How to specify the Hurricane™

 

Specification:

The roof ventilators shall be CSR Edmonds Hurricane Turbine Ventilators as indicated in the drawing. They shall be manufactured from aluminium with vertical turbine vanes and incorporate the Tandaco Bearing System.

The bases shall be vari-pitch or ridge mounting and dampers shall/shall not be provided.

The Ventilators shall be supported by a 15 year warranty as provided by CSR Edmonds. Dee Why NSW Australia.

Determining the Number of Ventilators Required.

The number and size of ventilators required to provide an optimal, cost effective ventilation scheme for any project depends on the air exchange rate provided. In turn, this depends on the exhaust performance of a ventilator installed on the project and the volume of air subject to ventilation.

Hurricane vent exhaust rates were previously based around an historical formula for predicting the performance of gravity discharge vents, with modification for the for the turbine action of the ventilators. The calculations assumed a 6m stack height and 10°C temperature differential. A similar calculation has been used by most vent manufactures around the globe.

The historical formula had obvious flaws - it made no allowances for differences in the exhaust efficiency between ventilatiors caused by variations in vent design or weight. Similarly, published exhaust rates did not cater to stack height or temperature differential.

AS4740

Australian standard.AS4740-Natural Ventilators - Classification and performance - prescribes for the first time a scientific procedure to establish the performance of a ventilator.

The procedure enables the determination of:

                      Coefficient of discharge - Cd, and

                      Flow coefficient - Cf

for a ventilator. Once determined, this enables the flow rate for the ventilator to be esablished using the formulas:

where Pw = wind siphoning pressure = ( σ /2 ) ( CfVt ) 2
                 σ= air density at ambient temp
                 Cf = Flow Coefficent
                 Vt = wind velocity
                 Ps = stack pressure = σ g h T/T
                 F = effective areodynamic area = Cd x A
                 Pw = wind siphoning pressure
                 T = assumed temperature differential between air intake and air exhaust
                 T = assumes outside ambient temperature
                 A = throat area of ventilator

Edmonds has established an algorithm which applies to each of its Hurricane vent sizes and can be applied to any project. The algorithm is exclusive to the Edmonds Hurricane (and those assembled from Edmonds full components only) as it is based on tested Cd and Cf for Hurricane. The Cd and Cf for other vents vary widely with speherical shape vents showing considerably lower Cf.

The Edmonds Planning Algorithm.

The development of this algorithm has been costly and is regarded as exclusive intellectual property for Edmonds. Edmonds invites any prospective customer or consultant to seek assistance with their projects.

 

Table of Recommended Air Changes Per Hour in Zone of Occupation
Factories and workshops	5 to 10
Warehouses	5 to 8
Gymnasiums and squash courts	5 to 10
Assembly halls	10 to 15
Garages	10 to 15
Toilets	12 to 15
Laundries	12 to 20
Air change rate must perform to the local health department's code covering the type of installation.
Stables	Air change rate is dependent upon the number of animals confined, but can range between 10 to 50.
Piggeries
Poultry houses

 

VENTILATOR SIZE	APPROXIMATE DIMENSIONS			WEIGHT (kg)
	DIM "A"	DIM "B"	DIM "C"
H100	107	313	290	1.8
H150	155	363	332	2.4
H300	308	500	477	4.9
H400	410	564	561	6.3
H450	462	658	648	8.1
H500	511	700	702	9.2
H600	602	724	766	12.8
H700	705	796	876	15.8
H800	799	858	1003	20.6
H900	897	936	1096	24.1