SitaVent pipe lead-through: The vapour barrier cap keeps things in order. Open pipe lead-throughs are not impermeable to moisture and air exchange. Sita offers a small, useful add-on component. The vapour barrier cap means that cables can be fed through vapour-tight. To ensure that everything fits perfectly, the holes are made on site with punch pliers or a hole punch. A pipe clamp is also supplied to ensure that the vapour barrier cap is securely fixed.