Category: Hot tap welding test

Introduction to Hot Tapping in Piping

Hot tapping is the technique used to attach a branch connection to a pipe while the system is in service, and then creating an opening in that pipe by drilling or cutting. While hot taps are most often done in piping system, they may also be done on pressure vessels and storage tanks to add nozzles.

Hot tapping permit adding connections without depressurization or disruption of process operations.

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They may also be used to make piping connections where it would be inconvenient to prepare the system for hot work. Hot tapping is also used to isolate pipe sections for maintenance by plugging or stoppling the line.

Hot tapping is an inherently dangerous operation. Therefore, hot tapping should generally be used only when it is impractical to take the system out of service.

When specifying hot tapping, care is required in inspection, design, and testing to ensure that this operation is done in a safe and reliable manner.

Therefore, a hot tapping should be considered only after other options are evaluated and rejected. Each hot tapping should be properly designed, the hot tapping location thoroughly inspected, and the installation procedures reviewed.

Like, Share and Subscribe this article for authors enthusiasm and motivation. Tags: hot tapping.

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I would like to add: What shall be done before performing hot tapping, based on several cases when I was involved for this activity. Check actual hot tapping location for roundness, defect or any lamination and record them. Check actual pipe wall thickness, because hot tapping has some wall thickness range requirements to be considered.

Check the actual operation pressure and temperature when you want to do the hot tap this will help to confirm the integrity of main pipe when you do the cutting. Check review hot tap fitting selected with vendor. Check and review hot tap machine required space, in case you are in a limited area. In case you have never done it in similar case, or worse, when it is critical them mock up is highly recommended.

To help you understand and confirming several things: a. Welding WPS b.

Hot tapping in tanks according to API 653

Weld penetration depth, to ensure pipe integrity when you do the hot tap c. Welding highest temperature and welding technique required to ensure you have the main pipe strong and good enough to go through hot tapping process as designed. Calculate all the weight and re-calculate in case additional temporary support required.To ensure hot tapping procedures are safe, secure and economically viable, its important to do a preliminary safety check. Along with a activity worklow, this 7 step hot tapping safety checklist can aide you in your attempts to hot tap.

hot tap welding test

Ensure that the colleague in charge of the process is committed to being present during the process. Them, and other colleagues, should be trained and familiar with the process, welding procedures and the use and location of applicable equipment.

A plan should have also been prepared to monitor and control process variables within their required limit. The area where the connection is to be made must be identified and physically marked. The metal thickness should also have been verified at this point, taking into consideration measurements that meet the current metal condition. Any imperfections that may prevent a proper weld should have been evaluated and approved by a trained member of the team.

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All necessary testing for flammable vapors and hazardous air contaminants should have been conducted at this stage. At the same time, personal protective equipment PPE should be made available to personnel, including fire retardant clothing.

A dedicated fire watch team has to be established and equipped with suitable fire extinguisher or pressurised fire hose. This person s should understand all their duties and be able to communicate strongly with all members of the team.

All hot tapping permits, including confined space entry if requiredneed to be obtained and approved.

hot tap welding test

Signs and barriers should be provided to isolate the area from any unauthorised people. Just like any process in the world, a contingency plan should be in place. For hot tapping, and emergency action plan should also be drawn up. This should include a communication plan to all relevant parties involved, firewatch has been familiarised with equipment on site, and all technical specifications such as temperature, pressure and process material are recorded.

After all these preparations have been put in place, the trained personnel should inspect the weld, hot tapping machine itself and both elements together before pushing the button on the process. Once work has been started it should proceed without interruption until the hot tap has been completed and the valved closed. For ultimate safety, the American Petroleum Insititute recommend that the fire watch team should remain at the site for 30 minutes after the process has been completed.

Personnel Ensure that the colleague in charge of the process is committed to being present during the process. Thickness verified The area where the connection is to be made must be identified and physically marked. Hazards and contaminants All necessary testing for flammable vapors and hazardous air contaminants should have been conducted at this stage.

hot tap welding test

Fire watch A dedicated fire watch team has to be established and equipped with suitable fire extinguisher or pressurised fire hose. Permits and barriers All hot tapping permits, including confined space entry if requiredneed to be obtained and approved. Contingency plan Just like any process in the world, a contingency plan should be in place. All safety procedures should also be in place to prepare for any emergency.Hot tapping, also known as pressure tapping, is a method of connecting either by drilling or cutting to a pressurised system, such as a pipeline or pressure vessel, without removing the pipe or tank from service.

This prevents costly and potentially dangerous environmental hazards while allowing for continued operation. Hot tapping strictly refers to the installation of connections to pipelines while they remain in service. In the welding context, it is commonly used for any welding onto in-service equipment. Hot tapping is frequently used in order to repair areas that have undergone mechanical damage or corrosion, or to add branches for system modifications.

