scope:

Scope

This publication covers the safety aspects to be considered when hot tapping, or when welding without hot tapping on in-service piping or equipment. It is not a substitute for job planning. A detailed, written procedure for hot tapping and welding should be prepared or reviewed before starting each job to ensure that all proper steps are taken. These procedures may need to be revised in response to unique problems or situations that may arise concerning the safety of personnel and facilities.

The hot tap and welding procedures described in this publication apply to piping and equipment fabricated from ferritic and austenitic steel. Other materials, such as aluminum, copper, plastic, and cast iron may require special hot tap or welding procedures.

Hot tapping is the technique of attaching a mechanical or welded branch fitting to piping or equipment in service, and creating an opening in that piping or equipment by drilling or cutting a portion of the piping or equipment within the attached fitting. Hot tapping is usually performed when it is not feasible, or it is impractical, to take the equipment or piping out of service, or to purge or clean it by conventional methods. A hot tap connection can often be safely made without interfering with the process operation.