Underground infrastructure


Today the majority of the cities have an underground metro network as they allow rapid transit time while transporting a large number of users. Moreover the reduced private traffic will produce less pollutants on the surface lived area. It is forecasted that in 2050 64% of the people will live in greater metropolitan areas so the mobility will become more and more a critical issue. Metro and Rapid Transit Systems will become an integrated way of daily life.

The international connections between countries, in our case Europe, is one of the relevant issues that will enable to achieve a greater level of interchanges for a mutual benefit. European Community has defined 10 strategic corridors called TEN-T (rail and roads) agreed in Maastricht in 1992 with a presumed horizon in 2030.

The plan of such infrastructure (design, construction, operation) should satisfy a “sustainable development” firstly mentioned and defined by Brundtland Report (Our Common Future, United Nations World Commission on Environment and Development-WCED, 1986) and at the 1992 Summit Rio.

The sustainable development concept is based on three pillars:
•Social: meeting needs in terms of health, education, housing, employment etc.
•Economic: creating wealth and improving living standards
•Environmental: preserving species, natural resources, and energy resources

It is common to represent the three pillars, that should roughly have the same weight, with the following figure:


The pillars are not independent, they interact with one another. The following figure illustrate the phenomenon


For further information please see “Road Tunnel Operations First Step Towards a Sustainable Approach” PIARC, Technical Committee C3.3, Seoul 2015.

Furthermore technical aspects as safety and energy savings must be taken into account.

Following the tragic fire accidents of Mont Blanc, Gotthard and Tauern tunnels European Community released the ED2004/54/CE relevant to increase safety in the existing and future tunnels which has been adopted by all European Countries. The main focus is the ventilation in case of fire inside a tunnel. The task is to keep the smoke under control with suitable ventilation systems and create safe escape routes for the users. For further information please see “Systems and Equipment for fire and Smoke Control in road Tunnels” PIARC, Technical Committee C3.3, 2006.

Energy resources are not unlimited and consequently we should pay attention of this aspect. European Commission has supported a dedicated study. The research focus on the potential savings in the energy consumption in the various industrial activities. For the underground segment (mining, tunnels, metro, rail etc.) it is estimated a today value of 3000 GWh. The target was to achieve improvements of 3% for fan efficiency and 17.5% on ventilation systems. If the target is reached a 600 GWh power would be saved. The research was carried out in 2001 before the global financial crisis so the scenarios could nowadays be different and therefore not in line with what was forecasted. For further information please see “ Market Study for Improving Energy Efficiency for Fans” Final Report 2001, support from European Commission under the SAVE Program, Project XVII/4.1031/Z/99-313.

More practical approach, that is currently used, is the Life Cycle Cost (LCC) that has become an important aspect of tunnel management for private tunnels owners, as well as for government agencies. Remarkable reduction in energy can be achieved if the total life cost of equipment is considered; normally between 25 to 30 years. For further information please see “Best Practice Life Cycling Analysis for Tunnel equipment” PIARC Report2016R01EN.

Our products have been designed with the highest possible efficiency, special care has been taken on the blade design resulting in an optimization of fluid dynamics characteristics; special truly reversible blade profile can guarantee 100% reversibility keeping the fan efficiency at high level. The fans are suitable to operate in an aggressive environment like road tunnels and are suitable for Corrosivity Category C5-I as per EN 12944-2.

Systemair Group has for several years set up a dedicated division named MRT (Metro, Road & Rail, Tunnel) which especially focused in underground ventilation business and can cover all underground works.

Tunnel during construction: our AXC axial fan range can deliver fresh air to dilute pollutants inside the tunnel; dry dedusters to reduce dust content especially quartz with certified performances; air/water chillers, specially in hot climate zones to keep the air temperature at an acceptable level for working squads. International standards are available: e.g. BS 6164:2011, however is widely used a Swiss Norm: Norme Suisse SN 531 196 “ Ventilation des Chantiers Souterrains” that covers both ventilation and dust control.


Final ventilation of road/rail tunnels: our AJ/AJ-TR unidirectional/reversible jet fans for longitudinal ventilation with the highest N/kW ratios; AXC/AXR unidirectional/reversible axial fan range for semi transverse/transverse ventilation. Full package of fans, fire/overpressure dampers for safety exits and escape routes in order to safely evacuate the people. There are several Standards around the world: Austria (RVS), Norway (Manual 021), Germany (RABT), Italy (ANAS), USA (NFPA) and PIARC (2012R05EN) which is widely accepted. All these documents give design procedures both for sanitary/fire ventilation. 


Should the noise be an important issue for inside/outside environment our engineers can make acoustic evaluation and design suitable silencers or technical solutions to mitigate the final noise level.

Metro and Rapid Transit Systems: our AXC/AXR unidirectional/reversible axial fan range for “push-pull systems”; AHU, silencers, inverters and full air distribution products. Particular care of equipment working during fire emergency to create safe and clean escaping routes. These complex underground works, during the design stage, needs a detailed fluid dynamic analysis so there are several CFD programs available e.g. SES (Subway Environmental Simulation), USA.


Systemair invests in R&D programs and own one of the most modern testing laboratories in Europe where we can perform air, noise, vibration tests in accordance to ISO, EN Standards; the laboratory is certified by AMCA and furthermore, for customer’s benefits, FAT tests can be carried out. The MRT division shares Systemair’s vision: satisfying the customers, anticipating needs, supporting them along the process of making each single project an opportunity for mutual benefit and growth.

For further information please contact:
Frank Poppe
Angelo Vismara

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