Project: Altamira FLNG Phase I, Mexico · Scope: 24-inch concrete weight coated (CWC) pipeline, newbuild · Joints: 160 · System: Allter Visco-Rite™ 70 / Allter Tape™ PE / Allter Protectamesh / Allter MSS80 heat-shrink sleeve.
Field joints are where a pipeline coating is most likely to fail. On a concrete weight coated line the challenge doubles: the joint has to be corrosion-protected and brought level with the concrete so it survives the stinger rollers during pipelaying. This is the four-layer build-up we applied on all 160 joints.
Surface preparation
Minimum ST2 (hand tool clean) or ST3 (power tool clean), followed by degreasing and cleaning with isopropanol. No blast-cleaning, no primer: Allter Visco-Rite™ bonds to a clean, dry-to-damp steel surface and does not depend on a surface profile.
1. Allter Visco-Rite™ 70 — corrosion prevention layer
Allter Visco-Rite™ 70 is applied by removing the release liner and placing the adhesive side directly on the pipe, using a straight wrapping procedure with a double layer on the weld. Each joint was holiday tested with a high-voltage tester at 25 kV.
2. Allter Tape™ PE — mechanical outer wrap
An Allter Tape™ PE mechanical protection layer is wrapped over the Allter Visco-Rite™ with 50% overlap. Its job is purely mechanical: it protects the inner visco-elastic corrosion-prevention layer during handling and laying.
3. Allter Protectamesh — cutback infill
Allter Protectamesh is applied in a single wrap as infill, bringing the cutback section level with the concrete weight coating so the pipe runs smoothly through the laying equipment. The wraps are held in place with straps.
4. Allter MSS80 heat-shrink sleeve — sacrificial protection
The Allter MSS80 heat-shrink sleeve is the sacrificial mechanical layer: it takes the impact of the stinger rollers and protects the Protectamesh underneath during the pipelaying operation.
Why this build-up
Every layer has one job. Allter Visco-Rite™ stops corrosion and stays permanently visco-elastic, so it self-recovers around the weld and never cracks or disbonds. The three layers on top exist only to get the joint through the lay spread intact. Separating those functions is what makes the system simple to apply on a moving vessel and predictable for 30+ years on the seabed.
Download the case study (PDF) Allter Visco-Rite™ product page
