GB/T 13477.3-2017 focuses on the determination of extrudability of building sealing materials. It specifies the specifications of special standard appliances and details the preparation steps of sealing material samples. Under specific pressure and time conditions, the standard appliance is used to extrude the sealing material, and the extrusion performance of the material is evaluated by accurate measurement of the extrusion amount. This standard unifies the test specification, which can effectively evaluate the extrusion difficulty of sealing materials during construction applications, provides a key basis for mass control of building sealing materials and construction convenience, and helps to ensure the smooth development of sealing projects.