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Pipeline Safety

Did you know natural gas pipelines are the safest energy transportation system in the United States? We are committed to making them even safer.

The American Petroleum Institute's Safety Management System

In 2017 we integrated the industry leading standards set by the American Petroleum Institute (API1173) into our existing programs and standards to form a single, umbrella framework providing a disciplined and formal method to manage pipeline safety risks and compliance issues. Learn more about the structure and benefits in our Safety Management System brochure.

In accordance with federal regulations, some segments along transmission pipelines have been designated as High Consequence Areas (HCAs) and supplemental hazard assessment and prevention programs (called Integrity Management Programs) have been developed.

National Grid is guided by an Integrity Management Program (IMP), which has been developed in accordance with rules established by the U.S. Department of Transportation (DOT) and local state regulatory agencies, which govern the program. The IMP was developed through the cooperation of industry experts, from both within and outside of National Grid, and meets or exceeds all federal requirements. The primary goal is to continuously improve safety by identifying, assessing and managing risks to natural gas pipelines.

At National Grid, we are committed to the safe operation of all of our natural gas facilities, including pipelines.  We:

  • Built upon our already extensive integrity management programs to meet or exceed new federal IMP regulations. 
  • Identified pipelines in the IMP to federal and state regulators. 
  • Use the best technologies available to continually assess pipeline integrity through leakage surveys, monitoring of our corrosion prevention technologies and other such programs. 
  • Use up to three different assessment methods to assure that we identify any areas of concern, which are prioritized and managed according to established and approved engineering practices. 
  • Use damage prevention methods that include ongoing patrols, construction inspection, periodic reassessments and active participation in state-wide damage prevention programs. 
  • Use communications plans that have been developed to inform and educate the public, emergency responders and other officials about gas pipelines, their safety and integrity and how all parties can contribute to even greater gas pipeline safety.

Excess Flow Valve Notification

Customers may request installation of an excess flow valve (EFV), a safety device that slows the flow of natural gas in the event of a service line break. An EFV is not required for normal operation of your gas line. In fact, you may already have an EFV installed. There is a charge for this service. Certain conditions must exist for this installation.  For more information, please email or call 1-877-MyNGrid (877-696-4743).

Federal regulation 49 C.F.R. §192.383(d) regarding gas pipeline safety requires National Grid to notify customers of their right to request installation of an Excess Flow Valve (EFV) on their existing gas service line under certain circumstances. An EFV is a mechanical safety device installed inside a gas service line between the gas main in the street and the gas meter. The EFV is designed to minimize the flow of natural gas in the event of a service line break. A potential benefit is, in the event that an excavator accidentally digs up the gas service line, the valve would operate to minimize or shut off the flow of gas.

If the customer’s service line operates at a pressure of less than 10 pounds per square inch gauge throughout the year, the customer’s service line is exempt from EFV installation.

Customers with loads of 1,000 standard cubic feet of gas per hour (SCFH) or less are eligible for an EFV unless one or more of the following conditions exist: (1) the customer’s service line operates at a pressure of less than 10 pounds per square inch gauge throughout the year, (2) the gas company has prior experience with contaminants in the gas stream that could interfere with the EFV’s operation or cause loss of service to a customer; (3) there is potential for interference with necessary operation or maintenance activities, such as blowing liquids from the line; or (4) an EFV meeting the performance standards set forth in the federal regulations is not commercially available to the gas company.

EFVs do not operate on all gas service lines and certain parameters may exist where installation of an EFV is not warranted. Many customers already have an EFV installed on their existing service line. If you would like to determine if you are eligible to have an EFV installed on your gas service line, call National Grid at 1-877-MyNGrid (877-696-4743) or email

Installation requires Dig Safe® notification and excavation where the existing gas service line connects to the gas distribution main. Gas service will be interrupted to the customer.

Customers may pay a basic installation charge of $3,900. Additional costs may apply based on location-specific installation needs. The Massachusetts Department of Public Utilities (MDPU) is currently reviewing a request by National Grid to allow the EFV to be installed without a direct charge to the customer. Customer requests for EFV installations will be scheduled to occur after the MDPU’s final decision on payment responsibility and customers will be charged in compliance with the MDPU’s decision. In the future, additional costs may be incurred to maintain and/or replace the EFV and these costs may be charged to the customer.