When a certain section of pipe is damaged or rusted or requires modifications such as addition or removal of a valve, and the output of the particular pipeline or plant cannot be halted, then the particular pipeline must have a conduit attached to it for temporary or permanent purposes. This process shall go one step ahead of hot tapping as see in our earlier blog on this topic. 

Hot tapping and line stoppling are two techniques used in the oil and gas industry to work on live pipelines. While both methods involve making modifications to a pipeline while it is in operation, they differ in their objectives and the way they are carried out.

Hot Tapping:

Hot tapping is a technique used to make a connection to an existing pipeline while it is under pressure. This method is used when it is not feasible to shut down the pipeline to make a new connection or to relieve pressure. Hot tapping involves drilling a hole into the pipeline while it is under pressure and installing a connection or valve. Once the connection is made, the pipeline can be used as usual. This technique is commonly used to install new branch lines or to connect a new pipeline to an existing one.

Hot tapping is a complex and highly specialized technique that requires extensive training and experience. The equipment used for hot tapping must be carefully designed and maintained to ensure safe and efficient operation. Safety is a key concern when using hot tapping techniques, as any mistake can result in a catastrophic failure of the pipeline. Therefore, only trained and qualified professionals should perform hot tapping operations.

Line Stoppling:

Line stoppling is a technique used to temporarily stop the flow of a product through a pipeline. This technique is used when maintenance or repair work needs to be carried out on a section of the pipeline. Line stoppling involves installing a mechanical plug or valve into the pipeline to block the flow of the product. Once the flow has been stopped, the maintenance or repair work can be carried out.

A Section that requires isolation for repairs or modification can be carried out with Line stoppling after performing multiple hot tapping operations.

A Hydraulic Stopple with a swivel arm is commonly used to stop flow in one direction and complement conduit created ahead of it. A completion Plug is installed after finishing the operation.

Line stoppling is typically used for maintenance or repair work, but it can also be used to isolate a section of the pipeline for other reasons. For example, if a section of the pipeline is damaged or contaminated, line stoppling can be used to isolate the affected section while repairs or cleanup are carried out

Differences between Hot Tapping and Line Stoppling:

Objective: The main objective of hot tapping is to make a connection to an existing pipeline while it is under pressure. On the other hand, the main objective of line stoppling is to temporarily stop the flow of a product through a pipeline to allow for maintenance or repair work.

Equipment: The equipment used for hot tapping and line stoppling is different. Hot tapping requires a drilling machine that can drill a hole into the pipeline while it is under pressure. Line stoppling, on the other hand, requires a mechanical plug or valve that can be installed into the pipeline to block the flow of the product. The Flow rate of the product, the temperature shall affect the selection of the machine and the seals used.

Hot tapping Cutter and Pilot Drill                   Pivoting plugging head for line stoppling (single train)           Completion plug 

Inflatable gas bag used for ensuring noxious gases do not leak despite line stopping

Skill Requirements: Both hot tapping and line stoppling require highly specialized skills and experience. However, the skill requirements for each technique are different. Hot tapping requires a high level of expertise in drilling and welding, while line stoppling requires a high level of expertise in mechanical systems and valves.There are specific standards to be followed for Hot Tapping for example: ASME B 31.3, ASME B 31.4, & ASME B 31.8

Safety: Safety is a key concern for both hot tapping and line stoppling operations. However, the risks associated with each technique are different. Hot tapping carries a higher risk of pipeline failure due to the drilling process, while line stoppling carries a higher risk of mechanical failure due to the use of a mechanical plug or valve. Depending on the line medium the criticality of the Hot tapping operations spark free nature is stressed upon.

In conclusion, hot tapping and line stoppling are two techniques used in the oil and gas industry to work on live pipelines. While both methods involve making modifications to a pipeline while it is in operation, they differ in their objectives, equipment, skill requirements, and safety risks. It is important to use tested and certified equipment to make sure that it does not fail during operation. It is important to record all the data necessary for performing the hot tapping operation.