Roof Exhaust Fans

Product Overview

Heavy-duty industrial roof exhaust fans provide direct mechanical air extraction for commercial, industrial, and institutional facilities. These units mount directly onto roof curbs to continuously extract contaminated air, process heat, humidity, and chemical fumes from enclosed spaces. Standard configurations feature an upblast discharge design, direct-drive or belt-driven motor assembly, heavy-gauge housing, and gravity-operated backdraft dampers to prevent backflow when inactive. Built for continuous-duty operation in harsh outdoor environments, these units comply with AMCA air and sound performance standards.

Direct Drive Roof Exhaust Fan
The Direct Drive Roof Exhaust Fan is a roof-mounted ventilation unit engineered for continuous exhaust applications in commercial and industrial facilities.
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Low Profile Roof Exhaust Fan
The Low Profile Roof Exhaust Fan is engineered for continuous mechanical exhaust in facilities with strict architectural height restrictions, low clearance limits, or high wind load requirements.
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High Volume Roof Exhaust Fan
Industrial High Volume Roof Exhaust Fans provide continuous, heavy-duty air extraction for large-span manufacturing plants, logistics warehouses, and commercial facilities requiring high...
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Centrifugal Roof Exhaust Fan
The Centrifugal Roof Exhaust Fan is a weather-resistant, curb-mounted ventilation unit engineered to extract high volumes of contaminated air, heat, or moisture from commercial and industrial...
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Axial Roof Exhaust Fan
The Industrial Axial Roof Exhaust Fan is engineered for high-volume, low-static-pressure exhaust applications across commercial and industrial facilities.
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Industrial Roof Exhaust Fan
Heavy-duty industrial roof exhaust fans engineered for continuous-duty extraction of hot air, noxious fumes, steam, and particulate-laden air from large industrial and commercial facilities.
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Key Features

01/

Upblast Discharge Configuration: Forces contaminated air, smoke, or grease-laden vapors straight up and away from the roof surface, protecting roofing membranes from chemical degradation and heat damage.

02/

Corrosion-Resistant Housing Construction: Built from heavy-gauge marine-grade aluminum (Alloy 3003/5052) or hot-dip galvanized steel finished with exterior-grade polyester powder coating.

03/

Precision-Balanced Impellers: Backward-inclined centrifugal wheels or high-efficiency axial blades dynamically balanced to ISO 1940 Grade 6.3 standards to minimize mechanical vibration and bearing wear.

04/

Drive Options: Direct-drive configurations eliminate belt maintenance and power transmission losses; belt-drive configurations allow adjustable airflow performance via variable pitch sheaves.

05/

Integrated Curb Cap Base: One-piece heavy-gauge spun aluminum or welded steel base featuring pre-punched mounting holes for leak-proof installation onto standard roof curbs.

06/

Gravity-Operated Dampers: Lightweight aluminum butterfly dampers open automatically upon fan pressurization and seal tightly when offline to prevent thermal loss and weather infiltration.

Technical Specifications

Parameter	Specification Range	Unit / Standard
Airflow Capacity	1,000 - 50,000	CFM (1,700 - 85,000 m3/h)
Static Pressure	Up to 750	Pa (3.0 in. wg)
Impeller Diameter	300 - 1,200	mm (12 - 48 inches)
Motor Power	0.18 - 22	kW (0.25 - 30 HP)
Voltage / Frequency	208-460V, 3PH, 50/60Hz	IEC / NEMA compliant
Motor Protection	IP55 / IP56 (Class F Insulation)	IEC 60034
Operating Temp.	-40C to +80C	Standard industrial duty
Housing Material	Aluminum 5052 / Galvanized Steel (14-18 Gauge)	ASTM B209 / ASTM A653

Construction & Working Principle

The assembly consists of four primary structural blocks: The curb cap base, windband housing, motorized impeller module, and butterfly discharge dampers.

Air Intake: Internal negative pressure draws air upward through the roof penetration opening into the fan inlet cone.

Air Acceleration: The motorized impeller imparts kinetic energy to the airstream.

Discharge: Air is redirected vertically through the windband. Velocity pressure forces the aluminum butterfly dampers open, discharging exhaust gases safely above the roofline. When power cuts, gravity snaps the dampers shut, sealing the building interior against rain, debris, and thermal drafts.

