Power Roof Ventilators (Upblast Fan)
Roof-mounted upblast ventilator with rhombus hood, weather-tight curb cap and aluminium impeller.
About the Power Roof Ventilators (Upblast Fan)
A power roof ventilator (PRV) discharges contaminated indoor air vertically away from the building so it does not get re-entrained into outdoor-air intakes or stick to the roof. The upblast configuration — exhaust pointed straight up — is the building-code default for kitchen and grease exhaust because it lifts plumes well above the roofline. Our PRVs use a rhombus-shaped hood with side cooling fins, so the motor stays in the cool, dry, free-air space rather than sitting in the contaminated air stream.
Engineering Advantages
Vertical discharge prevents recirculation through fresh-air intakes — building-code preferred for contaminated exhaust
Motor in the airstream-free zone runs cooler and lasts longer
Single-piece weather-tight curb cap eliminates roof leaks
Hood withstands high wind speed without lift-off
Key Features
- Rhombus hood — withstands high-speed wind, with cooling fins for motor longevity
- Curb cap — single-piece, weather-tight, with punched mounting holes
- Galvanised housing construction
- Backward-inclined aluminium impeller
- Low power consumption / low sound level
- Available in single and three phase
Construction & Materials
- Aluminium hood and curb cap — corrosion-resistant for outdoor service
- Rhombus-profile hood for low wind loading and structural rigidity
- Galvanised steel housing with continuous welded seams
- Backward-inclined aluminium impeller with hub-mounted balance plugs
- Birdscreen on hood discharge as standard
How to Choose the Right Variant
- 1Calculate exhaust airflow per code (e.g. 0.50 m/s capture velocity over hood face for kitchen Type-I hoods)
- 2Add static pressure for grease filter, duct run, and discharge resistance
- 3Provide minimum 3 m horizontal clearance from any fresh-air intake on the same roof
- 4For grease duty, specify spark-resistant construction and easy clean-out access
Installation Notes
- Mount on a code-compliant pre-fabricated curb (minimum 200 mm above roof finish)
- Seal the curb-to-deck joint with continuous flashing — no fasteners through the field of the membrane
- Wire through a gas-tight conduit; provide a service disconnect within sight of the unit
- Allow safe roof access — most service is done in place
Maintenance Schedule
- Wash hood and impeller every 6 months for grease applications, annually otherwise
- Inspect curb gasket and flashing annually for weather seal integrity
- Tighten all hood-to-curb fasteners after the first storm season
Industries Served
Standards & Compliance
- Designed in line with AMCA 99 / NFPA 96 (kitchen exhaust) where applicable
- Curb construction per SMACNA HVAC roof-curb guidance
Frequently Asked Questions
Why upblast and not horizontal discharge?
Upblast lifts the contaminated plume well above the roofline, reducing the chance of re-entrainment into outside-air intakes. Most building codes mandate upblast for grease and lab exhaust.
Can the hood be opened for cleaning?
Yes — the hood is hinged and held by latches so the impeller is fully accessible without removing the unit from the curb.
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Need help selecting the right fan?
Our engineers will help you size the power roof ventilators (upblast fan) to your exact application — capacity, static pressure, and installation constraints.
