Step Ahead

How Rope Access Cut Costs for Refractory Lining Inspection in Half

web@mistrasgroup.com (MISTRAS Group) — Thu, 28 May 2026 20:12:49 GMT

MISTRAS’ Benicia, California rope access team recently delivered faster, safer, and more visible mechanical inspection by utilizing rope access and real-time camera technology in lieu of traditional scaffolding.

The Challenge

When a client required a visual inspection of their reactor/regen refractory lining, the obvious approach would have involved building extensive scaffolding throughout the vessel.

This method would have required:

A large crew
Multiple shifts
High costs
Additional safety considerations

Scaffolding can also create visual obstructions during inspections, and because it is mechanical in nature, it even carries the potential to cause additional damage inside the asset.

Rope Access: A Safer, Modern, Cost-Effective Approach

However, the Benicia team approached the challenge differently. Initially tasked with eliminating fall hazards before scaffolding construction, the team recognized an opportunity to perform the inspection entirely through rope access, leveraging prior experience completing similar inspections.

The Results

Through rope access, the team completed the client’s reactor/regen visual inspection in a single 16-hour shift, a process that would have traditionally required six to seven shifts using scaffolding.

By eliminating the need for extensive staging and reducing the manpower requirement from roughly 10–15 personnel to a small team of 6 highly-skilled rope access technicians, the client benefited from:

Significantly lower labor and setup costs
Faster turnaround times
Improved safety
Reduced visual obstructions caused by scaffolding

Real-Time Visibility with Camera Technology

Additionally, the team utilized 360° body-mounted cameras (Fig. 1) to provide the client with real-time, high-quality photos and video throughout the inspection process. This allowed the client:

Full visibility into the condition of the vessel as the work was being performed,
More time to evaluate findings
Better insight to plan any necessary repairs

Figure 1

MISTRAS’ Benicia, CA Rope Access Mechanical Services include:

All methods of NDT (MT, PT, UTT, PAUT, RT, CR, ET)
Visual API-510 , 570 ,653 & 936
Welding
Cleaning
Part Replacements, Light Bulbs, Speakers, Sprinkler Heads
Coatings, Painting, and Removal
Cooling Towers Inspection
Video live feed camera inspections
Blasting
Bridge Inspections
Marine Vessel Inspections

Unlock the possibilities of rope access for mechanical services with MISTRAS’ Benicia Team.

MISTRAS' Anchorage Team Expands Welding Qualification Services

web@mistrasgroup.com (MISTRAS Group) — Thu, 16 Apr 2026 04:00:00 GMT

MISTRAS Group recently introduced welder qualification and welding procedure development services at its Anchorage location.

New Welding Qualification Services Offered:

Welding Qualification & Certification
- WPQ per ASME Section IX
- AWS D1. 1 welder testing
- API 1104 pipeline qualifications
- Contractor qualification testing
- Position testing (1G-6G pipe & plate)
PQR & WPS Development
- Welding Procedure Specifications (WPS)
- Procedure Qualification Records (PQR)
- Procedure qualification testing
- Code-compliance verification
Welding & NDT Training
- NDT training for inspectors & technicians
- Welder skill development
- Pre-employment welding tests
- Union & contractor training support
Repair & Troubleshooting
- Weld failure analysis
- Welding technique troubleshooting
- Consumable comparisons
- Heat input trials

How This Benefits Clients:

Ensure welds meet industry standards
Reduce risk and rework
Improve weld consistency and reliability
Qualify welders through hands-on evaluation
Develop procedures for specific materials and applications
Supporting Alaska’s Oil & Gas Industry

Contact the MISTRAS Anchorage team today for more information on welding qualification and procedure development services.

Dig Validation Isn’t the Finish Line—It’s the Start of the Investigation

web@mistrasgroup.com (MISTRAS Group) — Thu, 02 Apr 2026 04:00:00 GMT

The Challenge:

During pipeline dig validations, it’s common for NDE findings to be treated as the final word. But in many cases, there is more to the story than what the NDE company finds.

Without involving the ILI vendor, critical context can be lost. What appears to be a missed call may be the result of growth, feature evolution, or something unexpected.

