Ventilation systems

Air renewal, in occupied buildings where the air is used up or polluted very quickly is a fundamental requirement of building comfort, especially in airports which cater for thousands of travellers each day. Individual zones such as offices, shops, terminal buildings, airport gates and restaurants all have different requirements. Despite the need to introduce fresh air to these zones, the space temperatures must also be maintained at the required level.

Specifics – Air Quality, demand-controlled ventilation

The quality of the indoor airport environment is a key issue for the protection of passengers’ and staff health and well-being. The significance of well-being in buildings was first recognised in conjunction with a noted increase in symptoms and complaints associated with buildings (Sick building syndrome). 'Sick Buildings' can lead to a reduction in the productivity of individuals or even an entire staff.

If the oxygen (O2) content of the air is too low, the carbon dioxide (CO2) level becomes too high. This can occur in overfilled, generally also overheated zones and can produce conditions ranging from drowsiness and lack or concentration to nausea and fainting. The air purity also plays a role; smoke, dust and stale air also cause discomfort - the only solution is to introduce a source of new, fresh air. Measurement of CO2 exhaled from the occupants in airport zones provides a perfect measurement of room occupancy. Mixed-gas or "VOC" sensors (Volatile Organic Compounds) which detect oxidisable (combustible) gases, measure additional odours and bad air from dirty ventilation systems, carpets, dust, smoke, fumes etc. Elements perceived by humans as bad air.

Siemens new combined CO2/VOC sensors combine CO2 with VOC to provide optimum room air quality measurement. The VOC values are transmitted as a maximum value (CO2 or VOC whichever is highest). These new sensors respond not only to combustible gases and vapours, but also to the humidity in the indoor air. Based upon Siemens case studies, the installation of CO2 or VOC based demand-controlled ventilation (DCV) into HVAC equipment is a proven method of protecting the air quality levels for occupants and at the same time saving huge amounts of energy, by reducing plant when not required. The patented Siemens sensors which measure indoor air CO2 / VOC concentrations are standard devices available globally from Siemens and available in room or duct variants.

Air conditioning System

Our sense of well-being and efficiency is affected not only by the room temperature, but also by the humidity, cleanliness, and freshness of the air – in other words indoor conditions must be tuned as finely as possible to the human organism and senses. An air conditioning plant can influence these factors. The air is treated by use of heating coils, cooling coils, and air humidifiers. Siemens has a range of control systems, field devices and interfaces for all types of air conditioning systems; from large Air Handling Plants serving airport terminals down to local devices serving individual gates. All systems operate automatically, can be networked around the airport, and make the best possible use of the available energy.

Specifics – Humidity

Humidity control is typically only used in critical environments, however if the air is too dry, people’s mucous membranes are irritated by dust particles in the air and any excessively humid air is perceived to be “muggy” and uncomfortable. High relative humidity also provides the moisture necessary to promote harmful chemical reactions in materials (such as mould growth and insect activity) – a potential problem for certain airports.