8. Line Lifting Methods for Addressing Corrosion Under Pipe Supports (CUPS)
- Connor Tiegs
- Aug 13
- 9 min read
In industrial environments like petrochemical facilities and refineries, pipelines are critical assets, often spanning miles to transport products between processing and storage units. These pipelines are typically supported on ground-level structures or multi-story racks, which can lead to Corrosion Under Pipe Supports (CUPS) - a common and potentially dangerous issue where pipes meet support structures. Over time, this corrosion reduces wall thickness at touchpoints, compromising the pipeline’s integrity and increasing the risk of leaks or even structural failures.
To manage CUPS, non-intrusive inspection techniques, such as Electromagnetic Acoustic Transducer (EMAT) and Guided Wave Ultrasonics, allow operators to evaluate corrosion severity without lifting the pipelines, but these are only qualitative measures and do nothing to address the problem. Line lifting remains essential for gaining free access to the corroded section of the pipe for direct inspection and the ability to perform permanent repairs.
Several conventional methods exist for lifting pipelines, but they are often limited in terms of safety, cost, and practicality, especially for on-stream applications. This article examines the most common pipeline lifting techniques, discussing their strengths and limitations, and highlights essential engineering and safety standards that support a proactive approach to managing CUPS effectively. By exploring these options, operators can make informed decisions to enhance safety, efficiency, and reliability in pipeline maintenance.
8.1 Conventional Lifting Methods
8.1.1. Chain Falls, Chain Blocks & Come Alongs
Chainfalls or come alongs are one of the most widely used tools for pipeline lifting. They are affordable, readily available, and relatively quick to deploy. However, using chainfalls imposes inherent safety risks which users must be aware of. Chainfalls lack a mechanical locking mechanism, meaning once the load is lifted it creates a suspended load rather than a static structure.
Consequently, it’s unsafe to work beneath a suspended load, which is necessary when performing maintenance on the bottom section of a raised pipe. Additionally, chainfalls cannot remain suspended without crew supervision, requiring the load to be lowered and re-raised between work shifts. This repeated handling increases risk exposure and operational complexity.
A significant safety concern with chainfalls is the lack of precise load measurement. Without an indicator to gauge the load on the device or the stress applied to the piping, operators must rely on an imprecise sense of “feel” to judge the acceptable load level. This approach risks overloading the equipment, which could lead to catastrophic failure. In such a scenario, the raised pipe could suddenly drop onto the support under its own weight and tension, potentially causing further damage or even a dangerous loss of containment at the pipe touchpoint.
Lastly, chainfalls require manual operation, which places crews in close proximity to the load, directly within the danger zone in the event of equipment failure or a loss of containment.
Due to limited awareness within the industry about safer, more advanced lifting methods, chainfalls have long been the most popular option for line lifting. However, the inherent safety risks associated with chainfalls have historically restricted their use to out-of-service piping, where the stakes are lower.
Chainfalls also come with significant operational limitations. They are designed to lift only single lines at a time and must be rigged to an overhead structure, such as a pipe rack or an additional strongback. This requirement reduces productivity and drives up indirect costs, making chainfalls less efficient for large-scale or complex lifting projects where multiple lines need to be raised simultaneously.
8.1.2. Cranes
Cranes are commonly used for lifting larger pipes or those resting on ground-level supports, providing more power than chainfalls and the capability to handle heavier loads. However, cranes also present limitations and safety risks similar to those of chainfalls.
Like chainfalls, cranes create a suspended load, as they lack a secure locking mechanism to secure the load in the raised position. This means that cranes must lower and re-raise loads between work shifts, a requirement that can be prohibitive for complex tasks that necessitate a pipe’s elevation for extended periods. The repeated need to lift and lower a suspended load increases the risk exposure for crews and introduces potential hazards over prolonged work scopes.
One advantage of cranes is that they allow operators to measure the load, giving crews a clearer idea of the weight being lifted. However, cranes are generally restricted to lifting at a single point on the pipeline, making coordinated lifts across multiple points impractical and risky. This limitation poses a significant challenge for larger bore piping, where lifting at a single location can overstress the pipe, increasing the likelihood of bending, deformation, or damage. In contrast, a coordinated lift with multiple lifting points would distribute stress more evenly, providing better control and reducing the risk of structural damage.
