Water Penetration Table
No louvre manufacturer
will guarantee that their louvres will exclude water under
all conditions of wind and rain.
Whilst mechanical
means can be provided to help combat water penetration, the
first consideration should be keeping the air velocity through
the louvre to a minimum.
Water penetration
tests were conducted using a combined rain droplet and wetted
wall method (a rain droplet only method will understate the
water penetration results). The combined method simulates
more realistically the actual operating conditions a louvre
will experience when installed.
A rainfall in
excess of 100 mm/hr was used. For comparison, a 1 in 50 year
storm event is 70mmlhr, whilst 'heavy rainfall' is 6 mm/hr
(NIWA Climate Data Bank, Aug 2000).
The table below shows two velocity points. The first is
the free area velocity at which occasional water droplets
passed through the louvre. The second free area velocity is
when significant water droplets passed through the louvre.
| Louvre Type |
Occasional Penetration
Free Area Velocity (m/s)
|
Significant Penetration
Free Area Velocity (m/s)
|
| EXH100(1) |
1.4
|
2.1
|
| WPL50 |
4.1
|
4.7
|
| WPL80 |
4.4
|
5.1
|
| WPL100 |
4.8
|
5.4
|
| WPL V 100 |
4.9
|
5.4
|
(1) Water penetration
is not normally a factor to be considered with louvres optimised
and used exclusively for exhaust conditions.
|