There are distinct economic and environmental advantages to performing this welding without removing a pipe from service and possibly venting quantities of greenhouse gases, such as methane. Problems can occur with hot tapping when the risk of burn-through, unstable decomposition of the flowing product and the risk of hydrogen cracking are not considered adequately. Burn-through occurs when welding onto a pressurised pipe if the unmelted area beneath the weld pool is not strong enough to contain the internal pressure of the pipe.

The greater the wall thickness of the pipe, the less the risk of burn-through. Unstable decomposition of the flowing product can cause violent reactions when heated under pressure; this is prevented by taking special precautions to prevent the internal wall temperature exceeding a critical temperature.

This critical temperature is dependent on the nature of the flowing product. The risk of hydrogen cracking is increased for hot tapping in comparison to other welding situations, due to the flowing product increasing the rate of heat flow from the weld region. This leads to shorter cooling times, with an associated increased risk of forming hard microstructures and thus greater susceptibility to hydrogen cracking. The cracking risk can be reduced by the use of low-hydrogen electrodes, and through careful selection of heat input.

Preheat control is sometimes possible, but the cooling capacity of the flowing contents can make this an inefficient approach. Temper bead deposition sequences can be used to control hardness. Safe procedures for hot tap welding can be devised using computer heat flow modelling techniques, and qualified using flow loops.

TWI have the capacity to carry out such modelling, and can advise on specific aspects of in-service welding operations including weld qualification and testing. See further information about Materials and Corrosion Managementor contact us.

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Promoting, selling, recruiting, coursework and thesis posting is forbidden. Students Click Here. Related Projects. Experts your recommendation is requested in selecting the test medium for one of our hot tapping job.

As per the procedure after the welding of hot tap fittings Split Tee and installation of hot tap valvewe need to test the weld integrity of hot tap fitting by hydro testing the connection. The existing line is high temperature and high pressure steam line. Hence water cannot be utilized since the run pipe is with elevated temperature. Experts please recommend a testing medium for the above the mentioned case considering the risk factor.According to API 3.

This means that a tank can continue to be in operation whilst maintenance or modifications are being done to it. This is in complete compliance with the API standard, but following some rules. API, Paragraph 9.

Extreme Pipeline Connection While Pipes Still in Service - Hot Tapping With TONISCO Valves

API Paragraph 9. Hot tapping is more common in pipelines, althought the principles are the same that for tanks.

hot tap welding test

In a normal pipe hot tapping operation, you wish 2 or 3 things. You want flow in the pipe so you can cool the welded zone, given that the liquid works as a heat sink. You want no gases or vapors in the pipe 3. You want to weld nozzles and reinforcements to the pipe without penetrating too much in the base metal, because of pressure. With tanks it is the same, with the diferrence that flow conditions in tanks are close to stagnant. Hot taps are not permitted on shell material requiring thermal stress relief 2.

Welding shall be done with low hydrogen electrodes. Hot taps shall not be installed on laminated or severely pitted shell plate. As an inspector, you have to make sure that thickness measures are taken in the proposed area for a hot tap. Hot taps are not permitted on tanks where the heat of welding may cause environmental cracking such as caustic cracking or stress corrosion cracking.

Minimum spacing in any direction toe-to-toe of welds between the hot tap and adjacent nozzles shall be equivalent to the square root of RT where R is the tank shell radius, in inches, and T is the shell plate thickness, in inches. Minimum distance between the toe of the hot tap weld and a vertical seam should be 12in.

Tank venting, with vapors reaching the exterior area where welding is taking place. Product within the tank rising and overflowing. Inadvertently allowing the liquid level within the tank to fall below the point of welding, exposing the vapor space within the tank to an ignition source.The Hot Tap Welding Simulator presents clearly organized thermal analysis results in an easily operated interface, uses state-of-the-art simulation methods, and is conveniently located on a cloud-based delivery platform, the Equity Engineering Cloud EEC.

Employing a cloud-based infrastructure allows the simulator to be run on a desktop, tablet, or other mobile device without the need for installation or manual updating of the software. Once you log in, you are ready to go! The software is maintained with the latest updates and always-on cloud computing resources return calculation results faster than ever before. For over a decade, E 2 G has developed and maintained an advanced computational model for the simulation of hot tap welding, which supports the safety of the welder and the integrity of the pipeline.

Using Finite Element Analysis FEAthe model simulates the complete thermal history of the welding process, allowing for the risk of failure due to burn-through and cold cracking to be reliably assessed.

Additionally, the Hot Tap Welding Simulator includes support for multiple geometries including full encirclement sleeves, branches and Weldolets as well as customizable fluid mixtures. Our goal is to facilitate upgrades and conversions, quickly answer your questions, and help you benefit from our state-of-the-art software products. I Have Unanticipated Damage. Now What? Is My Facility Code Compliant?

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Should I Run, Repair, or Replace? Where Should I Start? What are My Design Requirements? Consulting Services. Advanced Analysis. API University. Priority Support. E 2 G is available to contact for priority support services: Contact E 2 G.

