Description
|
MODEL |
VOLTAGE – POWER – RPM |
AIR FLOW |
Thrust Power (N) |
LENGTH |
EXPLANATION |
|
FJF-AK 315-2 |
380 (V) 1.10 Kw 2.900 rpm |
4,500 m3/h |
24N |
1626mm |
Axial Jet Fan |
|
FJF-AK 315-2-4 |
380 (V) 1.00 /0.25 KW 2.900 /1.410 rpm |
4,500 /2,250 m3/h |
24N |
1776mm |
Axial Jet Fan |
|
FJF-AK 355-2 |
380 (V) 1.50 Kw2.900 rpm |
6,500 m3/h |
40N |
2006mm |
Axial Jet Fan |
|
FJF-AK 355-2-4 |
380 (V) 1.30 /0.33 Kw 2.900 /1.430 rpm |
6.500 /3.250 m3/H |
40 n |
2476mm |
Axial Jet Fan |
| What is a Jet Fan Used for? | |
| Jet fans are used simultaneously for normal ventilation function and smoke evacuation functions. In parking lot ventilation systems that operate in a certain scenario, they also serve for smoke evacuation when ventilation is required in foreseen situations. Jet fans, which work under the guidance of air quality sensors and smoke detectors installed in parking areas, start to operate in the first stage when the indoor air quality deteriorates, and if any smoke is detected, the fans are activated in the second stage. Jet fans are driven by two-speed motors. The fact that land costs have reached high values in large metropolises has made it necessary to build multi-storey buildings. Building as many floors as possible at the altitude between the foundation and the roof determined by the building control and licensing organizations, forcing the height of the floors to be used for parking purposes to be at the minimum level, and code losses resulting from mechanical installations have made jet fans necessary in this regard. In parking lots that are ventilated with a jet fan, it allows the air to be directed to certain sections without the need for air ducts. | |
| Advantages of Jet Fan Systems Compared to Other Systems: | |
| Jet fan systems can operate without the need for air ducts or other installations to transfer air. In large volume areas, the project is solved at much more affordable costs than air duct connected systems. Jet fan ventilation systems integrated with automation systems can be easily used from control centers. |
Basic Theory of Jet Ventilation System
In parking lots, jet fans can be used instead of air ducts to evacuate both CO and explosive gasoline gases (CH4). The presence of carbon monoxide in parking lots is an indication that other harmful gases (for example, benzene) are also present. As a result, German authorities have reduced the CO limits in car parks from 100 ppm to 50-60 ppm, depending on the federal state concerned. The ventilation system is activated by sensors that monitor the CO and CH4 levels in the parking lot. The number of sensors required depends on the general layout of the car park and varies from one per 100 m2 to one per 500 m2. CH4 sensors are generally mounted close to the ground (approximately 30 cm above the ground), while CO sensors are mounted at head level (approximately 150 cm above the ground). If sensors with 4-20 mA output are used, they can be connected to a CTS control system to adjust the permissible limits.
Figure 4 shows a possible closed system design consisting of jet fans and an extractor fan mounted on a shaft. The evacuation unit generally consists of a grill, an aspirator and, if necessary, a noise absorber. When the setting limit is exceeded, the aspirator starts to operate first, followed by the jet fans. In open car parks where no ventilation system is required, natural ventilation can be supported by jet fans. This prevents “dead” areas from forming. The same applies to car parks that fail to meet the open parking requirements by a very small margin. In such facilities, the relevant conditions can be met by using jet fans alone. In such cases, the best solution is usually to use 100% reversible axial fans. These fans can provide the same thrust force in both directions. Thus, the flow direction can be changed according to wind conditions.
Figure 4 shows a possible closed system design consisting of jet fans and an extractor fan mounted on a shaft. The evacuation unit generally consists of a grill, an aspirator and, if necessary, a noise absorber. When the setting limit is exceeded, the aspirator starts to operate first, followed by the jet fans. In open car parks where no ventilation system is required, natural ventilation can be supported by jet fans. This prevents “dead” areas from forming. The same applies to car parks that fail to meet the open parking requirements by a very small margin. In such facilities, the relevant conditions can be met by using jet fans alone. In such cases, the best solution is usually to use 100% reversible axial fans. These fans can provide the same thrust force in both directions. Thus, the flow direction can be changed according to wind conditions.
