Windows Performance Requirements

A window must be aesthetically acceptable in the context of building design and surrounding environment

Windows should be selected or designed to resist wind loadings, be easy to clean and provide for safety and security. They should be sited to provide visual contact with the outside.

Habitable upper floor rooms should have a window for emergency escape. Min. opening area, 0.330 m ². Min. height and width, 0.450 m. Max height of opening, 1.100 m above floor.

Windows Conventional Types

Timber Casement Windows

High Performance Timber Casement Windows

The standard range of casement windows used in the UK was derived from the English Joinery Manufacturer s Association (EJMA) designs of some 50 years ago. These became adopted in BS 644: Timber windows. Specification for factory assembled windows of various types. A modified type is shown on the preceding page. Contemporary building standards require higher levels of performance in terms of thermal and sound insulation (Bldg. Regs. Pt. L and E), air permeability, water tightness and wind resistance (BS ENs 1026, 1027 and 12211, respectively). This has been achieved by adapting Scandinavian designs with double and triple glazing to attain U values as low as 1 2 W/m ²K and a sound reduction of 50dB.

Further refs:

• BS 6375: Performance of windows.

• BS 6375-1: Classification for weather tightness.

• BS 6375-2: Operation and strength characteristics.

• BS 7950: Specification for enhanced security performance. Horizontal section Vertical section

Metal Casement Windows

Metal Windows ~ these can be obtained in...