Hot Tapping which is also called pressure tapping is the act of joining branch connections to pipelines while they are still operating, and further creating openings on them. This way, the system keeps functioning while repairs are ongoing. This procedure is also environmentally-friendly.
Hot tapping is widely known because of its installation process. It does not affect the functionality of the pipelines. For instance, there are mechanical damages such as corrosion on pipelines, tapping is applied to fix up those damages.
This process is not only used on pipes, it is sometimes used to attach nozzles to storage tanks or used on pressure vessels such as compressed glass cylinders, glassware, autoclaves, etc. These hot tapping pipeline services can be only be rendered by a hot tapping company for safety reasons.
Every part of this process requires utmost care – the inspecting, designing, and testing – to ensure proper installation and safety. This is why it should only be considered as an option if other options have been thoroughly evaluated and do not seem applicable.
Despite how dangerous it sounds, this technique has its advantages, especially if it is done by a reputable service company. Asides from the fact that you still have access to the product in the pipeline while the system is being worked on, here are other advantages of the hot tapping procedure:
- Continued operation of the system.
- Expansion of the system.
- Applicable to different materials and sizes of pipelines.
On the other hand, if the job is not done by the right persons, there is a risk of improper installation of the branch connectors and blowouts which may lead to pipe wall thinning. This is why employing the services of a company in this field cannot be overemphasized. They have the knowledge and experience required for the job, and you could call them back if anything goes wrong.
How to Set Up a Hot Tap
First is the creation of openings on the pipes, also called drillings. Three important elements are needed for this drilling. They include the fitting, valve, and machine.
Fitting is usually connected to pipes during welding. The valve is connected to the fitting and the machine is connected to the valve. All materials such as the bolts and valve that will be utilized during this setup should be new because they will be permanently installed. If worn-out materials are utilized, the set up will likely come apart in the long run.
The fitting on the pipes is usually tested for pressure. Pressure testing helps to ensure that the fitting is in good shape and that the welding has no leaks. It also prevents blowouts from excessive pressure on the fittings.
Common Terminologies Used In the Set-Up
- Cutter: It is usually joined to the cutter holder.
- Pilot: It is usually joined to the bottom of the machine to enable it to fit into the adapter.
- Tap adapter: It contains the pressure from the pipeline. The adapter also covers the bolts, cutter, and cutter holder to the valve during the drilling of the pipes.
- Coupon: This is a part of the pipes that is taken out while the pipe walls are being drilled.
- Line stop: They begin with a hot tap but their job is to prevent fluid from flowing within the pipelines. Unlike a hot tap, a bigger cutter is good for line stops. The size of the hole on the pipe wall makes it possible for the head of the line stopper to go into the pipes.
Here’s how it is set up:
There are two important elements required for its setup. They are a hot tap machine and a line stop actuator. A line stop actuator helps to position the head of the line stop.
- Completion plug: A completion plug is used to take out the valve for the stop by setting it in the stop.
That said, let’s get into the procedures involved:
- Gathering the necessary tools and materials needed for the procedure.
- Lifting the machine to the pipe system.
- Advancing pilot assembly (also called cutter assembly) to reach the major pipe.
- Advancing pilot assembly after its complete rotation so the u-wires can fall.
- Withdrawing the coupon and cutter with the ones kept using the u-wires.
- Stopping the flow of fluid between two consecutive tap locations.
- Draining the fluid between the two successive tap locations. The drainage system depends on the type of fluid -gaseous or liquid. For gas, you could use a vent; for liquid, a drain.
- Installation of the needed pipe components.
- Filling the fluid again between the two successive tap locations to maintain its original pressure.
- Fluid flow begins from the central pipeline.
- Removal of the machine.
Check out this video to better understand the procedures above.
Situations Where This Tap Process Should Be Avoided
A hot tap procedure is not advisable:
- If the pipe contains a flammable mixture.
- If it contains acids, peroxides, chlorides, and dangerous chemicals that react to welding, a part of the setting up process.
- If it contains caustic.
- If it contains chlorine or pure oxygen.
- If it cannot be confirmed that there is no hydrocarbon in the lines.
- If a monel pipe contains sulfur compounds.
- If a stainless steel type contains a catacarb solution.
The success and safety of a project like hot tapping pipeline services depends largely on the kind of service you choose to employ. Ensure that the company you hire is qualified and licensed and that they have the right knowledge and experience required for the job.
Remember that all the materials that will be used during this project should be new, except in cases where some components will eventually be removed. For example, the valve and machine will eventually be removed so they do not need to be fastened with new bolts or nuts.
No doubt, this is one dangerous project but if entrusted in the right hands, such as a reputable hot tapping pipeline services company, there will be little to no concerns with safety or reliability.