Air Tightness Performance - One of the Five Key Characteristics of System Windows & Doors

Air Tightness Performance

This performance metric measures air leakage through windows/doors per unit length of opening seams or unit area. It evaluates the assembly’s ability to block uncontrolled air infiltration when closed.

Importance
Thermal Efficiency: Higher air tightness = less heat transfer (reducing energy loss by up to 30%).

Cross-Performance Impact: Directly affects water tightness, sound insulation, and thermal insulation.

Grading System (GB/T 7106-2008):

Class 1 (lowest) to Class 8 (highest)

Jiangsu Province requirement: Class 6

Key Factors Influencing Air Tightness

1. Seal Design (Triple-Seal Structure Example)

a. Inner/Outer Gaskets

Function: First and last line of defense against air infiltration.

Material: EPDM (Ethylene Propylene Diene Monomer)

Superior elasticity (-40°C to 120°C)

UV/ozone resistant (outperforms obsolete PVB rubber)

b. Middle Pressure-Equalizing Gasket

Critical Role: Primary air barrier; determines ultimate performance.

Installation Methods:

One-Piece Bending: Requires skilled labor (risk of over-bending or shrinkage gaps).

90° Vulcanized Welding: Seamless continuity, no weak joints.

2. Hardware Integration

Locking Mechanism:

Multi-point locks ensure uniform compression of gaskets.

Minimum 6 locking points for Class 6+ performance.

Strike Plate Alignment: Even 1mm misalignment can increase leakage by 15%.

Technical Validation
Test Standard: GB/T 7106-2008 (simulates 100Pa wind pressure)

Passive House Benchmark: ≤0.6 ACH @50Pa (vs. 3-10 ACH in conventional buildings)

Case Study:
Wispera’s triple-seal system achieved Class 8 (≤0.5 m³/(h·m²) @100Pa) in Nanjing’s Four Seasons Hotel, reducing HVAC costs by 22%.