The Difference NDE/ILI Integration Makes:

Operators who include the ILI vendor gain a far clearer picture. By cutting out and shipping pipe samples for comprehensive evaluation, deeper insights emerge through:

Advanced NDE (pit gauging, laser scanning, granular correlation)
Independent verification using additional ILI pull testing

For nearly 20 years, MISTRAS member-company Onstream Pipeline Inspection has supported pipeline operators with an industry-leading, ready-to-deploy ILI tool fleet, high-quality inspection reporting, and comprehensive Post-ILI validation services. Our validation capabilities include pipe sample assessment, such as pit gauging, ultrasonic wall thickness measurements, laser scanning, feature correlation, outlier analysis, pull testing, and detailed ILI Validation Results Reporting.

Read on to see how integration doesn’t just streamline the process—it strengthens confidence in the data, improves correlation accuracy, and enhances integrity decision-making across the asset lifecycle.

Case Study: Onstream ILI validation reveals previously-unknown 50% external corrosion missed even by NDE!

Onstream MFL reported through-wall internal corrosion features. The joint was removed and verified by an NDE company. The through-wall features were obvious, and internal/external discrimination was generally accurate; however, some nearby internal corrosion indications reported by MFL could not be confirmed during field validation.

What conclusions would you draw?

The NDE report assumed the “missing” features were simply MFL false positives. The case would have been closed, but Onstream requested the pipe for pull testing and independent verification. The same “false positive” features were again visible in the pull test.

Onstream then stripped and sandblasted the external pipe surface. This had not been done by the NDE company, assuming all the corrosion was internal. A series of external pinholes were revealed with depths up to 50%!

This independent validation completely changed the game for corrosion mitigation. The through-wall features themselves, initially assumed to be internal in origin, may in fact have been external.

Case Study: Extremely Fast Corrosion Growth Rates Confirmed by Pull Testing of Cutout Joint

A leak occurred when three through-wall holes appeared on a single joint. This pipeline had been inspected only a year prior, and the three deepest features reported on this joint were 47, 35 and 34 percent deep. Did these three features grow into leaks in only a year? Or did the inspection miss major features?

The joint was removed. Before being split and laser scanned, it was pull tested with the same MFL tool used during the inspection a year prior. The results were surprising. Dozens of large new features were detected, including all three holes. The pull test showed that all three through-wall features had not grown from features that existed a year ago – all three were brand new and had grown from zero to 100% in only a year!

Note the band of shallow internal corrosion at 6:00 visible in both inspection and pull test, which appears unchanged. The identical detection of these shallow features demonstrates the repeatability of the ILI tool. Meanwhile, several large pits at 4:00 and 8:00 have appeared in the year between inspection and pull test. Three of these reached 100% depth!

After pull testing, the joint was split and laser scanned. Many of the new internal features had depths exceeding 70%.

A review of the rest of the pipeline identified several other joints with deep features that appeared between 2018 and 2024 MFL inspections with depths up to 63%. Surprisingly, none of these leaked before the even newer features on the cutout joint. But they did serve as a warning that rapid growth was a possibility.

With 6 years between inspections, the growth rate is highly uncertain. Did these features appear 6 years ago, or less than 1 year ago? It’s impossible to know for sure. The pull test performed after the leak proved the growth rate was at the highest end of the possible range.

Lessons Learned

Corrosion can grow extremely rapidly – from zero to 100% in less than a year!
Growth rates vary widely from feature to feature. Even on the same joint of pipe, some features didn’t change in 6 years, while others grew very quickly. It’s the fastest-growing feature, not the average growth rate, that matters most.
The longer the span between inspections, the more uncertainty around growth rate. Don’t assume the features started growing immediately after the last inspection. They may be much newer and much faster growing!
Pull testing before splitting the pipe is very useful for determining the true growth rate.

Bottom Line

Dig validation is not the end of the investigation; it’s an opportunity to better understand asset condition and active threats. Integrating the ILI vendor into the validation process brings inspection data, field findings, and independent verification together for a more complete assessment, improving ILI / NDE correlation confidence and supporting integrity decisions. At Onstream, these validation services are a standard part of our offering.

To learn more, please reach out to our Onstream team: Contact - ONSTREAM | Pipeline Inspection Services

Adaptive Speed Control: Advancing Inline Inspection in Low Pressure Gas Gathering Pipelines

web@mistrasgroup.com (MISTRAS Group) — Thu, 19 Mar 2026 04:00:00 GMT

Inline Inspection (ILI) has long been a cornerstone of pipeline integrity management, yet its effectiveness depends heavily on maintaining a stable and predictable tool velocity. In today’s operating environment—where pipeline throughput is economically critical—operators are increasingly reluctant to reduce flow rates simply to accommodate inspection tools. This tension is especially pronounced in gas gathering systems, where low pressures, high flow rates, and variable operating conditions create significant challenges for traditional ILI technologies.

