co2 control for classroom concentration

ASHRAE Technical FAQ

Question What is the allowable level of carbon dioxide in an occupied space? Long Answer CO 2 at very high concentrations ( greater than 5000 ppm) can pose a health risk. Refer to Appendix D, Summary of Selected Air Quality Guidelines in ASHRAE Standard , "Ventilation for Acceptable Indoor Air Quality". However, in most buildings, concentrations almost never rise to these levels ...

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Classroom carbon dioxide concentration, school attendance ...

BACKGROUND We tested the hypothesis that classroom carbon dioxide (CO2 ) concentration is inversely related to child school attendance and educational attainment. METHODS Concentrations of CO2 were measured over a 35 day period in 60 naturally ventilated classrooms of primary school children in Scotland. Concentrations of CO2 were related to the class average annual attendance …

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Classroom conditions and CO2 concentrations and teacher ...

Overall, approximately 20% of the measured classroom CO2 concentrations were above 1000 parts per million (ppm), ranging from 352 to 1591 ppm. In multivariate analyses, the odds of reporting neurophysiologic (, headache, fatigue, difficulty concentrating) symptoms among teachers significantly increased (OR = , 95% CI = ) for every 100 ppm increase in maximum classroom CO2 ...

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Guidelines on ventilation, thermal comfort and indoor air ...

Version control Version Amendments Author/reviewer Approved by Date V1: 06 05 2016 Draft for Public Consultation For ... concentration in February, for a secondary maths classroom in a school in the North West of England. Graphs provided by SE Controls..... 92 Figure Average occupied CO 2 concentration in July, for a secondary maths classroom in a school in the North West of England ...

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Why Measure Carbon Dioxide Inside Buildings?

2 measurement taken in the same classroom during the last period of the day. Assuming the ventilation rate and occupancy of the classroom have remained fairly consistent throughout the day, it is reasonable to assume that a CO 2 concentration below about 1,000 ppm indicates 15 cfm per person, assuming also that the outside air CO 2 is in the 350 ppm range (650 ppm differential inside minus ...

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Associations Between Classroom CO Concentrations and ...

concentration of carbon dioxide (CO 2) has often been used as a surrogate for the ventilation rate per occupant, including in schools (, Lee and Chang, 1999). Indoor CO 2 concentrations exceed outdoor concentrations due to the metabolic production of CO 2 by building occupants. For example, for adult office workers, assuming a ventilation rate of L s1 per person and a typical outdoor ...

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Associations Between Classroom CO Concentrations and ...

Associations Between Classroom CO 2 Concentrations and Student Attendance in Washington and Idaho Our Mission To advance environmental and economic wellbeing by providing unmatched energy services, products, education and information based on worldclass research. Overview Our staff of approximately 100 people (energy engineers, energy specialists, technical experts, software …

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The Ventilation Problem in Schools: Literature Review

of control for potential confounders. RESULTS Carbon Dioxide Concentrations and Ventilation Rates in Schools . Figure 1 plots peak values of CO. 2. concentration measured in classrooms from studies with 20 or more classrooms. The plot only includes data from measurements when classrooms were occupied or measurements characterized as during the school day. Study information is provided in …

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Identifying poorly ventilated areas and using CO2 monitors

Check that mechanical systems provide outdoor air, temperature control, or both. If a system only recirculates air and has no outdoor air supply, the area is likely to be poorly ventilated ; Identify areas that feel stuffy or smell bad ; Using carbon dioxide (CO2) monitors. People exhale carbon dioxide (CO2) when they breathe out. If there is a buildup of CO2 in an area it can indicate that ...

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Measuring Carbon Dioxide Inside Buildings – Why is it ...

The HVAC control system can use the CO 2 values to automatically modulate the volume of OSA that is brought in so indoor CO 2 is maintained at or below a preset target concentration. This strategy is known as Demand Controlled Ventilation (DCV). DCV systems are especially useful for spaces that experience variable occupancy rates, such as cafeterias, gymnasiums, classrooms and conference …

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Carbon Dioxide as a Fire Suppressant: Examining the Risks ...

· Use Controls. Despite the use of carbon dioxide in firefighting applications above its lethal concentration, NFPA 12 does not limit its use in occupied areas. The standard calls for safeguards such as predischarge alarms and time delays to ensure prompt evacuation prior to discharge, prevent entry into areas where carbon dioxide has been discharged, and provide means for prompt rescue of any ...

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Associations between Classroom Co Concentrations and ...

Associations between Classroom Co 2 Concentrations and Student ... control systems could provide continuous ventilation during occupied times, regardless of occupant thermal comfort demands. KEYWORDS carbon dioxide, schools, children, ventilation, attendance 3 . INTRODUCTION Existing information on the relationships between indoor air and environmental quality (IEQ) in classrooms …

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[PDF] Control of Carbon Dioxide Concentration in ...

Abstract This paper reports on research carried out to develop natural ventilation control strategies for densely occupied learning spaces with the intention of improving indoor air quality and heating energy consumption. Investigations were carried out for two test cases according to the characteristics given in CIBSE Guide A (2006) and Building Bulletin (BB) 101 (UK Department for Education ...

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The Atmosphere: Getting a Handle on Carbon Dioxide ...

· The concentration of carbon dioxide in Earth’s atmosphere is currently at nearly 412 parts per million (ppm) and rising. This represents a 47 percent increase since the beginning of the Industrial Age, when the concentration was near 280 ppm, and an 11 percent increase since 2000, when it was near 370 ppm. Crisp points out that scientists know the increases in carbon dioxide are caused ...

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Energy Saving Fact Sheet Ventilation and Indoor Air Quality

classrooms be provided with 15 cfm/person for outside airflow to the classroom.* ASHRAE further recommends that concentrations of carbon dioxide (CO 2) be maintained below 1,000 ppm in classrooms and 800 ppm in offices. (ppm = parts per million, the number of molecules of carbon dioxide per million air molecules) The fresh air we inhale will have about 350 ppm of background carbon …

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