While cranes serve as a viable option for some lifting tasks, these limitations restrict their use in scenarios where multiple, simultaneous lift points are required, especially on complex or large-diameter pipelines.
Cranes are costly to operate, which makes them less practical for large-scale, proactive maintenance projects involving hundreds of touchpoints. The high operational costs can quickly add up, rendering cranes prohibitive for extensive maintenance scopes where multiple lifts are required.
Beyond cost, cranes also have a considerable operating footprint. Their size and maneuvering space requirements make it difficult for them to access the majority of pipe touchpoints located within multi-level pipe racks. Processing units are often highly congested with other equipment and work crews, and the presence of a crane can obstruct key access points, restricting movement and access for nearby work crews. This blockage can delay other essential tasks, making crane use undesirable in areas where efficient space management is critical.
While cranes are effective for certain lifting scenarios, their limitations in terms of cost, accessibility, and space requirements mean they’re not always suitable for compact or elevated pipeline systems within congested processing units.
8.1.3. Traditional Pipe Rack Jacks
Traditional pipe rack jacks use mechanical screws to elevate pipes by attaching the device beneath support beams. These jacks are reliable for short-term, static lifting and do not require an overhead structure for rigging but these systems have notable limitations.
They can only lift single lines at a time and are only rated to lift lines up to 8” in diameter since they have a limited lifting capacity. These systems can be heavy and cumbersome to use, and are often limited to ground-level pipe supports as long as they have sufficient clearance beneath the support (up to 30” of clearance beneath the beam is required).
These devices cannot be remotely operated so crews again are required to be in the danger zone to operate the tool so it’s not best practice to use these on live equipment.
For certain applications, pipe jacks are useful, but they lack the flexibility and safety features required for more complex lifting operations.
8.1.4. Pillow Bags & Crib Stacks
Inflatable pillow bags are sometimes used to lift ground-level pipelines by positioning the bags between the pipe and the ground and inflating them with compressed air. However, to provide the necessary lifting force and height, pillow bags require a specific amount of clearance. In most cases, this means additional cribbing material or crib stacks must be built up under the pipeline. This process can be labor-intensive, as a crib stack is needed at each lift location, and the amount of cribbing material required increases as the gap between the pipe and the ground widens.
Once inflated, pillow bags are held in place by a single closed valve, leaving them vulnerable to accidental deflation. If the valve fails or is disturbed, the pipe could drop suddenly, posing a severe risk to any crew working beneath the pipeline. This lack of stability is a major safety concern, as it places personnel in the danger zone with minimal protection against sudden load shifts.
Pillow bags also offer limited control over the lift, which can result in uneven elevations that overstress certain sections of the pipeline, increasing the likelihood of structural failure. Due to these control limitations and safety risks, pillow bags are generally unsuitable for high-risk or extended-duration lifting tasks. Their use is typically discouraged in scenarios where precision and safety are paramount, as they lack the reliability and stability needed for sensitive or prolonged operations.
8.2. Ovolifts Pipe Jacks
Ovolifts has engineered a specialized range of pipe rack jacks designed to meet these demanding requirements of pipeline lifting with precision, safety, and efficiency. Unlike traditional lifting methods, Ovolifts’ pipe jacks are equipped with hydraulic remote operation capabilities, allowing operators to activate the lift from a safe distance. This remote functionality keeps personnel out of the danger zone during the critical initial lift phase, significantly reducing exposure to potential hazards - an essential feature when working on live pipelines.
Ovolifts' jacks also incorporate a mechanical lockout mechanism, transforming each lift from a suspended load into a stable, locked position. This lockout system prevents accidental shifts or drops, enabling safe, extended access to the pipe touchpoints. Additionally, Ovolifts’ jacks utilize existing support structures, eliminating the need for excessive rigging and significantly reducing setup time and costs. This ergonomic design, combined with multi-line lifting capabilities, makes Ovolifts’ solution ideal for complex, large-scope projects where multiple adjacent lines need simultaneous lifting.
To ensure optimal performance and pipeline integrity, Ovolifts’ pipe jacks utilize hydraulics which provides real-time feedback on the load being applied. When paired with thorough engineering and pipe stress analysis, these readings allow operators to confirm that stress levels remain within safe limits throughout the lift. This comprehensive approach, supported by detailed lift plans tailored to each site, ensures that Ovolifts’ pipe rack jacks deliver safe, efficient, and controlled lifting operations, enabling operators to perform critical maintenance without compromising safety or productivity.
