20" Axial AC Standard Metal Blower

Allegro 20" Axial AC Standard Metal Blower — High-Volume Ventilation for Large Confined Spaces

The Allegro 9525 is a 20-inch axial AC blower engineered for maximum airflow output in demanding construction, industrial, manufacturing, and confined space ventilation applications. Built around a 16-gauge cold rolled steel housing powder-coated in safety orange, this unit delivers up to 4,650 CFM of free-air flow from a 1/2 HP motor running on 115V AC. Designed for contractors and trades professionals who require a durable, portable, and certified ventilation solution, the 9525 is UL Listed and certified to CSA Standard C22.2 No.113.

Technical Specifications

Available Items

Compared to smaller-diameter axial blowers in the Allegro lineup, the 20" 9525 delivers substantially higher free-air CFM than the 16" standard metal blower (3,400 CFM) while remaining in the standard output class — making it the right choice when large-area ventilation is needed without stepping up to a 2 HP high-output motor. For applications requiring even greater airflow, Allegro also offers the 20" High Output Metal Blower (9525-50) at 2 HP and 7,500 CFM free air, and an explosion-proof variant (9525-01) for hazardous environments.

Key Features & Benefits

High-Volume Axial Airflow

Delivering 4,650 CFM in free air, 3,150 CFM through one 90° bend, and 2,950 CFM through two 90° bends, this blower is designed for applications requiring a maximum amount of output. The axial design is optimized for high airflow with lower pressure, making it well-suited for shorter duct runs and spaces where moving large volumes of air quickly is the priority.

16-Gauge Cold Rolled Steel Housing

The heavy-duty steel housing withstands the rigors of job site use while the powder-coated safety orange finish provides high visibility and corrosion resistance. This construction ensures longer blower life and helps lower total cost of ownership over time.

Interchangeable Flange for Intake or Exhaust Mounting

The interchangeable flange allows the blower to be configured for either intake (supply) or exhaust (extraction) ventilation without additional hardware. This flexibility lets contractors adapt the unit to the specific ventilation strategy required for each confined space entry.

Glass Reinforced Polypropylene Three-Blade Fan with Aluminum Hub

The PPG three-blade impeller is engineered to move high volumes of air efficiently within the steel housing. The aluminum hub provides a secure, durable connection between the blade assembly and the motor shaft.

Integrated Carrying Handles

Built-in carry handles make it straightforward to transport the blower to and from the job site, even in tight access situations. The 4 rubber feet provide stable placement on uneven surfaces once positioned.

UL Listed and CSA Certified

The 9525 is UL Listed and certified to CSA Standard C22.2 No.113 (Fans and Ventilators), giving contractors and safety managers documented assurance that the unit meets recognized North American product safety standards. International wiring configurations (9525-E) are also available for global project requirements.

Common Applications

Confined Space Ventilation

Provides fresh air supply or contaminant extraction in manholes, vaults, tunnels, vessels, and other permit-required confined spaces prior to and during worker entry, in compliance with OSHA ventilation requirements.

Construction Site Ventilation

Moves large volumes of air through enclosed structures, basements, or partially completed buildings to control dust, fumes, and humidity during active construction phases.

Industrial Facility Ventilation

Supports air quality management in manufacturing plants, distribution centers, and industrial facilities where high-volume airflow is needed across large open areas or through ductwork with minimal bends.

Manufacturing Process Ventilation

Exhausts process fumes, heat, or airborne particulates from manufacturing work zones, helping maintain safe ambient air conditions for workers.

Ductwork, Hoppers, Silos, and Storage Bins

Suitable for ventilating enclosed storage structures and process vessels where large-diameter, high-CFM airflow is required to purge or refresh the internal atmosphere.

Compatible Materials

• Standard (non-hazardous) atmospheres in confined spaces
• Construction site enclosures and partially completed structures
• Industrial and manufacturing work zones
• Ductwork systems with minimal 90° bends
• Manholes, vaults, tunnels, and pipelines
• Hoppers, silos, storage bins, and vessels

Product Documents

• Allegro Ventilation Blowers Linecard

Frequently Asked Questions

Q: What is the free-air CFM rating of the 9525?
A: The 20" Axial AC Standard Metal Blower (9525) delivers 4,650 CFM in free air, 3,150 CFM through one 90° bend, and 2,950 CFM through two 90° bends.

Q: Can this blower be used for both intake and exhaust ventilation?
A: Yes. The interchangeable flange allows the 9525 to be mounted for either intake (supply air) or exhaust (extraction) configurations without additional hardware.

Q: Is the 9525 available in an international wiring configuration?
A: Yes. The 9525-E variant is wired to meet international standards for use outside the US.

Q: Is this blower suitable for use in hazardous (explosive) atmospheres?
A: No. The standard 9525 is rated for non-hazardous environments only. For hazardous locations, Allegro offers the 20" Axial Explosion-Proof Metal Blower (9525-01 / 9525-01E).

Q: What certifications does the 9525 carry?
A: The 9525 is UL Listed and certified to CSA Standard C22.2 No.113 (Fans and Ventilators).

Q: How far should the blower be set back from a confined space opening?
A: Allegro recommends setting the blower back a minimum of five (5) feet from the opening when ventilating a manhole or tank, to prevent hazardous gases purged from the confined space from being drawn back into the blower intake and recirculated into the space.