Standard GB/T7107-2002 building windows airtightness performance grading and testing methods, building windows airtightness performance refers to the external window in the closed state, to prevent air infiltration capacity", airtightness grading index using pressure difference of 10Pa when the unit length of the slit air infiltration and unit area air infiltration as a Grading indicators, divided into 1~5 levels.
The airtightness of doors and windows refers to the air infiltration of doors and windows per unit open seam length or per unit area. It assesses the windows and doors in the closed state, the ability to prevent air infiltration. Doors and windows airtightness of the level of performance, the loss of heat has a great impact, the better the airtightness, the less heat exchange, the smaller the impact on the room temperature. Therefore, to improve the airtightness of windows and doors is the key to energy saving windows and doors. We heating in winter or cooling in summer through the air conditioning in which a quarter of the energy through the gaps in the windows and doors consumed. So improve the airtightness of windows and doors is imperative to reduce the gap between the door and window frames and fans and fans.