AFU CO2 18000L Carbon Dioxide Filter: Engineering Analysis of a High-Capacity CO₂ Absorption Filter for Civil Defence Shelters
Maintaining breathable air inside sealed civil defence shelters requires more than conventional particulate filtration. Even when outside contaminants are excluded, carbon dioxide (CO₂) produced by occupants continuously accumulates within the enclosed space. Dedicated CO₂ absorption filters are therefore used as part of shelter air-regeneration systems to control indoor carbon dioxide concentration during extended occupancy.
The AFU CO2 18000L Carbon Dioxide Filter is a replaceable high-capacity CO₂ absorption filter designed for use with the ARC CO2 18000L scrubber and compatible systems. According to the manufacturer, the filter provides a carbon dioxide absorption capacity of 18,000 litres, making it suitable for large civil defence shelters and other protected facilities. SHELTER
Introduction
Air quality management inside sealed protective structures differs fundamentally from ordinary building ventilation. During closed-mode operation, fresh outdoor air may be unavailable, requiring internal air regeneration systems to maintain safe atmospheric conditions.
According to the manufacturer, the AFU CO2 18000L filter is intended to remove carbon dioxide generated by human respiration and integrate into dedicated CO₂ scrubber systems used in:
civil defence shelters;
underground bunkers;
industrial protective facilities;
other enclosed spaces operating without continuous fresh-air supply. SHELTER
Official product page:
Purpose of the Filter
The manufacturer states that the AFU CO2 18000L filter is designed to:
absorb carbon dioxide from recirculated air;
fit directly into the ARC CO2 18000L scrubber;
be compatible with other systems after dimensional verification;
support longer occupancy inside enclosed shelters by reducing accumulated CO₂. SHELTER
Unlike NBC/CBRN filters, which remove external airborne contaminants, this filter performs air regeneration by removing carbon dioxide produced inside the shelter.
Operating Principle
According to the published technical documentation, the AFU CO2 18000L filter functions as a replaceable CO₂ absorption cartridge within a shelter air-regeneration system.
The manufacturer states that:
the filter absorbs carbon dioxide released during human respiration;
replacement filters should remain hermetically sealed until installation;
after the package is opened and operation begins, the regeneration process starts immediately. Atmas Group
Engineering Construction
The technical documentation specifies that the filter consists of:
a metal filter housing;
an internal chemical absorbent based on soda lime;
hermetically sealed packaging for long-term storage before activation. Atmas Group
The sealed storage configuration helps preserve the chemical absorbent until deployment.
Technical Specifications
The manufacturer publishes the following technical specifications:
Parameter | Specification |
CO₂ absorption capacity | 18,000 L |
Nominal airflow | 570 / 680 / 760 m³/h |
Filter weight | 165 kg |
Compatible system | ARC CO2 18000L scrubber |
Installation | Replaceable filter module |
These specifications are taken directly from the official product documentation. SHELTER
Carbon Dioxide Capacity
One of the principal engineering characteristics of the AFU CO2 18000L filter is its absorption capacity.
According to the manufacturer:
one filter can absorb up to 18,000 litres of carbon dioxide;
the filter is intended for large shelter installations requiring long-duration air regeneration. SHELTER
Airflow Characteristics
The filter is designed to operate with three nominal airflow rates:
570 m³/h
680 m³/h
760 m³/h
These airflow options allow the filter to integrate with compatible shelter ventilation and CO₂ scrubber systems operating at different performance levels. SHELTER
Filter Replacement
The manufacturer describes the AFU CO2 18000L as a replaceable filter element.
According to the published information:
spare filters should remain sealed before use;
replacement can be performed quickly;
the filter is intended to fit directly into the ARC CO2 18000L scrubber while remaining compatible with other systems after measurement verification. Atmas Group
Application Areas
According to the official documentation, the AFU CO2 18000L filter is intended for:
civil defence shelters;
underground bunkers;
industrial protected facilities;
enclosed protective rooms requiring controlled CO₂ concentration. SHELTER
Integration with Shelter Systems
The AFU CO2 18000L is designed to function as one component of a complete shelter environmental control system.
According to the manufacturer, it operates together with:
CO₂ scrubbers;
shelter ventilation equipment;
air-regeneration systems.
Its role is specifically to remove carbon dioxide from recirculated air rather than filter external contaminants. SHELTER
Storage Characteristics
The technical documentation specifies that:
filters are supplied in hermetically sealed packaging;
factory-sealed storage time is up to three years;
activation begins after the package is opened and the scrubber starts operating. Atmas Group
Conclusion
The AFU CO2 18000L Carbon Dioxide Filter is a dedicated replaceable CO₂ absorption module intended for use in large civil defence shelters and protected facilities. According to the manufacturer's published specifications, it provides an absorption capacity of 18,000 litres of carbon dioxide, operates at nominal airflow rates of 570, 680, or 760 m³/h, weighs 165 kg, and integrates with the ARC CO2 18000L scrubber as part of a shelter air-regeneration system. The filter uses a metal housing with a soda lime absorbent, is supplied in hermetically sealed packaging, and is designed for long-term storage prior to deployment. SHELTER
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