What to Consider When Choosing a Fan System for Disaster Recovery

Fans are an important component in disaster recovery equipment. After a client experiences hurricane, flood or water damage, it’s important to select a fan and damper system that can effectively assist with your recovery efforts and maximize efficiencies. By understanding how a fan system affects performance in regards to the needs of the space, you’ll have a better idea about the best fan and damper design for your project.

Considerations for Selecting a Fan for Disaster Recovery Equipment

• Motor type: A fan’s motor affects its size, maintenance requirements, weights and energy efficiencies.
• Avoiding System Effect: A System Effect occurs when: 1) An inlet is not fully developed, symmetrical or swirl-free, and 2) Outlet ducting does not allow a fan’s asymmetrical flow profile to diffuse and approach a fully developed flow. When a System Effect occurs, a fan will not achieve its rated performance.
• Fan speed: Increases in fan speeds that exceed the maximum safe velocity can damage its structural elements, exponentially increase energy inefficiencies, cause increased noise, and result in duct and fitting leaks. Match a fan’s maximum operating speed to the motor’s capacity, power requirements, the size of the space and the speed needed to overcome a System Effect.
• Type of installation: Refer to the manufacture’s literature regarding the installation type it modeled when it tested the fan. If your installation doesn’t match the type the manufacturer used in its test, you may experience a System Effect.
• Safety features: In 1997, the U.S. Department of Energy estimated that 60 percent of the fans in building systems were oversized because of the safety features included in the designs. Manufacturers sometimes include safety features to compensate for uncertainties in a fan system’s design or because of assumed higher pressure requirements. Incidentally, fans that have multiple safety features may not operate as efficiently, quietly and stably as they could.
• Volume flow rates and pressure: The best type of fan, blades and speed depends on a system’s pressure and volume flow rate. Propeller fans, for example, are best for moving air against low pressure, while centrifugal fans are may work better with high-pressure systems.

Fan Damper Selection Considerations

Each fan system has requirements regarding how to control air volume. Dampers offer a low-cost and low-maintenance option to control airflow in a fan system. In some types of fans, dampers come standard. Most of the time, however, you’ll find them as an accessory that you must tailor to fit the needs of your application, control sensitivities, temperature needs, and the disaster recovery equipment.

Dampers types include:

• Those that you install on a fan’s inlet, outlet or in a different location within the system
• Automatic, motor-operated or manually operated dampers, as well as modulated control dampers
• Light to heavy construction designs
• Different blade types, shapes and arrangements

When considering the type of damper to choose for a fan system, consider the following factors:

• Cost, including initial costs and operating costs
• Air volume control requirements
• Horsepower, as it relates to air volume and power consumption
• The distribution of air after the fan
• Temperatures
• Airborne particulates
• The presence of corrosives

Choosing the right fan system for disaster recovery equipment can optimize its performance and efficiencies. The best design is a properly engineered fan system that followed a tailored approach based on the type of damage that a building experienced. At Polygon, our engineers design custom disaster recovery equipment based on your needs, the building and the damage it suffered to complement your recovery efforts. We’re happy to supply all the rental equipment—from inlet/outlet transitions to transformers—so you can focus on the other aspects of a restoration. Contact Polygon today to schedule a complimentary consultation and receive a free estimate.

[Photo from kov-A-c via CC License 2.0]