Composite wrap technology has become a cornerstone of modern asset integrity management, particularly in the oil, gas, water, and industrial processing sectors. Engineered composite repair systems, designed and installed in line with international standards such as ISO 24817 and ASME PCC-2, provide a safe, cost-effective, and long-lasting solution for pipes, tanks, and other pressurised or structural components suffering from corrosion or damage.
But one of the most common questions we receive is:
“What types of pipework and vessel substrates can actually be repaired using composite wraps?”
The short answer is: almost all metallic substrates, provided the correct engineering design and surface preparation procedures are followed. However, each material type presents unique challenges and considerations. In this blog, we’ll explore the most common substrates encountered in industry and discuss how engineered composite wraps can restore their integrity and extend their service life.
Carbon steel is by far the most widely used material in the oil & gas, petrochemical, and water industries. It offers excellent strength and weldability at relatively low cost, which makes it the default choice for pipelines, tanks, and process vessels.
Its Achilles’ heel is corrosion—both internal (from process fluids) and external (from weather, seawater, or under insulation, known as CUI). Left unchecked, corrosion can lead to wall thinning, leaks, and even catastrophic failures.
Composite wraps are ideally suited to carbon steel repairs:
Key Benefit: Composite wraps not only restore structural integrity but also prevent further corrosion by isolating the steel from the environment.
Stainless steels (304, 316, duplex, and super duplex grades) are used where higher corrosion resistance is needed, such as in seawater systems, chemical plants, or food and pharmaceutical processing.
One of the biggest difficulties is achieving adequate surface preparation. Stainless steels are much harder than carbon steels, making mechanical abrasion by hand or with power tools largely ineffective. This means that grit blasting is typically required to achieve the required surface roughness for strong adhesion of the composite system.
Composite wraps can effectively contain and reinforce stainless steel:
Key Benefit: Extends the life of stainless-steel systems without costly replacement or risk of welding-induced sensitisation.
Cast iron and ductile iron are often used in municipal water networks, sewage systems, and some industrial services due to their strength and relative affordability.
Cast iron is brittle and does not lend itself well to welding or conventional repairs. Once corroded or cracked, replacement has historically been the only reliable option.
Composite wraps offer a breakthrough:
Key Benefit: Offers a non-intrusive, no-hot-work repair option for a historically difficult-to-repair material.
Copper, brass, bronze, and CuNiFe (copper–nickel–iron) alloys are widely used in specialised systems, particularly where seawater resistance is essential. Common applications include firewater lines, seawater cooling systems, desalination plants, and some LPG services.
Non-ferrous alloys corrode differently to steels, often via dezincification (brass), erosion-corrosion, or selective attack. CuNiFe, for instance, is chosen for its excellent resistance to seawater corrosion, but it is still vulnerable to erosion and localised attack in high-velocity flows.
Another challenge is that these alloys are generally much softer than carbon steel or stainless steel. This means that during surface preparation, care must be taken not to remove too much material. Aggressive mechanical abrasion or over-grinding risks creating excessive wall loss or even a through-wall defect, turning a cosmetic defect into a leak.
Composite wraps are highly effective on copper-based alloys:
Key Benefit: Provides reinforcement and isolation while preserving wall thickness, extending the life of critical non-ferrous alloy systems.
Aluminium is lighter than steel and is used in some storage tanks, piping, and marine structures where weight savings are critical.
Aluminium’s oxide layer makes adhesion difficult, and welding repairs are challenging due to the risk of porosity and distortion.
Composite Wrap Repair
Specialised surface preparation (abrasion followed by solvent cleaning) allows reliable adhesion. Composite wraps:
Key Benefit: Extends aluminium component life without complex metallurgical challenges.
Galvanised steel is often used in utilities, water lines, and HVAC systems for its improved resistance to atmospheric corrosion.
Once the zinc coating is breached, galvanised steel corrodes rapidly. Welding burns off protective coatings, leaving the joint more vulnerable.
Composite wraps are highly compatible, provided the surface is abraded to remove the zinc layer at the bond interface.
Key Benefit: Provides a durable repair without damaging the galvanised coating further.
High-performance alloys such as titanium, Inconel, and Hastelloy are used in highly corrosive or high-temperature services, such as offshore risers, chemical reactors, and aerospace.
While incredibly resistant, these alloys are not invincible. Localised damage, erosion, or mechanical wear can occur, but welding repairs are prohibitively expensive and technically challenging.
Composite wraps provide an elegant alternative:
Key Benefit: A cost-effective safeguard for some of the industry’s most expensive materials.
Many tanks, pipelines, and equipment are supported by concrete saddles, plinths, or foundations. In water and wastewater infrastructure, large-diameter concrete pipes are also common.
Concrete suffers from spalling, cracking, and chemical attack (particularly from sulphates or acidic effluents). Reinforcement corrosion can accelerate deterioration.
Composites are widely used in civil infrastructure:
Key Benefit: Extends the life of civil structures without demolition or reconstruction.
GRP and composite pipes are used in seawater, chemical, and offshore services due to their corrosion resistance and lightweight nature.
GRP can develop delamination, cracking, or joint failures. Repairs using the same materials can be labour-intensive and require specific cure conditions.
An additional challenge is that the damage in a GRP pipe may be more extensive than what is visible on the surface. Subsurface delaminations, resin micro-cracking, or fibre damage can extend further along the pipe than the initial defect area observed. This means that the true extent of repair required is often longer than the visibly affected section, and inspections must take this into account to ensure full structural integrity.
Engineered composite wraps (epoxy/glass or carbon) are an excellent match:
Key Benefit: Composite-to-composite repairs are lightweight, durable, and fast to deploy, provided proper assessment is made to cover all affected areas.
While engineered composite wraps are versatile, the repair design must always be tailored to the substrate, defect type, operating conditions (pressure, temperature), and fluid service.
Key considerations include:
Importantly, both ISO 24817 and ASME PCC-2 require that qualification testing is performed for a specific pipe material and the method of surface preparation used for that material. This means performance data from carbon steel with grit blasting cannot automatically be applied to stainless steel, cast iron, or other substrates with different preparation methods. Operators should therefore always confirm with vendors that the composite repair system has been tested and qualified for the pipe material in question and the chosen method of surface preparation.
From carbon steel fuel lines suffering CUI to titanium risers offshore and even concrete plinths in wastewater plants, engineered composite wraps can repair and protect an extraordinary range of substrates. Their adaptability, non-intrusive application, and compliance with international standards make them one of the most powerful tools in the asset integrity toolkit.
By understanding the unique challenges of each substrate and selecting the right composite system, operators can dramatically extend the life of critical infrastructure—safely, sustainably, and cost-effectively.
