Air Tightness (A)
The air tightness test measures the volume of air that would pass through a closed window at an air pressure differential that represents a wind speed of 40 kph (25 mph). Performance is indicated by a number rating from A1 to A3, The higher the number, the more airtight the product.

Water Tightness (B)
On windows the performance rating for water tightness is represented by the letter ‘B’. Water tightness testing involves applying a uniform water spray at increasing air pressure (to simulate wind-driven rain) until water penetrates the window. Performance is indicated by a number ranging from B1 to B7 for windows, and from B1 to B4 for sliding doors, The higher the number, the more watertight the product.

Wind-Load Resistance (C)

For windows, the performance rating for wind-load resistance is represented by the letter ‘C’. Resistance to wind-load is a measure of the product’s structural strength and is tested by applying increasing levels of air pressure to simulate the wind force. Air pressure is applied until the product’s operation is impaired. There are up to five levels of wind resistance for windows (C1 to C5) and three levels (C1 to C3) for sliding doors, The higher the number, the better the performance.

Forced-Entry Resistance (F)
The performance rating for forced-entry resistance is represented by the letter ‘F’. The standards for windows include a test to indicate how well the product may thwart entry within five minutes. One of two ratings is assigned, F1 or F2. For windows, F1 means the product has a lock, while F2 indicates it has a lock and it passes hand and tool manipulation tests. This test is optional for windows that are installed higher than two meters from the ground. F2 represents the higher level of security.

Screen Strength/Ease of Operation (S/E)
For windows, the performance rating for screen strength is represented by the letter ‘S’. Sliding doors are tested for ease of operation and the letter ‘E’ represents the performance rating. Insect screens are not intended to serve any purpose other than to keep insects out. They are tested for tear, damage or retention in windows when subjected to loads. A rating of S2 is stronger than.