Expert guide for buying jet and exhaust fans for transportation tunnels in Tehran

Transport tunnels, as vital arteries in the development of urban and intercity infrastructure, play a vital role in facilitating traffic and reducing traffic. However, the closed environment of tunnels brings serious challenges for the safety and health of users. The most important of these challenges are the accumulation of toxic gases from the combustion of car engines (such as carbon monoxide, nitrogen oxides, and suspended particles), smoke from fires, and heat produced. To deal with these risks, intelligent and powerful ventilation systems, especially Jet Fans and Exhaust Fans, form the safety backbone of tunnels.

In the city of Tehran, despite the expansion of the network of highways and numerous tunnels (such as Hemet, Hakim, Resalat, Laleh tunnels, etc.), the need for ventilation equipment with international standards is felt more than ever. As a leader in providing industrial ventilation solutions, Nasim Fan Alborz guarantees the life and financial safety of users and owners of these structures by providing a wide range of jet and exhaust fans for tunnels. This article deals with the technical and practical examination of the selection and purchase of jet and exhaust fans for transport tunnels in Tehran and describes the key points that every supervising engineer and contractor should know.

Why is tunnel ventilation different from jet and exhaust fans?

Understanding the difference between the performance of jet fans and exhaust fans is essential for the correct purchase and optimal design of the tunnel ventilation system. Each of these equipments has a specific task and works in different scenarios.

1. Jet fans: for air flow and drift, jet fans, which are also known as "thrust fans", are responsible for the main task of creating air flow along the axis of the tunnel. These fans are usually installed on the ceiling or walls of the tunnel and by throwing air at a high speed, they direct the polluted air towards the exit vents (which are managed by exhaust fans).
The main advantage of jet fans is the lack of long ducting. This feature reduces the free height of the tunnel and reduces construction costs. Also, under normal driving conditions, jet fans operate at low speed to manage pollution, but increase their speed in emergency situations such as heavy traffic.

2. Exhaust fans: to remove smoke in emergency situations, exhaust fans or mechanical chimneys are responsible for the quick removal of smoke and toxic gases in the event of a fire. In a fire scenario, the ventilation system must quickly change mode and pump the smoke out of the tunnel instead of pushing it through the tunnel. Exhaust fans must be able to work at very high temperatures (usually up to 400 degrees Celsius for one hour) so that they do not fail during a fire.

The intelligent combination of these two systems, i.e. the use of jet fans for daily ventilation and exhaust fans for emergency evacuation, is the gold standard of safety in modern tunnels of the world, including Tehran tunnels.

Choosing a suitable fan for transportation tunnels in Tehran is a complex engineering decision that is influenced by several factors. When buying jet and exhaust fans, you should pay special attention to the following criteria:

A) Airflow & Static Pressure
The most important parameter in jet fans is thrust, which is measured based on Newton (N). This force determines how much air the fan can move at a given speed and pressure. For long tunnels in Tehran, accurate hydrodynamic calculations are needed to determine how many fan jets and with what thrust force are enough to cover the length of the tunnel. On the other hand, exhaust fans must have high static pressure to overcome the resistance of the exhaust channels and chimney valves.

B) Resistance to temperature and harsh conditions (Fire Rating)
According to international standards (such as EN 12101-3 for exhaust fans and EN 12101-8 for jet fans), the equipment must have a temperature tolerance certificate.

• Exhaust fans: must be able to withstand a temperature of 400 degrees Celsius for at least 60 minutes (S-300 or S-400).
• Jet fans: must also be resistant to the heat caused by fire and, if necessary, have an internal cooling system or special insulation. For weather conditions and safety of Tehran tunnels.

C) Noise Level
Although the main tunnels are usually far from residential areas, the entrances and exits of Tehran urban tunnels (such as Hemet and Hakim tunnels) are located close to the urban context. Therefore, jet and exhaust fans should have low noise so as not to cause noise pollution. The aerodynamic design of the blades in Alborz's jet fans has minimized the noise.

D) Material and corrosion (Corrosion Resistance)
The air inside the tunnels contains moisture, salt particles (if antifreeze is used in winter) and acid gases. The body of jet and exhaust fans should be made of stainless steel or aluminum with special anti-corrosion coatings to be resistant to corrosion and have a long service life.

e) Control and intelligence system
Modern jet and exhaust fans should be connected to building management systems (BMS) and tunnel traffic control systems. This connection allows the fans to operate automatically and coordinately based on traffic intensity, pollutant concentration (CO and VI sensors) and in the event of an accident.

Tehran has special challenges in ventilation of tunnels due to its foothills topography and high density of cars. The north-south tunnels of Tehran usually have steep slopes, which makes heavy vehicles produce more emissions on the uphills. Also, the presence of suspended dust in the air of Tehran increases the need for more accurate periodic filtration and maintenance.

Nasim Van Alborz, understanding these challenges, offers the following solutions:

Choosing a contractor and supplier of ventilation equipment is one of the most important decisions in construction projects. Nasim Van Alborz is the best business partner for you for the following reasons:

• Successful experience in large projects: Cooperation with large infrastructure projects in Tehran and surrounding provinces.
• Reliable warranty and after-sales service: Providing written warranty for jet and exhaust fans and quick access to spare parts.
• Competitive pricing: By eliminating intermediaries and direct import or production with global standards, the best We provide pricing for purchasing jet and exhaust fans.
• Speed in delivery: Adequate warehousing and strong logistics result in fast delivery of orders, which is vital for construction projects.

To ensure the perfect performance of jet and exhaust fans in Tehran tunnels, it is necessary to observe the following points:

• Periodic inspection of the blades: Ensure that the screws are tight and the blades are not broken or deformed.
• Bearing cleaning: Lubricate or replace the bearings according to the manufacturer's instructions.
• Control systems test: Ensure that the fans are properly connected to the tunnel control center and function properly. Sensors.
• Inspection of thermal insulation: in exhaust fans, ensuring that the thermal insulation is healthy to prevent heat transfer to the engine body.

Purchasing jet and exhaust fans for transport tunnels in Tehran is more than a business transaction, it is a social and safety responsibility. Choosing poor quality equipment can have irreparable consequences for human lives and national infrastructure. Nasim Fan Alborz is a reliable partner for engineers, contractors and owners of tunnels in Tehran by providing high-quality products, specialized advice and committed after-sales services.

We at Nasim Fan Alborz are committed to providing cleaner air and a safer environment for all road users in Tehran by providing the best ventilation solutions. If you are designing, building or renovating a tunnel and need technical advice or a price inquiry for jet and exhaust fans, contact us.

To receive the price list of jet and exhaust fans, free consultation with expert engineers of Nasim Fan Alborz and place an order, contact our sales experts. We are ready to provide the best ventilation solution according to the budget and needs of your project.

📞 Direct contact number: 09126173497
🌐 Official website: https://nasimfan.com

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