Centrifugal High Output Blower

Allegro Centrifugal High Output Blower – Fast Purge Times for Large Confined Spaces

The Allegro 9504-50 Centrifugal High Output Blower is a heavy-duty ventilation unit engineered for larger confined space environments that demand faster purge times and reliable airflow. Built around a 3/4 HP cage-enclosed electric motor, it delivers higher CFM output than standard blowers, making it well-suited for construction, industrial, and manufacturing applications. The one-piece polyethylene housing in safety orange is both tough and lightweight, while dual 8" flanged ports support positive ventilation or fume extraction. UL Listed and CSA Certified to CSA Standard C22.2 No. 113, this blower meets recognized safety standards for professional use.

Technical Specifications

Available Items

Compared to lighter-duty ventilation fans, the 9504-50 combines a higher-output 3/4 HP motor with dual 8" flanged ports and a steel base for stability — a combination that supports both positive-pressure ventilation and fume extraction in demanding job-site conditions. The cage-enclosed motor and powder-coated steel components add a level of durability and operator protection not found in basic plastic blower units. UL Listing and CSA certification provide documented compliance for contractors working in regulated environments.

Key Features & Benefits

3/4 HP Cage-Enclosed Electric Motor

The 3/4 HP motor delivers higher CFM output than lower-rated blowers, enabling faster purge times in large confined spaces. The cage enclosure protects the motor from incidental contact and debris, extending service life on active job sites.

Dual 8" Flanged Ports

Both the intake and exhaust ports feature 8" (20.3 cm) flanges, allowing direct connection to standard ducting for positive ventilation or fume extraction. This flexibility lets contractors configure the blower to push fresh air in or pull contaminated air out depending on the application.

Tough, Lightweight Polyethylene Housing

The one-piece safety orange polyethylene housing resists impact and corrosion while keeping overall weight manageable at 52 lbs. The high-visibility color improves site safety by making the unit easy to spot in low-light confined space environments.

Powder-Coated 16-Gauge Steel Base

The heavy-gauge steel base with feet provides a stable platform that resists tipping during operation, an important consideration when running ducting in tight or uneven spaces. The powder-coat finish protects against rust and abrasion in harsh job-site conditions.

Integrated Carry Handle & On/Off Switch

The built-in carry handle allows a single worker to reposition the blower without additional equipment, reducing setup time between tasks. The on/off switch provides convenient, immediate control without requiring the operator to unplug the unit.

UL Listed & CSA Certified

Certification to CSA Standard C22.2 No. 113 and UL Listing confirm the blower meets recognized electrical safety requirements. This documentation supports compliance on regulated job sites and simplifies equipment approval processes for contractors.

Common Applications

Confined Space Ventilation

Designed specifically for larger confined space environments, the 9504-50 purges hazardous fumes and introduces fresh air quickly to meet entry safety requirements.

Fume Extraction

With ducting attached to the exhaust port, the blower draws contaminated air out of enclosed work areas during welding, painting, or chemical application tasks.

Construction Site Ventilation

Suitable for ventilating tunnels, utility vaults, manholes, and other below-grade or enclosed construction spaces where air quality must be maintained during active work.

Industrial & Manufacturing Environments

The durable polyethylene and steel construction withstands the demands of industrial facilities where continuous or repeated ventilation cycles are required.

Compatible Materials

• Standard 8" ventilation ducting (intake and exhaust)
• Confined spaces in concrete, steel, and masonry structures
• Utility vaults, manholes, and below-grade enclosures
• Industrial and manufacturing enclosures requiring air quality control

Frequently Asked Questions

Q: Is the 9504-50 available in a 220V international version?
A: Yes. The 9504-50E is the 220V AC / 50 Hz variant for international use. Note that the 9504-50E does not meet CSA C22.2 No. 113 requirements.

Q: What ducting size is compatible with this blower?
A: Both the intake and exhaust ports feature 8" (20.3 cm) flanges. Allegro recommends pairing the blower with compatible 8" ducting for optimal performance.

Q: Is the motor protected against contact or debris?
A: Yes. The 3/4 HP electric motor is cage-enclosed, providing protection for both the motor and the operator during operation.

Q: Can this blower be used for both positive ventilation and fume extraction?
A: Yes. The dual 8" flanged ports allow the unit to be configured for positive-pressure ventilation (pushing fresh air in) or fume extraction (pulling contaminated air out) depending on ducting setup.