The ideal autonomy of a refuge chamber?

The issue of autonomy is paramount in defining the need for refuge chambers. Beyond the number of people to be sheltered, it is in fact the determination of the time they will have to spend inside, until the intervention of the rescue services or the end of the incident, that influences the dimensioning of the shelter. This time must be assessed as part of the project risk assessment. 

The risk assessment is carried out according to several criteria such as the configuration of the work site, the type of work carried out, the number of people underground, the number and type of motorized machinery operating underground, the fire risk, and the means of evacuation.

A shelter is in autonomous mode when it is deprived of outside resources such as air and electricity. In this case, the shelter operates autonomously thanks to emergency batteries, a reserve of breathable air or an air filtration system.

Other resources essential to life, such as water or food, must also be stored in sufficient quantities for the duration of the shelter’s autonomy.

The autonomy of a shelter is generally between 24 and 36 hours.

One of the world references is the Western Australian Government’s compendium of recommendations, Department of Mines and Petroleum, Refuge chambers in underground mines. This recommends a minimum autonomy of 36 hours based on a worst-case scenario.

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Underground refuge chambers solutions

The standard range complies with ITA and EN standards, offering the necessary personnel safety features.

The narrow range has a modular design to integrate the refuge into small spaces such as narrow galleries and veins.

The compact range is characterised by refuges that are easily movable and can accommodate a limited number of people.

The customizable range adapts to your specific needs, for example to be integrated on specific equipment (tunnel boring machine or rescue vehicle).

Feedback from incidents around the world suggests that most shelters are used for less than 10 hours. However, no single event in one mine can be compared with another, making standardization of a duration of autonomy impossible.

Below is a list of the different types of mines with the recommended battery life.

autonomie recommandée EN

UNDERGROUND MINES

The ideal duration of a rescue and rescue shelter for underground mines can vary from 8 to 48 hours. In this environment the most frequent dangers are fires, rock falls and the propagation of dangerous gases or fumes, it is in these cases that rescue shelters have a vital role.

In terms of safety standards for underground mining operations, many countries use Western Australia’s DMP standards for emergency and rescue shelters as a reference. These standards are based on a worst-case scenario, so the ideal autonomy of a shelter has been set at 36 hours.

Although longer incidents and extreme cases are less frequent, they are still common.

Based on the diverse and varied incidents that have already occurred in underground mines around the world, a reference in terms of the autonomy of a shelter cannot be clearly determined as an ideal duration. This ideal duration of autonomy of a shelter has nevertheless been suggested to be between 2 to 10 hours, despite the fact that extreme cases are less frequent, they can occur at any time.

COAL MINES

The duration of a coal mine rescue shelter can vary from 48 to 96 hours. In the coal industry, the most common hazards include fires, explosions, rock falls, dangerous gases and fumes, and flooding.

Coal mines contain large quantities of fuel that can burn at any time and for several days, so safety, rescue and evacuation standards are different from those of hard rock mines.

The Mine Safety and Health Administration (MSHA) has determined that there is a need for emergency and rescue shelters within the coal operations and that these shelters must be able to sustain the lives of the operators for at least 96 hours. This time frame is intended to facilitate rescues and allow rescue workers time to gain access to trapped miners. In addition, prior to any rescue intervention, it is necessary to monitor the atmosphere in a mine beforehand in order to allow the risk to be determined and also to allow measures and precautions to be taken by the rescue teams.

The most important autonomy is therefore for coal mines because coal is a good fuel and a fire can last for several days.

TUNNEL EXCAVATIONS

The autonomy of a rescue and rescue shelter for tunnel projects can vary from 24 to 72 hours. Risks that may involve the use of a refuge in the tunneling and underground construction industry are fire, explosion and dangerous gases.

Internationally, the International Tunnelling and Underground Space Association (ITA) is the leading industry organization that represents and sets health and safety standards for the industry. The need for emergency and rescue shelters must be assessed as part of the risk assessment of the tunneling project. As in the mining industry, the duration of a tunneling emergency shelter is evaluated based on the time required to perform a rescue. A minimum of 24 hours is recommended by the agency, with the possibility of providing additional resources to extend this period if required by the risk assessment.