Gilberts (Blackpool) - High Performance Weather Louvres

High Performance Weather Louvres – Selection Criteria

High Performance Louvre Selection - WH Series

Table 1

In order to effectively size a high performance louvre one must firstly establish the parameters that are important to the system design. These may be:-

a) Maximum pressure drop through the louvre as calculated from Table 1.

b) Maximum effectiveness based upon a wind velocity of 13m/s established from Table 2.

Example 1

If the maximum pressure drop that can be accommodated is 16 Pa, then the ventilation rate per m² of louvre area that can be handled from Table 1 would be 1.5m³/s.

If this is now related to Table 2 the effectiveness of the louvre would then be 98%.

Example 2

If the effectiveness or water repellent nature of the louvre is paramount and a 99% efficiency is important, then from Table 2 a 1m/s face velocity or 1m³/s per square metre of louvre area would be the maximum volume that can be accommodated. This would then give a pressure drop from Table 1 of 7.5 Pa.

Classification

From the New European Standard EN 13030, louvres will be classified using both the COEFFICIENT OF ENTRY or DISCHARGE (CE or CD) and a water penetration rate.

Classifications are as follows:-

The water repellent classification is denoted by the following chart:-

ie. 0.99 EFFECTIVENESS = 99% water repellent efficiency.

The combined classification would have the water repellent class reference first followed by the coefficient of entry or discharge i.e.

A - 2 (up to 1m/s face velocity)

Example Louvre Sizing

Required louvre with an effectiveness of no less than 0.99 and a maximum pressure drop of 16 Pa.

Total Intake Volume 5m³/s

From Table 2 maximum ventilation rate per m² of louvre area that will give 0.99 effectiveness = 1m³/s.

From Table 1 pressure drop = 7.5 Pa, which is below the maximum requirement. Therefore, louvre area required = 5/1 = 5m FACE AREA.

Alternative

If an effectiveness of 0.98 would suffice, then from Table 2 a volume of 1.5m³/s per m² face area would be allowed.

This would give a pressure drop of 16 Pa.

Therefore, new louvre size would be:-
⁵⁄_1.5 = 3.33m² FACE AREA

Penthouse Louvres

For Penthouse louvres the face area of all sides should be calculated and the addition related to the above calculations for total face area.

Test Results

All Gilberts louvres have been subject to simulated weather conditions on the BSRIA Test Rig, which follows the requirements and specification of the new European Standard EN13030. All graphs and information are developed from test results.

The WH/75 louvre assemblies have a CD/CE of approximately 0.3

WP/75 louvre assemblies have a CD/CE of approximately 0.27

WH/75 = Class A2 up to 1 m/s

WP/75 = Class B3 up to 0.5 m/s