Jet Ventilation for Smoke Control
Many conditions, both technical and legal, must be taken into account regarding fire control in underground car parks. In Denmark, the relevant standards are still under preparation. These standards will be based on functional conditions rather than the system, but the details are not yet known. Previously, fire protection requirements were based on walls, doors, entrances, horizontal partitions and sprinkler systems. All of these delay or even stop the spread of fire. However, most of the casualties during a fire are caused by the smoke rather than the fire itself. That’s why smoke extraction systems must perform various functions. These include the following functions:
– Evacuating the smoke to allow people in the parking lot to escape without being affected by the smoke.
– Controlling smoke in a way that allows firefighters to enter the parking lot, control the fire, and get close enough to extinguish it.
Certain conditions are also frequently imposed by local fire authorities. It should be noted that due to the relatively low ceiling height in underground car parks (about 2.5 m), there are no smoke-free floors left in the event of a fire. The area around the fire will soon be filled with smoke and this smoke will begin to spread around. Figure 5 gives an example of this situation. On the one hand, fresh air is taken in by axial flow fans and used air is discharged, on the other hand, the air inside is carried within the parking lot by jet fans.
In case of a fire, the jet fans are turned off in accordance with the required smoke evacuation speed and the fresh air and exhaust fans are operated at the highest power. This allows anyone who may be in the parking lot to escape. After the building is evacuated or the fire brigade arrives, jet fans start working and push the air towards the aspirator. This has two benefits:
– First, smoke accumulates within a relatively limited area (see Figures 5a and 5b), which allows the location of the fire to be located and extinguished.
– Second, it keeps the temperature near the fire low so firefighters can get closer to the fire.
– Another benefit is that the damage to the building is minimized thanks to the large amount of air cooling the smoke and building surfaces.
It should be noted that smoke control in relation to CO ventilation requires that the amount of air taken in and discharged be many times higher. The system must therefore be sized for smoke control if necessary. Using jet fans for smoke control requires detailed analysis of all possible fire scenarios.
– Where are the escape routes?
-How long does it take to vacate the parking lot?
– What is the likely size of a fire? What happens if more than one vehicle catches fire?
– How much smoke is expected, how hot can the smoke be, how can it affect visibility?
– How long does it take for the fire department to arrive?
– What is the action plan to use in case of fire?
– Where can the smoke be evacuated?
– How can a vehicle fire progress?
As can be seen from the above explanations, it is clear that the local fire department has an important role. For this reason, planning must be done in cooperation with fire authorities.
– Evacuating the smoke to allow people in the parking lot to escape without being affected by the smoke.
– Controlling smoke in a way that allows firefighters to enter the parking lot, control the fire, and get close enough to extinguish it.
Certain conditions are also frequently imposed by local fire authorities. It should be noted that due to the relatively low ceiling height in underground car parks (about 2.5 m), there are no smoke-free floors left in the event of a fire. The area around the fire will soon be filled with smoke and this smoke will begin to spread around. Figure 5 gives an example of this situation. On the one hand, fresh air is taken in by axial flow fans and used air is discharged, on the other hand, the air inside is carried within the parking lot by jet fans.
In case of a fire, the jet fans are turned off in accordance with the required smoke evacuation speed and the fresh air and exhaust fans are operated at the highest power. This allows anyone who may be in the parking lot to escape. After the building is evacuated or the fire brigade arrives, jet fans start working and push the air towards the aspirator. This has two benefits:
– First, smoke accumulates within a relatively limited area (see Figures 5a and 5b), which allows the location of the fire to be located and extinguished.
– Second, it keeps the temperature near the fire low so firefighters can get closer to the fire.
– Another benefit is that the damage to the building is minimized thanks to the large amount of air cooling the smoke and building surfaces.
It should be noted that smoke control in relation to CO ventilation requires that the amount of air taken in and discharged be many times higher. The system must therefore be sized for smoke control if necessary. Using jet fans for smoke control requires detailed analysis of all possible fire scenarios.
– Where are the escape routes?
-How long does it take to vacate the parking lot?
– What is the likely size of a fire? What happens if more than one vehicle catches fire?
– How much smoke is expected, how hot can the smoke be, how can it affect visibility?
– How long does it take for the fire department to arrive?
– What is the action plan to use in case of fire?
– Where can the smoke be evacuated?
– How can a vehicle fire progress?
As can be seen from the above explanations, it is clear that the local fire department has an important role. For this reason, planning must be done in cooperation with fire authorities.
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