This article summarizes the development, deployment, and performance of a modern speed control ILI system in two low‑pressure gas gathering segments, demonstrating how tailored configurations and operational planning can overcome long‑standing inspection challenges.

The Operator’s Gathering System: A Complex Inspection Environment

The case study centers on a 65‑mile, 24‑inch gas gathering loop installed in 2016. The system collects natural gas from regional wells and delivers it to fourteen compression stations before sending it onward to nine processing plants. The loop is divided into multiple piggable segments, each with unique flow characteristics.

Two segments were selected for inspection:

Both segments also experience extremely low differential pressures—typically only 10–15 psig between launcher and receiver—making tool propulsion and velocity control especially difficult.

Why Low‑Pressure Gas Gathering Lines Are Hard to Inspect

ILI in gas gathering systems is notoriously challenging. Several factors contribute to this:

1. High Velocity Fluctuations

Low-pressure gas behaves unpredictably, causing rapid changes in tool speed. These fluctuations can distort magnetic fields in MFL tools, leading to data gaps. The figure below shows an example of an ILI tool velocity chart for a 280 psig gathering line inspection under more ideal operating conditions. There are several instances where the tool speed significantly exceeds the ideal range of 6.5 mph, with a ~+/- 5 mph range surrounding the target velocity, creating data gaps.

2. Risk of Tool Damage

High-speed surges can cause the tool to impact tight fittings or the receiver barrel, posing potential equipment risks.

3. Low Differential Pressure

With only 10–15 psig of differential pressure, launching and propelling an ILI tool becomes difficult. Tools may stall or surge unpredictably.

4. Limited Operational Flexibility

Increasing pressure or reducing flow—common strategies for stabilizing tool velocity—were not viable. Doing so would have required shutting in wells, disrupting production, and increasing costs.

5. Alternative Methods Were Not Feasible

Hydrostatic testing, robotic crawlers, tethered tools, and liquid batching were all evaluated and rejected due to cost, complexity, or incompatibility with the system’s geometry and flow conditions.

Given these constraints, the operator sought a solution that could maintain throughput while still delivering high-quality integrity data.

Speed Control Technology: How It Works

Speed control systems regulate ILI tool velocity by adjusting a bypass valve that allows gas to flow through the tool. The simplified block diagram outlines the primary function of a speed control system.

The logic module compares real-time tool speed to the target velocity. If the tool is too slow, the valve closes to increase speed; if too fast, the valve opens to allow more gas to bypass and reduce tool speed.

Key Factors Affecting Performance

There are several key factors impacting bypass performance, including:

Line pressure and gas density
Tool drag, influenced by debris and line cleanliness
Pipeline geometry

A major challenge is predicting Δp (pressure drop across the tool), which can vary by up to 35% between pipelines. This variability makes it difficult to estimate bypass capability without real-world testing.

The plot below shows the estimated gas bypass curves for a large diameter MFL-based ILI tool as a function of line pressure. The red dashed line is the target velocity for the ILI, which the speed control will try to maintain. The volume of gas able to be bypassed decreases with increasing line pressure, as indicated in the plot. Furthermore, the plot includes a lower and upper gas velocity limit, the difference between these lines is to account for the potential Δ𝑝 variance between different pipelines.

Transmission Pipeline Benchmark: High Pressure, Predictable Dynamics

Before tackling the gathering system, the speed control system had been proven in high-pressure transmission pipelines. An example of the typical transmission pipeline operating conditions is shown in the table.

At these operating parameters, the speed control tool was expected to run as a steady state system, with limited dynamic movement maintaining the target tool speed. In addition, given the maximum flow conditions, the speed control was anticipated not to reach full bypass capacity. The figure below shows the target velocity (red dashed), the tool run speed (blue solid), and the operation of the speed control valve (black dotted). Reviewing the tool speed, the velocity of the tool exceeded the target range, as indicated in the plot. The speed control valve opened, bypassing gas, until the tool velocity came back within the target tool velocity range. The overspeed and 100% opening of the speed control valve were due to a hard tool launch. Most notable from the plot is the limited movement of the speed control valve; the dynamic response of the valve, once the tool was in the target speed range, was very limited. This speed control valve's dynamic response is characteristic of the steady flows expected in gas transmission pipelines. Lastly, the speed control valve was open approximately ~50% throughout the inspection, indicating the speed control still had capacity to bypass more gas, aligning with the predictions outlined in the table.

