BAL Windtower Roof
Ventilation Systems

Fire Screen / Ember Basket

BAL roof ventilator


Roof Ventilators in High Fire Risk Areas

In consideration of the possibility that flying debris could somehow enter the ventilator during a firestorm, Condor engineers have developed a  device to address that possibility and ensure greater safety to the roof (attic) void.

The basket (optional equipment) is fabricated in 0.8mm perforated stainless steel with a hole aperture of 2mm (as shown in diagram) The basket surface has a free air value equivalent to 120% of ventilator throat diameter.


Free Air is the unrestricted value of the open area. You cannot select a free area of a fixed value and then insert mesh, (resistance) and expect it to perform as per the original selection . The resistance caused by the mesh alters the initial flow value.

Simply said, if the mesh has a 50% resistance then the size of the ventilator needs to be altered to bring it to the original value deemed essential.

Flow resistance should be noted when sizing.


This is a potentially dangerous practice and can result in creating the very thing you are attempting to guard against as well as diminish performance.

Dust and fibre, carried by the upward flow will rapidly increase to resistance and eventually seal the underside of the ventilator throat rendering it inefficient, if not inoperable altogether.

If ignited, can potentially fall back into the void and do the very thing you are trying to avoid.

The necessity with flywire type screens is that they need to be cleaned periodically ( every 3 months) for any roof ventilator to be able to perform as expected.

For roof types such as raked and cathedral, each situation is resolved to the circumstances as exist.

In all cases Condor engineers will be able to advise as to solutions available.

Specifications are;

Roof ventilator to be Condor Dreadnaught SS/SR (size) with custom base to suit (roof pitch) & (roof profile) and to include matching Flowmaster BAL stainless steel ember basket.

BAL roof ventilator
Condor Ventilation