The process
Basement car parks and tunnels use jet fans and extract fans rated for smoke extract, with silencers at the discharge. The fans run on carbon monoxide sensors in normal operation and at full speed in a fire.
The gas at the fan
Ambient air with vehicle exhaust, moved by jet fans and extract fans, with the smoke extract case setting the high temperature rating of the motor.
Selection for this duty
| Construction | Axial fans in weatherproof cowls, or supply and exhaust units with filters as the air quality requires |
| Density at the fan | At about 35°C the gas density is close to 1.15 kg/m³, 95% of standard air. Pressure developed and power drawn fall in the same ratio, so the selection is made at this density and the motor is checked at cold start. |
An axial fan in a weatherproof cowl mounted on an inclined or flat roof, exhausting hot air from the ridge of a factory shed. Client-stated blade types for the Roof Extractor in general: Axial.
Industries
Other fans in car parks and tunnels
Roof Extractor in other processes
Induction Furnace Melt ShopsForge ShopsIron and Non-ferrous FoundriesDyeing and Finishing HousesWelding and Fabrication ShopsTyre Curing PressesShipyard Hull and Block FabricationGenerator and Engine RoomsFactory Shed VentilationJute Mills
Information needed to select or quote
- Gas volume and temperature. Actual flow at the inlet, normal and upset temperature, moisture.
- Dust or pollutant. Inlet loading, particle size distribution, whether it is abrasive, sticky, hygroscopic or combustible; for gases, the species and concentration.
- Required outlet. The emission limit or clean gas concentration the unit must meet.
- Site. Available space and height, material of construction preferences, and how the collected material is to be discharged.