Hot Tap Guidelines

By Vincent A. Carucci

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 on pipe, they may also be done on pressure vessels and storage tanks. The figure illustrates a typical hot tap installation.

As an example, Carmagen engineers developed the design details and procedures that were used to hot tap two nozzles into a crude tower. In this case, the nozzles were needed to install bypass lines around plugged distributor trays, and were located about 150 ft. above grade.

Hot taps permit adding connections without depressurization or disruption of process operations. 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 taps are successfully completed every day. However, remember that a hot tap is an inherently dangerous operation. Therefore, hot taps should generally be used only when it is impractical to take the system out of service. When specifying hot taps, care is required in inspection, design, and testing to ensure that this operation is done in a safe and reliable manner. Therefore, a hot tap should be considered only after other options are evaluated and rejected. Each hot tap should be properly designed, the hot tap location thoroughly inspected, and the installation procedures reviewed.

Sometimes A Hot Tap Should Not Be Done

Hot taps may be made in most cases without difficulty. However, hot tapping is not recommended in some cases and requires extra precautions in others. Each case must be evaluated based on the particular service, pipe material, and hot tap location.

Hot tapping is not recommended under any of the following conditions:

You Can Hot Tap, But ...

Services or conditions where hot tapping may be permitted, but where special precautions are necessary, are listed below.

This article provided an introduction to what a hot tap is, when it should not be done, and when it may be done with special precautions. Other articles will discuss hot tap location, design, installation, inspection, and safety considerations.

 Typical Hot Tap Installation