Quick Facts:
- Pressure control and relief systems are used extensively in gas and liquid pipelines to provide overpressure protection.
- Because of the importance of preventing the accidental overpressure of liquid and gas transmission pipelines, national standards have been established to require that pipelines include protection against accident overpressure. These national standards include requirements for design and testing of pressure control and relief devices.
- Pressure control devices include relief valves (set to open at specified pressures), pressure sensors and compressor control switches.
- Pipeline operators are required to ensure that configuration control is maintained on pressure control and relief devices and that equipment is in good operating condition.
What are pressure control and relief devices and why do failures occur?
- Examples of pipeline equipment responsible for pressure control and relief include:
- Relief valves that open when pressure rises above a set pressure .
- Pressure sensors that monitor pressure of the liquid or gas in the pipeline.
- Pressure control devices receive input from pressure sensing devices and regulate pipeline equipment to raise or lower operating pressure.
- As these components wear due to operation some may fail and allow an inadvertent release of liquid product or gas.
- Settings for pressure control and relief devices could be set incorrectly or the settings could drift over time, resulting in a device lifting prematurely or failing to lift when required.
What are the risks from pressure control and relief device failures?
- Equipment failures are not one of the more prevalent causes of pipeline failures.
- Pressure control and relief devices prevent pipeline ruptures that are caused by overpressure.
- Gradual degradation of pipeline components could result in a failure of a pressure control device to properly operate. Failure of a pressure control device could result in premature opening of a relief valve (resulting in leakage of the pipeline) or the failure of a device to operate during an overpressure situation whereby resulting in a pipeline rupture.
- Equipment failures such as premature lifting of relief valves generally will cause minor spills but not the type of catastrophic rupture/release that can be associated with a pipe failure.
- The quality of an operator’s preventive maintenance program is an important factor in determining the frequency of equipment failures.
What is being done to improve reliability of pressure control and relief devices?
- To reduce the threat from inadvertent pipeline releases, OPS has issued new regulations that require operators to develop integrity management programs for both liquid and gas transmission pipelines located where a leak or rupture could do the most harm, i.e., could impact high consequence areas (HCAs). The rules require liquid and gas transmission pipeline operators to develop and implement preventive measures to reduce the risk from equipment and other types of failures.
- Improved preventive measures implemented by operators should result in a decrease in these types of failures.
Pressure control and relief devices: What more can be done?
- Public : Be aware of pipelines located near you. Be observant for signs of pipeline damage, leakage, or signs of vandalism, tampering, or other security concerns. Also, be observant to changes in the immediate vicinity of the pipeline such as river washouts, flooding, or other ground movement or settling that could impact a buried pipeline. Report any concerns you have regarding pipeline safety to the pipeline operator immediately. Always respect the pipeline right-of-way, and do not dig or build on a pipeline right-of-way without first contacting the pipeline operator or your state one-call center.
- Industry : Pipeline operators and industry stakeholders can continue to develop and implement improved strategies for increasing the quality of their pipeline systems and expertise of their personnel involved in the implementation of their integrity management programs.
- Regulators : OPS and state regulators must continue to inspect pipeline operators to ensure that risks to pipelines are identified and mitigated at the earliest possible time and ensure that personnel performing safety-sensitive functions are properly trained and qualified with the appropriate level of expertise and experience.
Pressure control and relief devices: Where can I learn more?
- Community Assistance and Technical Services
- http://64.78.42.182/sweethaven/MechTech/hydraulics01/moduleMain.asp?whichMod=0501
- Code of Federal Regulations 49 CFR Part 192, Transportation of Natural Gas - specifically 49CFR192.195, Protection against accidental overpressuring
- Code of Federal Regulations 49 CFR Part 195, Transportation of Hazardous Liquid by Pipeline - specifically 49CFR195.428, Overpressure safety devices and overfill protection systems.
- Examples of pipeline equipment responsible for pressure control and relief include:
- Relief valves that open when pressure rises above a set pressure .
- Pressure sensors that monitor pressure of the liquid or gas in the pipeline.
- Pressure control devices receive input from pressure sensing devices and regulate pipeline equipment to raise or lower operating pressure.
- As these components wear due to operation some may fail and allow an inadvertent release of liquid product or gas.
- Settings for pressure control and relief devices could be set incorrectly or the settings could drift over time, resulting in a device lifting prematurely or failing to lift when required.
What are the risks from pressure control and relief device failures?
- Equipment failures are not one of the more prevalent causes of pipeline failures.
- Pressure control and relief devices prevent pipeline ruptures that are caused by overpressure.
- Gradual degradation of pipeline components could result in a failure of a pressure control device to properly operate. Failure of a pressure control device could result in premature opening of a relief valve (resulting in leakage of the pipeline) or the failure of a device to operate during an overpressure situation whereby resulting in a pipeline rupture.
