Hot or pressure tapping is used in many industrial pipeline companies. This method involves the cutting or drilling of a pressurized system to create a new branch. The pressure vessels and pipelines are the ones who are often undergoing these kinds of services because they don’t involve the removal of the entire tank or pipe from the service. This method is where the operation continues while ensuring that no environmental hazards like gases are leaked.
The hot tapping method is the installation of pipeline connections while they remain functional. Companies that offer hot tapping services employ these methods to repair the parts that have experienced corrosion or damages. The other branches may also be added for possible system modifications. Many use this because of its environmental and economic benefits.
Since the welding can be done without removing an entire pipe, the result is that there will be a decrease in the release of methane and other harmful gases into the atmosphere. Of course, there are still issues that can occur, but they are minimal. There’s the risk of unstable decomposition of product flows, cracking hydrogen, and burn-throughs, but they can easily be remedied with the right contractors’ help.
The instances of burn-throughs happen when the welding is done on a highly-pressurized pope. The area beneath the weld pool may be weak, and it’s not enough to contain the internal pressure that the pipe can exhibit. The solution for this is to have greater pipe walls to lessen any issues and risks of burn-throughs.
Some may have encountered an unstable decomposition of the product flow. This can result in many violent reactions where it can be caused by heat flowing under pressure. This can be prevented by taking measurements and precautions. The internal wall should never exceed a temperature at a critical level. The critical temperature can depend on the product that flows on the pipe. What is considered as a critical temperature in the gas may not be the case in water.
There’s the risk of hydrogen cracking that is usually common in many welding instances. The cracking can happen when there is an increase in heated product flow all throughout the pipe. The heat comes from the area that’s being welded. When the pipes are heated, the cooling times are significantly reduced, and there can be a development of microstructures that will put the entire system at risk of hydrogen cracking.
The risk of cracking can be significantly lessened with the help of electrodes that are low in hydrogen. The right contractors also ensure that the heat input was selected with caution. Preheat controls may be present in some companies, but the content’s cooling capacity can depend on the product being transported in the pipes.
With this said, preheat controls may not be an efficient solution to cracking. Some may also find that the temper bead deposition can help as they can control hardness, but this requires proper operation and control.
There are safer procedures that are usually done by legitimate contractors. Some are utilizing computers for modeling the heat flow techniques, and others are using the flow loops. Some of the reasons for these approaches is that many wanted to control the cooling capacity of live pipelines, and there are measuring techniques available to aid them.
When the Hot Tapping is not Applicable
- If the pipes contain flammable or combustible substances or a mixture
- If there are chlorides, acids, peroxides, and other harsh chemicals present. These types of materials can decompose in the heat of the welding, and they can become hazardous (example: acetylene or sulfuric acid)
- If the piping has caustic substances
- If there are chlorine or pure oxygen
- The airlines can’t assure the total absence of hydrocarbons
- The type is a Monel piping that has sulfur compounds inside
- If everything is consisting of stainless steel with catacarb solutions
4 Considerations to Know about
Before the hot tapping process is started, there are a few considerations and planning that engineers should make. Here are some of them.
- The Overall State of the Pipeline
It’s essential to do an audit before the hot tapping procedure. This is to determine the type, operating pressure, and diameter of the materials that will be attached to the parent pipeline. Other factors to consider are contingency strategies in case there are accidents and the location of the procedure.
- Costs of Shutdowns
Aside from the direct costs of welding, equipment, labor, and materials, there are also the costs of operation shutdowns to consider. Shutdowns happen when the procedure fails, and it’s no longer feasible to continue.
There are references and histories where company data will show how much it would cost the company to shut down the entire operation temporarily, so it’s essential to include these pieces of information.
- A Financially Viable Solution
There are indeed gas-saving benefits that many owners could reap when it comes to hot tapping. However, there are also the added financial expenses regarding additional accessories, skilled labor, machines, and a lot more to dent a company’s balance sheets.
The savings that can be made if everything becomes successful is also the other side of things. However, it’s important to know whether this new technique is financially viable before starting anything.
- Fittings on Steel Pipes
There are steel pipes that may require specific fittings for the procedure to be successful. When these steel pipes are tapped, they should have a welded branch connection that is attached to the parent pipeline. You can learn more about the hot tapping process on this page. It’s not usually possible for those tapping with asbestos cement, concrete, or cast iron to add the fittings to the existing headers.
There are alternate methods in these scenarios, like mechanical joint saddles or compression sleeves with split cast irons. These should be taken into consideration before starting the work for a more successful outcome. With the information above, one can start a hot tapping technique that will benefit the pipelines or do repairs without interrupting the company’s overall operations.