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Humans are the main indoor source of carbon dioxide (CO 2) in most buildings. Indoor CO 2 levels are an indicator of the adequacy of outdoor air ventilation relative to indoor occupant density and metabolic activity. Indoor CO 2 levels above 500 ppm can lead to higher blood pressure and heart rate, and increased peripheral blood circulation. [85]
As the sensor reads the increasing amount of carbon dioxide levels in a space, the ventilation increases to dilute the levels. When the space is unoccupied, the sensor reads normal levels, and continues to supply the unoccupied airflow rate. This rate is determined by the building owner standards, along with the designer and ASHRAE Standard 62. ...
For this model the standard provides a graph of acceptable indoor temperature limits at prevailing mean outdoor temperatures (a mean of the daily mean outdoor temperatures of the previous 7–30 days). An accompanying table lists provisions for higher operative temperatures at air speeds above 0.3 m/s (59 ft/min) and up to 1.2 m/s (240 ft/min).
Minimum Efficiency Reporting Value, commonly known as MERV, is a measurement scale designed in 1987 by the American Society of Heating, Refrigerating and Air-Conditioning Engineers to report the effectiveness of air filters in more detail than other ratings.
Ventilation guidelines are based on the minimum ventilation rate required to maintain acceptable levels of effluents. Carbon dioxide is used as a reference point, as it is the gas of highest emission at a relatively constant value of 0.005 L/s. The mass balance equation is: Q = G/(C i − C a) Q = ventilation rate (L/s) G = CO 2 generation rate
Air changes per hour is a measurement intended to communicate the air change effectiveness of a space’s ventilation system. Discussion around the ASHRAE standard 62, Ventilation for Acceptable Indoor Air Quality led to the development of a more direct method of measuring air change effectiveness with the use of a tracer gas. [1]
Such standards generally are expressed as levels of specific air pollutants that are deemed acceptable in ambient air, and are most often designed to reduce or eliminate the human health effects of air pollution, although secondary effects such as crop and building damage may also be considered. [5]
NO 2 is the oxide measured and used as the indicator for the entire NO x family as it is of the most concern due to its quick formation and contribution to the formation of harmful ground level ozone. [18] In 1971 the primary and secondary NAAQS for NO 2 were both set at an annual average of 0.053 ppm. The EPA reviewed this NAAQS in 1985 and ...