I wasn't able to find specific documentation on safety procedures for dealing with abandoned gas lines and regulatory requirements for decommissioning in our current safety knowledge base, but here is general safety guidance based on industry standards and best practices:

When dealing with abandoned gas lines, safety is paramount to prevent explosions or leaks. Here are some general safety procedures:

1. Initial Assessment: A qualified professional should assess the abandoned gas line to determine the type of gas, pressure, and overall condition of the line. 2. Isolation: The first step is to isolate the abandoned gas line from the active gas system. This typically involves physically disconnecting the line and capping or plugging the open ends. 3. Purging: The abandoned gas line should be purged of any residual gas. This can be done by using an inert gas like nitrogen or carbon dioxide to displace any remaining flammable gas. When flammable gas lines or other parts of equipment are being purged of air or gas, open lights or other sources of ignition shall not be permitted near uncapped openings. 4. Leak Testing: After capping and purging, the abandoned gas line should be tested for leaks. This can be done using a gas detector or a soap-and-water solution to check for bubbles. 5. Documentation: All steps taken during the decommissioning process should be documented, including the date, time, procedures used, and the names of the personnel involved. 6. Removal or Abandonment in Place: Depending on the location and condition of the abandoned gas line, it may be removed entirely, or it may be abandoned in place. If the line is abandoned in place, it should be filled with a non-corrosive material like sand or foam to prevent future use or collapse. 7. Marking: The location of the abandoned gas line should be clearly marked on site maps and records to prevent accidental damage during future excavation or construction activities. Aboveground piping systems shall be marked in accordance with the American National Standard Scheme for the Identification of Piping Systems, ANSI A13.1-1956

Regulatory Requirements for Gas Line Decommissioning:

• Local Codes and Regulations: Gas line decommissioning is typically governed by local codes and regulations. These regulations may specify the procedures to be followed, the qualifications of the personnel involved, and the documentation required.
• Permitting: In many jurisdictions, a permit is required before decommissioning a gas line. The permitting process ensures that the decommissioning work is performed safely and in compliance with applicable regulations.
• Inspections: After decommissioning, the work may be subject to inspection by local authorities to verify that it has been performed correctly and that the abandoned gas line is safe.
• Environmental Regulations: Decommissioning activities must comply with all applicable environmental regulations. This may include measures to prevent the release of gas into the atmosphere or contamination of soil or water.

It's important to consult with local authorities and qualified professionals to ensure that gas line decommissioning is performed safely and in compliance with all applicable regulations.