Pipeline and Hazardous Materials Safety Administration’s (PHMSA) March 16 proposed regulations for natural gas pipeline safety focuses on legacy pipe integrity.
Legacy pipe is a type of pipe no longer manufactured and that PHMSA considers to have potential problems related to manufacturing imperfections. Legacy construction techniques are historic practices no longer used for construction or repair, including non-standard fittings and certain joints and couplings.
PHMSA’s March 16 proposal would require enhanced inspection and integrity programs for legacy pipelines, and those in a newly created ‘moderate consequence area.’ PHMSA had already required enhanced programs for ‘high consequence areas’ – those with higher potential human/property density (e.g. 20 buildings for human occupancy) within 220 yards of certain pipelines. Moderate consequence areas will expand to areas with five buildings for human occupancy within a calculated potential impact radius (PIR) area using the radius = 0.69(square root of (pressure times diameter squared) formula. Pressure in interstate natural gas pipelines can be several hundred to 1,500 pounds per square inch (psi). Natural gas pipelines can be 6 to 48 inches in diameter. The new moderate consequence area can range up to over 1000 feet.
PHMSA’s proposal is based upon the provisions of the Pipeline Safety, Regulatory Certainty, and Job Creation Act of 2011, General Accounting Office Report GAO – 13 -168 recommending use of Automatic Shut – off Valves or Remote Control Valves, and National Transportation Safety Board recommendations.
The proposed rule also requires enhanced verification of maximum allowable operating pressure (MOAP), new Guided Wave Ultrasonic Testing (GWUT) integrity assessment criteria, seismic risk assessment criteria, and additional inspections to address coating integrity and cathodic protection issues. PHMSA was concerned that improper use of Pipeline Intervention Gadget (PIG) at the launch and receive point resulted in pipeline damage, and proposed pressure relief devices for new PIGs.
PHMSA estimates its proposed rule will result in net GHG emissions abatement over 15 years of 69,000 to 122,000 metric tons of methane and 14,000 to 22,000 metric tons of carbon dioxide, based on the estimated number of incidents averted and emissions from pressure tests and upgrades.
Legacy pipeline issues have been a PHMSA target and topic of national standard consideration for gas and liquid pipelines for several years. A pre-publication draft of the rule is available here: The rule will be put out for 60 days comment.
Contact Philip Hoover for additional information.