![]() ![]() For example, a louvre could have Class A weather performance at a face velocity of 0.5m/s, but only Class C weather performance at a face velocity of 2.0m/s. It is worth noting that a louvre can have a different weather performance class at different face velocities. Table 1 below summarises the volume of allowable rain penetration for the different classes of weather performance. In addition to the simulated wind at 13m/s, air is drawn through the louvre by a mechanical ventilation unit at a range of set face velocities (0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0 and 3.5 m/s). In this area the penetrated rain is collected and measured. Behind the louvre (to the right on the diagram) is a collection duct, which is sealed at the other end by a water eliminator. In the weather section (labelled above) the rejected rain is collected and drained. Following this, the test itself is run until the results become stable but for a minimum of 30 minutes.Īs represented in Figure 1, this test is achieved by fan driven, wind simulation equipment driving air towards the louvre at a standard face velocity of 13m/s (30mph), whilst nozzles spray water parallel to the airstream at a rate of 75l/h (litres per hour), to simulate rain. Test 1: Water Penetration (Effectiveness)Įach test is preceded by a suitable ‘pre-test’ soak. A description of how the rig is used for each type of test is given in the following sections. This diagram is taken from a BSRIA weather test report, examples of which can be found here. The rain rejection performance can be established over a wide range of conditions using simulated wind speed, water and ventilation rates.įigure 1 shows a schematic representation of the rig used by BSRIA during a typical test.įigure 1 – Typical BSRIA rig for testing of weather louvres. The tests themselves are based on methods that simulate the real-life operating conditions a louvre will undergo when installed. The HEVAC/BSRIA test method enables clients to relate one manufacturers’ performance against another at set benchmarks, helping to make specification easier. Overall Performance: a combined measure of the above.Pressure Drop (Discharge Loss Coefficient): how freely the louvre allows air to pass through.Water Penetration (Effectiveness): the ability to prevent rain penetrating the louvre.The Industry standard for weather testing of louvres in the UK was developed by BSRIA in collaboration with HEVAC (Heating, Ventilation and Air Conditioning Manufacturers Association), and was adopted in 2001 as British and European Standard: BS EN 13030:2001.īS EN 13030:2001 tests louvres in 3 key performance areas: The purpose of an external louvre, often called a ‘weather louvre’, is to enable airflow whilst rejecting rain and other elements. ![]()
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