What should you do where a PVC p-trap under a sink penetrates into a fire rated wall?

When a PVC p-trap under a sink penetrates into a fire-rated wall, it is essential to treat this situation as a through-penetration system. This is because a through-penetration occurs when a material (in this case, the PVC pipe) passes through a fire-rated barrier, which can compromise the wall's integrity and fire-resistance rating. Properly addressing this issue is critical to maintaining fire safety by preventing the spread of fire and smoke between compartments.

By treating it as a through-penetration system, appropriate firestop materials and methods can be employed to effectively seal the penetration. This ensures that the fire-rated barrier continues to perform as intended, thereby safeguarding the building structure and allowing for adequate protection for its occupants.

Other choices do not ensure the proper fire safety measures are taken. Ignoring the penetration would significantly undermine the fire-resistive integrity of the wall. Sealing it with foam insulation is not a recognized method for firestopping and may not adequately prevent the spread of fire or smoke. Using a standard firestop collar might not be suitable for non-metallic pipes like PVC, as specific firestop systems are designed depending on the type of material, making it necessary to follow the guidelines for through-penetration systems