This steady-state behavior is typical of transmission systems, where pressures and flows are more consistent. Below are images of the ILI tool post transmission pipeline inspection.

Applying Speed Control in Low‑Pressure Gathering Pipelines

The pipeline owner operates a super gathering system that requires routine ILI to manage the asset integrity. It was understood by all parties that while speed control tools have the capability to reduce tool speed under high flow conditions, there were upper limits to the flow. The Operator’s Integrity engineers, Operations and Control Center, along with the ILI Vendor, agreed upon a plan where the flow would be reduced for the duration of the ILI run to the least possible without shutting in any wells. Similarly, the average line pressure would also be increased to the maximum possible without shutting in any wells, along with trying to maintain a large enough differential to keep the tool moving without stopping.

With agreed-upon plans in place, the first ILI speed control tool run was attempted in Segment-1 in May 2025. The average operating pressure was maintained at 167 psig with a differential of 60 psig. The run was completed with the ILI tool travelling at an average speed of 5.8mph, which was below the tool’s maximum specification. The tool experienced some short areas of speed excursion totaling the equivalent of 3.86% of the total distance. Overall, the tool run was successful with 100% sensor coverage.

Encouraged by the success of the tool run in Segment-1, a run was conducted in Segment-2 in June 2025. The pipeline operating parameters for Segment-2 are included in the table below. The average operating pressure was maintained at 181 psig with a differential of 20 psig.

The graph below shows the tool velocity and speed control valve dynamics for this gathering line. The target tool velocity is indicated by the dashed red line, which was set to 6 mph. The speed control was able to maintain the tool velocity close to the target set point. There was an ~+/- 1 mph range surrounding the target velocity. The speed control valve was very active in maintaining this velocity, as indicated by the valve position (black dotted line) in Figure 9. The speed control valve dynamics were as expected, given the low line pressure and high gas flows. Contrasting the speed control valve dynamics in the transmission example, the valve was making 30-50% position changes to maintain velocity, as expected. The tool experienced minimal areas of speed excursion, totaling the equivalent of 0.72% of the total distance. This tool run was also deemed successful with 100% sensor coverage.

The line conditions were dry as expected based on the cleaning results. The tool came out very clean with no debris. The images below show the condition of the ILI tool pre and post-inspection. The dry conditions contributed to the speed control performance and improving bypass capability. Throughout the inspection, the speed control was never 100% open or limited in bypass capability, resulting in the ability to maintain the target speed and handle the significant gas dynamics from the low-pressure line.

Conclusion: A New Path Forward for Low‑Pressure ILI

The successful deployment of speed control in these gathering segments represents a meaningful advancement for operators facing similar challenges. Historically, low-pressure gas gathering lines have been difficult—and sometimes impossible—to inspect using conventional ILI tools. This often forced operators to choose between:

Costly hydrostatic testing
Production shutdowns
Increased excavation and NDT
Shortened re-inspection intervals
Accepting reduced data quality

Speed control offers a practical alternative that avoids these trade-offs. The trials in Segment‑1 and Segment‑2 demonstrate that adaptive speed control systems can reliably manage tool velocity in low-pressure, high-flow gas gathering pipelines—environments once considered unsuitable for MFL ILI. The plots below show the tool speed comparison of an ILI in a 400 psi line without speed control, compared to Segment 2 at 180 psi with speed control. The technology maintained near-target speeds, minimized excursions, and delivered full sensor coverage without requiring throughput reductions or operational disruptions.

For operators managing aging infrastructure, this capability is transformative. It enables proactive integrity management, reduces operational risk, and supports safer, more efficient pipeline operations—all without sacrificing production.

Interested in adaptive speed control? Contact our Onstream team today: Contact - ONSTREAM | Pipeline Inspection Services

How Rope Access Helped Avoid Major Scaffold Costs During a Critical Inspection

web@mistrasgroup.com (MISTRAS Group) — Thu, 05 Mar 2026 05:00:00 GMT

MISTRAS Group recently completed a complex rope access inspection on a high-elevation piping system where traditional crane access was unavailable due to ongoing construction activities.

The inspection required technicians to scan the bottom section of piping located nearly 100 feet in the air and spanning approximately 50 feet between supports.

The Challenge:

With crane and man-basket access unavailable, the customer faced two difficult options:

Delay the inspection
Build extensive scaffolding

Estimated scaffold costs ranged from $80,000–$100,000, along with additional schedule impacts.

The Rope Access Solution:

Using advanced rope access techniques, the MISTRAS team safely completed the inspection while helping the customer avoid significant costs and delays.