8.3. Criteria for an Ideal Pipeline Lifting Solution
For safe and effective access, the ideal pipe-lifting device should offer the following features:
8.3.1. Remote Lifting Capabilities
Remote operation, such as hydraulically activated jacks with flexible hose lengths, allows personnel to maintain a safe distance during the lifting process. This minimizes exposure to hazards during the critical initial lift phase, especially on live lines.
8.3.2. Mechanical Lockout Mechanism
A locking mechanism transforms the lifted load from a suspended state to a static, locked-in position, ensuring safety for extended or complex operations. This feature is particularly crucial when working on live lines.
The locking mechanism works independently of the hydraulic cylinder which provides the lifting power. Once the jacks are locked into position the hydraulic cylinders can actually be removed.
8.3.3. Ergonomic
Lifting equipment should utilize existing support structures, minimizing the need for additional rigging and reducing setup time and costs.
8.3.4. Multi-Line Lifting Capabilities
In some scenarios, multiple adjacent lines require lifting, such as is required for large scope projects or when replacing supports. A multi-line lifting setup improves productivity and cost-efficiency.
The image above shows the Ovolifts Multi-Jack lifting 7 lines in a single operation which improves productivity.
8.3.5. Load Readings
Using hydraulics tells operators how much load is being applied in the form of a pressure gauge. When this is paired with the engineering calculations it ensures the piping is not overstressed during the critical lift. Ovolifts provides a comprehensive Lift Plan which includes a calculation showing the hydraulic pressures that correlated with the lifting loads for each lift so there is no uncertainty on site during the lifts.
The hydraulic pressures have to be adjusted for jack geometry, hydraulic cylinder specifications and attachment points.
8.3.6. Engineering
Comprehensive engineering, including pipe stress analysis, is essential to ensure that pipe stresses remain within allowable limits throughout the lift. Additionally, a detailed lift plan helps address site-specific conditions, ensuring equipment remains within operating limits and providing guidance on safe lifting points and configurations.
8.3.7. Lift Height Control
Ovolifts pipe jacks are the only tools available that allow technicians to mechanically restrict the maximum lift height achievable. Once set, the operator of the hydraulic power pack can rest assured knowing that they cannot inadvertently exceed the maximum permissible lift height determined by the pipe stress analysis and lift plan.
This adds a critical layer of safety to protect personnel and equipment by ensuring the piping cannot be overstressed which is always a concern when working on piping damaged by Corrosion Under Pipe Supports (CUPS).
8.3.8. Synchronized Lifting From More Than One Support
The manifold which forms part of the hydraulic power pack allows multiple jacks to be connected to the same circuit allowing multiple jacks to be safely lifted simultaneously. Because each jack is connected to the same circuit there is no chance of overloading any single jack more than others which is something that no other lifting device can achieve.
Synchronized lifting is a critical procedure for safely handling situations where certain pipelines cannot be lifted at a single touchpoint. This is especially important for piping with significant wall loss, as concentrating the lifting force at a single location may lead to overstressing and potential failure. By distributing the lifting load evenly across multiple points, synchronized lifting ensures the integrity of the pipe is maintained during the process.
8.3.9. Spark Proof Construction
All of Ovolifts pipe rack jacks are constructed from a material that prevents sparks due to impact or friction which is a critical safety feature when working in environments where flammable gases, vapors or dust may be present such as in oil refineries or chemical processing plants.
8.3.10. Versatile
Ovolifts pipe rack jacks can lift from any size and shape of support. The standard configuration works of an I-beam but using simple brackets it’s easy to adapt this configuration to circular supports, concrete sleepers and channel beams to name a few.
8.3.11. Able To Handle Large Loads
Most lifting equipment, excluding cranes and airbags, is typically limited to lifting small-bore piping up to around 8 inches in diameter and cannot support the substantial loads generated by larger bore piping. The Ovolifts Mega-Jack, however, is specifically designed to overcome these limitations. Rated at an impressive 44,000 lbs (20 metric tonnes), the Mega-Jack provides unmatched lifting power. Furthermore, by utilizing multiple jacks in series, this capacity can be increased even further, effectively eliminating load restrictions and enabling the safe and efficient lifting of virtually any pipe size.
For more information on Ovolifts capabilities and services, please reach out:
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