API RP 2201:2003 (R2010)

Hot tapping is the technique of attaching a welded branch fitting to piping or equipment in service, and then creating an opening in that piping or equipment by drilling or cutting a portion of the piping or equipment within the attached fitting. (In certain specific situations a bolted or mechanical fitting may be used. This approach is not common practice in oil processing and petrochemical facilities and this document does not address any considerations unique to 'hot tapping without welding'.) Hot tapping is usually performed when it is not feasible, or is impractical, to take the equipment or piping out of service, or to purge or clean it by conventional methods. With proper review to determine that a hot tap is appropriate, and development and conformance to job-specific procedures, many hot tap connections have been safely made without interfering with the process operation. This publication covers the safety aspects to be considered before and during hot tapping on in-service piping or equipment. It provides: -- aids to recognize, review, and address safety concerns; -- a review of potential hot tapping concerns based on industry experience; -- guidance on planning hot taps; -- application of 'hazard versus risk' concepts applied to hot tapping; -- elements to consider during the hot tap process from job analysis through completion; -- suggestions on 'what to do if things go wrong.' This publication is not: -- a substitute for job-specific planning; -- a set of work procedures. Virtually every hot tapping job is different. A detailed, written, job-specific hot tap procedure should be available before starting each job to help ensure that appropriate measures are addressed. If there are standing procedures for hot tapping they should be reviewed for applicability to the specific job to be done. These procedures may need revision in response to unique job specific problems or situations that may arise concerning the safety of personnel and facilities. The hot tap approach described in this publication applies to piping and equipment fabricated from ferritic and austenitic steel. Other materials, such as aluminum, copper, plastic, and cast iron may be unsuitable for hot tapping or welding or may require special procedures. Hot tapping is a 'change' subject to review based on facility 'management of change' processes or procedures. PURPOSE This publication provides information to assist in safely conducting hot tapping operations on equipment in service in the petroleum and petrochemical industries. No document can address all situations nor answer all potential questions. However, the understanding of potential hazards, and application of this knowledge, can help reduce the probability and severity of incidents.