Why use a gas detector?
With increasing attention to indoor healthy air quality and energy efficiency, the demand for gas detection instruments and IAQ controllers in the HVAC market has recently become increasingly high. Specifically, the common types of gas detectors/ventilation controllers are CO2 or carbon dioxide detectors. These controllers sense the level of carbon dioxide and once it reaches a sufficiently high level, they will send a signal to control ventilation equipment to remove and replace air in the space. Usually, these sensors will send a proportional signal to the damper motor, which will adjust accordingly to allow fresh air to enter the space. In addition, many controllers also have relays that open or close contacts to turn on or off the power supply for exhaust and/or supplementary fans.
Carbon dioxide, a carbon dioxide detector that can monitor the space occupied by humans or animals to remove excessive carbon dioxide as a byproduct of respiration. High levels of carbon dioxide are associated with the so-called 'sick building syndrome'. Most building regulations require a certain amount of replenishment or turnover of air to avoid the accumulation of large amounts of CO2 and the resulting health problems. Typically, CO2 detectors have adjustable set points, analog signals, and one or more relays.
Carbon monoxide and nitrous oxide, CO, NO2, detectors are used for operating internal combustion engines in spaces such as parking garages, service garages, small engine workshops, warehouses, underground garages, and generator rooms. Carbon monoxide is a byproduct of gasoline combustion, while nitrogen dioxide is a byproduct of diesel combustion. Similar to CO2 controllers, these units monitor gas and send proportional analog signals, and/or make relays in contact with stage fans to replace toxic air in a given space.
Although it is possible to maintain only a constant ventilation rate, this is usually not preferred as the ventilation rate should match the demand and typically change with the demand for these gases. In addition, as mentioned in the previous article, building ventilation and related building pressure should be balanced. Therefore, in most cases, requirement control systems are desirable. This type of system will remove toxic air as needed and replace it with an equal amount of fresh supplementary air. The driving factor in the system is the correct application of IAQ gas detectors/controllers.
