5. VENTILATION Underground ventilation types

5. VENTILATION OF UNDERGROUND STRUCTURES

In planning for an underground building, the foremost consideration is combating the dank dark cave trope. Careful management and design of the aspects of light and air-essential for life and health - make it possible to create pleasant and safe spaces underground. Temperature difference is a key moderator of air flow and quality in underground spaces. [5.1] As this is a seasonal variable, mechanical systems are often introduced to supplement natural ventilation and ensure the well-being of inhabitants.

Underground Ventilation Types Uses: Construction, General

Construction ventilation is the supply of air during the construction process. Air is supplied through the shafts down into the space. There should be at least two shafts, one with a fan for pulling air in, another with a fan for pulling air out. [5.4] This falls into the category of Hybrid Ventilation, and it uses elements of Natural Ventilation and Mechanical Ventilation

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figure 5.1 construction hybrid ventilation General: Natural Ventilation Natural ventilation is generally used in vernacular earth-sheltered buildings. These structures are usually excavated by hand, and are not extremely deep for that reason. If the space has a fire for heating and cooking, a vent is made to pull smoke out, but the main ventilation comes from the entrance. [5.5] Because ventilation of underground spaces is dependent on temperatures and humidity level, a seasonal approach to ventilation planning is recommended. The temperature of the mass of earth around the underground structure helps to stabilize internal temperatures, which will increase with machines used, the number of people in the space, and explosions caused by illegal procedures in the Lanark Institute.

figure 5.2 natural ventilation of a vernacular house in Spain

General: Mechanical Ventilation In deep structures line mines, more sophisticated ventilation systems with ducts must be used. Ducting and vents control the flow of air in different working sections of the mine. This allows for less overall energy consumption by having less airflow in sections that are not being mined. [5.4]

figure 5.3 section showing ventilation system of metal mine