Applications

Manufacturing & Machining Plants

Removes welding fumes, machining oil mist, and localized heat loads from production floors.

Commercial Kitchens & Restaurants

Extracts grease-laden cooking vapors through UL-762 certified restaurant exhaust configurations.

Chemical & Wastewater Facilities

Vents corrosive gases utilizing specialized fiberglass-reinforced plastic (FRP) or epoxy-coated internal components.

Warehouses & Logistics Centers

Relieves thermal stratification beneath large metal roofs during summer months.

Available Options

Explosion-Proof Motors: ATEX or Class I, Division 1 / Division 2 explosion-proof electrical packages for volatile environments.

Special Coatings: Acid-resistant phenolic coatings, coal tar epoxy, or marine-grade anodization for coastal and chemical plant installations.

Vibration Isolation Springs: Seismic and wind-load rated spring isolators or rubber-in-shear mounts for rooftop structural protection.

Bird Screens & Security Guards: Heavy-duty welded wire mesh screens compliant with OSHA safety mandates.

Inverter Duty Motors: Compatible with Variable Frequency Drives (VFDs) for dynamic airflow regulation tied to building automation systems (BAS).

Manufacturing & Quality

Production utilizes automated CNC laser cutting, CNC turret punching, and robotic MIG/TIG welding cells housed in a 35,000-square-meter facility. Sheet metal components are formed on CNC press brakes to maintain strict dimensional tolerances (± 0.5 mm).

Balancing Protocol

Every completed impeller assembly undergoes dual-plane electronic dynamic balancing on Schenck balancing rigs to verify residual unbalance remains below ISO 1940 Grade 6.3 limits.

Electrical Testing

100% of assembled motor-fan units undergo dielectric strength testing (1,500V for 1 minute) and full-load running current checks prior to packaging.

Surface Treatment

Steel parts pass through a 7-stage iron phosphate wash system before electrostatic powder application, achieving salt-spray corrosion resistance exceeding 1,000 hours per ASTM B117 standards.

Certifications

ISO 9001:2015 quality management system compliance; motors carry CE, UL, and CSA electrical certifications.

FAQ

Q: What is the maximum static pressure this exhaust fan can handle in a duct system?

A: Standard centrifugal upblast models maintain stable operation up to 750 Pa (3.0 in. wg). For extended duct runs exceeding this threshold, inline centrifugal or utility set fans should be specified instead of direct roof exhausters.

Q: How do you prevent rainwater from leaking into the building through the roof curb?

A: The unit features an integrated structural curb cap with an engineered overhanging drip edge. When paired with a properly flashed roof curb and closed-cell neoprene gasketing between the curb top and fan base flange, the joint forms a watertight seal rated for wind-driven rain.

Q: Can these fans be tied to a Variable Frequency Drive (VFD) for demand-controlled ventilation?

A: Yes. When ordered with inverter-duty rated motors (NEMA MG1 Part 31 compliant), the fans operate safely across a frequency range from 30Hz to 60Hz without overheating or bearing fluting issues.

Q: What is the standard lead time for bulk project orders?

A: Standard configurations ship within 15 to 20 business days. Custom engineered units requiring special voltage motors, protective coatings, or specific airflow performance curves require 25 to 35 business days.

Q: Are replacement parts such as belts, bearings, and motors locally interchangeable?

A: Yes. All drive components, pulleys, pillow-block bearings, and motors utilize standard metric or NEMA industrial frame sizes sourced globally from tier-one manufacturers (e.g., SKF, ABB, Siemens), ensuring straightforward local maintenance.

Q: What packaging methods are used to prevent damage during ocean freight?

A: Units are bolted onto fumigation-free heat-treated wooden skids, wrapped in heavy-duty polyethylene moisture barrier film, and secured inside reinforced export-grade corrugated wooden crates to prevent transit impact and forklift damage.

Request a Quote

To receive a formal quotation, engineering data sheets, or performance curves for your project requirements, submit your specifications below:
Required Airflow (CFM or m3/h)
Static Pressure (Pa or in. wg)
Electrical Supply (Voltage / Phase / Frequency)
Special Environment Requirements (Corrosive, Explosion-Proof, High Temperature)
Target Quantity & Delivery Port

With abundant experience, we are one of the most reliable roof exhaust fans manufacturers and suppliers in China. Please feel free to wholesale high quality roof exhaust fans made in China here from our factory. We also accept customized orders.