Technical

HEVAC, the building services sector of the federation of Environmental Trade Associations (FETA), did not take up a Pan-European louvre test method and approached BSRIA to formulate a louvre test method typical of installation conditions.

The Building Services Research and Information Association (BSRIA) is an independent company providing impartial advice, product testing and research. The BSRIA response was accepted by HEVAC as their standard for weather testing of louvres.

The test is some 10m long, incorporating a 3m² wall into which is set 1m² louvre to be tested. The louvres are tested for three performance areas.

i) Effectiveness: ability to reject rain from penetrating the louvre, both with and without simulated wind.

ii) Co-efficient for discharge (Cd): air flow rate (pressure loss) characteristic.

iii) Overall Performance: effectiveness x Cd. This can mislead since a poorly weathered louvre can hide behiind a good airflow, gaining the same performance factor as a highly weathered, reasonable airflow louvre.

E.g.
Louvre A 50% effective x 0.4 Cd = 20
Louvre B 100% effective x 0.2 Cd = 20

Gill Air believe louvres will continue to be specified in accordance with the many criteria to which they are asked to perform. These elements are the ability to blend or contrast with the building, size limitations both in face area and depth, the flexibility to follow design shapes such as triangles, corners, access doors etc, and to form a homogeneous continuous unit. The HEVAC standard will of course enable the specifier to relate one manufacturers performance against another at set benchmarks and this will need out spurious information occasionally claimed.