Refuge chamber scrubbing systems use chemical reactions to remove contaminants from the air within a sealed environment. In an emergency, an air scrubber helps manage breathable air levels by changing the composition of gases exhaled by inhabitants.
In any sealed environment, the natural by-products of inhabitants including CO2 and CO can build up and poison the air. In high enough concentrations, both CO2 and CO can cause serious injury, leading to a loss of consciousness and eventually, death. Removal of these harmful gases is, therefore, a vital necessity for any refuge shelter, particularly if mains air has failed or become compromised.
Air scrubbing is the process of removing contaminants or undesired gases from the air. It differs from filtration, in that a filter is a mesh that screens the air and captures solid particles, whereas scrubbing uses chemical reactions to change the composition of gases as they pass through the system.
“Monitoring and removing excess carbon dioxide and carbon monoxide is an essential aspect of refuge chambers. Both gases have potentially harmful effects on occupants is the gases are not sufficiently removed.” Continue reading the related article: Hazardous Gases: Carbon Dioxide and Carbon Monoxide
Carbon Dioxide in a Refuge Chamber
Carbon dioxide (CO2) is a colourless and odourless gas, existing in Earth’s atmosphere as a trace gas at a concentration of about 0.04 per cent (400 ppm) by volume.
CO2 is produced by all aerobic organisms when they metabolize carbohydrate and lipids to produce energy by respiration. It is returned to the air via the lungs of air-breathing land animals, including humans. It is also produced by combustion of wood, carbohydrates and fossil fuels such as coal, peat, petroleum and natural gas.
Carbon dioxide is not classified as toxic or harmful in its own right, but it is an asphyxiant gas. In concentrations above 1%, it can cause drowsiness and slight shortness of breath; levels above 7% can cause suffocation and unconsciousness within a few minutes. Occupational exposure levels are set at 0.5% for a duration of eight hours.
How Does CO2 Scrubbing Work?
Carbon dioxide scrubbing uses soda lime to generate a chemical reaction that converts CO2 into inert substances.
Air is passed through the MARCISORB CO2 Cartridge and the carbon dioxide is removed by a water-mediated base catalysed chemical reaction, converting the CO2 to calcium carbonate and water as shown in the diagram opposite.
Every aspect of the MARCISORB CO2 chemical has been specifically engineered to work in conjunction with MineARC refuge chamber technology; from chemical grain size and shape down to packing density, moisture content and usage time calculations.
Carbon Monoxide in a Refuge Chamber
Carbon monoxide (CO) is a colourless, odourless and tasteless gas that is slightly less dense than air. It is toxic to haemoglobic animals (including humans) when encountered in concentrations above 35ppm.
Carbon monoxide is caused by incomplete combustion and is present in exhaust gases of vehicles and combustion engines. It is also present in human blood – a normal, healthy adult produces around 10ml/day of CO, and virtually all of this is excreted through natural air expiration. Higher levels have been noted with heavy smokers.
Carbon monoxide poisoning is a common type of fatal air poisoning; combining with haemoglobin to produce carboxyhaemoglobin, which is ineffective at delivering oxygen around the body. Concentrations as low as 667ppm (0.667%) may cause 50% of the body’s haemoglobin to convert to carboxyhaemoglobin, resulting in seizure, coma and even fatality.
Occupational exposure levels are limited to 50ppm of CO over the long term. The effects of CO are compounded in the enclosed environment of a refuge chamber and therefore must be removed.
How Does CO Scrubbing Work?
Carbon monoxide is scrubbed from the air using a catalytic process. The reaction is exothermic, which means heat is generated as a by-product.
The MARCISORB CO Cartridge is a highly active transition metal oxide catalyst, formulated for the oxidisation of contaminants such as CO. Air is passed through the MARCISORB CO Cartridge, converting carbon monoxide into CO2 and H2O. The carbon dioxide produced is then removed by MARCISORB CO2.
Only one CO cartridge is required per portable refuge chamber. The cartridges are also effective at removing other gases, such as ethylene oxide, hydrogen and ethane.
MineARC Refuge Chamber Scrubber Technology
Series IV Scrubbing System
The MineARC Series IV Electrical Scrubbing System is considered to be the most advanced refuge chamber technology in the world. It boasts a host of unique features including a superior digital control system and intelligent voice audio navigation (i.V.A.N).
- Advanced digital control system
- i.V.A.N Intelligent Voice Audio Navigation
- Intuitive operation
- Motion sensor event logging
- Enhanced network, battery and temperature monitoring
- LCD display
ELVP Scrubbing System
MineARC’s ELVP (Extra-Low-Voltage-Portable) Scrubbing System provides a low cost, portable scrubbing option that allows the refuge chamber to sit stand-alone in standby mode for up to six weeks at a time.
- Extra-low voltage control system
- Basic system and battery monitoring
- 6-week standby mode capability
- LED indicators
Contact us for further information regarding MineARC’s Scrubbing Systems.