Carbon Dioxide monitors in buildings are a critical tool in ensuring the comfort and productivity of occupants through better air quality.
What is Carbon Dioxide?
Most people have heard that increasing levels of Carbon Dioxide in the atmosphere are causing climate change, but it can also have serious effects in the workplace and other enclosed spaces such as schools, theatres and hospitals. It has the chemical formula CO2 and is the most oxidised form of carbon which makes it inert. What does that mean? Essentially, CO2 won’t chemically react with other materials, in fact it is used in fire extinguishers. Because it is inert however, at high levels it is a threat to health and in very high concentrations is an asphyxiant.
Effects of Carbon Dioxide
Poor indoor air quality in buildings can decrease productivity and cause discomfort amongst visitors. However, research shows that reducing CO2 concentrations in the workplace increases productivity, so monitoring and controlling CO2 levels is essential to guarantee the best productivity in commercial buildings.
A study from Harvard University showed that cognitive function scores were better in controlled, so-called green building conditions than in conventional buildings. Many other studies have shown that higher CO2 levels reduce brain activity and affect higher cognitive functions.
Many studies have investigated how increasing the ventilation rate in schools can reduce absences. Furthermore, it was found that a higher ventilation rate decreased the number of sick days. Monitoring and controlling CO2 can assist commercial buildings in ensuring a suitable fresh air mix helping reduce the costs associated with sick leave.
An increase in asthma symptoms have also been linked to CO2 levels increasing sick leave.
The effects of different levels of CO2 are illustrated in the table below.
Greystone Energy Systems inc.
Carbon Dioxide levels
Standards for CO2 levels vary in different countries. The most widely accepted standard is the American Society of Heating, Refrigeration, and Air Conditioning Engineers (ASHRAE) Standard 62.
ASHRAE recommends that indoors, using CO2 as an indicator of ventilation, CO2 concentrations be maintained at—or below—1,000 ppm in schools and 800 ppm in offices. The level of CO2 of the fresh air entering the HVAC system has a direct influence on the indoor concentrations so it is necessary to measure this to maintain accurate indoor levels. ASHRAE recommends that indoor CO2 levels should not exceed the outdoor concentration by more than about 600 ppm.
The Health and Safety Executive in the UK recommends that CO2 levels consistently higher than 1500ppm in an occupied room indicate poor ventilation and action should be taken to improve it.
Monitoring CO2
As building occupancy rates increase and urban spaces become more crowded, the monitoring of CO2 becomes more important to ensure the effective operation of the HVAC system, especially where energy constraints demand more circulation of air.
Ensuring adequate ventilation is fundamental to indoor air quality, so making sure your ventilation system is working correctly is fundamental and monitoring CO2 levels is a useful measure.
Carbon dioxide monitors should be placed in areas that will give the best readings. Small spaces where the same number of people use the space for over an hour such as meeting rooms will give more applicable readings than where the occupancy changes over short time frames such as small retail spaces.
In mid-size spaces such as larger offices and meeting rooms where occupancy remains moderately constant for periods over an hour, CO2 monitoring yields reasonably accurate data. Data from monitoring in areas where the occupancy changes rapidly such as some retail settings is useful but should be treated with caution.
In larger venues such as theatres and concert halls where large numbers of people congregate, multiple monitors should be deployed to get meaningful data.
CO2 Monitors from Greystone
To ensure that your HVAC system is working efficiently, you can check it by using your levels of CO2. The amount of CO2 in a building is usually related to the amount of fresh air that is brought indoors. In general, the higher the concentration of CO2 in the building, the lower the amount of fresh air exchange.
Improving ventilation can help to reduce indoor CO2 and its effects. To do so, you need the data from monitoring to know when to make a change.
ACS supplies a range of carbon dioxide monitors and transmitters for duct, room and outdoors to give facility managers and tenants the ability to implement measures to keep the air healthy and safe.
Talk to us about the Greystone Carbon Dioxide sensors and transmitters. Give us a call or go to https://www.acontrols.co.za/air-quality-gas/carbon-dioxide-2/