- Equipment failures such as premature lifting of relief valves generally will cause minor spills but not the type of catastrophic rupture/release that can be associated with a pipe failure.
- The quality of an operator’s preventive maintenance program is an important factor in determining the frequency of equipment failures.
What is being done to improve reliability of pressure control and relief devices?
- To reduce the threat from inadvertent pipeline releases, OPS has issued new regulations that require operators to develop integrity management programs for both liquid and gas transmission pipelines located where a leak or rupture could do the most harm, i.e., could impact high consequence areas (HCAs). The rules require liquid and gas transmission pipeline operators to develop and implement preventive measures to reduce the risk from equipment and other types of failures.
- Improved preventive measures implemented by operators should result in a decrease in these types of failures.
Pressure control and relief devices: What more can be done?
- Public : Be aware of pipelines located near you. Be observant for signs of pipeline damage, leakage, or signs of vandalism, tampering, or other security concerns. Also, be observant to changes in the immediate vicinity of the pipeline such as river washouts, flooding, or other ground movement or settling that could impact a buried pipeline. Report any concerns you have regarding pipeline safety to the pipeline operator immediately. Always respect the pipeline right-of-way, and do not dig or build on a pipeline right-of-way without first contacting the pipeline operator or your state one-call center.
- Industry : Pipeline operators and industry stakeholders can continue to develop and implement improved strategies for increasing the quality of their pipeline systems and expertise of their personnel involved in the implementation of their integrity management programs.
- Regulators : OPS and state regulators must continue to inspect pipeline operators to ensure that risks to pipelines are identified and mitigated at the earliest possible time and ensure that personnel performing safety-sensitive functions are properly trained and qualified with the appropriate level of expertise and experience.
Pressure control and relief devices: Where can I learn more?
- Community Assistance and Technical Services
- http://64.78.42.182/sweethaven/MechTech/hydraulics01/moduleMain.asp?whichMod=0501
- Code of Federal Regulations 49 CFR Part 192, Transportation of Natural Gas - specifically 49CFR192.195, Protection against accidental overpressuring
- Code of Federal Regulations 49 CFR Part 195, Transportation of Hazardous Liquid by Pipeline - specifically 49CFR195.428, Overpressure safety devices and overfill protection systems.
- To reduce the threat from inadvertent pipeline releases, OPS has issued new regulations that require operators to develop integrity management programs for both liquid and gas transmission pipelines located where a leak or rupture could do the most harm, i.e., could impact high consequence areas (HCAs). The rules require liquid and gas transmission pipeline operators to develop and implement preventive measures to reduce the risk from equipment and other types of failures.
- Improved preventive measures implemented by operators should result in a decrease in these types of failures.
Pressure control and relief devices: What more can be done?
- Public : Be aware of pipelines located near you. Be observant for signs of pipeline damage, leakage, or signs of vandalism, tampering, or other security concerns. Also, be observant to changes in the immediate vicinity of the pipeline such as river washouts, flooding, or other ground movement or settling that could impact a buried pipeline. Report any concerns you have regarding pipeline safety to the pipeline operator immediately. Always respect the pipeline right-of-way, and do not dig or build on a pipeline right-of-way without first contacting the pipeline operator or your state one-call center.
- Industry : Pipeline operators and industry stakeholders can continue to develop and implement improved strategies for increasing the quality of their pipeline systems and expertise of their personnel involved in the implementation of their integrity management programs.
- Regulators : OPS and state regulators must continue to inspect pipeline operators to ensure that risks to pipelines are identified and mitigated at the earliest possible time and ensure that personnel performing safety-sensitive functions are properly trained and qualified with the appropriate level of expertise and experience.
Pressure control and relief devices: Where can I learn more?
- Community Assistance and Technical Services
- http://64.78.42.182/sweethaven/MechTech/hydraulics01/moduleMain.asp?whichMod=0501
- Code of Federal Regulations 49 CFR Part 192, Transportation of Natural Gas - specifically 49CFR192.195, Protection against accidental overpressuring
- Code of Federal Regulations 49 CFR Part 195, Transportation of Hazardous Liquid by Pipeline - specifically 49CFR195.428, Overpressure safety devices and overfill protection systems.
- Community Assistance and Technical Services
- http://64.78.42.182/sweethaven/MechTech/hydraulics01/moduleMain.asp?whichMod=0501
- Code of Federal Regulations 49 CFR Part 192, Transportation of Natural Gas - specifically 49CFR192.195, Protection against accidental overpressuring
- Code of Federal Regulations 49 CFR Part 195, Transportation of Hazardous Liquid by Pipeline - specifically 49CFR195.428, Overpressure safety devices and overfill protection systems.
Date of Revision: 010405