The process
Confined space work inside hull blocks and tanks needs forced ventilation through flexible ducting, fume extraction at the welding, and roof extractors in the fabrication sheds.
The gas at the fan
Ventilation air for tanks and compartments during fabrication, with welding fume and blasting dust. Portable and fixed axial and centrifugal fans with flexible ducting.
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 shipyard hull and block fabrication
Roof Extractor in other processes
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.