Key safety measures included:

Detailed pre-task planning
Complex rescue support onsite
Ground barricades
Fully tethered tools
Strict adherence to safety procedures

Delivering Safety, Savings & Efficiency:

By combining rope access expertise with advanced inspection capabilities, MISTRAS helped the customer:

Avoid costly scaffold installation
Complete the inspection safely
Maintain operational efficiency
Keep the project on schedule

The project is another example of how MISTRAS delivers practical inspection solutions in challenging environments while helping customers stay a step ahead.

Learn More About MISTRAS Rope Access Services:

Discover how MISTRAS Rope Access Solutions can help reduce costs, improve access, and support safe, efficient inspections in hard-to-reach areas here.

How Drone Technology Improved an Offshore ISIP Campaign

web@mistrasgroup.com (MISTRAS Group) — Wed, 18 Feb 2026 05:00:00 GMT

Offshore inspections often involve complex logistics, difficult access conditions, and tight operational timelines. During a recent offshore In-Service Inspection Program (ISIP), MISTRAS utilized drone technology to help simplify the inspection process and improve overall visibility for the customer.

By capturing real-time visual data from hard-to-access areas, the team supported a safer, more efficient inspection scope while minimizing operational disruption. The use of drones also reduced the need for additional access methods and helped streamline execution throughout the campaign.

Supporting Safer and More Efficient Offshore Inspections

Client feedback recognized the team’s technical knowledge, communication, flexibility, and commitment to safety and quality during the project. Collaboration between field personnel and the customer helped ensure the inspection scope was completed efficiently while adapting to challenges along the way.

Drone-assisted inspections continue to play an increasing role in offshore asset integrity programs by helping operators:

Improve access to difficult inspection areas
Reduce safety exposure
Increase inspection visibility and data collection
Support faster, more efficient project execution

Advancing Offshore Asset Integrity with Drone Technology

By combining advanced drone capabilities with experienced inspection personnel, MISTRAS continues to help offshore operators execute inspection and integrity programs with greater efficiency and confidence.

Step Ahead

How Rope Access Cut Costs for Refractory Lining Inspection in Half

MISTRAS’ Benicia, California rope access team recently delivered faster, safer, and more visible mechanical inspection by utilizing rope access and real-time camera technology in lieu of traditional scaffolding.

The Challenge

Rope Access: A Safer, Modern, Cost-Effective Approach

The Results

Real-Time Visibility with Camera Technology

MISTRAS’ Benicia, CA Rope Access Mechanical Services include:

MISTRAS' Anchorage Team Expands Welding Qualification Services

MISTRAS Group recently introduced welder qualification and welding procedure development services at its Anchorage location.

New Welding Qualification Services Offered:

How This Benefits Clients:

Dig Validation Isn’t the Finish Line—It’s the Start of the Investigation

The Challenge:

The Difference NDE/ILI Integration Makes:

Case Study: Onstream ILI validation reveals previously-unknown 50% external corrosion missed even by NDE!

Case Study: Extremely Fast Corrosion Growth Rates Confirmed by Pull Testing of Cutout Joint

With 6 years between inspections, the growth rate is highly uncertain. Did these features appear 6 years ago, or less than 1 year ago? It’s impossible to know for sure. The pull test performed after the leak proved the growth rate was at the highest end of the possible range.Lessons Learned

Bottom Line

Adaptive Speed Control: Advancing Inline Inspection in Low Pressure Gas Gathering Pipelines

Why Low‑Pressure Gas Gathering Lines Are Hard to Inspect

Speed Control Technology: How It Works

Key Factors Affecting Performance

Transmission Pipeline Benchmark: High Pressure, Predictable Dynamics

Applying Speed Control in Low‑Pressure Gathering Pipelines

Conclusion: A New Path Forward for Low‑Pressure ILI

How Rope Access Helped Avoid Major Scaffold Costs During a Critical Inspection

The Challenge:

The Rope Access Solution:

Delivering Safety, Savings & Efficiency:

Learn More About MISTRAS Rope Access Services:

How Drone Technology Improved an Offshore ISIP Campaign

Supporting Safer and More Efficient Offshore Inspections

Advancing Offshore Asset Integrity with Drone Technology

With 6 years between inspections, the growth rate is highly uncertain. Did these features appear 6 years ago, or less than 1 year ago? It’s impossible to know for sure. The pull test performed after the leak proved the growth rate was at the highest end of the possible range.

Lessons Learned