What Does Emergency Flow Restricting Device (EFRD) Mean?
An emergency flow restricting device (EFRD) is a safeguard that stops the flow of fluid in a pipeline in the event of an accidental release. It can be a check valve that automatically prevents backflow when the pipeline is shut down or a remote control valve (RCV) that enables timely closure from a pipeline control center.
EFRDs are crucial for mitigating the impact of pipeline failures, especially in high consequence areas (HCAs).
Safeopedia Explains Emergency Flow Restricting Device (EFRD)
Pipeline failures can result in the uncontrolled release of hazardous substances, which can affect the surrounding environment and endanger public safety. Oil and gas operations must put measures in place to prevent these events from occurring, mitigate their effects when they do, and respond to them as quickly as possible. Emergency flow restricting devices can be installed in pipelines as one of these mitigation measures.
Check Valve and Remote Control Valve Systems
In hazardous liquid pipeline regulations, EFRDs are defined as either a check valve or an remote control valve:
- A check valve permits fluid to flow freely in one direction and contains a mechanism to automatically prevent flow in the opposite direction.
- A remote control valve is operated at a remove from the valve itself by a supervisory control and data acquisition (SCADA) system. It may be connected by fiber optics, microwave, telephone lines or satellite.
The United States Department of Transportation's (DOT) Hazardous Liquid Pipeline Integrity Management rule (CFR 195.452) requires operators to:
- Identify where pipeline releases could adversely affect high consequence areas
- Periodically inspect and repair pipelines
- Conduct a risk analysis to determine appropriate mitigation measures
- Determine whether an EFRD is needed
High consequence areas for pipelines carrying hazardous liquids include:
- Populated areas
- Environmentally sensitive areas
- Commercially navigable waterways
Determining the Need for an EFRD
As per CFR 195.452, an operator must determine the need for an EFRD on a pipeline segment to protect an HCA in the event of the release of a hazardous liquid. If it is determined that an EFRD is needed, it must be installed with consideration to the following factors:
- Speed of leak detection and pipeline shutdown capabilities
- Type of material carried by the pipeline
- Rate of potential leakage
- Potential volume of a release
- Topography or pipeline profile
- Potential for ignition
- Proximity to power sources
- Location of nearest response personnel
- Specific terrain between the pipeline segment and the HCA
- Expected benefits of reducing spill size