Mariehamn uses new smoke control solution for Miramar underground car park

The car park area is divided into four zones and 13 jet thrust fans controlled by carbon monoxide detectors are installed into the ceiling. The fans are inactive when the car park is closed.

Fläkt Woods has recently provided ventilation to the new Miramar Garaget Car Park in Mariehamn, Åland in Finland. With a capacity of 130 vehicles and an extension to the City Library’s existing car park, Fläkt Woods has provided smoke control solutions to enable optimum ventilation

The Miramar car park has one access route, therefore the need for ventilation is essential through natural or fan assisted requirements. With no heating and open walls to allow for supply, exhaust and smoke extraction, Fläkt Woods was able to provide the right solution.

The building developer for the car park is Mariehamn City Technical Services. Modern technical solutions were selected in order to reduce building and operating costs. The project was managed by Lars-Göran Åström from the Technical Services and the ventilation system was designed by Ture Karlsson from TURING AB. 

Compensation air is supplied through the openings in the walls.
Innovative Jet Thrust Fan Design

The car park is divided into four zones and has 13 jet thrust fans installed in the ceiling, a fan for normal extraction and smoke control as well as another fan for boosting smoke control in the common shaft. “The carbon monoxide content of the air controls the fans”, says Ture Karlson. “When the use of the car park is limited and the CO level is low, the exhaust fan runs at minimum output and the jet thrust fans are inactive. As the load increases and the CO concentration gets higher, the jet fans are powered up, steering the air masses towards the exhaust fan, which at that point runs at maximum output.”

Fläkt Woods system solutions has many advantages compared to a traditional ducted system, the ceiling mounted jet thrust fans are energy effective due to demand control. Installing a traditional ducted ventilation system is more expensive and it consumes more energy.

Jet thrust fans generate strong air flows along the ceiling, these air flows make the air masses in the car park migrate to its desired direction. With lower pressure, main extract fans can be used as they do not have to cope with system resistances found in ducted systems. At the Miramar Garaget car park the incoming air is supplied mainly through the openings in the walls. The jet fans make the air move towards the extract shaft, where a 1000 mm diameter axial fan blows the exhaust air outdoors.

All fans were run at maximum output to test the smoke extraction in the car park.

Demand Control Ventilation for smoke extraction

The air flow for normal ventilation at the Miramar Garaget car park is 10,2 m3/s and for smoke extraction the air flow is 23,5 m3/s. In case of a fire, the fire brigade will operate the equipment switching to boosted mode. Once the fire brigade has switched the smoke extraction system on, the axial fan that is on standby will start up at full speed, all other fans in the facility will also run at full speed to boost the flue gas extraction. Therefore allowing the fire brigade to focus on extinguishing the fire.

Antti Kontkanen from Fläkt Woods has sold the jet thrust fans for this project. According to Kontkanen, this system solution provides the customer with a facility where great emphasis is put on fire safety and energy efficiency. This project is the first on Åland to use the jet thrust system. Kontkanen believes that ducted systems in enclosed car parks are history. He says that the jet thrust system is exceptionally appealing for enclosed car parks with more than 3000 m2 of floor space. The simple installation of the system helps shorten the duration of the building project. Equally, the jet thrust fans do not require too much space. 

The 13 jet thrust fans at the Miramar Garaget car park endure two hours at the temperature of 300 °C. The exhaust air is taken out by a JMHT 100 axial fan and another similar axial fan only comes into operation in case of a fire. These large JMHT fans endure two hours at 400 °C.




It is also possible to supply warm exhaust air from the library building above to be used as circulated air
Consultant Ture Karlson (right) from Turing AB in Mariehamn has designed the ventilation and smoke extraction system for Miramar Garaget. On the left is project manager Lars-Göran Åström from the City of Mariehamn










For more information, please contact Antti Kontkanen,, +358 20 442 3270