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Choosing filter fans for outdoor electrical enclosures: Key considerations

filter fans

When selecting filter fans for outdoor electrical enclosures, assessing heat load, environmental exposure, and expert advice play crucial roles. From electrical equipment to environmental considerations, here are expert tips for smart selection.

Filter fans are devices designed to safeguard electrical enclosures by controlling heat and preventing the entry of liquid and solid particles. They provide an additional layer of protection, reducing thermal load and filtering out particles larger than 5 microns, ensuring the safety and optimal functioning of enclosed equipment.

Understanding filter fans: their role in protecting electrical enclosures
Filter fans safeguard electrical enclosures from external environmental harm, managing heat and preventing the entry of liquid and solid substances. They offer an added shield, reducing thermal load and sieving out particles above 5 microns, ensuring equipment safety. The combination of dual fans and filters maintains ideal temperatures and curbs dust accumulation and damage.

When choosing a filter fan, evaluating the enclosure’s heat load, required temperature, and operating environment is crucial. For outdoor setups, factors like rain, snow, ice, and sunlight pose specific risks to electrical equipment and should be considered.

 Filter fans protect electrical enclosures from external environmental damage. From heat control to mitigating the ingress of liquid and solid objects, filter fans provide another layer of protection for the electrical equipment housed within enclosures. Filter fans protect critical equipment by reducing thermal load and filtering out airborne particles larger than 5 microns. The dual fan and filter composition keeps electrical equipment running at optimal temperatures while mitigating dust and other particulate matter from causing buildup and damage.

When selecting a filter fan for an enclosure, it’s important to consider the application’s heat load, optimal temperature, and environmental conditions in which it will be operating. Environmental considerations are particularly important for outdoor enclosures, as rain, snow, ice, and sunlight pose risks to electrical equipment.

Challenges for outdoor applications
Filter fans are necessary for a wide range of outdoor electrical equipment. Some applications, however, require intentionality and extra consideration when choosing the appropriate filter fan. These include irrigation pump panels, water and wastewater, lighting control boxes for traffic signals or fields and stadiums, outdoor communication and information technology structures, energy storage and charging systems (such as in electric vehicles), and transportation systems, including bridges, toll stations, and electrical rail equipment.

When properly designed and integrated, outdoor filter fans can provide an energy-efficient heat load maintenance solution while protecting enclosures from dust, ice, water, and sunlight. However, many filter fans do not effectively protect critical electrical equipment.

When improperly designed, filter fans can be subject to ice and dust buildup or damage from UV radiation and rainwater. These conditions can cause short-circuiting within the enclosure. While there are workarounds for water infiltration, such as adding a rain hood, these additional steps increase space requirements and initial investment costs.

Tips for selecting the correct filter fan
Considering these challenges, there are some tips or key factors to consider when selecting a filter fan for an outdoor electrical enclosure.

Consider heat load and environment.
Selecting an outdoor filter fan begins with determining the application’s heat load and airflow requirements while considering environmental exposure. Electrical enclosures in dry, hot weather require different filter fan needs than those used in areas with snow, ice, and highly variable temperatures. A filter fan that can accommodate each of these possibilities is best for applications where environmental conditions cannot be determined ahead of time.

While determining application needs, it is beneficial to consult with an expert to help determine specific risk factors. An expert can help with considerations around which airborne particulates are present and if they are corrosive, what ambient temperatures can be expected and how direct or indirect sunlight can affect operating temperatures. 

The Pfannenberg Outdoor Rated Filterfan® (NEMA 3R rated) is designed for outdoor weather where direct sunlight and extreme weather, like rain and ice formation, are important factors. This filter fan utilizes UV-resistant plastics to prevent premature degradation from direct sunlight. Additionally, the filter fan’s design protects against the ingress of falling dirt, rain, sleet, snow, and even external ice formation.

Weight maintenance needs
Filter fans generally require little maintenance outside of regular filter replacement. However, it is crucial to change the filter as specified by the manufacturer, as filter clogs reduce airflow, causing extra strain on the fan and increasing the potential for overheating.

Well-designed filter inserts provide longer service life, including the filter for Pfannenberg’s Outdoor Rated Filterfan® described above. Pfannenberg’s fluted filter-mat enables longer mean time between maintenance, delivering three times longer service life than standard designs. It accomplishes this with its increased dust-holding capacity. As a result, the need for service is reduced, saving maintenance time, costs, and stress, which is especially helpful for electrical enclosures located in remote areas.

Balance protection, airflow, and initial investment costs
Filter fans for outdoor applications require a design that balances airflow optimization with low initial investment. A filter design that minimizes maintenance needs should also ensure unrestricted airflow throughout the fan’s service life. However, it must do so without compromising on water and dust protection capabilities. Combining a filter that fits these needs with a filter fan housing design that does not require metal rain hoods achieves an excellent balance of protection, airflow management, and minimizing upfront costs.

Filter fans protect electrical equipment against overheating, moisture, and airborne particles, ensuring safe and efficient operation. Outdoor environments pose unique challenges, demanding thorough research to find a suitable filter fan without major drawbacks. Assessing heat load, environmental factors, and maintenance requirements before choosing a filter fan can help manage costs. Whether it is pump panels, lighting control boxes, communication tech, or energy storage systems, adeptly chosen filter fans maintain the functionality and safety of outdoor electrical equipment.


Expertise shared by- Lucas Faulkner, Solutions Engineer, Pfannenberg USA.

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