Heat can quickly accumulate inside a refuge chamber, increasing with each additional person. This is a problem often underestimated; with cooling systems perceived more as a luxury than an essential part of life-sustaining safe refuge technology.
A refuge chamber is a sealed environment with numerous heat sources. A continuous increase of heat and humidity is caused by the occupants’ metabolic activity, scrubbing processes, electrical equipment and any ambient (external) heat.
The detrimental effects of inadequate or often absent cooling systems in refuge chambers of the past, unfortunately, prove this point. Antiquated shipping-container style chambers were often installed for safe refuge, however, when personnel became trapped for extended periods of time, they did more damage than good.
Fortunately, improved safety standards and a growing understanding of refuge chamber technology have seen the regulated implementation of artificial cooling and dehumidifying systems to help support life during an emergency. The internationally recognised West Australian Department of Mines Guideline for ‘Refuge Chambers in Underground Mines’ states,
‘When a full complement of people occupies a refuge chamber for a significant period, humidity and temperature can increase rapidly to potentially heatstroke-inducing levels. Refrigerative air conditioning will most effectively counter this potentially serious problem. The power supply must be adequate for the demands of the system.’
Air conditioning is a significant contributor to reducing the ill effects of heat stress and achieving a more comfortable temperature inside the refuge chamber. Using refrigeration technology through a split-system air conditioner allows the heat load inside the chamber to be lowered by way of a fan drawing warm air over a cold coil inside the unit.
If mains power is severed, air conditioning as an artificial coolant is still possible irrespective of power restrictions while running on battery power. The inverter technology allows the refrigerant compressor to run on a low power mode if the chamber’s air conditioner temperature is set at 30° C. This means the compressor is drawing the least amount of current possible; saving power while still cooling the chamber.
Due to the sealed environment, the heat generated from within a chamber cannot escape and the internal temperature will rise quite rapidly. Eventually, without some form of mitigation, this will lead to the refuge becoming uninhabitable and pose a severe hazard for its occupants
It is important to recognise that there are a number of mechanisms within a refuge chamber, including cooling, that works in unison to protect personnel from external hazards and provide a safe ‘go to’ area during an emergency.