
Why CO2 measurement?
The CO2 concentration in demandcontrolled ventilating (DCV)systems is used to regulate thesupply of fresh air. Stationary CO2
transmitters are used and should bechecked on a regular basis usinghand-held measuring instruments.
Percentage of people who are unhappy with indoor air quality at a specific CO2 concentration
CO2 concentration
Limit value for rooms (offices etc.):1,000 ppm
City air: 700 ppm
Fresh air: 330 to 400 ppm
0 ppm
500ppm
1,000ppm
Ideal ventilation
Over ventilated
5,000ppm
40,000ppm
Bad indoor air
quality
Human’s expired air: 40,000 to 52,000 ppm
Maximum labour safetyconcentration (lower toxiclimit): 5,000 ppm
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CO measurement technology
Threshold limit value(maximum workplace concentrationduring 8 hour day) for Germany
Slight headache within2 to 3 hours
Headache in forehead areawithin 1 to 2 hours, spreads to whole head area
Dizziness, nausea and twitching oflimbs within 45 minutes, unconsciousness within 2 hours
Headache, nausea, dizzinesswithin 20 minutes,death within 2 hours
Headache, nausea, dizzinesswithin 5 to 10 minutes,death within 30 minutes
Headache and dizzinesswithin 1 to 2 minutes,death within 10 to 15 minutes
Death within 1 to 3 minutes
Inhalation time and consequences
CO is formed from the incompletecombustion of carbon (fuel). It isvery dangerous for human beingsbecause it is highly toxic, invisibleand without odour.Why CO develops:- Lack of air- Excess air is too high- Flame cools too early
Highly poisonous CO can get intorooms through defect, badly maintained or falsely adjustedheating systems. The CO level in ambient air ismeasured to protect people frompoisoning by colourless andodourless carbon monoxide.
Effect of ambient CO on human body
Carbon monoxide (CO)
Carbon monoxide measurement
Just 1600 ppm (0.16 %) CO in breath leads to death within 2 hours.
30 ppm
200 ppm
400 ppm
800 ppm
1600 ppm
3200 ppm
6400 ppm
12800 ppm
CO concentration in air
0.003 %
0.02 %
0.04 %
0.08 %
0.16 %
0.32 %
0.64 %
1.28 %
