Challenges
Corrosion under pipe support (CUPS) is a major hidden threat and one of the most aggressive types of corrosion attack on piping systems. CUPS is caused by several factors. Traditionally, the design of pipe supports allows for crevices to be formed which can lead to crevice corrosion in the presence of moisture. Protective coating damages, metal to metal contact and galvanic corrosion also lead to CUPS. The most common causes of external piping failure in ageing assets are due to highly localised deterioration by corrosion in areas which are less accessible and difficult to inspect and repair. As a result, operators may face huge pipe replacement costs, loss of pressure containment and production or in some cases, explosion and massive economic consequences.
CUPS Remediation
CUPS remediation is often done via pipe lift-off to allow for the necessary remedial works at the expense of production downtime or prolonged shutdown period. For years, the industry is looking for a solution that can arrest CUPS without pipe lift-off and this engineering challenge is aggravated by the fact that most piping are designed to be dynamic and the relative movement between piping and their supports, including pipe vibration, made it very difficult to provide any effective and reliable long term corrosion protection.
In the past few years, IEV has worked on a wrapping system, using the proven long term performance, and high conformity and flexibility characteristics of microcrystalline Wax-Tapes supplied by Trenton, to develop an encapsulation system that can prevent CUPS for both static and dynamic pipe supports, without the need for pipe lift-off.
Wax-Tape anti-corrosion wraps are composed of microcrystalline waxes, plasticizers, corrosion inhibitors and other ingredients (no clay fillers) saturated into a non-woven, non-stitch bonded synthetic fabric, forming a tape wrapper. It also does not contain any siliceous mineral fillers.
TRENTON WAX-TAPE SYSTEM FOR STATIC PIPE SUPPORT: < 60° C
TRENTON WAX-TAPE SYSTEM FOR STATIC PIPE SUPPORT: > 60° C
TRENTON WAX-TAPE SYSTEM FOR DYNAMIC PIPE SUPPORT
The application is simple, as Trenton Wax-tapes are highly surface tolerant, requiring only a St2 finish, which can be achieved by manual wire brushing. After cleaning, the substrate is firstly protected by Microcrystalline Wax primer which inhibits corrosion as well as acts as a surface conditioner by filling the pores of the metal, penetrating any rust and displacing any moisture. Filler is then applied to fill any large voids to remove crevices and smoothen the profile before Wax-Tapes are wrapped to prevent any moisture from reaching the substrate. The wrapping technique is especially developed to allow maximum axial displacements between a dynamic pipe and a static support.
Third Party Certification
The testing of IEV’s CUPS Prevention solution was witnessed by SGS in March 2020 , who subsequently released certificates that verified the displacement limits of the system. The report concluded that Trenton Wax-tapes can be applied to protect CUPS on dynamic pipes which axial movement is in excess of 40mm without any damage or disbondment.
Field applications have commenced in downstream plants in Malaysia.