This standard specifies the test method for the compressive resistance of sealing materials used in building structural joints. The principle involves bonding the sealing material to be tested onto two parallel substrate surfaces to create a specimen. Under specified conditions, a testing machine compresses the specimen at a constant speed to a predetermined width (typically 75% or 80% of the initial width). The compressive characteristics of the material are evaluated by recording the pressure value at which the specified compression ratio is achieved. This test is significant for assessing the ability of sealing materials to withstand pressure loads in building joints, directly impacting the airtightness and watertightness of structures. The core equipment used in actual testing is a computer-controlled electronic universal testing machine, which must feature a constant loading speed of 5-6 mm/min and a force recording device. Modern models are also equipped with specialized compression fixtures and data analysis software, enabling real-time collection of force-displacement curves and automatic calculation of stress values.