Tornado Range

Technical Information

Compliance Statement

Wind Driven Turbine Ventilators

The units are of robust construction and supplied complete with a mounting and flashing system allowing for a simple installation to a variety of roof types. The turbine head IS OF ONION TYPE and CURVED vane type mounted on a rotating shaft complete with bearings and a turbine head support system. The top turbine head support arms are constructed from Zincalume. The turbine head is securely mounted on a circular throat, the size of the throat being as shown on the below drawings. The configuration of the turbine head construction minimize the inertia of the unit to enhance low wind speed performance. The throat is adjustable to suit the pitch of the roof system. A weather proof flashing (Base Plate) is incorporated with the adjustable throat. The  unit is manufactured from high quality Zincalume except for the shaft, which will be of high quality plated 16mm mild steel. The bearings are of the double row heavy-duty ball type as manufactured by KG and are factory sealed for life. Where required, the units shall be powder coated to an approved colour.

The units are manufactured to appropriate tolerances that ensure a stable performance at all wind speeds. Unless otherwise approved, Zincalume sheets are PRECISION cut to ensure clean edges. The whole unit is constructed so that its operation is noise free and prevents the ingress of water and dust.

The Standard is of the latest published edition of the Australian/New Zealand Standard 4740:2000 “Natural Ventilators – Classification & Performance.” Or equivalent.

Windmaster International warrant the units for a period of not less than 5 years. Windmaster International or Tornado Roof Ventilators certifies this warranty. A copy of the warranty certificate shall be included upon request at the time of any offer to supply.

The units are designed to be intrinsically maintenance free. There are no other maintenance requirement than an annual inspection and superficial cleaning
from time to time.

The units are packaged in such a way that they are supplied free of damage or defects. The packaging are robust and fit for the purpose. At the time of supply, the units will be inspected by Tornado Roof Ventilators and shall immediately proceed to remedy any defects or damage noted during the inspection.

Windmaster International shall supply a comprehensive installation procedure to ensure that the installation shall not impede the performance of the units nor in any way void the warranty.

The Department of Mechanical and Mechatronic Engineering from Stellenbosch University tested the performance of roof ventilators manufactured by Windmaster International. These roof ventilators include diameters of 250, 350, 500, 590 610, and 715 mm.

Wind tunnel tests were performed with the main objective to determine the air volume flow removed by the ventilator from a roof cavity as a function of the wind velocity to which it was exposed.

Technical Information

Superiority of the Product

The Tornado features such superior qualities as:

Click on image to enlarge or download

Tornado and Backdraft Specifications


Material Type

The Tornado is available in a choice of Galvanised and Zincalume material.

Galvanised Tornados are constructed of Mital specification Z 275 – 0.6mm and 1.2mm steel.


The structure of galvanised and zincalume unit makes it more durable and reliable in the long run in terms of:
– high velocity wind areas, hail storms and heavy rain
– general handling and transportation

WordPress Responsive Table

The below graph illustrates the performance difference of the various size ventilators as per tested extraction capacity reflected in the above table:

Tornado Laboratory Tests