PPR-AL-PPR is a five-layer composite pipe that enhances the benefits of standard PPR with a central aluminum core. This advanced construction combines an inner and outer layer of PPR with a welded aluminum tube, bonded by a strong adhesive. The primary advantage is a drastic reduction in thermal expansion—up to 75% less than standard PPR pipe. This allows for longer, straighter installation runs with fewer supports, similar to metal piping. The aluminum layer also adds rigidity, strength, and a 100% oxygen barrier.