Guides

Air, Water and Wind Performance

AEV

The acronym AEV describes the measurement of Air, Water, and Wind performance, which is crucial for evaluating the effectiveness of windows, doors, and curtain walls in buildings. Here is an overview of how each of these parameters is measured according to UK and European standards:


1. Air Permeability


Air permeability measures the amount of air that can pass through a window, door, or curtain wall under specified conditions. The test is typically conducted in accordance with EN 1026.


Testing Process


  • Pressure Differential:     A specified pressure difference is applied across the test specimen.
  • Measurement: The quantity of air leakage is measured and expressed in cubic metres per hour per square metre (m³/h/m²).
  • Classification: Products are categorised based on their air permeability performance, with lower air leakage indicating better performance.


2. Water Tightness


Water tightness assesses how well a window, door, or curtain wall can resist water penetration under simulated rain and wind conditions. The test follows EN 1026.


Testing Process


  • Simulated Rain:     Water is sprayed on the exterior surface of the specimen at a specified rate.
  • Pressure Differential: During the spraying, a series of pressure differences are applied to simulate wind-driven rain.
  • Observation: Any water penetration on the interior side is recorded.
  • Classification: The product is classified based on the highest pressure level at which no water penetration occurs.


3. Wind Resistance


Wind resistance measures the ability of a window, door, or curtain wall to withstand wind loads, including both structural performance under wind pressure and resistance to wind-induced deformation. This is tested in accordance with EN 12211.


Testing Process


  • Pressure Application:     Positive and negative pressures are applied cyclically to the specimen to simulate wind loads.
  • Deflection Measurement: The deflection or bending of the specimen is measured during and after the application of pressure.
  • Failure Inspection: The test checks for any permanent deformation, structural damage, or failure.
  • Classification: Based on the maximum pressure the specimen can withstand without significant deformation or failure, it is classified into different performance levels.



Air permeability (A), water tightness (E), and wind resistance (VC) relate to performance levels, using a similar format to A3, E3A, and VC2:


EN 1026 - Air Permeability (A)

Ranges from Class 1 (very high permeability) to Class 6 (extremely low permeability).


Rating Resistance
Class 1 Description: Very high air permeability
Performance: High levels of air leakage, less suitable for energy efficiency.
Class 2 Description: High air permeability
Performance: Allows a significant amount of air to pass through, moderate sealing effectiveness.
Class 3 Description: Moderate air permeability
Performance: Balances air leakage with ventilation needs, suitable for general applications.
Class 4 Description: Low air permeability
Performance: Provides good sealing with reduced air leakage, suitable for most buildings.
Class 5 Description: Very low air permeability
Performance: Highly sealed with minimal air leakage, ideal for energy-efficient buildings.
Class 6 Description: Extremely low air permeability
Performance: Nearly airtight, providing superior sealing for high-performance energy efficiency.

EN 1027 - Water Tightness (E)

Ranges from Class 1A (very low resistance) to Class 5B (maximum resistance).

Rating Resistance
Class 1A Description: Very low water tightness
Performance: Minimal resistance to water ingress, suitable for very sheltered environments.
Class 1B Description: Low water tightness
Performance: Basic resistance to water ingress, suitable for protected locations.
Class 2A Description: Moderate water tightness
Performance: Effective for standard weather conditions, suitable for average exposure.
Class 2B Description: Higher water tightness
Performance: Good resistance to water ingress, suitable for exposed areas with moderate rain.
Class 3A Description: Good water tightness
Performance: Provides strong resistance to water ingress, effective in average conditions.
Class 3B Description: Very good water tightness
Performance: High resistance to water ingress, suitable for regions with heavy rain.
Class 4A Description: High water tightness
Performance: Excellent resistance to water ingress, effective in severe weather conditions.
Class 4B Description: Very high water tightness
Performance: Superior resistance to water ingress, suitable for extreme weather conditions.
Class 5A Description: Excellent water tightness
Performance: Maximum resistance to water ingress, ideal for harsh environments.
Class 5B Description: Maximum water tightness
Performance: Provides the highest level of water resistance, suitable for the harshest conditions.

EN 12211 - Wind Resistance (VC)

Ranges from Class 1 (low resistance) to Class 6 (extremely high resistance).



Rating Resistance
Class 1 Description: Low wind resistance
Performance: Provides minimal resistance to wind loads, suitable for low-wind environments.
Class 2 Description: Moderate wind resistance
Performance: Effective against moderate wind pressures, suitable for average wind conditions.
Class 3 Description: Good wind resistance
Performance: Offers strong resistance to wind loads, suitable for standard wind conditions.
Class 4 Description: High wind resistance
Performance: Provides robust resistance to high wind pressures, suitable for exposed locations.
Class 5 Description: Very high wind resistance
Performance: Effective against very strong wind loads, suitable for high-wind areas.
Class 6 Description: Extremely high wind resistance
Performance: Maximum resistance to extreme wind conditions, suitable for the harshest environments.
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