Natural ventilation of industrial and commercial buildings, or of the above ceiling roof space in air-conditioned buildings, is a cost-effective means of exhausting hot air or achieving a sufficient degree of air change in the building.
Natural ventilation should also be considered as a means of venting smoke in a fire situation and as a means of helping to control condensation by removal of warm moist air from the building space.
The roof system can be designed to incorporate either a Dimond Fixed Ridge Ventilator or a series of Ampelair Turbo Ventilators.
Design information is given in this section to enable estimation of exhaust airflow rate and hence a reasonable basis on which to design for the air changes required.
Fixed Ridge Ventilators
The table gives approximate exhaust flow capacities for a range of stack heights (ridge height above ground), wind speeds at the ridge and internal temperature between ground level and ridge.
Achievement of these flows requires sufficient openings to provide free airflow into the building.
Dimond Fixed Ridge Ventilators are available in Zincalume®, Colorsteel®, ColorCote® and Aluminium material to match the
roofing material chosen.
Reference to Section 126.96.36.199 should be made if dissimilar materials are used.
Sizes up to and including the 300 throat can be fixed directly onto the roof without bracketing using hex head self-drilling screws, the same as the roof profile on every rib. Sizes above this require a bracketing system.
U.L.S = Ultimate Limit Slate load
Ampelair Wind Driven Ventilators
- Locked-on rotor mechanisms prevents loss or damage in high winds.
- Corrugated vanes provide more strength and stability.
- Square to round base on all models.
- Sealed dual bearing system excludes dust, grit and other foreign matter and retains lubricant.
- Paint finish available to match roof selection.
For design calculations refer to section 188.8.131.52.2 of Technical Manual