NCIDQ IDFX Practice Exam

Intumescent gasketing serves the critical function of expanding upon exposure to heat, thereby forming a seal that helps to prevent the passage of smoke and fire between spaces. When temperatures rise, typically during a fire, the material within the gasketing begins to swell and expand significantly. This expansion effectively fills the gaps around doors, improving the fire-resistance of the door assembly and enhancing life safety within a building by containing smoke and flames.

The other options do not accurately capture the primary role of intumescent gasketing. While insulation against heat provides certain protective properties, it does not address the specific expansion feature of intumescent materials. Similarly, enhancing the aesthetic quality of doors or securing the door frame to the wall are not functions of intumescent gasketing; these aspects pertain to different considerations in door and frame installation and design. Thus, the correct answer reflects the unique and essential fire-protection characteristic of intumescent gasketing.