Excess Flow Valves

About excess flow valves (EFVs) 

Natural gas is a safe and reliable fuel. Nevertheless, outside forces such as weather, natural disasters and third party excavation damage can cause a break in a natural gas service line, which is the underground line that runs from Piedmont’s main pipelines to the meter at your premise. An EFV is a mechanical safety device that may be installed on a natural gas service line. It is designed to automatically shut off the flow of natural gas in the service line in the event of a significant break, puncture or severance in the line.
 
An EFV is considered an optional, additional safety measure that may help mitigate the consequences of a service line break. While EFVs may help limit the effect of damages to service lines from excavation, the best way to prevent such incidents is to always call 811 before performing or allowing any type of excavation work on your property.

Based on federal regulation effective April 2017, customers have the option to request the installation of an EFV at their expense. EFVs cannot be installed on all natural gas service lines as operating characteristics and other limitations may prevent the installation of the device in some circumstances.  

EFV installation

Upon customer request, Piedmont will send a representative to the customer’s property to confirm that an EFV can be installed and to prepare a cost estimate. Upon acceptance of the cost estimate and prior to installation, customers will be required to enter into an agreement with Piedmont. The agreement will contain the terms and conditions of installation including the customer’s obligation to pay for all of the actual EFV installation costs. Piedmont may require a deposit in the full amount of the cost estimate prior to the start of EFV installation work.  

Installation work will be scheduled at a mutually agreeable date, subject to approval from permitting authorities, payment arrangements, work crew scheduling and weather conditions.

The EFV installation to be performed by Piedmont requires Call Before You Dig Notification (811), utility marking and soil excavation on or near the property where the existing natural gas service line connects to the natural gas main. Natural gas service to the customer’s home or business will be interrupted for a period of time, and the customer must be present for natural gas service to be restored upon completion of EFV installation.  

The cost of installing an EFV on an existing natural gas service line will be the sole responsibility of the customer requesting the installation. The cost to install an EFV varies depending on the location and difficulty of the installation; however, on average, the cost to install an EFV on an eligible service line is estimated to be in excess of $1,000.

Contact us

To learn more about the option of having an EFV installed on the natural gas service line for your premise, please call 800.752.7504.
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Frequently asked questions

  • An excess flow valve is a mechanical safety device that may be installed on a natural gas service line. It is designed to automatically shut off the flow of natural gas in the service line in the event of a significant break, puncture or severance in the line.
  • An excess flow valve operates similar to electrical circuit breakers that trip when the electricity current exceeds its limit. The excess flow valve is tripped by an excess flow of gas, causing a spring-loaded device inside the valve to automatically restrict the flow of gas. The valve automatically resets or reopens when the excess flow of gas has ceased or the service line gas pressure is significantly reduced.
  • No. An excess flow valve does not protect against small leaks on the service line or gas meter or leaks beyond the meter assembly, such as those involving a customer’s house piping or customer appliance malfunction. It is designed to activate when the service line is significantly damaged due to excavation or other similar activities. Prevention of service line damage remains the best form of protection, and all customers can place a free 811 call to have buried utilities marked before digging.
  • An excess flow valve is designed to allow normal operation of the service line. It will automatically restrict the flow of natural gas only when the service line has been significantly damaged and the flow of natural gas exceeds prescribed limits. An excess flow valve is not designed to restrict the flow of natural gas inside your home or structure in the event of damage to your house piping located downstream of the gas meter, and it is not capable of doing so.
  • Leave the area immediately and call 911 and Piedmont at 800.752.7504 (call from a neighbor’s house or from another location far from the smell of natural gas)
    • DO NOT use anything electrical that may create a spark; this includes cell-phones 
    • DO NOT operate any light switches 
    • DO NOT light a match 
    • DO NOT attempt to locate the source of a leak 
    • DO NOT attempt to stop a leak 
    • DO NOT return to the area until Piedmont Natural Gas or the emergency services have declared the area safe
  • Federal regulations require that existing customers receive notice of their option to request the installation of an excess flow valve on qualifying service lines.
  • For qualifying service lines, Piedmont or one of its approved contractors will install the excess flow valve.
  • The cost of installing an excess flow valve on an existing natural gas service line will be the sole responsibility of the customer requesting the installation.
  • The cost to install an excess flow valve varies depending on the location and difficulty of the installation; however, on average, the cost to install an excess flow valve on an eligible existing service line is estimated to be in excess of $1,000.
  • No. A deposit in the full amount of the cost estimate will be required prior to the start of the excess flow valve installation work.
  • No. The cost to install the excess flow valve must be billed separately and cannot be included on your normal monthly bill.
  • The excess flow valve is installed on the natural gas service line that runs underground between the gas main (usually located in or near the street, alley or utility right of way) and the gas meter on the customer’s property. Installation of an excess flow valve requires excavation near the natural gas main to expose the service line prior to installation. All areas excavated will be restored once installation is complete.
  • No. Only Piedmont or its approved contractor can do the installation.
  • Piedmont will send out a representative to your property to determine if an excess flow valve can be installed. Due to operating characteristics and limitations in some instances, an excess flow valve cannot be installed. Each customer location will be evaluated upon request.
  • The device is designed to last the lifetime of the natural gas line. However, if your natural gas service line is replaced in connection with overall system maintenance activities, the excess flow valve will also be replaced.
  • No. Once installed, the excess flow valve becomes part of Piedmont’s natural gas distribution system and it cannot be removed.
  • No. Installing an excess flow valve will neither increase nor decrease a customer’s natural gas usage.
  • Call Piedmont at 800.752.7504.
  • You may request to have an excess flow valve installed at your expense at any time.
  • Installation of an excess flow valve requires digging so that the service line is exposed prior to installation. Piedmont or its contractor will restore your property to its original condition, to the extent reasonably practicable, as part of the overall project cost. 
  • Yes. Installation of the excess flow valve will require us to temporarily shut off the gas supply to your property. As part of the installation process, your existing houseline piping must be retested and appliance pilots will be re-lit if your houseline piping and appliances are operating normally. If the houseline test fails or appliances do not pass inspection, you will be responsible for repairs before natural gas service can be fully restored.
  • Installation of the excess flow valve will be scheduled at a mutually agreeable date, subject to approval from permitting authorities, payment arrangements, work crew scheduling and weather conditions. The length of time to install will vary based on the complexity of the installation.
  • If someone has hired a contractor to do work that requires excavation, they should call 811 themselves or ask the contractor to do so before work begins. Property owners who see someone preparing to dig on their property and don’t see paint lines or flags marking the location of underground utilities should tell the workers to STOP and call 811 before they dig.