Fold-and-Form

A new PVC pipe reformed inside the existing one — installed folded and reshaped with steam. Chemical-free structural solution, ideal for potable water and pressure pipelines.

Fold-and-Form is a trenchless rehabilitation system that uses a factory-folded PVC liner with a reduced profile (in H, U, or C shape). Once inserted through an existing manhole, the liner is reformed with heat and pressure until it recovers its full circular shape, creating a new structural pipe tightly fitted inside the existing one.

How it works:

The process begins with CCTV inspection and deep cleaning of the existing pipeline. The pre-folded PVC liner, supplied in long-length reels, is then pulled through the manhole to cover the desired section. Once in position, controlled-pressure steam is applied inside the liner: heat reactivates the thermoplastic memory of the PVC, and pressure expands it until it bonds tightly to the internal pipe wall. As it cools, the liner becomes a new structural pipe ready for operation.

Why Fold-and-Form:

Unlike technologies that require reactive resins —such as CIPP— Fold-and-Form uses 100% pre-manufactured PVC: no volatile chemicals, no styrene, no emissions during installation. This makes it especially suitable for potable water lines —certified under NSF/ANSI 61— and for pressure pipelines, where it can safely operate up to 16 bar (230 psi). Additionally, its homogeneous and well-known material simplifies engineering design and structural calculations with precision.

At TUBEPOL, we apply this technology with liners certified under international ASTM F-1504 and ASTM F-1871 standards, installing solutions up to 1200 mm in diameter across long pipe runs. It is the ideal option for structural rehabilitation of in-service networks where water quality must be preserved and chemical emissions avoided during the process.