London has the oldest subway network in the world and, during the summer, it can reach temperatures close to the incredible 122 °F mark in the stations. Considering that the temperature indicated for thermal comfort is between 72,5 °F and 78 °F, you can imagine the discomfort caused by such a high temperature.

The antiquity of its facilities, which fascinates so many people, also makes its renovation harder, since, when the subway was conceived, ventilation ducts were not planned to house the modern air conditioning systems currently used in temperature control.

Relative humidity should also be considered to ensure the comfort of users. High or low humidity levels cause discomfort and even respiratory problems. When the air contains a low percentage of moisture, water from the elements available in the environment is absorbed.

That is, everything that is exposed to this condition will dehydrate, to a greater or lesser degree, according to its composition. Also, beyond the discomfort for the users, there is another problem when the relative humidity reaches high levels. This means that the air is charging a large amount of water in relation to the maximum allowed and, upon reaching a certain temperature, the water will condense, going from the state of steam to the liquid state. This scenario can be caused by the air cooling system itself, which may cause corrosive damage to parts of the equipment as well as hindering maintenance and reducing the useful life.

Control humidity and temperature in underground stations, more than provide a pleasant environment for passengers, can help save on system maintenance. Humidity and temperature transmitters enable the adjustment of air conditions through the operation of ventilation and heating devices in metro stations. In addition, they can be connected to a humidity control system, keeping the air always in ideal conditions.