Underground personnel must be able to reach a safe location when an undesirable atmosphere develops due to fire, toxic gas release, or other hazards. As an alternative to evacuation, refuge chambers provide a secure space isolated from external dangers. For this reason, AYSAN Refuge Chambers are equipped with two standard breathable air sources.
1 – Compressed Air
Compressed air is atmospheric air supplied from the surface through pipelines by a compressor. It is filtered through a system that includes:
a water separation filter to prevent moisture from entering,
a coalescing filter to remove fine water and oil particles,
a pre-filter for larger particles,
and an absorber filter to capture diesel residues and ultrafine oil particles.
After filtration, the air passes through a regulator and an automatic muffler (to reduce noise) before entering the chamber.
To maintain positive pressure inside the refuge chamber, the internal ball valve must remain slightly open while the chamber is in standby mode. Positive pressure prevents toxic gases from entering during entry or exit in a smoke-filled environment. Compressed air also keeps the internal atmosphere dry and clean.
2 – Scrubber System & Oxygen Cylinders
The scrubber system is designed to purify the air in confined spaces where human life must be supported for extended periods. Its purpose is to reduce the risk of carbon dioxide and carbon monoxide poisoning by removing CO₂ and CO from the air. The front panel of the Scrubber System includes interior lighting controls, external flashers, a siren, manual switches, an inverter/charger switch, and a battery monitoring display.
The Scrubber System operates together with oxygen cylinders. CO₂ is removed using AYSAN CO₂ cartridges, which must be replaced when their absorption capacity decreases. Chemical cartridges should be changed when the digital gas monitor or manual gas measuring tubes show CO₂ levels at or above 1%.
Through a catalytic process, carbon monoxide is converted into CO₂ and H₂O. The resulting CO₂ is then absorbed using soda-lime.
AYSAN Refuge Chambers are equipped with breathable oxygen cylinders with a minimum capacity of 8,500 litres per person. Oxygen is supplied from the cylinder directly into the safe haven through a medical-grade regulator. The number of cylinders required is determined by the chamber’s capacity and MSHA standards, which specify 37 litres of oxygen per person per hour for minimum safe holding time.