Ventilation - Air Cleaning Devices
What are air-cleaning devices?
What are air-cleaning devices for particulates?
Gases and vapours can be removed by using the following processes:
Adsorption The removal of a contaminant by contact with other materials such as activated alumina, activated charcoal and silica gel (referred to as adsorbers).
Absorption Absorbers remove soluble or chemically reactive gases from the gas stream by close contact with an appropriate liquid so that one or more of the air contaminants will dissolve in the liquid.
Catalytic conversion In this process, a catalyst converts a contaminant to a chemical form not considered to be hazardous. Catalysts are substances that alter the rate of a chemical reaction without being affected by the chemical reaction.
Thermal Oxidation (Combustion) The combustion process (also called incineration) converts volatile organic compounds (VOCs) to carbon dioxide and water vapour by burning them. It is a very effective means of eliminating VOCs. Typical applications for incineration devices include odour control, reduction in reactive hydrocarbon emissions, and reduction of explosion hazards.
What should be considered when selecting an air-cleaning device?
Following are some tips for selecting an air-cleaning device in your workplace. Remember that a qualified professional should make final decisions regarding the suitability of an air-cleaning device.
Are there any legal standards for air-cleaning devices?
Yes. Since the 1970's, all installations of air-cleaning devices require approval by municipal, provincial, and federal air pollution control authorities such as the ministry or department of environment. In addition, an approval is required by the provincial ministries/departments of labour if an air-cleaning device is installed for to allow re-circulation of exhaust air back into the building (for energy conservation). Some legal standards require that re-circulated air must be cleaned up to the extent that it does not contain more than 1/10th of the permissible standard of any contaminant. Consult with your local jurisdiction for more details.
- In a ventilation system, an air-cleaning device removes or captures the contaminants that are present in the air. The type of air cleaner used will depend on:
- type of air contaminant to be removed,
- concentration of the contaminant in the air,
- how much contaminant must be removed to meet any regulations or standards,
- type and concentration of toxic chemical contaminants,
- type and size of dust particles,
- temperature, humidity, etc.,
- fire safety and explosion control, and
- air pollution control regulations.
What are air-cleaning devices for particulates?
Gases and vapours can be removed by using the following processes:
Adsorption The removal of a contaminant by contact with other materials such as activated alumina, activated charcoal and silica gel (referred to as adsorbers).
Absorption Absorbers remove soluble or chemically reactive gases from the gas stream by close contact with an appropriate liquid so that one or more of the air contaminants will dissolve in the liquid.
Catalytic conversion In this process, a catalyst converts a contaminant to a chemical form not considered to be hazardous. Catalysts are substances that alter the rate of a chemical reaction without being affected by the chemical reaction.
Thermal Oxidation (Combustion) The combustion process (also called incineration) converts volatile organic compounds (VOCs) to carbon dioxide and water vapour by burning them. It is a very effective means of eliminating VOCs. Typical applications for incineration devices include odour control, reduction in reactive hydrocarbon emissions, and reduction of explosion hazards.
What should be considered when selecting an air-cleaning device?
Following are some tips for selecting an air-cleaning device in your workplace. Remember that a qualified professional should make final decisions regarding the suitability of an air-cleaning device.
- Before the air cleaning device is selected, it is very important to know maintenance and access requirements, the physical size of the equipment and how it will be installed in the plant as well as the methods of removing the collected contaminants.
- The air cleaner must be reliable. Many installations require monitoring or proof of continual operations by measuring conditions in the system.
- Maintenance and operating costs must be considered. The air cleaner must operate in stable conditions as well as variations such as plant start-up and shut down. Considerations also include if it must be accessible for maintenance or if the air cleaner must continue to operate while maintenance or repairs are being done.
- The device must meet local and national regulations (at start-up and over time)
Are there any legal standards for air-cleaning devices?
Yes. Since the 1970's, all installations of air-cleaning devices require approval by municipal, provincial, and federal air pollution control authorities such as the ministry or department of environment. In addition, an approval is required by the provincial ministries/departments of labour if an air-cleaning device is installed for to allow re-circulation of exhaust air back into the building (for energy conservation). Some legal standards require that re-circulated air must be cleaned up to the extent that it does not contain more than 1/10th of the permissible standard of any contaminant. Consult with your local jurisdiction for more details.
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