8" axial blower, light and compact, with compartment for ducting, choice of ducting, 15, 25 or 50 ft.

8" Axial Blower — Light, Compact, Integrated Canister, 831 cfm

The Allegro 8" / 20.32 cm diameter axial fan stands out for its light and compact design: the flexible duct is stored directly in a removable rigid canister attached to the blower by quick-clips, simplifying transport and storage on job sites. This blower can both extract (purge) or ventilate a confined space depending on the orientation chosen by the user: in extraction mode, it evacuates contaminated gases before entry; in ventilation mode, it pushes fresh air toward the worker inside. In practice, contaminated gases are extracted first, then a reading is taken with a gas detector equipped with a sampling pump (DETEC4GC); if everything is correct, the fan is reversed to push fresh air into the confined space. Because of the hazards of toxic vapours or particles in a confined space, be sure to equip your workers with gas detectors even if you have purged and ventilated the space. Allegro Industries manufacturer's codes: 9533-12, 9533-25, and 9533-50. This model is also available in 220V by special order.

The housing is made of lightweight polyethylene, a material that resists corrosion, UV rays, and most industrial chemicals, ensuring a long service life even in harsh environments. The nine polypropylene blades offer excellent resistance to moisture and chemical agents. The blower also features a powdered steel grill and a carrying handle moulded directly into the housing. According to the manufacturer, this compact blower is particularly quiet; however, it recommends wearing hearing protection for people working near the blower. The flexible duct is made of vinyl and polyester coated with PVC (polyvinyl chloride), with a class 1 steel frame, ASTM 227 standard, and nylon tie ends.

Motor Specifications

• Power: 1/3 HP
• Supply: 115 Volts AC, 60 Hz, 1 phase
• RPM: 2800 (at 115 VAC, 60 Hz)
• Current: 4.5 A (60 Hz)
• Power cord: 10 feet / 3.05 m AWG
• Plug type: NEMA 5-15P

Blower Specifications

• 9 polypropylene blades
• Airflow: 831 cfm / 1411.87 m³/h without ducting
• Powdered steel grill
• Moulded carrying handle
• Lightweight polyethylene housing
• Connection rings on both sides for duct attachment
• Flexible duct stored in removable rigid canister (quick-clips)

Duct Specifications

• Diameter: 8" / 20.32 cm
• Available lengths: 15 ft / 4.57 m, 25 ft / 7.62 m, or 50 ft / 15.2 m
• Material: vinyl and polyester coated with PVC (polyvinyl chloride)
• One ply
• High temperature resistant up to 180°F / 82.22°C
• Compressible for easy storage
• Class 1 steel frame
• Meets ASTM 227 standards
• Nylon tie ends

Advantages of the RA9533 Axial Blower for Your Job Sites

Light, Compact, and Easy to Carry

The integrated design of the RA9533 is its main strength in the field: the flexible duct stores directly in the removable rigid canister attached to the blower by quick-clips, no tools required. The whole unit forms a single easy-to-carry package, ideal for workers who need to move between multiple access points in the same workday. The polyethylene housing helps keep weight low without sacrificing durability.

Versatile Exhaust/Ventilation Operation

The connection rings on both sides of the housing allow a quick switch from exhaust mode to ventilation mode simply by reversing the fan. No tools are required for this operation, which represents a significant time saving during confined space interventions.

Built to Withstand Industrial Environments

The polyethylene housing combines light weight with resistance to chemical attack, UV rays, and corrosion. The polypropylene blades will not rust and resist water and common job-site chemicals. The vinyl/polyester PVC-coated flexible duct withstands temperatures up to 180°F / 82.22°C and compresses easily for storage.

Industries and Work Sites Where This Product Is Required

• Municipalities — inspection and maintenance of sewer manholes, valve chambers, and underground reservoirs
• Oil and gas (non-explosive spaces) — tanks and vessels
• Chemical and pharmaceutical — cleaning or inspecting reactors and mixing tanks
• Food processing — cleaning grain silos and fermentation tanks
• Civil engineering and construction — work in wells, caissons, and deep trenches
• Utilities — maintenance of underground electrical vaults and utility galleries
• Water treatment — pump wells, settling basins, and buried structures
• Mining (non-explosive atmosphere spaces) — underground confined spaces

Installation Tips and Usage Guidelines for the RA9533

The manufacturer recommends installing the blower more than 5 feet from the opening entrance. To choose the safest location, make the wind your ally: when purging, position the blower and yourself so that fumes disperse with the wind without returning toward you; when ventilating, place the blower with your back to the wind to avoid gas mixtures expelled from the confined space.

If you wish to replace your ventilation duct, two replacement lengths are available for this 8" model: 15 ft / 4.57 m and 25 ft / 7.62 m, available under references RA9500-15 or RA9500-25. If your blower needs a small repair, you can also consult the list of components under the download tab.

To choose the right blower for your confined space, we recommend using the application developed by Allegro Industries. This application allows you to select the correct fan based on the specific parameters of your space: gas hazard level (explosive or not), size and shape of the space, number of duct elbows, and more. First read the user guide (in English only): https://www.allegrosafety.com/how-to-use-our-confined-space-blower-selector/ — then access the blower selector directly: https://www.allegrosafety.com/blower-selector/.

FAQ — Allegro RA9533 Axial Blower

Is this blower explosion-proof?

No. The RA9533 is designed to ventilate confined spaces that do not present an explosion hazard. If your confined space contains or may contain flammable gases or vapours, you must use the explosion-proof model RA9548-25EX.

What is the difference between exhaust and ventilation with this blower?

In exhaust (purge) mode, the blower removes contaminated, toxic, or oxygen-depleted gases from the confined space before entry. In ventilation mode, it pushes fresh air inside to maintain a breathable atmosphere while workers operate within the space. To switch modes, simply reverse the blower — the connection rings on both sides make this a quick, tool-free operation.

What duct length should I choose for the RA9533?

Three lengths are available with this blower: 15 ft (4.57 m), 25 ft (7.62 m), and 50 ft (15.2 m). The choice depends on the depth of the confined space and the number of elbows in your installation. For typical situations, 25 ft is often a good compromise. For deeper spaces or more complex configurations, use the Allegro blower selector (see the Installation section above) to confirm sufficient airflow will be maintained.

Complementary Equipment Suggestions for Your Confined Space Ventilation

To complete your ventilation setup, the 8" flexible replacement duct in 15 or 25 ft (RA9500) fits directly onto this blower, and the weatherproof 50 ft 15 A extension cord (RA9540-50) extends power to the source. The manhole vent passage assembly (RA9510) maintains airflow at the opening while keeping access available. For atmosphere monitoring, the complete Altair 4X 4-gas detector kit with pump (DETEC4GC) is essential even after purging.

For confined space entry safety equipment, the Peakworks 6 D-ring confined space harness (FPH2000APLE) protects the worker during descent, and the Peakworks heavy-duty bag for fall protection equipment (FPBAG) makes it easy to carry that gear on site. The Peakworks 3-way confined space rescue kit with winch (FPLRK3) ensures recovery if needed, and the manhole barrier (EPTBB) secures the perimeter around the opening.

The texts coloured in green correspond to hyperlinks leading to specific safety equipment or to a general information link.