HelpDesk E2G.TDW provides hot tapping services and equipment that enable pipeline owners and operators to safely, efficiently, and cost effectively perform pipeline modification and repair activities without shutdown and with minimal disruption to product flow. In addition to saving pipeline owners and operators time and money by eliminating the need to blow down miles of line in between valves, line isolation plays an integral role in performing a variety of both planned and unplanned activities, including routine maintenance, new construction, expansions, and emergency interventions.

TDW designs and manufactures high-performance valves that improve safety and efficiency when conducting tapping and isolation operations on in-service pipelines, tanks, and storage vessels. TDW designs and manufactures a full suite of low-pressure fittings that enable operators to perform work on pipelines, tanks, and storage vessels without shutdown.

Developed through more than 95 years of experience in the pipeline industry, high-pressure fittings from TDW are furnished with patented features that can help operators safely and efficiently repair and maintain high-pressure lines without shutdown or interruption of service.

Repairing defects, dents, gouges, corrosion, and leaks in pipelines can be a costly and resource-intensive task. For more than 60 years, TDW has worked to make that task less costly and more efficient by offering a range of repair and reinforcement products that are capable of permanently restoring pipelines to their maximum operating pressure without having to replace the entire section. In-service pipeline welding requires a great deal of knowledge, experience, and expertise to be completed safely and cost-effectively.

Improper execution of welding can present any number of risks - from burn-through to hydrogen cracking to material degradation - that can compromise the integrity of the pipeline, as well as the safety of the people and environment around it.

TDW provides the most comprehensive hot tapping, plugging, pigging, and composite wrap installation instruction available in compliance with Department of Transportation covered tasks standards requirements. The result is reduced lead time, substantially faster deliveries, consistent quality, and compliance. TDW manufactures one of the industry's widest ranges of purpose-built pigs. This vast inventory includes cleaning, batching, gauging, liquids displacement, and specialty pigs, available in multiple diameters and designed to meet specific pipeline and product demands.

Customization and configuration options ensure tailored solutions for even the most complex pipeline conditions. Pig passage indicators - commonly referred to as PIG-SIGs, a term TDW originated more than 60 years ago - accurately detect pigs, spheres, scrapers, and other tools as they pass distinct points along the pipeline.

Pig tracking equipment enables operators to detect the exact location of pigs as they travel through the pipeline. By utilizing this technology, pipeline operators or service crews can respond rapidly to stalled pigs, which may pose an operational risk to the pipeline. The ability to pig a pipeline for cleaning, maintenance, and inline inspection ILI is essential to integrity assurance.

But a lack of launchers and receivers - the equipment that allow pigs, spheres, and ILI tools often referred to as smart pigs to enter and exit the pipeline while product flow continues - makes pigging impossible.

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Regular cleaning of pigs and other job site tools has an additional benefit: it extends their lives and helps avoid repair and replacement costs. With the TDW solvent-free, automated pig washer, pipeline owners and operators can efficiently and effectively maintain pigs and other tools at their shop or service center.

One of the most critical operations in pigging is opening the closure, which provides access to the pig trap during both launch and recovery operations. When the closure door is opened during the insertion or removal of a pig, there is a risk of explosive gas-air mixture. A well-planned, regular pigging regimen can help operators prolong the life of their pipelines, save money, maintain product flow, and minimize product sediment. TDW has more than seven decades of experience designing, manufacturing, and using pigging products, and our experienced technicians will work with operators to select the right pigs - and the right pigging program - for their pipeline and product.

With more thankilometersmiles of inline inspection ILI completed, TDW has the experience and expertise to help pipeline owners and operators achieve system integrity and reliability, resulting in an extension of the asset lifecycle.

Our dedicated personnel - powered by knowledge and focused on mitigating risk - partner with you to meet rigorous safety, regulatory, operational, and corporate demands. In-situ non-destructive evaluation NDE methods are used to verify and drive the accuracy of inline inspection ILI results while pipelines remain in service, enabling you to better characterize defects, prioritize repairs, and keep your product flowing. Field-proven with hundreds of offshore projects, SmartPlug double block and monitor DBM technology minimizes platform downtime by enabling operators to isolate pressurized pipelines so equipment maintenance, repairs, and replacements can be done without bleeding down the entire system.

The SmartTrack TM two-way communication system enables pipeline operators to improve the safety of pigging operations by providing real-time monitoring of pigs and tools within the pipeline. Not only does the SmartTrack system accurately track, position, and identify pigs and tools in thick-wall buried or subsea pipes, it can also be used to track and identify all SmartPlug isolation tools.

For more than five decades, TDW has helped pipeline owners and operators overcome complex subsea challenges - from tie-ins and decommissioning to pipeline emergency repair - efficiently and cost-effectively. Feasibility studies help pipeline owners and operators determine the most viable and safest solutions for offshore interventions, including the specific application of SmartPlug isolation technology and the SmartTrack pig tracking system.

By preventing flooding as a result of wet buckle during offshore pipe lay operations, the SmartLay system mitigates risk to the pipe lay vessel and crew, protects as-laid pipeline, and helps pipeline owners and operators eliminate costs associated with standby dewatering spreads.


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